From a20e59f6744f9b5ec96fe8cd0b2a84dfcee20fcd Mon Sep 17 00:00:00 2001
From: Vito Sansevero <vito.sansevero@gmail.com>
Date: Sat, 31 Oct 2026 16:43:15 -0700
Subject: [PATCH] feat(tagging): skipped tags hide matching suggestions (#431)

A Skipped tags list in System > Auto-tagging (D202) hides every suggested
tag whose words contain an entry's words, on every suggestion path
(Tag image, Auto-tag selected, the System batch, the legacy single and
batch routes), before the limit. Jobs snapshot the list at their start.
A read-only preview route counts what a list hides among the library's
tags and the downloaded WD14 label lists. The draft store compares list
and object drafts by value (sameDraft).
---
 TESTING.md                                    |  48 +++
 py/api/annotation_suggest.py                  |   8 +-
 py/api/annotations.py                         |  10 +-
 py/api/autotag_routes.py                      |  90 ++++++
 py/api/image_tag_jobs.py                      |  44 ++-
 py/api/settings_routes.py                     |  15 +
 py/autotag.py                                 |  20 +-
 py/config.py                                  |  26 +-
 py/tagging_defaults.py                        | 136 ++++++++-
 tests/browser/server.py                       |  29 +-
 tests/browser/system-tagging-concept.spec.mjs |  36 ++-
 .../browser/workspace-system-tagging.spec.mjs |  82 +++++
 tests/browser/workspace-tagging.spec.mjs      |  12 +
 tests/browser/workspace_tagging_fixture.py    |  55 +++-
 tests/fixtures/legacy_contract_snapshot.json  |   2 +
 .../js/workspace-image-tagging-state.test.js  |  14 +
 .../js/workspace-system-skipped-tags.test.js  | 247 +++++++++++++++
 tests/js/workspace-system-state.test.js       |  41 ++-
 tests/js/workspace-system-tagging.test.js     |   2 +-
 tests/test_api_annotation_suggest.py          |   9 +-
 tests/test_api_autotag.py                     |   5 +-
 tests/test_autotag_batch.py                   |   2 +
 tests/test_config.py                          |  28 +-
 tests/test_settings_sources.py                |  63 ++++
 tests/test_skipped_tags.py                    | 271 +++++++++++++++++
 tests/test_skipped_tags_routes.py             | 280 ++++++++++++++++++
 tools/vendor/frontend-coverage-baseline.json  |   6 +
 web/js/workspace/image-tagging-state.mjs      |  14 +-
 web/js/workspace/system-skipped-tags.mjs      | 246 +++++++++++++++
 web/js/workspace/system-state.mjs             |  22 +-
 web/js/workspace/system-tagging.mjs           |   6 +
 web/js/workspace/workspace.css                |  26 +-
 32 files changed, 1837 insertions(+), 58 deletions(-)
 create mode 100644 tests/js/workspace-system-skipped-tags.test.js
 create mode 100644 tests/test_skipped_tags.py
 create mode 100644 tests/test_skipped_tags_routes.py
 create mode 100644 web/js/workspace/system-skipped-tags.mjs

diff --git a/TESTING.md b/TESTING.md
index df7c6695..5826997e 100644
--- a/TESTING.md
+++ b/TESTING.md
@@ -4578,6 +4578,26 @@ the per-section hand-off panel, was retired by S12 (#329): every section is nati
   Cancel-only review matches the concept review shell` (system-tagging-concept.spec) and
   the batch tests of workspace-system-tagging.spec; the mutation check renames each grid
   label in turn.
+- **D202** (Auto-tagging, #431, beyond the concept): a "Skipped tags" block
+  (`.setting-block`, `data-setting="tag-skipped"`, `data-key="autotag_skipped_tags"`)
+  follows "Suggestions per image": the label and description in the concept's
+  setting-row tokens ("Suggested tags that contain one of these words are hidden.
+  Words are separated by spaces, _ or -; other characters such as ( ) belong to the
+  word."), an "Add a word or words" input (`#tag-skipped-input`) with Add (Enter adds
+  too), the entries as removable chips in the Tag image dialog's D83 chip markup (each
+  with its count, title "Hides N tags", or muted "none" with "Hides no known tag"), and
+  a `role="status"` preview line: "**Hides N tags from suggestions**: <up to 12>[ and K
+  more]. Tags already on images are not changed." ("Checked against library tags only;
+  no WD14 label list is downloaded." before the last sentence without a label list;
+  "No tags are skipped." for an empty list; "Checking…" while waiting; "The preview
+  could not be read." on failure). The client refuses an entry with "Enter a word.",
+  "No commas or line breaks.", "At most 50 characters.", "Already in the list." or "The
+  list is full (200)." under the input. The Tag image dialog's chip hint adds "N skipped
+  tags were not suggested." when the server hid any (the static mock's copy). Pinned by
+  the comparison's mapping (system-tagging-concept.spec: the block's tokens are the
+  concept row's), `skipped tags add, preview, remove, save and reload (D202)`, `skipped
+  tags preview checks library tags only …` (workspace-system-tagging.spec) and
+  `suggestions omit skipped tags and say how many were hidden` (workspace-tagging.spec).
 - **D158** (Sources, #247 D-Q4): the concept has no switch for prompts from workflows
   without a PromptManager node; the maintainer chose a visible switch over a config key.
   A `.setting-row` in the concept's toggle markup follows "Watch for new outputs":
@@ -5186,6 +5206,34 @@ saved values (`wd14_general_threshold`, `wd14_character_threshold`, `suggestion_
 `default_prompt`, `model_type`, `existing`), so the Tag image and Auto-tag selected
 dialogs start from them; a preset (the bulk review, Preview tagging review) wins.
 
+**Skipped tags** (#431, D202): `autotag.defaults.skipped_tags`, host draft
+`autotag_skipped_tags`, a list of at most 200 entries, each trimmed, 1–50 code points,
+no comma or control character, at least one word, no two with the same words (refused
+with "Skipped tags: at most 200 entries.", "Skipped tags: entry N is empty.", "… must be
+at most 50 characters.", "… must not contain a comma or a line break.", "… repeats entry
+M."); a save carrying it without `expected_revision` is refused ("Reload the page and try
+again."). A damaged saved list falls back to none with one warning. Words are the
+NFC, case-folded text split on runs of space, `_` and `-` (`tag_words`); an entry hides
+a suggested tag whose words contain the entry's words consecutively (`SkipMatcher`:
+`blurry` hides `very_blurry` and `blurry_background`, not `unblurry`; `(fate)` hides
+`saber_(fate)`, `fate` does not). `generate_tag_suggestions(skip=)` drops a match after
+the name check and before the dedupe and the limit, so skipped tags use up no slot
+(WD14 fills from lower scores; a language model may return fewer). Every path filters:
+`/image-annotations/suggest` (compiled per request; the answer adds `skipped`, the
+number of distinct names it hid), `/autotag/single`, and the `image-tags` (Auto-tag
+selected) and `autotag` (System batch, legacy `/autotag/start`) jobs, which snapshot the
+list at their start and log "Skipped tags: N entries" or "Skipped tags: none"; a save
+during a run does not change it. Hand-typed and stored tags are never filtered; the
+language models' hard-coded exclude list (`_parse_tags`) runs first. `POST
+/prompt_manager/autotag/skipped-tags/preview {entries}` (validated as a save) answers
+`count`, `sample` (12, library tags first, each part sorted case-folded),
+`sample_limit`, `per_entry [{entry, count}]` and `sources {library, wd14}` over the
+library's tags plus the category 0/4 names of each downloaded WD14 `selected_tags.csv`
+(read as UTF-8, cached by mtime and size; a missing list is skipped). It loads no model,
+opens no image, writes nothing and is `409 busy` while an exclusive job runs. Tests:
+`tests/test_skipped_tags.py`, `tests/test_skipped_tags_routes.py`, the settings and
+config tests, `tests/js/workspace-system-skipped-tags.test.js`.
+
 `GET /prompt_manager/autotag/models` reads the disk in the executor, never loads or
 downloads a model and carries no absolute path: per engine `name`, `label`,
 `size_label`, `description`, `size`, `downloaded`, `loaded` (GGUF also `model_exists`,
diff --git a/py/api/annotation_suggest.py b/py/api/annotation_suggest.py
index bb676d92..d3065316 100644
--- a/py/api/annotation_suggest.py
+++ b/py/api/annotation_suggest.py
@@ -102,11 +102,14 @@ def model_refusal(status: dict, model_type: str, model_name: str):
     return None
 
 
-def run_suggestions(service, capture_path: str, model_type: str, options: dict):
+def run_suggestions(
+    service, capture_path: str, model_type: str, options: dict, skip=None
+):
     """Blocking: load (or swap to) *model_type*, then suggest for the capture.
 
     The caller holds the model gate for the whole call; nothing is ever
-    downloaded (``load_model`` refuses a model that is not on disk).
+    downloaded (``load_model`` refuses a model that is not on disk). ``skip``
+    is the request's or job's compiled Skipped tags (#431).
     """
     if not service.is_model_loaded() or service.get_loaded_model_type() != model_type:
         service.load_model(model_type, options["use_gpu"])
@@ -116,6 +119,7 @@ def run_suggestions(service, capture_path: str, model_type: str, options: dict):
         prompt=options.get("instructions"),
         general_threshold=options.get("general_threshold"),
         character_threshold=options.get("character_threshold"),
+        skip=skip,
     )
 
 
diff --git a/py/api/annotations.py b/py/api/annotations.py
index 7f3ab943..1ab14008 100644
--- a/py/api/annotations.py
+++ b/py/api/annotations.py
@@ -35,6 +35,7 @@ from .media_target import media_target as _target
 from .images import _unavailable_link, _verified_title
 from .prompts import bad_request
 from .. import model_gate
+from ..tagging_defaults import SkipMatcher
 
 try:
     from ...database.annotations import (
@@ -640,6 +641,8 @@ class AnnotationRoutesMixin:
             owner = model_gate.new_owner("image-annotations")
             if not model_gate.try_acquire(owner):
                 return model_busy_response()
+            # #431: the Skipped tags as they are when the request is accepted.
+            skip = SkipMatcher(AutotagConfig.SKIPPED_TAGS).counting()
             try:
                 # From here the pin is the gate's to end: the worker ends it,
                 # or ``on_skipped`` does when the worker never starts.
@@ -653,6 +656,7 @@ class AnnotationRoutesMixin:
                     capture,
                     model_type,
                     options,
+                    skip,
                     on_skipped=functools.partial(store.release_use, token),
                 )
             except MissingBackendPackages as exc:
@@ -677,6 +681,8 @@ class AnnotationRoutesMixin:
                 "model_type": model_type,
                 "options": options,
                 "suggestions": suggestion_rows(pairs),
+                # How many distinct suggestions the Skipped tags hid (#431).
+                "skipped": len(skip.hidden),
             },
             headers={"Cache-Control": "no-store"},
         )
@@ -732,10 +738,10 @@ def _byte_range(request: web.Request, size: int):
     return start, stop
 
 
-def _pinned_suggestions(store, token, service, capture, model_type, options):
+def _pinned_suggestions(store, token, service, capture, model_type, options, skip=None):
     """Worker thread: infer on the capture, then end its pin (even on error)."""
     try:
-        return run_suggestions(service, capture.path, model_type, options)
+        return run_suggestions(service, capture.path, model_type, options, skip)
     finally:
         store.release_use(token)
 
diff --git a/py/api/autotag_routes.py b/py/api/autotag_routes.py
index 9e82d30d..f02c683b 100644
--- a/py/api/autotag_routes.py
+++ b/py/api/autotag_routes.py
@@ -40,6 +40,10 @@ BATCH_PREVIEW_BODY_MAX = 1024
 APPLY_BODY_MAX = 64 * 1024  # POST /autotag/apply: one image and its tags
 _HEX64 = re.compile(r"[0-9a-f]{64}")
 BATCH_JOB_BODY_MAX = 32 * 1024
+# Skipped tags preview (#431): 200 entries of 50 characters, with room for JSON.
+SKIPPED_PREVIEW_BODY_MAX = 64 * 1024
+SKIPPED_PREVIEW_LEASE = "Skipped tags preview"
+SKIPPED_PREVIEW_SAMPLE = 12
 REVIEW_REQUIRED = (
     "Replacing tags needs a review of each image. Use Preview tagging review, "
     "or choose Skip or Merge for a batch run."
@@ -247,6 +251,10 @@ class AutotagRoutesMixin:
         async def preview_autotag_batch_route(request):
             return await self.preview_autotag_batch(request)
 
+        @routes.post("/prompt_manager/autotag/skipped-tags/preview")
+        async def preview_skipped_tags_route(request):
+            return await self.preview_skipped_tags(request)
+
         @routes.post("/prompt_manager/autotag/start")
         async def start_autotag_route(request):
             return await self.start_autotag(request)
@@ -699,6 +707,83 @@ class AutotagRoutesMixin:
             return None, "existing must be one of " + ", ".join(EXISTING_POLICIES)
         return MODELS[model_type], None
 
+    async def preview_skipped_tags(self, request):
+        """Which known tags a Skipped tags list would hide (#431); no write.
+
+        ``{entries}`` is checked as a save checks it (the same 400 sentence).
+        The known tags are the library's plus the general and character names
+        of each downloaded WD14 label list; no model is loaded and no image is
+        opened. Refused (409 ``busy``) while an exclusive job runs.
+        """
+        from ..tagging_defaults import validate_skipped_tags
+
+        data, error = await self._batch_body(
+            request, ("entries",), SKIPPED_PREVIEW_BODY_MAX
+        )
+        if error is not None:
+            return error
+        try:
+            entries = validate_skipped_tags(data["entries"])
+        except ValueError as exc:
+            return web.json_response({"success": False, "error": str(exc)}, status=400)
+        try:
+            async with self._jobs.lease(SKIPPED_PREVIEW_LEASE):
+                result = await self._run_in_executor(self._skipped_preview, entries)
+        except JobBusy as busy:
+            return busy_response(busy)
+        except Exception:
+            self.logger.exception("The Skipped tags preview failed")
+            return web.json_response(
+                {"success": False, "error": _INTERNAL_ERROR}, status=500
+            )
+        return web.json_response({"success": True, **result})
+
+    def _skipped_preview(self, entries):
+        """Worker thread: the preview's counts over the known tags."""
+        from ..autotag import MODELS, get_autotag_service
+        from ..tagging_defaults import (
+            WD14_MODEL_TYPES,
+            SkipMatcher,
+            wd14_label_names,
+        )
+
+        library = self.db.get_all_tags()
+        known = {}  # case-folded -> (0 library / 1 label list, spelling)
+        for name in library:
+            known.setdefault(name.casefold(), (0, name))
+        lists = []
+        models_dir = getattr(get_autotag_service(), "models_dir", None)
+        for model_type in sorted(WD14_MODEL_TYPES, key=lambda t: MODELS[t]["name"]):
+            if models_dir is None:
+                break
+            path = Path(models_dir) / MODELS[model_type]["subdir"] / "selected_tags.csv"
+            try:
+                names = wd14_label_names(path)
+            except (OSError, ValueError) as exc:
+                self.logger.debug(f"No WD14 label list for {model_type}: {exc}")
+                continue
+            lists.append(MODELS[model_type]["name"])
+            for name in names:
+                known.setdefault(name.casefold(), (1, name))
+        matchers = [(entry, SkipMatcher([entry])) for entry in entries]
+        whole = SkipMatcher(entries)
+        hidden = [item for item in known.values() if whole.matches(item[1])]
+        hidden.sort(key=lambda item: (item[0], item[1].casefold()))
+        per_entry = [
+            {
+                "entry": entry,
+                "count": sum(1 for _, name in hidden if matcher.matches(name)),
+            }
+            for entry, matcher in matchers
+        ]
+        return {
+            "count": len(hidden),
+            "sample": [name for _, name in hidden[:SKIPPED_PREVIEW_SAMPLE]],
+            "sample_limit": SKIPPED_PREVIEW_SAMPLE,
+            "per_entry": per_entry,
+            "sources": {"library": len(library), "wd14": lists},
+        }
+
     async def preview_autotag_batch(self, request):
         """Review Tag output images: counts, model, backup and disk; no write.
 
@@ -1096,6 +1181,8 @@ class AutotagRoutesMixin:
 
     async def _suggest_single(self, target, model_type, options, base):
         from ..autotag import MODELS, MissingBackendPackages, get_autotag_service
+        from ..config import AutotagConfig
+        from ..tagging_defaults import SkipMatcher
         from .annotation_suggest import model_refusal
         from .annotations import _pinned_suggestions, _settled, _submit
 
@@ -1112,6 +1199,8 @@ class AutotagRoutesMixin:
         owner = model_gate.new_owner("legacy-single")
         if not model_gate.try_acquire(owner):
             return model_busy_response()
+        # #431: the legacy review hides the Skipped tags too (19A).
+        skip = SkipMatcher(AutotagConfig.SKIPPED_TAGS)
         store = self._capture_store()
         try:
             epoch = await self._run_in_executor(self.db.get_execution_epoch)
@@ -1151,6 +1240,7 @@ class AutotagRoutesMixin:
                     capture,
                     model_type,
                     options,
+                    skip,
                     on_skipped=functools.partial(store.release_use, capture.token),
                 )
             except MissingBackendPackages as exc:
diff --git a/py/api/image_tag_jobs.py b/py/api/image_tag_jobs.py
index 33b679c6..4886e1fc 100644
--- a/py/api/image_tag_jobs.py
+++ b/py/api/image_tag_jobs.py
@@ -39,6 +39,7 @@ from typing import NamedTuple
 from aiohttp import web
 
 from .. import model_gate
+from ..tagging_defaults import SkipMatcher
 from .admin import _plural, _time_left
 from .annotation_suggest import (
     OptionError,
@@ -170,6 +171,8 @@ class _Run:
     owner: object
     service: object = None
     roots: dict = field(default_factory=dict)
+    # The job's Skipped tags, compiled once at its start (#431).
+    skip: object = None
 
 
 @dataclass(frozen=True)
@@ -183,6 +186,9 @@ class _Spec:
     options: dict | None = None
     # A listing filter the start resolves into ``targets`` (#392).
     filter: dict | None = None
+    # The Skipped tags when the job was requested (#431); a later save does
+    # not change a running job.
+    skip: tuple = ()
 
     @property
     def title(self) -> str:
@@ -238,7 +244,11 @@ def _parse_auto(targets, data):
         )
     except OptionError as exc:
         return None, bad_request(str(exc))
-    return _Spec("auto", targets, model_type=model_type, options=options), None
+    skip = tuple(AutotagConfig.SKIPPED_TAGS)
+    return (
+        _Spec("auto", targets, model_type=model_type, options=options, skip=skip),
+        None,
+    )
 
 
 def parse_image_tag_request(data: dict):
@@ -329,6 +339,8 @@ class AutotagRun:
     keep_in_memory: bool
     backup_on: bool
     owner: object
+    # The Skipped tags when the job was started (#431).
+    skip: tuple = ()
 
 
 @dataclass(frozen=True)
@@ -400,6 +412,14 @@ def _load_model(service, model_type: str, use_gpu: bool) -> None:
         raise RuntimeError(f"{model_type} could not be loaded")
 
 
+def _skipped_tags_line(entries: tuple) -> str:
+    """The job log's one line about the Skipped tags it runs with (#431)."""
+    if not entries:
+        return "Skipped tags: none"
+    count = len(entries)
+    return f"Skipped tags: {count} {'entry' if count == 1 else 'entries'}"
+
+
 def _refusal(status: int, code: str, message: str) -> Refusal:
     response = web.json_response(
         {"success": False, "code": code, "error": message}, status=status
@@ -507,6 +527,7 @@ class ImageTagJobsMixin:
         released when the task ends, also before its runner ever starts.
         """
         from ..autotag import MODELS, get_autotag_service
+        from ..config import AutotagConfig
 
         backup_on = self._safety_backup_policy() == "on"
         status = await self._run_in_executor(get_autotag_service().get_models_status)
@@ -529,7 +550,13 @@ class ImageTagJobsMixin:
             response = model_busy_response()
             return None, Refusal(409, "model-busy", MODEL_BUSY_ERROR, response)
         run = AutotagRun(
-            model_type, existing, options, keep_in_memory, backup_on, owner
+            model_type,
+            existing,
+            options,
+            keep_in_memory,
+            backup_on,
+            owner,
+            skip=tuple(AutotagConfig.SKIPPED_TAGS),
         )
         admitted = False
         try:
@@ -598,7 +625,9 @@ class ImageTagJobsMixin:
             return _batch_cancelled(job)
         job.publish({"type": "phase", "phase": "model"})
         job.update(status_line="Loading the tagging model")
-        spec = _Spec("auto", (), model_type=run.model_type, options=run.options)
+        spec = _Spec(
+            "auto", (), model_type=run.model_type, options=run.options, skip=run.skip
+        )
         service = await self._prepare_tagging_model(job, spec, run.owner)
         if service is None:
             return "failed"
@@ -624,6 +653,7 @@ class ImageTagJobsMixin:
             f"Tagging started · {job.scope.get('label') or run.model_type} · "
             f"{_plural(total, 'image')} · {policy}"
         )
+        job.log_line(_skipped_tags_line(spec.skip))
         if job.cancelled:
             return _batch_cancelled(job)
         remaining = await self._autotag_prepass(job, targets, run.existing == "skip")
@@ -633,7 +663,9 @@ class ImageTagJobsMixin:
         spec = dataclasses.replace(
             spec, targets=tuple(item.target for item in remaining)
         )
-        loop_run = _Run(job, spec, epoch, run.owner, service)
+        loop_run = _Run(
+            job, spec, epoch, run.owner, service, skip=SkipMatcher(spec.skip)
+        )
         if not await self._tag_each_file(loop_run, done_before=done):
             job.update(status_line=STORAGE_RESTORED)
             job.log_line(f"Tagging stopped · {STORAGE_RESTORED}")
@@ -739,6 +771,9 @@ class ImageTagJobsMixin:
             started += f" · {spec.model_type}"
         job.log_line(started)
         run = _Run(job, spec, epoch, owner)
+        if spec.mode == "auto":
+            job.log_line(_skipped_tags_line(spec.skip))
+            run.skip = SkipMatcher(spec.skip)
         try:
             if spec.mode == "auto":
                 run.service = await self._prepare_tagging_model(job, spec, owner)
@@ -894,6 +929,7 @@ class ImageTagJobsMixin:
                 capture,
                 spec.model_type,
                 spec.options,
+                run.skip,
                 on_skipped=functools.partial(store.release_use, capture.token),
             )
         except Exception:
diff --git a/py/api/settings_routes.py b/py/api/settings_routes.py
index d617286f..d3d9fb93 100644
--- a/py/api/settings_routes.py
+++ b/py/api/settings_routes.py
@@ -56,7 +56,12 @@ _SETTINGS_FILE_KEYS = {
     "AUTOTAG_CHARACTER_THRESHOLD": ("autotag", "defaults", "character_threshold"),
     "AUTOTAG_TEMPLATE": ("autotag", "defaults", "template"),
     "AUTOTAG_SUGGESTION_LIMIT": ("autotag", "defaults", "suggestion_limit"),
+    "AUTOTAG_SKIPPED_TAGS": ("autotag", "defaults", "skipped_tags"),
 }
+# Whole-list settings (#431): a save without ``expected_revision`` would merge
+# a stale copy over a list changed elsewhere, so it is refused.
+_REVISION_REQUIRED = frozenset({"autotag_skipped_tags"})
+REVISION_REQUIRED_ERROR = "Reload the page and try again."
 # The thumbnail settings a running Convert outdated job fixes (#317).
 _THUMBNAIL_SETTINGS = ("THUMBNAIL_FORMAT", "THUMBNAIL_QUALITY", "THUMBNAIL_EDGE")
 # Attributes that live on GalleryConfig; the others on PromptManagerConfig.
@@ -176,6 +181,7 @@ def _validate_autotag_settings(data):
         MAX_SUGGESTION_LIMIT,
         MODEL_TYPES,
         validate_saved_threshold,
+        validate_skipped_tags,
         validate_template,
     )
 
@@ -219,6 +225,10 @@ def _validate_autotag_settings(data):
                 f"{MAX_SUGGESTION_LIMIT}."
             )
         updates["AUTOTAG_SUGGESTION_LIMIT"] = value
+    if "autotag_skipped_tags" in data:
+        updates["AUTOTAG_SKIPPED_TAGS"] = tuple(
+            validate_skipped_tags(data["autotag_skipped_tags"])
+        )
     return updates
 
 
@@ -283,6 +293,7 @@ class SettingsRoutesMixin:
                         ),
                         "autotag_template": AutotagConfig.TEMPLATE,
                         "autotag_suggestion_limit": AutotagConfig.SUGGESTION_LIMIT,
+                        "autotag_skipped_tags": list(AutotagConfig.SKIPPED_TAGS),
                         "cpu_count": PromptManagerConfig.max_worker_threads(),
                         "gallery_root_paths": root_paths,
                         "gallery_root_path": root_paths[0] if root_paths else "",
@@ -383,6 +394,10 @@ class SettingsRoutesMixin:
                     {"success": False, "error": "expected_revision must be a string"},
                     status=400,
                 )
+            if expected_revision is None and _REVISION_REQUIRED & set(data):
+                return web.json_response(
+                    {"success": False, "error": REVISION_REQUIRED_ERROR}, status=400
+                )
             try:
                 updates = self._validate_settings(data)
             except ValueError as ve:
diff --git a/py/autotag.py b/py/autotag.py
index 727af79d..1fed7368 100644
--- a/py/autotag.py
+++ b/py/autotag.py
@@ -30,9 +30,9 @@ except ImportError:
 # The tag template and thresholds live with the saved tagging defaults
 # (#328), so config.py never imports PIL.
 try:
-    from .tagging_defaults import DEFAULT_TAG_TEMPLATE
+    from .tagging_defaults import DEFAULT_TAG_TEMPLATE, read_wd14_label_rows
 except ImportError:
-    from py.tagging_defaults import DEFAULT_TAG_TEMPLATE
+    from py.tagging_defaults import DEFAULT_TAG_TEMPLATE, read_wd14_label_rows
 
 try:
     from ..utils import exit_signal
@@ -559,7 +559,6 @@ class AutoTagService:
         # A missing onnxruntime is refused by load_model before this runs
         # (#424); a ModuleNotFoundError here becomes the same refusal.
         import onnxruntime as ort
-        import csv
 
         config = MODELS[model_type]
         model_dir = self.models_dir / config["subdir"]
@@ -576,12 +575,8 @@ class AutoTagService:
 
         session = ort.InferenceSession(str(model_path), providers=providers)
 
-        # Read tag list from CSV
-        tags_list = []
-        with open(tags_path, "r", encoding="utf-8") as f:
-            reader = csv.DictReader(f)
-            for row in reader:
-                tags_list.append(row)
+        # Read tag list from CSV (the reader the Skipped tags preview shares)
+        tags_list = read_wd14_label_rows(tags_path)
 
         self.logger.info(
             f"WD14 model loaded ({len(tags_list)} tags, "
@@ -992,6 +987,7 @@ class AutoTagService:
         prompt: Optional[str] = None,
         general_threshold: Optional[float] = None,
         character_threshold: Optional[float] = None,
+        skip: Any = None,
     ) -> List[Tuple[str, Optional[float]]]:
         """The top ``limit`` suggestions as ``(name, confidence)`` pairs.
 
@@ -1000,7 +996,9 @@ class AutoTagService:
         ``None``. Names are distinct case-insensitively (first one wins).
         A name Save would reject (over 50 characters, a control character
         such as a newline, a comma) is skipped before the dedupe and the
-        ``limit`` count. ``prompt`` is used for this call only;
+        ``limit`` count. A name ``skip`` matches (a ``SkipMatcher``, the
+        Skipped tags compiled for this request or job, #431) is dropped next,
+        so it uses up no slot. ``prompt`` is used for this call only;
         ``custom_prompt`` is never changed.
         """
         if type(limit) is not int or not 1 <= limit <= MAX_SUGGESTION_LIMIT:
@@ -1017,6 +1015,8 @@ class AutoTagService:
                 name = validate_vocabulary_tag_name(raw)
             except ValueError:
                 continue
+            if skip is not None and skip.matches(name):
+                continue
             key = name.casefold()
             if key in seen:
                 continue
diff --git a/py/config.py b/py/config.py
index b5ad1e49..ab7c1071 100644
--- a/py/config.py
+++ b/py/config.py
@@ -587,6 +587,7 @@ try:
         MODEL_TYPES,
         WD14_MODEL_TYPES,
         validate_saved_threshold,
+        validate_skipped_tags,
         validate_template,
         validate_threshold,
     )
@@ -600,6 +601,7 @@ except ImportError:
         MODEL_TYPES,
         WD14_MODEL_TYPES,
         validate_saved_threshold,
+        validate_skipped_tags,
         validate_template,
         validate_threshold,
     )
@@ -617,6 +619,20 @@ def _valid_existing(value: Any) -> str:
     return value
 
 
+def _valid_skipped_tags(value: Any) -> Tuple[str, ...]:
+    return tuple(validate_skipped_tags(value))
+
+
+def _fallback_warning(key: str, error: ValueError, default: Any) -> str:
+    """The one load warning of a saved tagging default that fails its check."""
+    if key == "template":
+        return f"autotag.defaults.template {error}; using the built-in one"
+    if key == "skipped_tags":
+        reason = str(error).removeprefix("Skipped tags").lstrip(": ").rstrip(".")
+        return f"autotag.defaults.skipped_tags {reason}; using no skipped tags"
+    return f"autotag.defaults.{key} {error}; using {default!r}"
+
+
 def _valid_suggestion_limit(value: Any) -> int:
     if type(value) is not int or not 1 <= value <= MAX_SUGGESTION_LIMIT:
         raise ValueError(f"must be an integer from 1 to {MAX_SUGGESTION_LIMIT}")
@@ -639,6 +655,7 @@ class AutotagConfig:
     CHARACTER_THRESHOLD = 0.85
     TEMPLATE = DEFAULT_TAG_TEMPLATE
     SUGGESTION_LIMIT = DEFAULT_SUGGESTION_LIMIT
+    SKIPPED_TAGS: Tuple[str, ...] = ()
 
     # config.json key -> (attribute, validator, default)
     _KEYS = {
@@ -660,6 +677,8 @@ class AutotagConfig:
             _valid_suggestion_limit,
             DEFAULT_SUGGESTION_LIMIT,
         ),
+        # #431: words whose suggested tags are never offered.
+        "skipped_tags": ("SKIPPED_TAGS", _valid_skipped_tags, ()),
     }
 
     @classmethod
@@ -681,6 +700,7 @@ class AutotagConfig:
         }
         if defaults["template"] == DEFAULT_TAG_TEMPLATE:
             del defaults["template"]
+        defaults["skipped_tags"] = list(defaults["skipped_tags"])
         return {"defaults": defaults}
 
     @classmethod
@@ -698,11 +718,7 @@ class AutotagConfig:
             try:
                 setattr(cls, attr, validate(defaults[key]))
             except ValueError as error:
-                config_logger.warning(
-                    f"autotag.defaults.{key} {error}; using {default!r}"
-                    if key != "template"
-                    else f"autotag.defaults.template {error}; using the built-in one"
-                )
+                config_logger.warning(_fallback_warning(key, error, default))
                 setattr(cls, attr, default)
 
 
diff --git a/py/tagging_defaults.py b/py/tagging_defaults.py
index 575a65af..e76d4aca 100644
--- a/py/tagging_defaults.py
+++ b/py/tagging_defaults.py
@@ -4,8 +4,13 @@ Server-free on purpose: ``py.api`` must import without ComfyUI's ``server``
 module, which ``py/config.py`` needs; config re-exports all of this.
 """
 
+import csv
 import math
-from typing import Any
+import os
+import re
+import threading
+import unicodedata
+from typing import Any, Dict, Iterable, List, Set, Tuple
 
 # The tagging engines (``py/autotag.py`` MODELS) and the options they take.
 WD14_MODEL_TYPES = frozenset({"wd14-swinv2", "wd14-vit"})
@@ -88,3 +93,132 @@ def validate_template(value: Any, name: str = "instructions") -> str:
     if len(encoded) > MAX_INSTRUCTION_BYTES:
         raise ValueError(f"{name} {'are' if name == 'instructions' else 'is'} too long")
     return value
+
+
+# Skipped tags (#431): words whose suggested tags are never offered.
+MAX_SKIPPED_TAGS = 200
+MAX_SKIPPED_TAG_CHARS = 50
+_WORD_SEPARATORS = re.compile(r"[ _-]+")
+_FORBIDDEN_IN_ENTRY = re.compile(r"[,\x00-\x1f\x7f-\x9f\u2028\u2029]")
+
+
+def tag_words(text: str) -> Tuple[str, ...]:
+    """The words of a tag or a skipped entry: NFC, case-folded, split on runs
+    of space, ``_`` and ``-``. Every other character belongs to a word."""
+    folded = unicodedata.normalize("NFC", text).casefold()
+    return tuple(word for word in _WORD_SEPARATORS.split(folded) if word)
+
+
+def validate_skipped_tags(value: Any) -> List[str]:
+    """The Skipped tags list, each entry trimmed, or ValueError with the
+    sentence the System page shows (entries are numbered from 1)."""
+    if not isinstance(value, list):
+        raise ValueError("Skipped tags must be a list of words.")
+    if len(value) > MAX_SKIPPED_TAGS:
+        raise ValueError(f"Skipped tags: at most {MAX_SKIPPED_TAGS} entries.")
+    entries: List[str] = []
+    seen: Dict[Tuple[str, ...], int] = {}
+    for number, raw in enumerate(value, 1):
+        if not isinstance(raw, str):
+            raise ValueError(f"Skipped tags: entry {number} must be text.")
+        entry = raw.strip()
+        if not entry:
+            raise ValueError(f"Skipped tags: entry {number} is empty.")
+        if len(entry) > MAX_SKIPPED_TAG_CHARS:
+            raise ValueError(
+                f"Skipped tags: entry {number} must be at most "
+                f"{MAX_SKIPPED_TAG_CHARS} characters."
+            )
+        if _FORBIDDEN_IN_ENTRY.search(entry):
+            raise ValueError(
+                f"Skipped tags: entry {number} must not contain a comma "
+                "or a line break."
+            )
+        words = tag_words(entry)
+        if not words:
+            raise ValueError(f"Skipped tags: entry {number} is empty.")
+        if words in seen:
+            raise ValueError(
+                f"Skipped tags: entry {number} repeats entry {seen[words]}."
+            )
+        seen[words] = number
+        entries.append(entry)
+    return entries
+
+
+class SkipMatcher:
+    """Whether a suggested tag contains a skipped entry's words, consecutive
+    and whole (#431, 17B). Compiled once per request or job; the cost of a
+    check depends on the tag's words, not on the number of entries."""
+
+    def __init__(self, entries: Iterable[str] = ()):
+        self._entries = frozenset(filter(None, (tag_words(e) for e in entries)))
+        self._longest = max((len(words) for words in self._entries), default=0)
+
+    def __bool__(self) -> bool:
+        return bool(self._entries)
+
+    def matches(self, name: str) -> bool:
+        if not self._entries:
+            return False
+        words = tag_words(name)
+        for start in range(len(words)):
+            stop = min(len(words), start + self._longest)
+            for end in range(start + 1, stop + 1):
+                if words[start:end] in self._entries:
+                    return True
+        return False
+
+    def counting(self) -> "CountingSkip":
+        """A per-request view that also remembers which names it hid."""
+        return CountingSkip(self)
+
+
+class CountingSkip:
+    """A :class:`SkipMatcher` that records the distinct names it hid, so the
+    Tag image dialog can say how many skipped tags were not suggested."""
+
+    def __init__(self, matcher: SkipMatcher):
+        self._matcher = matcher
+        self.hidden: Set[str] = set()
+
+    def matches(self, name: str) -> bool:
+        if self._matcher.matches(name):
+            self.hidden.add(name.casefold())
+            return True
+        return False
+
+
+# A WD14 label list's tags the engine can suggest: general (0) and character (4).
+WD14_SUGGESTED_CATEGORIES = frozenset({"0", "4"})
+_label_cache: Dict[str, Tuple[Tuple[int, int], Tuple[str, ...]]] = {}
+_label_cache_lock = threading.Lock()
+
+
+def read_wd14_label_rows(path) -> List[Dict[str, str]]:
+    """Every row of a WD14 ``selected_tags.csv``, read as UTF-8 and closed
+    before returning (the handle never outlives the call, for Windows)."""
+    with open(path, "r", encoding="utf-8", newline="") as handle:
+        return list(csv.DictReader(handle))
+
+
+def wd14_label_names(path) -> Tuple[str, ...]:
+    """The names a WD14 label list can suggest (categories 0 and 4), cached
+    by ``(mtime_ns, size)``. OSError and ValueError propagate (the caller
+    skips a missing or unreadable list)."""
+    key = os.fspath(path)
+    stat = os.stat(key)
+    stamp = (stat.st_mtime_ns, stat.st_size)
+    with _label_cache_lock:
+        cached = _label_cache.get(key)
+    if cached is not None and cached[0] == stamp:
+        return cached[1]
+    names = tuple(
+        name
+        for row in read_wd14_label_rows(key)
+        if row.get("category", "0") in WD14_SUGGESTED_CATEGORIES
+        and (name := (row.get("name") or "").strip())
+    )
+    with _label_cache_lock:
+        _label_cache[key] = (stamp, names)
+    return names
diff --git a/tests/browser/server.py b/tests/browser/server.py
index 65616c67..5d56771f 100644
--- a/tests/browser/server.py
+++ b/tests/browser/server.py
@@ -85,6 +85,9 @@ class TestModel:
     suggestions: list | None = None
     # The engine's model table (``py/autotag.py`` MODELS), set at startup.
     models_config: dict = {}
+    # Where the WD14 label lists live (the Skipped tags preview, #431), set at
+    # startup; the tagging fixture writes or removes a small list there.
+    models_dir = None
 
     def get_models_status(self) -> dict:
         from py.autotag import package_fields
@@ -115,21 +118,26 @@ class TestModel:
         return ["generated", Path(image_path).parent.parent.name]
 
     def generate_tag_suggestions(
-        self, image_path: str, *, limit: int, **kwargs: object
+        self, image_path: str, *, limit: int, skip=None, **kwargs: object
     ) -> list[tuple[str, float | None]]:
-        """Fixed scored suggestions (WD14) or unscored ones (language models)."""
+        """Fixed scored suggestions (WD14) or unscored ones (language models),
+        without the ones ``skip`` hides before the limit, as the engine does
+        (#431)."""
         scored = self.loaded is not None and self.loaded.startswith("wd14")
         if self.suggestions is not None:
-            return [
+            pairs = [
                 (name, confidence if scored else None)
-                for name, confidence in self.suggestions[:limit]
+                for name, confidence in self.suggestions
             ]
-        names = ["sandstone", "desert", "arch", "sky", "rock", "dune", "canyon"]
-        names += [f"tag_{index:02d}" for index in range(100)]
-        return [
-            (name, round(0.98 - index * 0.008, 3) if scored else None)
-            for index, name in enumerate(names[:limit])
-        ]
+        else:
+            names = ["sandstone", "desert", "arch", "sky", "rock", "dune", "canyon"]
+            names += [f"tag_{index:02d}" for index in range(100)]
+            pairs = [
+                (name, round(0.98 - index * 0.008, 3) if scored else None)
+                for index, name in enumerate(names)
+            ]
+        kept = [pair for pair in pairs if skip is None or not skip.matches(pair[0])]
+        return kept[:limit]
 
     def download_model(self, model_type: str, progress_callback=None) -> bool:
         raise AssertionError("browser tests never download a model")
@@ -233,6 +241,7 @@ def create_app(root: Path) -> web.Application:
 
     TestModel.models_config = autotag.MODELS
     model = TestModel()
+    model.models_dir = root / "models"
     autotag.get_autotag_service = lambda: model
     api = PromptManagerAPI()
     api.add_routes(routes)
diff --git a/tests/browser/system-tagging-concept.spec.mjs b/tests/browser/system-tagging-concept.spec.mjs
index ff79595c..f9062216 100644
--- a/tests/browser/system-tagging-concept.spec.mjs
+++ b/tests/browser/system-tagging-concept.spec.mjs
@@ -33,6 +33,8 @@ test.afterEach(async ({ page, request, browserName }) => {
 const PREVIEW_URL = '/prompt_manager/autotag/batch/preview';
 const MODEL_OPTIONS = ['WD14 SwinV2 · ~400 MB', 'WD14 ViT · ~400 MB', 'GGUF JoyCaption · ~4.5 GB', 'HuggingFace JoyCaption · ~16 GB'];
 const SUGGESTIONS = 'From 1 to 100: the most suggestions Generate shows for one image.';
+const SKIPPED_DESCRIPTION = 'Suggested tags that contain one of these words are hidden. Words are separated by spaces, _ or -; '
+    + 'other characters such as ( ) belong to the word.';
 const BATCH = 'Tag each output image from its own pixels with the model above. Prompts are not changed. Review the scope first.';
 
 /** Runs in the page: Auto-tagging's surface under `mainSelector`: rows, field, actions, operation, geometry and tokens. */
@@ -70,6 +72,16 @@ function measureTagging(mainSelector) {
             ...css(actions, 'display', 'flexWrap', 'columnGap', 'justifyContent'),
             primary: css(actions.querySelector('.ca-primary'), 'backgroundColor', 'color', 'fontSize', 'paddingTop', 'paddingLeft'),
             plain: css(actions.querySelector('button:not(.ca-primary)'), 'backgroundColor', 'color', 'fontSize', 'borderTopColor') },
+        // D202 (#431): the Skipped tags block (the concept has none).
+        skipped: (block => block && { tree: [...block.children].map(name), key: block.dataset.key,
+            text: [...block.firstElementChild.children].map(node => [node.localName, text(node), node.localName === 'label' ? node.htmlFor : null]),
+            add: [...block.querySelector('.skip-add').children].map(node => [name(node), node.id, node.placeholder ?? null, text(node)]),
+            preview: [text(block.querySelector('.skip-preview')), block.querySelector('.skip-preview').getAttribute('role')],
+            ...css(block, 'paddingTop', 'paddingBottom', 'borderTopWidth', 'borderTopColor'),
+            label: css(block.querySelector('label'), 'fontSize', 'fontWeight', 'color'),
+            description: css(block.querySelector('.setting-block-text p'), 'fontSize', 'color', 'marginTop'),
+            input: css(block.querySelector('input'), 'fontSize', 'backgroundColor', 'color', 'borderTopColor') })(
+            surface.querySelector(':scope > .setting-block')),
         operations: [...surface.querySelectorAll(':scope > .operation')].map(row => ({ tree: [...row.children].map(name),
             title: text(row.querySelector('h3')), description: text(row.querySelector('p')),
             actions: [...row.querySelectorAll('.row-actions > button')].map(item => [text(item), item.className]) })),
@@ -108,8 +120,9 @@ function mapTaggingConcept(reference, { template, phone }) {
     const [preview] = reference.actions.buttons;
     return {
         ...reference,
-        // D133 adds a row after the thresholds; D134 adds the operation after the actions.
-        tree: [...reference.tree.slice(0, 6), 'div.setting-row', ...reference.tree.slice(6), 'div.operation'],
+        // D133 adds a row after the thresholds, D202 the Skipped tags block after it; D134 adds the operation after the
+        // actions.
+        tree: [...reference.tree.slice(0, 6), 'div.setting-row', 'div.setting-block', ...reference.tree.slice(6), 'div.operation'],
         rows: [
             // D132 (OQ5, OQ6): the four real engines with their download size, and the chosen one's live status.
             { ...model, text: [model.text[0], ['p', 'Downloaded. Not loaded.', null]],
@@ -121,6 +134,20 @@ function mapTaggingConcept(reference, { template, phone }) {
             { ...general, text: [['label', 'Suggestions per image', 'tag-suggestions'], ['p', SUGGESTIONS, null]],
                 control: { ...general.control, id: 'tag-suggestions', value: '10' } },
         ],
+        // D202 (#431): the Skipped tags block in the concept's setting-row tokens: its label and description as a row's,
+        // the row's padding and rule above, the concept's field input; an empty list says so.
+        skipped: { tree: ['div.setting-block-text', 'div.skip-add', 'p.skip-problem.small', 'div.skip-chips.tags', 'p.skip-preview.small'],
+            key: 'autotag_skipped_tags',
+            text: [['label', 'Skipped tags', 'tag-skipped-input'], ['p', SKIPPED_DESCRIPTION, null]],
+            add: [['input', 'tag-skipped-input', 'Add a word or words', ''], ['button', 'tag-skipped-add', '', 'Add']],
+            preview: ['No tags are skipped.', 'status'],
+            paddingTop: reference.row.paddingTop, paddingBottom: reference.row.paddingBottom,
+            borderTopWidth: reference.row.borderTopWidth, borderTopColor: reference.row.borderTopColor,
+            label: reference.label,
+            description: { fontSize: reference.description.fontSize, color: reference.description.color,
+                marginTop: reference.description.marginTop },
+            input: { fontSize: '12px', backgroundColor: reference.field.textarea.backgroundColor, color: reference.field.textarea.color,
+                borderTopColor: reference.field.textarea.borderTopColor } },
         // The saved template (the server's default until one is saved) replaces the concept's sample text.
         field: { ...reference.field, textarea: { ...reference.field.textarea, value: template } },
         // D132: Download (for an engine already on disk, "Download again") and Unload replace the two simulated jobs.
@@ -198,12 +225,13 @@ test('auto-tagging comparison detects mutations', async ({ page, request }) => {
     const expected = mapTaggingConcept(concept, saved);
     const production = await productionTagging(page, 'dark');
     expect(diffInventory(expected, production)).toEqual([]);
-    // Unmapped, the section differs only where D132, D133 and D134 are recorded (and the saved template's text).
+    // Unmapped, the section differs only where D132, D133, D134 and D202 are recorded (and the saved template's text).
     expect(diffInventory(concept, production).map(item => item.path.split('.').slice(0, 3).join('.'))
         .filter((path, index, all) => all.indexOf(path) === index).sort()).toEqual([
         'actions.buttons.1', 'actions.buttons.2', 'field.textarea.value', 'operations.0.actions', 'operations.0.description',
         'operations.0.title', 'operations.0.tree', 'operations.length', 'rows.0.control', 'rows.0.text', 'rows.4.control', 'rows.4.controlBelow',
-        'rows.4.flexWrap', 'rows.4.text', 'rows.4.tree', 'rows.length', 'tree.6', 'tree.7', 'tree.8', 'tree.9', 'tree.length'].sort());
+        'rows.4.flexWrap', 'rows.4.text', 'rows.4.tree', 'rows.length', 'skipped', 'tree.6', 'tree.7', 'tree.8', 'tree.9', 'tree.10',
+        'tree.length'].sort());
     const measure = () => page.evaluate(measureTagging, '#workspace-main');
     const paths = async () => diffInventory(expected, await measure()).map(item => item.path);
     // A removed row.
diff --git a/tests/browser/workspace-system-tagging.spec.mjs b/tests/browser/workspace-system-tagging.spec.mjs
index 5a5a640a..eff83024 100644
--- a/tests/browser/workspace-system-tagging.spec.mjs
+++ b/tests/browser/workspace-system-tagging.spec.mjs
@@ -418,3 +418,85 @@ test('a model that is not downloaded cannot be reviewed for a batch; the button
     await expect(dialog(page)).toHaveCount(0);
     expect(page.modelCalls.filter(call => call.includes('/batch/preview'))).toEqual([]);
 });
+
+// D202 (#431): Skipped tags: add (button and Enter), the preview over the library's tags and the WD14 label list, the
+// per-chip counts, remove, Save preferences and a reload; a list the server refuses highlights the block.
+const SKIPPED_PREVIEW = '/prompt_manager/autotag/skipped-tags/preview';
+const skippedBlock = page => surface(page).locator(':scope > .setting-block[data-setting="tag-skipped"]');
+const skippedInput = page => page.locator('#tag-skipped-input');
+const skippedChips = page => skippedBlock(page).locator('.skip-chips .chip.tag-suggestion');
+const skippedPreview = page => skippedBlock(page).locator('.skip-preview');
+
+test('skipped tags add, preview, remove, save and reload (D202)', async ({ page, request }) => {
+    await openTagging(page);
+    await expect(skippedBlock(page).locator('label')).toHaveText('Skipped tags');
+    await expect(skippedBlock(page)).toHaveAttribute('data-key', 'autotag_skipped_tags');
+    await expect(skippedPreview(page)).toHaveText('No tags are skipped.');
+    await expect(skippedPreview(page)).toHaveAttribute('role', 'status');
+    // The label list on disk (blurry, blurry_background, signature, …) and the library tags (warm_light, …).
+    let answer = page.waitForResponse(item => item.url().endsWith(SKIPPED_PREVIEW));
+    await skippedInput(page).fill('blurry');
+    await skippedInput(page).press('Enter');
+    expect((await answer).status()).toBe(200);
+    await expect(skippedInput(page)).toHaveValue('');
+    await expect(skippedPreview(page)).toHaveText('Hides 2 tags from suggestions: blurry, blurry_background. '
+        + 'Tags already on images are not changed.');
+    answer = page.waitForResponse(item => item.url().endsWith(SKIPPED_PREVIEW));
+    await skippedInput(page).fill('light');
+    await page.getByRole('button', { name: 'Add', exact: true }).click();
+    await answer;
+    await expect(skippedPreview(page)).toHaveText('Hides 3 tags from suggestions: warm_light, blurry, blurry_background. '
+        + 'Tags already on images are not changed.');
+    await expect(skippedChips(page)).toHaveText(['blurry2×', 'light1×']);
+    await expect(skippedChips(page).first()).toHaveAttribute('title', 'Hides 2 tags');
+    // An entry that hides nothing is muted; a duplicate is not added and the line under the input says so.
+    answer = page.waitForResponse(item => item.url().endsWith(SKIPPED_PREVIEW));
+    await skippedInput(page).fill('zebra');
+    await skippedInput(page).press('Enter');
+    await answer;
+    await expect(skippedChips(page).last()).toHaveClass(/\bnone\b/);
+    await expect(skippedChips(page).last()).toHaveAttribute('title', 'Hides no known tag');
+    await skippedInput(page).fill('Blurry');
+    await skippedInput(page).press('Enter');
+    await expect(page.locator('#tag-skipped-problem')).toHaveText('Already in the list.');
+    await expect(skippedInput(page)).toHaveAttribute('aria-invalid', 'true');
+    await skippedInput(page).fill('a, b');
+    await skippedInput(page).press('Enter');
+    await expect(page.locator('#tag-skipped-problem')).toHaveText('No commas or line breaks.');
+    // Remove zebra, then save.
+    await skippedChips(page).last().getByRole('button', { name: 'Remove zebra', exact: true }).click();
+    await expect(skippedChips(page)).toHaveCount(2);
+    await expect(status(page)).toHaveText('Unsaved changes.');
+    await save(page).click();
+    await expect(status(page)).toHaveText('Saved to the server configuration.');
+    expect((await serverJson(request, SETTINGS_URL)).settings.autotag_skipped_tags).toEqual(['blurry', 'light']);
+    await openTagging(page);
+    await expect(skippedChips(page)).toHaveText(['blurry2×', 'light1×']);
+    // Removing a chip and adding it back is no change.
+    await skippedChips(page).last().getByRole('button', { name: 'Remove light', exact: true }).click();
+    await expect(status(page)).toHaveText('Unsaved changes.');
+    await skippedInput(page).fill('light');
+    await skippedInput(page).press('Enter');
+    await expect(status(page)).toHaveText('No unsaved changes.');
+});
+
+test('skipped tags preview checks library tags only without a label list, and a refused save highlights it', async ({ page, request }) => {
+    await expect(await request.post('/__test__/tagging/defaults', { data: { general: 0.35, character: 0.85, limit: 10,
+        labels: false } })).toBeOK();
+    await openTagging(page);
+    const answer = page.waitForResponse(item => item.url().endsWith(SKIPPED_PREVIEW));
+    await skippedInput(page).fill('blurry');
+    await skippedInput(page).press('Enter');
+    await answer;
+    await expect(skippedPreview(page)).toHaveText('Hides 0 tags from suggestions. Checked against library tags only; no WD14 '
+        + 'label list is downloaded. Tags already on images are not changed.');
+    // The server is the authority: a list it refuses keeps the draft, says why and highlights the block.
+    await page.route(`**${SETTINGS_URL}`, route => (route.request().method() === 'POST'
+        ? route.fulfill({ status: 400, contentType: 'application/json',
+            body: JSON.stringify({ success: false, error: 'Skipped tags: entry 1 is empty.' }) })
+        : route.fallback()));
+    await save(page).click();
+    await expect(status(page)).toHaveText('Skipped tags: entry 1 is empty.');
+    await expect(skippedBlock(page)).toHaveAttribute('aria-invalid', 'true');
+    await page.unrouteAll({ behavior: 'ignoreErrors' });
+});
diff --git a/tests/browser/workspace-tagging.spec.mjs b/tests/browser/workspace-tagging.spec.mjs
index b61abbca..b3b2cef6 100644
--- a/tests/browser/workspace-tagging.spec.mjs
+++ b/tests/browser/workspace-tagging.spec.mjs
@@ -849,3 +849,15 @@ test('a failed listing re-read after a save says so and keeps the cards (M2)', a
     await expect(page.locator('#gallery-continuation [aria-disabled="true"]')).toHaveCount(0);
     await page.unroute(failing);
 });
+
+// #431: the saved Skipped tags hide matching suggestions before the limit (WD14 fills it from lower scores), and the
+// chip hint says how many were not suggested.
+test('suggestions omit skipped tags and say how many were hidden', async ({ page, request }) => {
+    await expect(await request.post('/__test__/tagging/defaults', { data: { general: 0.35, character: 0.85, limit: 4,
+        skipped: ['desert', 'rock'] } })).toBeOK();
+    await openTag(page);
+    const answer = await (await generated(page)).json();
+    expect(answer.skipped).toBe(2);
+    await expect(chips(page).locator(':scope > span:first-child')).toHaveText(['sandstone', 'arch', 'sky', 'dune']);
+    await expect(dialog(page).locator('#tag-suggestions > p.small')).toHaveText(`${CHIP_HINT} 2 skipped tags were not suggested.`);
+});
diff --git a/tests/browser/workspace_tagging_fixture.py b/tests/browser/workspace_tagging_fixture.py
index 4fe5bce9..26afa4eb 100644
--- a/tests/browser/workspace_tagging_fixture.py
+++ b/tests/browser/workspace_tagging_fixture.py
@@ -226,6 +226,7 @@ def register_tagging_commands(
         return download["result"]
 
     _set_defaults(model, DEFAULTS)  # the server starts on the standard ones
+    _write_labels(model, True)
 
     @routes.post("/__test__/tagging/reset")
     async def reset(request: web.Request) -> web.Response:
@@ -244,6 +245,7 @@ def register_tagging_commands(
         model.loaded = None
         restore_download()
         _set_defaults(model, DEFAULTS)
+        await api._run_in_executor(_write_labels, model, True)
         # A test that ends with the dialog open leaves its capture behind; drop
         # every capture so the next test starts below the store's limits.
         await api._run_in_executor(api.close_annotation_captures)
@@ -353,13 +355,22 @@ def register_tagging_commands(
 
         ``{"general": g, "character": c, "limit": n}``: the WD14 thresholds
         (in [0, 1]) and the persisted suggestion count (1..100), so a test can
-        tell the server's values from the dialog's built-in ones. Reset
-        restores the standard 0.35 / 0.85 / 10.
+        tell the server's values from the dialog's built-in ones. Optional
+        ``skipped`` sets the saved Skipped tags (#431) and ``labels`` (true or
+        false) writes or removes the fake WD14 SwinV2 label list the Skipped
+        tags preview reads. Reset restores the standard 0.35 / 0.85 / 10, no
+        skipped tags and the label list.
         """
         data = await request.json() if request.can_read_body else None
         if request.query or not _valid_defaults(data):
             raise web.HTTPBadRequest()
         _set_defaults(model, (data["general"], data["character"], data["limit"]))
+        if "skipped" in data:
+            from py.config import AutotagConfig
+
+            AutotagConfig.SKIPPED_TAGS = tuple(data["skipped"])
+        if "labels" in data:
+            await api._run_in_executor(_write_labels, model, data["labels"])
         return web.json_response({"success": True})
 
     @routes.get("/__test__/tagging/captures")
@@ -394,6 +405,33 @@ def _set_defaults(model, values) -> None:
         AutotagConfig.MODEL_TYPE = "wd14-swinv2"
         AutotagConfig.EXISTING = "skip"
         AutotagConfig.TEMPLATE = model.default_prompt
+        AutotagConfig.SKIPPED_TAGS = ()
+
+
+# The fake WD14 SwinV2 label list (general 0, character 4, rating 9): the
+# names the Skipped tags preview checks beside the library's tags (#431).
+FAKE_LABELS = (
+    ("blurry", "0"),
+    ("blurry_background", "0"),
+    ("signature", "0"),
+    ("watermark", "0"),
+    ("t-shirt", "0"),
+    ("half-closed_eyes", "0"),
+    ("saber_(fate)", "4"),
+    ("general", "9"),
+)
+
+
+def _write_labels(model, present: bool) -> None:
+    """Write (or remove) the fake label list under the fake models folder."""
+    path = Path(model.models_dir) / "WD14-SwinV2" / "selected_tags.csv"
+    if not present:
+        path.unlink(missing_ok=True)
+        return
+    path.parent.mkdir(parents=True, exist_ok=True)
+    lines = ["tag_id,name,category,count"]
+    lines += [f"{i},{name},{cat},1" for i, (name, cat) in enumerate(FAKE_LABELS)]
+    path.write_text("\n".join(lines) + "\n", encoding="utf-8")
 
 
 def _valid_defaults(data: object) -> bool:
@@ -402,9 +440,20 @@ def _valid_defaults(data: object) -> bool:
         and not isinstance(value, bool)
         and 0 <= value <= 1
     )
+    optional = {"skipped", "labels"}
+    if isinstance(data, dict) and "skipped" in data:
+        try:
+            from py.tagging_defaults import validate_skipped_tags
+
+            validate_skipped_tags(data["skipped"])
+        except ValueError:
+            return False
+    if isinstance(data, dict) and not isinstance(data.get("labels", True), bool):
+        return False
     return (
         isinstance(data, dict)
-        and set(data) == {"general", "character", "limit"}
+        and {"general", "character", "limit"} <= set(data)
+        and set(data) <= {"general", "character", "limit"} | optional
         and unit(data["general"])
         and unit(data["character"])
         and type(data["limit"]) is int
diff --git a/tests/fixtures/legacy_contract_snapshot.json b/tests/fixtures/legacy_contract_snapshot.json
index 2ba298bf..4fa2a827 100644
--- a/tests/fixtures/legacy_contract_snapshot.json
+++ b/tests/fixtures/legacy_contract_snapshot.json
@@ -105,6 +105,7 @@
     "POST /prompt_manager/autotag/batch/preview",
     "POST /prompt_manager/autotag/download/{model_type}",
     "POST /prompt_manager/autotag/single",
+    "POST /prompt_manager/autotag/skipped-tags/preview",
     "POST /prompt_manager/autotag/start",
     "POST /prompt_manager/autotag/unload",
     "POST /prompt_manager/bulk/category",
@@ -188,6 +189,7 @@
     "settings.autotag_existing",
     "settings.autotag_general_threshold",
     "settings.autotag_model_type",
+    "settings.autotag_skipped_tags",
     "settings.autotag_suggestion_limit",
     "settings.autotag_template",
     "settings.cpu_count",
diff --git a/tests/js/workspace-image-tagging-state.test.js b/tests/js/workspace-image-tagging-state.test.js
index 0f4a033a..97a4f183 100644
--- a/tests/js/workspace-image-tagging-state.test.js
+++ b/tests/js/workspace-image-tagging-state.test.js
@@ -936,3 +936,17 @@ test('#515: text typed before Retry after a failed first observation follows the
     assert.equal(c.state.manual, 'Minimal, warm_light, dunes');
     assert.equal(c.state.statusText, '');
 });
+
+test('the chip hint says how many skipped tags were not suggested (#431)', async () => {
+    const { skippedNote } = await load();
+    assert.equal(skippedNote(0), '');
+    assert.equal(skippedNote(undefined), '');
+    assert.equal(skippedNote(1), ' 1 skipped tag was not suggested.');
+    assert.equal(skippedNote(2), ' 2 skipped tags were not suggested.');
+    for (const [skipped, hint] of [[2, 'Remove anything you do not want to add. 2 skipped tags were not suggested.'],
+        [0, 'Remove anything you do not want to add.'], ['3', 'Remove anything you do not want to add.']]) {
+        const { c } = await opened({ [`POST ${SUGGEST}`]: () => response(200, { ...suggested(), skipped }) });
+        await c.generate();
+        assert.equal(c.state.chipHint, hint, String(skipped));
+    }
+});
diff --git a/tests/js/workspace-system-skipped-tags.test.js b/tests/js/workspace-system-skipped-tags.test.js
new file mode 100644
index 00000000..3a7ea101
--- /dev/null
+++ b/tests/js/workspace-system-skipped-tags.test.js
@@ -0,0 +1,247 @@
+// System › Auto-tagging "Skipped tags" (#431, D202): the add input, the chips, the client checks and the preview line.
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const skippedModule = import('../../web/js/workspace/system-skipped-tags.mjs');
+const stateModule = import('../../web/js/workspace/system-state.mjs');
+const coreModule = import('../../web/js/shared/toolkit/core.js');
+
+/** A minimal DOM: elements with children, attributes, listeners (aborted by their signal) and focus. */
+function fakeDOM() {
+    const previous = global.document;
+    class Element {
+        constructor(tag) {
+            this.tagName = tag.toUpperCase();
+            this.children = [];
+            this.attributes = {};
+            this.listeners = [];
+            this.dataset = {};
+            this.className = '';
+            this.id = '';
+            this.value = '';
+            this.title = '';
+            this.disabled = false;
+            this._text = '';
+        }
+        get localName() { return this.tagName.toLowerCase(); }
+        get textContent() { return this._text + this.children.map(child => (typeof child === 'string' ? child : child.textContent)).join(''); }
+        set textContent(text) { this.children = []; this._text = String(text); }
+        append(...nodes) { for (const node of nodes) { if (typeof node !== 'string') node.parentNode = this; this.children.push(node); } }
+        replaceChildren(...nodes) { this.children = []; this._text = ''; this.append(...nodes); }
+        querySelectorAll(selector) {
+            assert.equal(selector, 'button');
+            const found = [];
+            const walk = node => { for (const child of node.children) if (typeof child !== 'string') { if (child.tagName === 'BUTTON') found.push(child); walk(child); } };
+            walk(this);
+            return found;
+        }
+        focus() { global.document.activeElement = this; }
+        setAttribute(name, value) { this.attributes[name] = String(value); }
+        getAttribute(name) { return Object.hasOwn(this.attributes, name) ? this.attributes[name] : null; }
+        removeAttribute(name) { delete this.attributes[name]; }
+        addEventListener(type, callback, options = {}) {
+            if (options.signal?.aborted) return;
+            const entry = { type, callback };
+            this.listeners.push(entry);
+            options.signal?.addEventListener('abort', () => { this.listeners = this.listeners.filter(item => item !== entry); });
+        }
+        dispatch(type, event = {}) {
+            return Promise.all(this.listeners.filter(item => item.type === type).map(({ callback }) => callback({ type, target: this, ...event })));
+        }
+    }
+    global.document = { createElement: tag => new Element(tag), activeElement: null };
+    const walk = (node, found = []) => { found.push(node); node.children.forEach(child => typeof child !== 'string' && walk(child, found)); return found; };
+    return { find: (root, predicate) => walk(root).find(predicate), restore() { global.document = previous; } };
+}
+
+const tick = () => new Promise(resolve => setTimeout(resolve, 5));
+
+async function mounted({ saved = ['blurry'], answer, host = true } = {}) {
+    const { skippedTagsBlock } = await skippedModule;
+    const { createSystemDrafts } = await stateModule;
+    const { createScope } = await coreModule;
+    const dom = fakeDOM();
+    const drafts = createSystemDrafts({
+        readBrowser: () => ({}), readRuntime: () => ({}),
+        readHost: async () => ({ values: host ? { autotag_skipped_tags: saved } : {}, revision: 'sha256:one' }),
+        writeBrowser: async () => ({}), writeHost: async () => ({ success: true, persisted: true }), writeRuntime: async () => ({}),
+    });
+    const scope = createScope();
+    const posts = [];
+    const api = {
+        post: (url, body, options) => {
+            posts.push({ url, body, signal: options.signal });
+            if (answer) return answer(body, options);
+            return Promise.resolve({ success: true, count: body.entries.length, sample: body.entries, sample_limit: 12,
+                per_entry: body.entries.map((entry, index) => ({ entry, count: index })), sources: { library: 3, wd14: ['WD14 SwinV2'] } });
+        },
+    };
+    const block = skippedTagsBlock({ api, scope, drafts, delay: 1 });
+    scope.cleanup(drafts.subscribe(block.repaint));
+    block.repaint();
+    await drafts.reloadHost();
+    const byId = id => dom.find(block.node, node => node.id === id);
+    const chips = () => dom.find(block.node, node => node.className === 'tags skip-chips');
+    const preview = () => dom.find(block.node, node => node.className === 'small skip-preview');
+    const add = async text => { byId('tag-skipped-input').value = text; await byId('tag-skipped-add').dispatch('click'); };
+    return { dom, drafts, scope, block, byId, chips, preview, posts, add };
+}
+
+test('words split like the server: NFC, lower case, space, _ and - only', async () => {
+    const { entryWords } = await skippedModule;
+    assert.deepEqual(entryWords('Half-closed_eyes'), ['half', 'closed', 'eyes']);
+    assert.deepEqual(entryWords('saber_(fate)'), ['saber', '(fate)']);
+    assert.deepEqual(entryWords(' _ - '), []);
+    assert.deepEqual(entryWords('CAFÉ'), ['café']);
+});
+
+test('the client checks say why an entry is not added', async () => {
+    const { entryProblem, SKIPPED_COPY } = await skippedModule;
+    assert.equal(entryProblem('  sky ', ['blurry']), '');
+    assert.equal(entryProblem('   ', []), SKIPPED_COPY.empty);
+    assert.equal(entryProblem('_--', []), 'Enter a word.');
+    assert.equal(entryProblem('a, b', []), 'No commas or line breaks.');
+    assert.equal(entryProblem('a\nb', []), 'No commas or line breaks.');
+    assert.equal(entryProblem('x'.repeat(51), []), 'At most 50 characters.');
+    assert.equal(entryProblem('🏜'.repeat(50), []), '');
+    assert.equal(entryProblem('Blurry-Background', ['blurry background']), 'Already in the list.');
+    assert.equal(entryProblem('sky', Array.from({ length: 200 }, (_, i) => `w${i}`)), 'The list is full (200).');
+});
+
+test('the preview line states the count, the sample and the sources', async () => {
+    const { previewText, chipCount } = await skippedModule;
+    assert.deepEqual(previewText({ count: 15, sample: ['blurry', 'signature'], sources: { wd14: ['WD14 SwinV2'] } }), {
+        lead: 'Hides 15 tags from suggestions', rest: ': blurry, signature and 13 more. Tags already on images are not changed.' });
+    assert.deepEqual(previewText({ count: 1, sample: ['blurry'], sources: { wd14: [] } }), {
+        lead: 'Hides 1 tag from suggestions',
+        rest: ': blurry. Checked against library tags only; no WD14 label list is downloaded. Tags already on images are not changed.' });
+    assert.deepEqual(previewText({ count: 0, sample: [], sources: { wd14: ['WD14 ViT'] } }), {
+        lead: 'Hides 0 tags from suggestions', rest: '. Tags already on images are not changed.' });
+    assert.deepEqual(previewText(null).lead, 'Hides 0 tags from suggestions');
+    assert.deepEqual(chipCount(3), { title: 'Hides 3 tags', text: '3' });
+    assert.deepEqual(chipCount(1), { title: 'Hides 1 tag', text: '1' });
+    assert.deepEqual(chipCount(0), { title: 'Hides no known tag', text: 'none' });
+    assert.equal(chipCount(undefined), null);
+});
+
+test('the block shows the saved list, previews it and carries its setting keys', async () => {
+    const view = await mounted({ saved: ['blurry', 'signature'] });
+    try {
+        assert.equal(view.block.node.dataset.setting, 'tag-skipped');
+        assert.equal(view.block.node.dataset.key, 'autotag_skipped_tags');
+        assert.equal(view.preview().textContent, 'Checking…');
+        await tick();
+        assert.deepEqual(view.posts.map(post => [post.url, post.body]),
+            [['/prompt_manager/autotag/skipped-tags/preview', { entries: ['blurry', 'signature'] }]]);
+        assert.equal(view.preview().textContent, 'Hides 2 tags from suggestions: blurry, signature. Tags already on images are not changed.');
+        const chips = view.chips().children;
+        assert.deepEqual(chips.map(chip => [chip.className, chip.title, chip.textContent]), [
+            ['chip tag-suggestion none', 'Hides no known tag', 'blurrynone×'],
+            ['chip tag-suggestion', 'Hides 1 tag', 'signature1×']]);
+        assert.equal(chips[1].children[2].getAttribute('aria-label'), 'Remove signature');
+    } finally { view.scope.dispose(); view.dom.restore(); }
+});
+
+test('add and remove draft the list; a list set back is clean; Enter adds', async () => {
+    const view = await mounted();
+    try {
+        await view.add('  closed eyes ');
+        assert.deepEqual(view.drafts.get('host', 'autotag_skipped_tags'), ['blurry', 'closed eyes']);
+        assert.equal(view.byId('tag-skipped-input').value, '');
+        assert.equal(view.drafts.dirty(), true);
+        view.byId('tag-skipped-input').value = 'sky';
+        let prevented = false;
+        await view.byId('tag-skipped-input').dispatch('keydown', { key: 'Enter', preventDefault: () => { prevented = true; } });
+        assert.equal(prevented, true);
+        await view.byId('tag-skipped-input').dispatch('keydown', { key: 'a' });
+        assert.deepEqual(view.drafts.get('host', 'autotag_skipped_tags'), ['blurry', 'closed eyes', 'sky']);
+        // Remove the two added chips: the list equals the saved one and nothing is unsaved (sameDraft).
+        const removeButton = index => view.chips().children[index].children.at(-1);
+        removeButton(2).focus();
+        await removeButton(2).dispatch('click');
+        assert.equal(global.document.activeElement, removeButton(1), 'focus moves to the neighbour');
+        await removeButton(1).dispatch('click');
+        assert.deepEqual(view.drafts.get('host', 'autotag_skipped_tags'), ['blurry']);
+        assert.equal(view.drafts.dirty(), false);
+        await tick();
+        // Only the last list of a quick series is asked for.
+        assert.deepEqual(view.posts.map(post => post.body.entries), [['blurry']]);
+    } finally { view.scope.dispose(); view.dom.restore(); }
+});
+
+test('a refused entry is not added and the line under the input says why', async () => {
+    const view = await mounted();
+    try {
+        const problem = () => view.byId('tag-skipped-problem').textContent;
+        await view.add('Blurry');
+        assert.equal(problem(), 'Already in the list.');
+        assert.equal(view.byId('tag-skipped-input').getAttribute('aria-invalid'), 'true');
+        assert.equal(view.byId('tag-skipped-input').value, 'Blurry');
+        await view.byId('tag-skipped-input').dispatch('input');
+        assert.equal(problem(), '');
+        assert.equal(view.byId('tag-skipped-input').getAttribute('aria-invalid'), null);
+        await view.add('a,b');
+        assert.equal(problem(), 'No commas or line breaks.');
+        await view.add(' ');
+        assert.equal(problem(), 'Enter a word.');
+        assert.deepEqual(view.drafts.get('host', 'autotag_skipped_tags'), ['blurry']);
+    } finally { view.scope.dispose(); view.dom.restore(); }
+});
+
+test('a full list disables Add and says so', async () => {
+    const view = await mounted({ saved: Array.from({ length: 200 }, (_, i) => `w${i}`) });
+    try {
+        assert.equal(view.byId('tag-skipped-add').disabled, true);
+        assert.equal(view.byId('tag-skipped-problem').textContent, 'The list is full (200).');
+        await view.chips().children[0].children.at(-1).dispatch('click');
+        assert.equal(view.byId('tag-skipped-add').disabled, false);
+        assert.equal(view.byId('tag-skipped-problem').textContent, '');
+    } finally { view.scope.dispose(); view.dom.restore(); }
+});
+
+test('an empty list says no tags are skipped without a request', async () => {
+    const view = await mounted({ saved: [] });
+    try {
+        await tick();
+        assert.equal(view.preview().textContent, 'No tags are skipped.');
+        assert.deepEqual(view.posts, []);
+    } finally { view.scope.dispose(); view.dom.restore(); }
+});
+
+test('a failed preview says so; a newer list aborts the older request', async () => {
+    let calls = 0;
+    const view = await mounted({ answer: (body, options) => {
+        calls += 1;
+        if (calls === 1) return new Promise((_resolve, reject) => options.signal.addEventListener('abort', () => reject(new Error('aborted'))));
+        return Promise.reject(Object.assign(new Error('busy'), { code: 'busy' }));
+    } });
+    try {
+        await tick();
+        assert.equal(view.posts.length, 1);
+        await view.add('sky');
+        assert.equal(view.posts[0].signal.aborted, true);
+        await tick();
+        assert.equal(view.preview().textContent, 'The preview could not be read.');
+        // The list stays editable.
+        assert.equal(view.byId('tag-skipped-input').disabled, false);
+    } finally { view.scope.dispose(); view.dom.restore(); }
+});
+
+test('before the settings are read the controls are disabled', async () => {
+    const view = await mounted({ host: false });
+    try {
+        assert.equal(view.byId('tag-skipped-input').disabled, true);
+        assert.equal(view.byId('tag-skipped-add').disabled, true);
+        await view.add('sky');
+        assert.equal(view.drafts.get('host', 'autotag_skipped_tags'), undefined);
+    } finally { view.scope.dispose(); view.dom.restore(); }
+});
+
+test('leaving the section aborts a request in flight and the pending timer', async () => {
+    const view = await mounted({ answer: (_body, options) => new Promise((_r, reject) => options.signal.addEventListener('abort', () => reject(new Error('x')))) });
+    await tick();
+    assert.equal(view.posts.length, 1);
+    view.scope.dispose();
+    assert.equal(view.posts[0].signal.aborted, true);
+    view.dom.restore();
+});
diff --git a/tests/js/workspace-system-state.test.js b/tests/js/workspace-system-state.test.js
index edef02d7..2331b574 100644
--- a/tests/js/workspace-system-state.test.js
+++ b/tests/js/workspace-system-state.test.js
@@ -402,11 +402,12 @@ test('a partial host save keeps what saved, adopts its revision and fails only t
     assert.equal(drafts.statusText(), 'missing can\'t be used: not found. Remove it or reconnect it, then save.');
     // The next save carries the revision the saved part produced: no false "changed elsewhere".
     domains.outcome.host = null;
-    drafts.set('host', 'gallery_root_paths', ['a']);
+    // (#431: a list equal to the saved one is no change, so a different one is drafted.)
+    drafts.set('host', 'gallery_root_paths', ['a', 'b']);
     const second = await drafts.save();
     assert.equal(second.host, 'saved');
     assert.equal(domains.calls.at(-1)[2].expected_revision, 'sha256:lora');
-    assert.deepEqual(domains.calls.at(-1)[1], { gallery_root_paths: ['a'] });
+    assert.deepEqual(domains.calls.at(-1)[1], { gallery_root_paths: ['a', 'b'] });
     // Without a server reason, the status says some were saved and the highlighted ones were not.
     domains.outcome.host = () => { throw Object.assign(new Error('boom'), { partial: { saved: ['x'], revision: 'sha256:three' } }); };
     drafts.set('host', 'x', 1);
@@ -429,3 +430,39 @@ test('runtime adapter maps config.level to runtime_level and back', async () =>
     assert.deepEqual(runtimeBody({ runtime_level: 'WARNING' }), { level: 'WARNING' });
     assert.deepEqual(runtimeBody({ runtime_level: 'CRITICAL', console_logging: true }), { level: 'CRITICAL', console_logging: true });
 });
+
+test('sameDraft compares arrays and plain objects by value, keys in any order (#431)', async () => {
+    const { sameDraft } = await source;
+    assert.equal(sameDraft(1, 1), true);
+    assert.equal(sameDraft(Number.NaN, Number.NaN), true);
+    assert.equal(sameDraft(0, -0), false);
+    assert.equal(sameDraft(['a', 'b'], ['a', 'b']), true);
+    assert.equal(sameDraft(['a', 'b'], ['b', 'a']), false);
+    assert.equal(sameDraft([], []), true);
+    assert.equal(sameDraft([], {}), false);
+    assert.equal(sameDraft({ gguf: 'x', hf: 'y' }, { hf: 'y', gguf: 'x' }), true);
+    assert.equal(sameDraft([{ id: 'a', name: 'n' }], [{ name: 'n', id: 'a' }]), true);
+    assert.equal(sameDraft({ a: 1 }, { a: 2 }), false);
+    assert.equal(sameDraft('a', ['a']), false);
+    assert.equal(sameDraft(null, {}), false);
+    assert.equal(sameDraft(new Date(0), new Date(0)), false);
+});
+
+test('a list draft set back to the saved list is clean, and a save cleans it (#431)', async () => {
+    const domains = adapters({ host: { autotag_skipped_tags: ['blurry'] } });
+    const drafts = await loaded(domains);
+    drafts.set('host', 'autotag_skipped_tags', ['blurry', 'signature']);
+    assert.equal(drafts.dirty('host'), true);
+    // Removing the added chip builds a new array equal to the saved one.
+    drafts.set('host', 'autotag_skipped_tags', ['blurry']);
+    assert.equal(drafts.dirty('host'), false);
+    drafts.set('host', 'autotag_skipped_tags', ['signature']);
+    await drafts.save();
+    assert.equal(drafts.dirty('host'), false);
+    assert.deepEqual(drafts.saved('host').autotag_skipped_tags, ['signature']);
+    // A reload whose list equals the draft's (a new array) keeps nothing dirty.
+    drafts.set('host', 'autotag_skipped_tags', ['sky']);
+    domains.readHost = async () => ({ values: { autotag_skipped_tags: ['sky'] }, revision: 'sha256:three' });
+    await drafts.load('host');
+    assert.equal(drafts.dirty('host'), false);
+});
diff --git a/tests/js/workspace-system-tagging.test.js b/tests/js/workspace-system-tagging.test.js
index 317b9149..7697edd7 100644
--- a/tests/js/workspace-system-tagging.test.js
+++ b/tests/js/workspace-system-tagging.test.js
@@ -201,7 +201,7 @@ test('opening the section reads the model status once; the select waits for it',
         assert.deepEqual(byId('tag-model').options.map(option => option.textContent),
             ['WD14 SwinV2 · ~400 MB', 'WD14 ViT · ~400 MB', 'GGUF JoyCaption · ~4.5 GB', 'HuggingFace JoyCaption · ~16 GB']);
         assert.deepEqual(surface.children.map(node => node.className),
-            ['', '', 'setting-row', 'setting-row', 'setting-row', 'setting-row', 'setting-row', 'field', 'row-actions', 'operation']);
+            ['', '', 'setting-row', 'setting-row', 'setting-row', 'setting-row', 'setting-row', 'setting-block', 'field', 'row-actions', 'operation']);
     } finally { scope.dispose(); dom.restore(); }
     const failed = await mounted({ modelsFail: true });
     try {
diff --git a/tests/test_api_annotation_suggest.py b/tests/test_api_annotation_suggest.py
index 7d1b3539..b874356a 100644
--- a/tests/test_api_annotation_suggest.py
+++ b/tests/test_api_annotation_suggest.py
@@ -73,6 +73,7 @@ class FakeTagger:
         self.calls = []
         self.read_paths = []
         self.read_bytes = []
+        self.skips = []
         self.download_model = MagicMock(side_effect=AssertionError("downloaded"))
         self.load_error = None
         self.block = None  # (entered, proceed) events
@@ -115,8 +116,10 @@ class FakeTagger:
         prompt=None,
         general_threshold=None,
         character_threshold=None,
+        skip=None,
     ):
         self.read_paths.append(image_path)
+        self.skips.append(skip)
         with open(image_path, "rb") as handle:
             self.read_bytes.append(handle.read())
         self.calls.append(
@@ -132,9 +135,11 @@ class FakeTagger:
             entered, proceed = self.block
             entered.set()
             proceed.wait(WAIT)
+        # As the engine does (#431): a skipped tag uses up no slot.
+        kept = [pair for pair in SCORED if skip is None or not skip.matches(pair[0])]
         if self.loaded.startswith("wd14"):
-            return list(SCORED[:limit])
-        return [(name, None) for name, _ in SCORED[:limit]]
+            return list(kept[:limit])
+        return [(name, None) for name, _ in kept[:limit]]
 
 
 class SuggestTestCase(AnnotationAPITestCase):
diff --git a/tests/test_api_autotag.py b/tests/test_api_autotag.py
index 1ef568b2..d8cb6978 100644
--- a/tests/test_api_autotag.py
+++ b/tests/test_api_autotag.py
@@ -129,8 +129,10 @@ class FakeAutotagService:
         prompt=None,
         general_threshold=None,
         character_threshold=None,
+        skip=None,
     ):
-        """The suggestion entry point (#379): the fixed tags, at most ``limit``."""
+        """The suggestion entry point (#379): the fixed tags, at most ``limit``,
+        without the ones ``skip`` hides (#431)."""
         self.suggest_calls += 1
         tags = self.generate_tags(
             image_path,
@@ -138,6 +140,7 @@ class FakeAutotagService:
             general_threshold=general_threshold,
             character_threshold=character_threshold,
         )
+        tags = [name for name in tags if skip is None or not skip.matches(name)]
         return [(name, None) for name in tags[:limit]]
 
 
diff --git a/tests/test_autotag_batch.py b/tests/test_autotag_batch.py
index 4b63d2f9..4374a31d 100644
--- a/tests/test_autotag_batch.py
+++ b/tests/test_autotag_batch.py
@@ -54,6 +54,8 @@ class PerImageTagger(HookedTagger):
         names = self.by_bytes.get(self.read_bytes[-1])
         if names is None:
             return result
+        skip = kwargs.get("skip")  # as the engine does (#431)
+        names = [name for name in names if skip is None or not skip.matches(name)]
         return [(name, 0.9) for name in names][: kwargs["limit"]]
 
 
diff --git a/tests/test_config.py b/tests/test_config.py
index f2d9a353..145b339e 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -444,6 +444,7 @@ class TestAutotagConfig(unittest.TestCase):
                 "CHARACTER_THRESHOLD",
                 "TEMPLATE",
                 "SUGGESTION_LIMIT",
+                "SKIPPED_TAGS",
             )
         }
 
@@ -487,6 +488,7 @@ class TestAutotagConfig(unittest.TestCase):
                     "general_threshold": 0.35,
                     "character_threshold": 0.85,
                     "suggestion_limit": 10,
+                    "skipped_tags": [],
                 }
             },
         )
@@ -526,6 +528,7 @@ class TestAutotagConfig(unittest.TestCase):
             "character_threshold": 0.7,
             "template": "Tags only.",
             "suggestion_limit": 15,
+            "skipped_tags": ("blurry", "closed eyes"),
         }
         fallback = {
             "model_type": "wd14-swinv2",
@@ -534,6 +537,7 @@ class TestAutotagConfig(unittest.TestCase):
             "character_threshold": 0.85,
             "template": config_module.DEFAULT_TAG_TEMPLATE,
             "suggestion_limit": 10,
+            "skipped_tags": (),
         }
         bad_values = {
             "model_type": ["wd14-convnext", 3, None],
@@ -544,6 +548,8 @@ class TestAutotagConfig(unittest.TestCase):
             # 4000 characters are at most 16,000 UTF-8 bytes, so the 16 KiB
             # byte cap can only be met past the character cap.
             "template": ["", "   ", "x" * 4001, "\U0001f600" * 4097, "\ud800", 7],
+            # #431: the whole list falls back; entries are never dropped one by one.
+            "skipped_tags": ["blurry", ["a,b"], ["sky", "Sky"], [""], ["x"] * 201],
         }
         for key, values in bad_values.items():
             for value in values:
@@ -552,7 +558,7 @@ class TestAutotagConfig(unittest.TestCase):
                     with tempfile.TemporaryDirectory() as tmpdir:
                         path = os.path.join(tmpdir, "config.json")
                         with open(path, "w") as f:
-                            json.dump({"autotag": {"defaults": saved}}, f)
+                            json.dump({"autotag": {"defaults": saved}}, f, default=list)
                         with self.assertLogs(
                             "prompt_manager.config", level="WARNING"
                         ) as logs:
@@ -565,6 +571,26 @@ class TestAutotagConfig(unittest.TestCase):
                     }
                     self.assertEqual(loaded, dict(good, **{key: fallback[key]}))
 
+    def test_skipped_tags_load_trimmed_and_warn_once_when_damaged(self):
+        """#431: the list is kept as typed (trimmed); a damaged list is
+        replaced by no skipped tags with one warning naming the reason."""
+        PromptManagerConfig.update_config(
+            {"autotag": {"defaults": {"skipped_tags": [" blurry ", "(fate)"]}}}
+        )
+        self.assertEqual(self.config_class.SKIPPED_TAGS, ("blurry", "(fate)"))
+        with self.assertLogs("prompt_manager.config", level="WARNING") as logs:
+            PromptManagerConfig.update_config(
+                {"autotag": {"defaults": {"skipped_tags": ["sky", "a,b"]}}}
+            )
+        self.assertEqual(self.config_class.SKIPPED_TAGS, ())
+        self.assertEqual(
+            [record.getMessage() for record in logs.records],
+            [
+                "autotag.defaults.skipped_tags entry 2 must not contain a comma"
+                " or a line break; using no skipped tags"
+            ],
+        )
+
     def test_tagging_validators_moved_with_their_messages(self):
         validate_threshold = config_module.validate_threshold
         validate_template = config_module.validate_template
diff --git a/tests/test_settings_sources.py b/tests/test_settings_sources.py
index 2fda8459..ef05eea7 100644
--- a/tests/test_settings_sources.py
+++ b/tests/test_settings_sources.py
@@ -1025,6 +1025,7 @@ class TestAutotagDefaultsSettings(SourcesTestCase):
         "CHARACTER_THRESHOLD",
         "TEMPLATE",
         "SUGGESTION_LIMIT",
+        "SKIPPED_TAGS",
     )
     SAVED = {
         "autotag_model_type": "gguf",
@@ -1069,6 +1070,7 @@ class TestAutotagDefaultsSettings(SourcesTestCase):
                 "CHARACTER_THRESHOLD": 0.8,
                 "TEMPLATE": "Tags only.",
                 "SUGGESTION_LIMIT": 15,
+                "SKIPPED_TAGS": (),
             },
         )
         settings = (await self._get())["settings"]
@@ -1166,3 +1168,64 @@ class TestAutotagDefaultsSettings(SourcesTestCase):
                 self.assertEqual(status, 400, data)
                 self.assertEqual(data["error"], message)
                 self.assertEqual((self._config_bytes(), self._runtime()), before)
+
+    async def test_skipped_tags_save_trimmed_and_read_back(self):
+        """#431: the list is saved as typed (trimmed), published at once and
+        read back by GET /settings."""
+        self._write_config({"custom": {"keep": True}})
+        settings = (await self._get())["settings"]
+        self.assertEqual(settings["autotag_skipped_tags"], [])
+        revision = (await self._get())["revision"]
+        status, data = await self._post(
+            "/prompt_manager/settings",
+            {
+                "expected_revision": revision,
+                "autotag_skipped_tags": [" blurry ", "closed eyes", "(fate)"],
+            },
+        )
+        self.assertEqual(status, 200, data)
+        saved = self._read_config()
+        self.assertEqual(
+            saved["autotag"]["defaults"],
+            {"skipped_tags": ["blurry", "closed eyes", "(fate)"]},
+        )
+        self.assertEqual(saved["custom"], {"keep": True})
+        self.assertEqual(self.autotag.SKIPPED_TAGS, ("blurry", "closed eyes", "(fate)"))
+        settings = (await self._get())["settings"]
+        self.assertEqual(
+            settings["autotag_skipped_tags"], ["blurry", "closed eyes", "(fate)"]
+        )
+
+    async def test_bad_skipped_tags_are_refused_with_their_sentence(self):
+        self._write_config({"custom": {"keep": True}})
+        revision = (await self._get())["revision"]
+        before = (self._config_bytes(), self._runtime())
+        for value, message in (
+            (["sky", "  "], "Skipped tags: entry 2 is empty."),
+            (["x" * 51], "Skipped tags: entry 1 must be at most 50 characters."),
+            (
+                ["a, b"],
+                "Skipped tags: entry 1 must not contain a comma or a line break.",
+            ),
+            (["blurry", "Blurry"], "Skipped tags: entry 2 repeats entry 1."),
+            ([f"w{i}" for i in range(201)], "Skipped tags: at most 200 entries."),
+        ):
+            with self.subTest(value=value[:3]):
+                status, data = await self._post(
+                    "/prompt_manager/settings",
+                    {"expected_revision": revision, "autotag_skipped_tags": value},
+                )
+                self.assertEqual(status, 400, data)
+                self.assertEqual(data["error"], message)
+                self.assertEqual((self._config_bytes(), self._runtime()), before)
+
+    async def test_skipped_tags_without_a_revision_are_refused(self):
+        """A list saved without expected_revision could merge a stale copy."""
+        self._write_config({"custom": {"keep": True}})
+        before = (self._config_bytes(), self._runtime())
+        status, data = await self._post(
+            "/prompt_manager/settings", {"autotag_skipped_tags": ["blurry"]}
+        )
+        self.assertEqual(status, 400, data)
+        self.assertEqual(data["error"], "Reload the page and try again.")
+        self.assertEqual((self._config_bytes(), self._runtime()), before)
diff --git a/tests/test_skipped_tags.py b/tests/test_skipped_tags.py
new file mode 100644
index 00000000..9db3c68e
--- /dev/null
+++ b/tests/test_skipped_tags.py
@@ -0,0 +1,271 @@
+"""Skipped tags (#431): the words whose suggested tags are never offered.
+
+The normalizer, the entry validation, the whole-word matcher, the WD14 label
+reader and the filter in ``AutoTagService.generate_tag_suggestions``. No model
+is loaded: ``_scored_tags`` is replaced by a fixed list.
+"""
+
+import os
+import tempfile
+import unicodedata
+import unittest
+from pathlib import Path
+from unittest.mock import patch
+
+from py.tagging_defaults import (
+    MAX_SKIPPED_TAG_CHARS,
+    MAX_SKIPPED_TAGS,
+    SkipMatcher,
+    tag_words,
+    validate_skipped_tags,
+    wd14_label_names,
+)
+
+# The design's matching table: (entry, tag, hidden).
+MATCHING = (
+    ("blurry", "blurry", True),
+    ("blurry", "blurry_background", True),
+    ("blurry", "very_blurry", True),
+    ("blurry", "slightly_blurry_background", True),
+    ("blurry", "unblurry", False),
+    ("blur", "blurry", False),
+    ("blurry background", "blurry_background", True),
+    ("blurry background", "Blurry-Background", True),
+    ("background blurry", "blurry_background", False),
+    ("shirt", "t-shirt", True),
+    ("shirt", "shirt_lift", True),
+    ("closed eyes", "half-closed_eyes", True),
+    ("girl", "1girl", False),
+    ("girl", "2girls", False),
+    ("girls", "multiple_girls", True),
+    ("fate", "saber_(fate)", False),
+    ("(fate)", "saber_(fate)", True),
+    ("saber", "saber_(fate)", True),
+    (":d", ":d", True),
+    ("café", unicodedata.normalize("NFD", "café"), True),
+)
+
+
+class TestWords(unittest.TestCase):
+    def test_words_split_only_on_space_underscore_and_hyphen(self):
+        self.assertEqual(tag_words("Half-closed_eyes"), ("half", "closed", "eyes"))
+        self.assertEqual(tag_words("saber_(fate)"), ("saber", "(fate)"))
+        self.assertEqual(tag_words("  a__b--c  d "), ("a", "b", "c", "d"))
+        self.assertEqual(tag_words("_-- _"), ())
+        self.assertEqual(tag_words(":d"), (":d",))
+
+    def test_words_are_nfc_and_case_folded(self):
+        self.assertEqual(
+            tag_words("CAFÉ"), tag_words(unicodedata.normalize("NFD", "café"))
+        )
+        self.assertEqual(tag_words("Straße"), ("strasse",))
+
+
+class TestMatcher(unittest.TestCase):
+    def test_every_row_of_the_matching_table(self):
+        for entry, tag, hidden in MATCHING:
+            with self.subTest(entry=entry, tag=tag):
+                self.assertIs(SkipMatcher([entry]).matches(tag), hidden)
+
+    def test_a_tag_without_words_never_matches(self):
+        matcher = SkipMatcher(["blurry"])
+        for tag in ("", "_", "- _"):
+            with self.subTest(tag=tag):
+                self.assertFalse(matcher.matches(tag))
+
+    def test_an_empty_matcher_hides_nothing_and_is_false(self):
+        self.assertFalse(SkipMatcher())
+        self.assertFalse(SkipMatcher([]).matches("blurry"))
+        self.assertTrue(SkipMatcher(["blurry"]))
+
+    def test_entries_of_different_lengths_are_all_checked(self):
+        matcher = SkipMatcher(["sky", "closed eyes", "very long entry here"])
+        self.assertTrue(matcher.matches("blue_sky"))
+        self.assertTrue(matcher.matches("half-closed_eyes"))
+        self.assertTrue(matcher.matches("a_very_long_entry_here_b"))
+        self.assertFalse(matcher.matches("very_long_entry"))
+
+    def test_counting_view_records_the_distinct_names_it_hid(self):
+        counting = SkipMatcher(["blurry"]).counting()
+        self.assertTrue(counting.matches("blurry"))
+        self.assertTrue(counting.matches("Blurry"))
+        self.assertTrue(counting.matches("blurry_background"))
+        self.assertFalse(counting.matches("sky"))
+        self.assertEqual(counting.hidden, {"blurry", "blurry_background"})
+
+
+class TestValidation(unittest.TestCase):
+    def test_entries_are_trimmed_and_kept_as_typed(self):
+        self.assertEqual(
+            validate_skipped_tags(["  Blurry ", "closed eyes", "(fate)"]),
+            ["Blurry", "closed eyes", "(fate)"],
+        )
+        self.assertEqual(validate_skipped_tags([]), [])
+
+    def test_caps_count_code_points_after_trimming(self):
+        self.assertEqual(
+            validate_skipped_tags([" " + "🏜" * MAX_SKIPPED_TAG_CHARS + " "]),
+            ["🏜" * MAX_SKIPPED_TAG_CHARS],
+        )
+        entries = [f"word{index}" for index in range(MAX_SKIPPED_TAGS)]
+        self.assertEqual(validate_skipped_tags(entries), entries)
+
+    def test_every_refusal_sentence(self):
+        cases = (
+            ("blurry", "Skipped tags must be a list of words."),
+            (
+                [f"w{index}" for index in range(MAX_SKIPPED_TAGS + 1)],
+                "Skipped tags: at most 200 entries.",
+            ),
+            (["ok", 3], "Skipped tags: entry 2 must be text."),
+            (["ok", "   "], "Skipped tags: entry 2 is empty."),
+            (["_ --"], "Skipped tags: entry 1 is empty."),
+            (["x" * 51], "Skipped tags: entry 1 must be at most 50 characters."),
+            (
+                ["a, b"],
+                "Skipped tags: entry 1 must not contain a comma or a line break.",
+            ),
+            (
+                ["a\nb"],
+                "Skipped tags: entry 1 must not contain a comma or a line break.",
+            ),
+            (
+                ["a\x7fb"],
+                "Skipped tags: entry 1 must not contain a comma or a line break.",
+            ),
+            (
+                ["blurry", "sky", "Blurry"],
+                "Skipped tags: entry 3 repeats entry 1.",
+            ),
+            (
+                ["blurry background", "blurry-Background"],
+                "Skipped tags: entry 2 repeats entry 1.",
+            ),
+        )
+        for value, message in cases:
+            with self.subTest(value=value):
+                with self.assertRaises(ValueError) as caught:
+                    validate_skipped_tags(value)
+                self.assertEqual(str(caught.exception), message)
+
+
+class TestWd14Labels(unittest.TestCase):
+    def setUp(self):
+        directory = tempfile.TemporaryDirectory()
+        self.addCleanup(directory.cleanup)
+        self.path = Path(directory.name) / "selected_tags.csv"
+
+    def write(self, rows):
+        lines = ["tag_id,name,category,count"]
+        lines += [f"{i},{name},{category},1" for i, (name, category) in enumerate(rows)]
+        self.path.write_text("\n".join(lines) + "\n", encoding="utf-8")
+
+    def test_only_general_and_character_names_are_read(self):
+        self.write(
+            [
+                ("blurry", "0"),
+                ("general", "9"),
+                ("saber_(fate)", "4"),
+                ("artist", "1"),
+                ("café", "0"),
+            ]
+        )
+        self.assertEqual(
+            wd14_label_names(self.path), ("blurry", "saber_(fate)", "café")
+        )
+
+    def test_the_list_is_read_again_only_when_the_file_changes(self):
+        self.write([("blurry", "0")])
+        with patch(
+            "py.tagging_defaults.read_wd14_label_rows",
+            wraps=__import__(
+                "py.tagging_defaults", fromlist=["x"]
+            ).read_wd14_label_rows,
+        ) as reader:
+            self.assertEqual(wd14_label_names(self.path), ("blurry",))
+            self.assertEqual(wd14_label_names(self.path), ("blurry",))
+            self.assertEqual(reader.call_count, 1)
+            self.write([("blurry", "0"), ("sky", "0")])
+            os.utime(self.path, ns=(1, 2))
+            self.assertEqual(wd14_label_names(self.path), ("blurry", "sky"))
+            self.assertEqual(reader.call_count, 2)
+
+    def test_a_missing_list_raises_for_the_caller_to_skip(self):
+        with self.assertRaises(OSError):
+            wd14_label_names(self.path)
+
+
+class FilterService:
+    """``AutoTagService`` with a fixed model output instead of a model."""
+
+    def __init__(self, scored):
+        from py.autotag import AutoTagService
+
+        self.service = AutoTagService.__new__(AutoTagService)
+        self.service._scored_tags = lambda *args, **kwargs: list(scored)
+
+    def suggest(self, limit, skip=None):
+        return self.service.generate_tag_suggestions(
+            "image.png", limit=limit, skip=skip
+        )
+
+
+class TestFilter(unittest.TestCase):
+    def test_skipped_tags_do_not_use_up_slots(self):
+        """WD14: the next-best tags above the thresholds fill the limit."""
+        scored = [
+            ("blurry", 0.99),
+            ("sky", 0.9),
+            ("blurry_background", 0.8),
+            ("cloud", 0.7),
+            ("sun", 0.6),
+            ("sea", 0.5),
+        ]
+        service = FilterService(scored)
+        self.assertEqual(
+            service.suggest(3, SkipMatcher(["blurry"])),
+            [("sky", 0.9), ("cloud", 0.7), ("sun", 0.6)],
+        )
+        self.assertEqual(service.suggest(3), scored[:3])
+
+    def test_a_language_model_may_return_fewer_than_the_limit(self):
+        service = FilterService([("blurry", None), ("sky", None), ("signature", None)])
+        self.assertEqual(
+            service.suggest(10, SkipMatcher(["blurry", "signature"])), [("sky", None)]
+        )
+
+    def test_order_is_invalid_name_then_skip_then_dedupe_then_limit(self):
+        hidden = []
+
+        class Recording:
+            def matches(self, name):
+                hidden.append(name)
+                return name.startswith("skip")
+
+        service = FilterService(
+            [
+                ("bad,name", None),
+                ("  Sky ", None),
+                ("skip_me", None),
+                ("sky", None),
+                ("cloud", None),
+                ("sun", None),
+            ]
+        )
+        self.assertEqual(
+            service.suggest(2, Recording()), [("Sky", None), ("cloud", None)]
+        )
+        # The refused name never reaches the matcher; trimmed names do; the
+        # duplicate is checked after the skip; nothing after the limit.
+        self.assertEqual(hidden, ["Sky", "skip_me", "sky", "cloud"])
+
+    def test_the_counting_view_reports_hidden_names(self):
+        counting = SkipMatcher(["blurry"]).counting()
+        FilterService([("blurry", 0.9), ("sky", 0.8), ("Blurry", 0.7)]).suggest(
+            5, counting
+        )
+        self.assertEqual(counting.hidden, {"blurry"})
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/tests/test_skipped_tags_routes.py b/tests/test_skipped_tags_routes.py
new file mode 100644
index 00000000..a21a9013
--- /dev/null
+++ b/tests/test_skipped_tags_routes.py
@@ -0,0 +1,280 @@
+"""Skipped tags on every suggestion path, and their preview (#431).
+
+Tag image (``/image-annotations/suggest``), Auto-tag selected (the
+``image-tags`` job), the System batch (the ``autotag`` job), the legacy
+``/autotag/start`` and ``/autotag/single`` all hide a suggested tag whose
+words contain a skipped entry; a job runs with the list it started with.
+``POST /autotag/skipped-tags/preview`` counts what a list would hide among
+the library's tags and the downloaded WD14 label lists, writing nothing.
+"""
+
+import tempfile
+from pathlib import Path
+
+try:
+    from test_autotag_legacy import LegacyTestCase
+except ImportError:
+    from tests.test_autotag_legacy import LegacyTestCase
+
+from py.config import AutotagConfig
+
+PREVIEW = "/prompt_manager/autotag/skipped-tags/preview"
+
+
+class SkippedTestCase(LegacyTestCase):
+    async def get_application(self):
+        app = await super().get_application()
+        self.addCleanup(
+            setattr, AutotagConfig, "SKIPPED_TAGS", AutotagConfig.SKIPPED_TAGS
+        )
+        AutotagConfig.SKIPPED_TAGS = ()
+        return app
+
+    def job_lines(self, job):
+        return [line.split(" ", 1)[1] for line in job.log]
+
+
+class TestEveryPathHidesSkippedTags(SkippedTestCase):
+    async def test_tag_image_suggestions_omit_skipped_tags_and_count_them(self):
+        AutotagConfig.SKIPPED_TAGS = ("sandstone", "tag 001")
+        observed = await self.observed()
+
+        body = await self.suggest_ok(self.suggest_body(observed))
+
+        names = [row["name"] for row in body["suggestions"]]
+        self.assertNotIn("sandstone", names)
+        self.assertNotIn("tag_001", names)
+        # Skipped tags use up no slot: the next ones fill the limit.
+        self.assertEqual(len(names), 10)
+        self.assertEqual(names[:3], ["desert", "tag_000", "tag_002"])
+        self.assertEqual(body["skipped"], 2)
+
+    async def test_tag_image_without_skipped_tags_reports_zero(self):
+        observed = await self.observed()
+        body = await self.suggest_ok(self.suggest_body(observed))
+        self.assertEqual(body["suggestions"][0]["name"], "sandstone")
+        self.assertEqual(body["skipped"], 0)
+
+    async def test_auto_tag_selected_runs_with_the_list_of_its_start(self):
+        self.png("a.png")
+        self.png("b.png", color=(1, 2, 3))
+        AutotagConfig.SKIPPED_TAGS = ("desert",)
+
+        def save_mid_run(_path):
+            # A save while the job runs does not change that job.
+            AutotagConfig.SKIPPED_TAGS = ("sandstone",)
+
+        self.tagger.on_generate = save_mid_run
+        options = {
+            "general_threshold": 0.35,
+            "character_threshold": 0.85,
+            "suggestion_limit": 2,
+        }
+
+        job = await self.run_job(self.auto_body(["a.png", "b.png"], options=options))
+
+        self.assertEqual(job.state, "finished")
+        self.assertEqual(self.stored("a.png")["tags"], ["sandstone", "tag_000"])
+        self.assertEqual(self.stored("b.png")["tags"], ["sandstone", "tag_000"])
+        self.assertIn("Skipped tags: 1 entry", self.job_lines(job))
+
+    async def test_the_system_batch_hides_skipped_tags_and_logs_the_list(self):
+        self.image("a.png", (1, 2, 3), sees=["bird", "blurry_background", "sky"])
+        AutotagConfig.SKIPPED_TAGS = ("blurry", "watermark")
+
+        job = await self.run_batch(existing="merge")
+
+        self.assertEqual(self.stored("a.png")["tags"], ["bird", "sky"])
+        self.assertIn("Skipped tags: 2 entries", self.job_lines(job))
+
+        AutotagConfig.SKIPPED_TAGS = ()
+        self.image("b.png", (4, 5, 6), sees=["blurry"])
+        await self.relist()
+        job = await self.run_batch(existing="merge")
+        self.assertEqual(self.stored("b.png")["tags"], ["blurry"])
+        self.assertIn("Skipped tags: none", self.job_lines(job))
+
+    async def test_the_legacy_batch_hides_skipped_tags(self):
+        self.image("a.png", (1, 2, 3), sees=["bird", "signature"])
+        AutotagConfig.SKIPPED_TAGS = ("signature",)
+
+        response, frames = await self.legacy()
+
+        self.assertEqual(response.status, 200)
+        self.assertEqual(frames[-1]["type"], "complete", frames[-1])
+        self.assertEqual(self.stored("a.png")["tags"], ["bird"])
+
+    async def test_the_legacy_single_review_hides_skipped_tags(self):
+        prompt = self.prompt("a prompt")
+        image = self.link(
+            prompt, self.image("a.png", (1, 2, 3), sees=["bird", "t-shirt"])
+        )
+        AutotagConfig.SKIPPED_TAGS = ("shirt",)
+
+        status, data = await self.single({"image_id": image, "model_type": "wd14-vit"})
+
+        self.assertEqual(status, 200, data)
+        self.assertEqual(data["tags"], ["bird"])
+
+    async def test_hand_typed_and_stored_tags_are_never_filtered(self):
+        path = self.image("a.png", (1, 2, 3), sees=["bird"])
+        self.saved_set("a.png", path.read_bytes(), ["blurry_hand_tag"])
+        AutotagConfig.SKIPPED_TAGS = ("blurry",)
+
+        await self.run_batch(existing="merge")
+        job = await self.run_job(self.add_body(["a.png"], ["blurry"]))
+
+        self.assertEqual(job.state, "finished")
+        self.assertEqual(
+            self.stored("a.png")["tags"], ["blurry_hand_tag", "bird", "blurry"]
+        )
+
+
+def write_labels(directory, subdir, rows):
+    path = Path(directory) / subdir / "selected_tags.csv"
+    path.parent.mkdir(parents=True, exist_ok=True)
+    lines = ["tag_id,name,category,count"]
+    lines += [f"{i},{name},{category},1" for i, (name, category) in enumerate(rows)]
+    path.write_text("\n".join(lines) + "\n", encoding="utf-8")
+
+
+class TestPreview(SkippedTestCase):
+    async def asyncSetUp(self):
+        await super().asyncSetUp()
+        models = tempfile.TemporaryDirectory()
+        self.addCleanup(models.cleanup)
+        self.models_dir = Path(models.name)
+        self.tagger.models_dir = self.models_dir
+        for name in ("Blurry", "portrait", "my_signature_style"):
+            self.prompt(f"prompt with {name}", tags=[name])
+
+    async def preview(self, entries):
+        response = await self.client.post(PREVIEW, json={"entries": entries})
+        return response.status, await self.json_of(response)
+
+    async def test_library_tags_only_when_no_label_list_is_downloaded(self):
+        status, data = await self.preview(["blurry", "signature", "watermark"])
+
+        self.assertEqual(status, 200, data)
+        self.assertEqual(
+            data,
+            {
+                "success": True,
+                "count": 2,
+                "sample": ["Blurry", "my_signature_style"],
+                "sample_limit": 12,
+                "per_entry": [
+                    {"entry": "blurry", "count": 1},
+                    {"entry": "signature", "count": 1},
+                    {"entry": "watermark", "count": 0},
+                ],
+                "sources": {"library": 3, "wd14": []},
+            },
+        )
+
+    async def test_both_label_lists_join_the_library_tags(self):
+        write_labels(
+            self.models_dir,
+            "WD14-SwinV2",
+            [
+                ("blurry", "0"),
+                ("blurry_background", "0"),
+                ("watermark", "0"),
+                ("general", "9"),
+                ("saber_(fate)", "4"),
+            ],
+        )
+        write_labels(
+            self.models_dir,
+            "WD14-ViT",
+            [
+                ("blurry_foreground", "0"),
+                ("watermark", "0"),
+                ("fate_(series)", "3"),
+            ],
+        )
+
+        status, data = await self.preview(["blurry", "watermark", "(fate)", "general"])
+
+        self.assertEqual(status, 200, data)
+        # Library spellings first (case-folded duplicates are one tag), then the
+        # label lists' names, each part sorted case-folded; rating and copyright
+        # rows are never suggested, so never counted.
+        self.assertEqual(
+            data["sample"],
+            [
+                "Blurry",
+                "blurry_background",
+                "blurry_foreground",
+                "saber_(fate)",
+                "watermark",
+            ],
+        )
+        self.assertEqual(data["count"], 5)
+        self.assertEqual(
+            data["per_entry"],
+            [
+                {"entry": "blurry", "count": 3},
+                {"entry": "watermark", "count": 1},
+                {"entry": "(fate)", "count": 1},
+                {"entry": "general", "count": 0},
+            ],
+        )
+        self.assertEqual(
+            data["sources"], {"library": 3, "wd14": ["WD14 SwinV2", "WD14 ViT"]}
+        )
+
+    async def test_the_sample_holds_at_most_twelve(self):
+        write_labels(
+            self.models_dir,
+            "WD14-SwinV2",
+            [(f"sky_{index:02d}", "0") for index in range(20)],
+        )
+        status, data = await self.preview(["sky"])
+        self.assertEqual(status, 200, data)
+        self.assertEqual(data["count"], 20)
+        self.assertEqual(data["sample"], [f"sky_{index:02d}" for index in range(12)])
+
+    async def test_a_bad_list_is_refused_with_the_save_sentence(self):
+        for body, message in (
+            ({"entries": ["sky", "Sky"]}, "Skipped tags: entry 2 repeats entry 1."),
+            (
+                {"entries": ["a,b"]},
+                "Skipped tags: entry 1 must not contain a comma or a line break.",
+            ),
+            ({"entries": "sky"}, "Skipped tags must be a list of words."),
+        ):
+            with self.subTest(body=body):
+                response = await self.client.post(PREVIEW, json=body)
+                self.assertEqual(response.status, 400)
+                self.assertEqual((await response.json())["error"], message)
+        response = await self.client.post(PREVIEW, json={"entries": [], "x": 1})
+        self.assertEqual(response.status, 400)
+
+    async def test_preview_loads_no_model_opens_no_image_and_writes_nothing(self):
+        write_labels(self.models_dir, "WD14-SwinV2", [("blurry", "0")])
+        self.image("a.png", (1, 2, 3))
+        before = self.prompt_rows()
+
+        status, data = await self.preview(["blurry"])
+
+        self.assertEqual(status, 200, data)
+        self.assertEqual(self.tagger.load_calls, [])
+        self.assertEqual(self.tagger.read_paths, [])
+        self.assertEqual(self.prompt_rows(), before)
+        self.assertEqual(self.api._jobs.list(), [])
+
+    async def test_preview_is_busy_while_an_exclusive_job_runs(self):
+        async with self.api._jobs.hold(
+            "restore", "Restore library", admission="exclusive"
+        ):
+            status, data = await self.preview(["blurry"])
+        self.assertEqual(status, 409, data)
+        self.assertEqual(data["code"], "busy")
+        self.assertEqual(data["running"]["title"], "Restore library")
+
+
+if __name__ == "__main__":
+    import unittest
+
+    unittest.main()
diff --git a/tools/vendor/frontend-coverage-baseline.json b/tools/vendor/frontend-coverage-baseline.json
index eb695acc..72ef55d5 100644
--- a/tools/vendor/frontend-coverage-baseline.json
+++ b/tools/vendor/frontend-coverage-baseline.json
@@ -629,6 +629,12 @@
     "functions": 95,
     "statements": 98
   },
+  "workspace/system-skipped-tags.mjs": {
+    "lines": 80,
+    "branches": 80,
+    "functions": 80,
+    "statements": 80
+  },
   "workspace/system-state.mjs": {
     "lines": 98,
     "branches": 94,
diff --git a/web/js/workspace/image-tagging-state.mjs b/web/js/workspace/image-tagging-state.mjs
index 20d0c6d8..b1703a11 100644
--- a/web/js/workspace/image-tagging-state.mjs
+++ b/web/js/workspace/image-tagging-state.mjs
@@ -257,11 +257,18 @@ function initialState(source, preset) {
         image: null, savedTags: [], tagRevision: 0, currentTags: null, manual: '',
         model: preset?.model ?? MODEL_OPTIONS[0].id, options: {...DEFAULTS, ...preset?.options}, generated: false, suggestions: [],
         suggestionsText: COPY.modelChanged, statusText: '', generateSupported: false, generateReason: null, toast: null,
+        skippedCount: 0,
         // Bumped whenever the controller itself rewrites the option fields or the manual draft, never while typing.
         optionsRevision: 0, draftRevision: 0,
     };
 }
 
+/** #431: how many suggestions the saved Skipped tags hid, after the chip hint ('' when none). */
+export function skippedNote(count) {
+    if (!Number.isSafeInteger(count) || count <= 0) return '';
+    return count === 1 ? ' 1 skipped tag was not suggested.' : ` ${count.toLocaleString('en-US')} skipped tags were not suggested.`;
+}
+
 /** Derived labels and permissions; never stored independently of the fields they follow. */
 function derive(state) {
     const editable = EDITABLE.has(state.phase);
@@ -269,7 +276,7 @@ function derive(state) {
         ...state,
         primaryLabel: state.generated ? 'Approve selected tags' : 'Save manual tags',
         countText: state.generated ? `${state.suggestions.length} ${noun(state.suggestions.length, 'suggestion')}` : 'Not generated',
-        chipHint: state.suggestions.length ? COPY.chipHint : '',
+        chipHint: state.suggestions.length ? COPY.chipHint + skippedNote(state.skippedCount) : '',
         canSave: editable,
         canGenerate: editable && state.generateSupported,
         canRetry: RETRYABLE.has(state.phase),
@@ -445,13 +452,14 @@ export function createImageTaggingController({api, target, source = 'images', on
         const options = requestOptions(model, state.options);
         const stale = () => closed || serial !== generateSerial;
         set({phase: 'generating', statusText: COPY.generating});
-        let rows;
+        let rows, skippedCount;
         try {
             const value = await api.post(SUGGEST_URL, {
                 target: {...imageTarget}, capture_token: capture.token, expected_epoch: epoch, model_type: model, options,
             }, {signal: controller.signal});
             if (stale()) return false;
             rows = validateSuggestions(value, options.suggestion_limit);
+            skippedCount = Number.isSafeInteger(value.skipped) && value.skipped > 0 ? value.skipped : 0;
         } catch (error) {
             if (stale()) return false;
             const phase = isApiError(error) && REOPEN[error.code];
@@ -460,7 +468,7 @@ export function createImageTaggingController({api, target, source = 'images', on
         }
         generateAbort = null;
         set({
-            phase: 'ready', generated: true, suggestions: rows, suggestionsText: rows.length ? '' : COPY.empty,
+            phase: 'ready', generated: true, suggestions: rows, suggestionsText: rows.length ? '' : COPY.empty, skippedCount,
             statusText: `Suggestions from ${modelOf(model).label}. Approve tags to save.`,
         });
         return true;
diff --git a/web/js/workspace/system-skipped-tags.mjs b/web/js/workspace/system-skipped-tags.mjs
new file mode 100644
index 00000000..3fb0e989
--- /dev/null
+++ b/web/js/workspace/system-skipped-tags.mjs
@@ -0,0 +1,246 @@
+/**
+ * System › Auto-tagging "Skipped tags" (#431, D202): words whose suggested tags are never offered, on every suggestion
+ * path (the server filters; hand-typed and stored tags are never touched).
+ *
+ * A `.setting-block` after "Suggestions per image": the label and description, an "Add a word or words" input
+ * (`#tag-skipped-input`) with Add (Enter adds too), the entries as removable chips in the Tag image dialog's D83 chip
+ * markup, and a preview line (`role="status"`) that says how many known tags the list hides
+ * (`POST /prompt_manager/autotag/skipped-tags/preview`: the library's tags plus the downloaded WD14 label lists). The
+ * block carries `data-setting="tag-skipped"` and `data-key="autotag_skipped_tags"`, so a refused save highlights it.
+ * The list is the host draft `autotag_skipped_tags` (an array), saved by the one Save row. The client checks repeat the
+ * server's rules (the server is the authority): an empty, too long, comma or duplicate entry is not added and the line
+ * under the input says why; the list holds at most 200 entries.
+ */
+import { createButton } from '../shared/toolkit/core.js';
+
+export const SKIPPED_KEY = 'autotag_skipped_tags';
+export const PREVIEW_URL = '/prompt_manager/autotag/skipped-tags/preview';
+export const MAX_ENTRIES = 200;
+export const MAX_ENTRY_CHARS = 50;
+export const PREVIEW_DELAY_MS = 300;
+export const SAMPLE_LIMIT = 12;
+
+export const SKIPPED_COPY = Object.freeze({
+    label: 'Skipped tags',
+    description: 'Suggested tags that contain one of these words are hidden. Words are separated by spaces, _ or -; '
+        + 'other characters such as ( ) belong to the word.',
+    placeholder: 'Add a word or words',
+    add: 'Add',
+    chips: 'Skipped tags',
+    empty: 'Enter a word.',
+    comma: 'No commas or line breaks.',
+    long: `At most ${MAX_ENTRY_CHARS} characters.`,
+    duplicate: 'Already in the list.',
+    full: `The list is full (${MAX_ENTRIES}).`,
+    none: 'No tags are skipped.',
+    checking: 'Checking…',
+    failed: 'The preview could not be read.',
+    unchanged: 'Tags already on images are not changed.',
+    libraryOnly: 'Checked against library tags only; no WD14 label list is downloaded.',
+    hidesNothing: 'Hides no known tag',
+});
+
+const plural = (count, word) => `${count.toLocaleString('en-US')} ${word}${count === 1 ? '' : 's'}`;
+
+/** The words of an entry or a tag as the server splits them: NFC, lower case, split on space, `_` and `-`. */
+export const entryWords = text => String(text ?? '').normalize('NFC').toLowerCase().split(/[ _-]+/).filter(Boolean);
+const entryKey = text => entryWords(text).join(' ');
+
+/** Why `raw` cannot be added to `entries` (the line under the input), or '' when it can. */
+export function entryProblem(raw, entries) {
+    const entry = String(raw ?? '').trim();
+    if (!entryWords(entry).length) return SKIPPED_COPY.empty;
+    // Commas and control characters (a pasted line break), as the server refuses them.
+    if (/[,\u0000-\u001f\u007f-\u009f\u2028\u2029]/u.test(entry)) return SKIPPED_COPY.comma;
+    if ([...entry].length > MAX_ENTRY_CHARS) return SKIPPED_COPY.long;
+    const key = entryKey(entry);
+    if (entries.some(item => entryKey(item) === key)) return SKIPPED_COPY.duplicate;
+    if (entries.length >= MAX_ENTRIES) return SKIPPED_COPY.full;
+    return '';
+}
+
+/** A chip's title and count text for an entry the last preview counted (`count` undefined: not counted yet). */
+export function chipCount(count) {
+    if (!Number.isSafeInteger(count)) return null;
+    return count ? { title: `Hides ${plural(count, 'tag')}`, text: count.toLocaleString('en-US') }
+        : { title: SKIPPED_COPY.hidesNothing, text: 'none' };
+}
+
+/**
+ * The preview line for a preview answer (`{count, sample, sources}`): the bold lead "Hides N tags from suggestions",
+ * then the sample (": a, b and K more. ") and the closing sentences. Returns `{lead, rest}`.
+ */
+export function previewText(result) {
+    const count = Number.isSafeInteger(result?.count) && result.count > 0 ? result.count : 0;
+    const sample = Array.isArray(result?.sample) ? result.sample.filter(name => typeof name === 'string') : [];
+    const more = count - sample.length;
+    const listed = count && sample.length ? `: ${sample.join(', ')}${more > 0 ? ` and ${more.toLocaleString('en-US')} more` : ''}. ` : '. ';
+    const labels = Array.isArray(result?.sources?.wd14) && result.sources.wd14.length > 0;
+    return {
+        lead: `Hides ${plural(count, 'tag')} from suggestions`,
+        rest: `${listed}${labels ? '' : `${SKIPPED_COPY.libraryOnly} `}${SKIPPED_COPY.unchanged}`,
+    };
+}
+
+function el(tag, text, className) {
+    const node = document.createElement(tag);
+    if (text !== undefined) node.textContent = text;
+    if (className) node.className = className;
+    return node;
+}
+
+/**
+ * Build the block; `drafts` is the System draft store, `api` the workspace client. Returns `{node, repaint}`: System
+ * calls `repaint` whenever the drafts change (the chips follow the drafted list, and a changed list is previewed
+ * `PREVIEW_DELAY_MS` after the last change, one request at a time: a newer list aborts the older request).
+ */
+export function skippedTagsBlock({ api, scope, drafts, delay = PREVIEW_DELAY_MS }) {
+    const block = el('div', undefined, 'setting-block');
+    block.dataset.setting = 'tag-skipped';
+    block.dataset.key = SKIPPED_KEY;
+    const text = el('div', undefined, 'setting-block-text');
+    const label = el('label', SKIPPED_COPY.label);
+    label.htmlFor = 'tag-skipped-input';
+    text.append(label, el('p', SKIPPED_COPY.description));
+    const addRow = el('div', undefined, 'skip-add');
+    const input = el('input');
+    input.id = 'tag-skipped-input';
+    input.autocomplete = 'off';
+    input.placeholder = SKIPPED_COPY.placeholder;
+    input.maxLength = MAX_ENTRY_CHARS + 10;
+    input.setAttribute('aria-describedby', 'tag-skipped-problem');
+    const add = createButton(SKIPPED_COPY.add);
+    add.id = 'tag-skipped-add';
+    addRow.append(input, add);
+    const problem = el('p', '', 'small skip-problem');
+    problem.id = 'tag-skipped-problem';
+    problem.setAttribute('role', 'alert');
+    const chips = el('div', undefined, 'tags skip-chips');
+    chips.setAttribute('aria-label', SKIPPED_COPY.chips);
+    const preview = el('p', '', 'small skip-preview');
+    preview.setAttribute('role', 'status');
+    preview.setAttribute('aria-live', 'polite');
+    block.append(text, addRow, problem, chips, preview);
+
+    const entries = () => {
+        const value = drafts.get('host', SKIPPED_KEY);
+        return Array.isArray(value) ? value : null;
+    };
+    let counts = new Map();
+    let shown = null; // the list the chips show (JSON)
+    let pending = null; // the list the preview line is (or is being) made for (JSON)
+    let timer = null;
+    let request = null;
+    scope.cleanup(() => { clearTimeout(timer); request?.abort(); });
+
+    const say = message => {
+        problem.textContent = message;
+        if (message) input.setAttribute('aria-invalid', 'true');
+        else input.removeAttribute('aria-invalid');
+    };
+    const setList = next => drafts.set('host', SKIPPED_KEY, next);
+
+    function addEntry() {
+        const list = entries();
+        if (!list) return;
+        const message = entryProblem(input.value, list);
+        say(message);
+        if (message) return;
+        const entry = input.value.trim();
+        input.value = '';
+        setList([...list, entry]);
+    }
+
+    function removeEntry(index) {
+        const list = entries();
+        if (!list) return;
+        const buttons = [...chips.querySelectorAll?.('button') ?? []];
+        const focused = buttons.indexOf(document.activeElement);
+        setList(list.filter((_entry, at) => at !== index));
+        // The removed chip's focus moves to its neighbour's ×, else to the input.
+        if (focused >= 0) {
+            const left = [...chips.querySelectorAll?.('button') ?? []];
+            (left[Math.min(focused, left.length - 1)] ?? input).focus?.();
+        }
+    }
+
+    function renderChips(list) {
+        chips.replaceChildren(...list.map((entry, index) => {
+            const count = chipCount(counts.get(entry));
+            const chip = el('span', undefined, `chip tag-suggestion${count?.text === 'none' ? ' none' : ''}`);
+            if (count) chip.title = count.title;
+            chip.append(el('span', entry));
+            if (count) chip.append(el('span', count.text, 'tag-confidence'));
+            const remove = createButton('×');
+            remove.setAttribute('aria-label', `Remove ${entry}`);
+            scope.listen(remove, 'click', () => removeEntry(index));
+            chip.append(remove);
+            return chip;
+        }));
+    }
+
+    function showPreview(result) {
+        const { lead, rest } = previewText(result);
+        preview.replaceChildren(el('b', lead), rest);
+    }
+
+    async function runPreview(list) {
+        request?.abort();
+        const controller = new AbortController();
+        request = controller;
+        try {
+            const result = await api.post(PREVIEW_URL, { entries: list }, { signal: controller.signal });
+            if (controller.signal.aborted || scope.signal.aborted) return;
+            counts = new Map((Array.isArray(result?.per_entry) ? result.per_entry : [])
+                .filter(row => typeof row?.entry === 'string').map(row => [row.entry, row.count]));
+            showPreview(result);
+            renderChips(entries() ?? list);
+        } catch {
+            if (controller.signal.aborted || scope.signal.aborted) return;
+            preview.textContent = SKIPPED_COPY.failed;
+        } finally {
+            if (request === controller) request = null;
+        }
+    }
+
+    function schedule(list) {
+        clearTimeout(timer);
+        request?.abort();
+        request = null;
+        if (!list.length) {
+            counts = new Map();
+            preview.textContent = SKIPPED_COPY.none;
+            return;
+        }
+        preview.textContent = SKIPPED_COPY.checking;
+        timer = setTimeout(() => runPreview(list), delay);
+    }
+
+    function repaint() {
+        const list = entries();
+        input.disabled = add.disabled = list === null;
+        if (list === null) return;
+        const full = list.length >= MAX_ENTRIES;
+        add.disabled = full;
+        if (full && !problem.textContent) say(SKIPPED_COPY.full);
+        if (!full && problem.textContent === SKIPPED_COPY.full) say('');
+        const key = JSON.stringify(list);
+        if (key !== shown) {
+            shown = key;
+            renderChips(list);
+        }
+        if (key !== pending) {
+            pending = key;
+            schedule(list);
+        }
+    }
+
+    scope.listen(add, 'click', addEntry);
+    scope.listen(input, 'keydown', event => {
+        if (event.key !== 'Enter') return;
+        event.preventDefault?.();
+        addEntry();
+    });
+    scope.listen(input, 'input', () => { if (problem.textContent !== SKIPPED_COPY.full) say(''); });
+    return { node: block, repaint };
+}
diff --git a/web/js/workspace/system-state.mjs b/web/js/workspace/system-state.mjs
index eb666c9d..be57e156 100644
--- a/web/js/workspace/system-state.mjs
+++ b/web/js/workspace/system-state.mjs
@@ -76,6 +76,22 @@ export function statusText(outcome) {
     return saved.join(' ') || SETTINGS_STATUS.clean;
 }
 
+const plain = value => value !== null && typeof value === 'object'
+    && (Array.isArray(value) || Object.getPrototypeOf(value) === Object.prototype);
+/** JSON with every object's keys sorted, so key order never makes two values differ. */
+const canonical = value => JSON.stringify(value, (key, item) => (item && typeof item === 'object' && !Array.isArray(item)
+    ? Object.fromEntries(Object.keys(item).sort().map(name => [name, item[name]])) : item));
+
+/**
+ * #431: whether a draft equals a saved value: `Object.is`, or both are arrays or plain objects with the same JSON (keys
+ * sorted). A list setting (Skipped tags) whose added entry was removed again is clean, not a new array that differs.
+ */
+export function sameDraft(a, b) {
+    if (Object.is(a, b)) return true;
+    if (!plain(a) || !plain(b) || Array.isArray(a) !== Array.isArray(b)) return false;
+    return canonical(a) === canonical(b);
+}
+
 function requireDomain(domain) {
     if (!DRAFT_DOMAINS.includes(domain)) throw new TypeError(`Unknown settings domain: ${domain}`);
 }
@@ -112,7 +128,7 @@ export function createSystemDrafts(adapters) {
             values = await (domain === 'browser' ? adapters.readBrowser() : adapters.readRuntime());
         }
         baseline[domain] = { ...(values ?? {}) };
-        for (const [key, value] of drafts[domain]) if (Object.is(baseline[domain][key], value)) drafts[domain].delete(key);
+        for (const [key, value] of drafts[domain]) if (sameDraft(baseline[domain][key], value)) drafts[domain].delete(key);
         notify();
         return { ...baseline[domain] };
     }
@@ -124,7 +140,7 @@ export function createSystemDrafts(adapters) {
 
     function set(domain, key, value) {
         requireDomain(domain);
-        if (Object.is(baseline[domain][key], value)) drafts[domain].delete(key);
+        if (sameDraft(baseline[domain][key], value)) drafts[domain].delete(key);
         else drafts[domain].set(key, value);
         failedKeys[domain].delete(key);
         outcome = null;
@@ -153,7 +169,7 @@ export function createSystemDrafts(adapters) {
     function commit(domain, written) {
         for (const [key, value] of written) {
             baseline[domain][key] = value;
-            if (drafts[domain].has(key) && Object.is(drafts[domain].get(key), value)) drafts[domain].delete(key);
+            if (drafts[domain].has(key) && sameDraft(drafts[domain].get(key), value)) drafts[domain].delete(key);
         }
     }
 
diff --git a/web/js/workspace/system-tagging.mjs b/web/js/workspace/system-tagging.mjs
index 6a96f177..a958b22a 100644
--- a/web/js/workspace/system-tagging.mjs
+++ b/web/js/workspace/system-tagging.mjs
@@ -9,6 +9,7 @@
  * - "Existing tags", "General-tag confidence", "Character-tag confidence": the concept's labels and descriptions
  *   verbatim (they state the shipped defaults); host keys `autotag_existing`, `autotag_general_threshold`,
  *   `autotag_character_threshold`. D133 adds "Suggestions per image" (`autotag_suggestion_limit`, 1–100) after them.
+ * - D202 (#431): the "Skipped tags" block after it (system-skipped-tags.mjs, host key `autotag_skipped_tags`).
  * - The `.field` "LLM tag template" (`#tag-template`, `autotag_template`).
  * - `.row-actions`: "Preview tagging review" (`ca-primary`) opens the Tag image dialog for the image selected in Images
  *   with the section's current model and values, aria-disabled without one (the D115 sentence) or with an invalid
@@ -35,6 +36,7 @@ import { selectedImage } from './images.mjs';
 import { NO_SELECTION } from './vocabulary.mjs';
 import { showWorkspaceToast } from './toast.mjs';
 import { navigateTo } from './state.mjs';
+import { skippedTagsBlock } from './system-skipped-tags.mjs';
 
 export const MODELS_URL = '/prompt_manager/autotag/models';
 export const UNLOAD_URL = '/prompt_manager/autotag/unload';
@@ -410,6 +412,9 @@ export function mountTagging(container, { api, activity, scope, drafts, notify =
     // D133: the persisted suggestion count, which the concept does not show.
     add(settingRow({ id: 'tag-suggestions', label: 'Suggestions per image', description: SUGGESTIONS_DESCRIPTION,
         control: { type: 'number', min: 1, max: 100, step: 1 } }), 'tag-suggestions');
+    // D202 (#431): the words whose suggested tags are hidden on every suggestion path.
+    const skipped = skippedTagsBlock({ api, scope, drafts });
+    surface.append(skipped.node);
 
     const field = el('div', undefined, 'field');
     const templateLabel = el('label', 'LLM tag template');
@@ -454,6 +459,7 @@ export function mountTagging(container, { api, activity, scope, drafts, notify =
     const known = () => MODEL_IDS.includes(chosen());
 
     const repaint = () => {
+        skipped.repaint();
         const values = current();
         const unread = values.autotag_model_type === undefined;
         const failed = drafts.hostState?.() === 'failed' && unread;
diff --git a/web/js/workspace/workspace.css b/web/js/workspace/workspace.css
index bfcd4df7..eedce8b8 100644
--- a/web/js/workspace/workspace.css
+++ b/web/js/workspace/workspace.css
@@ -443,12 +443,12 @@ pre.prompt-text { font: inherit; font-size: 12px; line-height: 1.75; margin-bloc
    suggestions are removable chips, each the concept's `.chip` corner (4px; the later `.tag-suggestion` row rule would
    give 5px) around the row's 12px text in its checked suggestion row's tokens (`.tag-suggestion:has(input:checked)`,
    s1655): a name, the confidence and a × button. */
-#tag-suggestions .chip.tag-suggestion { display: inline-flex; gap: 6px; padding: 2px 2px 2px 8px; margin-bottom: 0; cursor: default; color: inherit; border-color: var(--ca-accent); background: var(--soft-blue); border-radius: 4px; /* D83 */ }
-#tag-suggestions .chip.tag-suggestion .tag-confidence { margin-inline-start: 0; /* D83 */ }
-.ca-tools #tag-suggestions .chip.tag-suggestion > button { min-block-size: 24px; min-inline-size: 24px; padding: 0 6px; /* D83 */ }
+#tag-suggestions .chip.tag-suggestion, .skip-chips .chip.tag-suggestion { display: inline-flex; gap: 6px; padding: 2px 2px 2px 8px; margin-bottom: 0; cursor: default; color: inherit; border-color: var(--ca-accent); background: var(--soft-blue); border-radius: 4px; /* D83 */ }
+#tag-suggestions .chip.tag-suggestion .tag-confidence, .skip-chips .chip.tag-suggestion .tag-confidence { margin-inline-start: 0; /* D83 */ }
+.ca-tools #tag-suggestions .chip.tag-suggestion > button, .ca-tools .skip-chips .chip.tag-suggestion > button { min-block-size: 24px; min-inline-size: 24px; padding: 0 6px; /* D83 */ }
 @media (pointer: coarse) {
     /* D83: the chip's × keeps the concept's 40px coarse target. */
-    .ca-tools #tag-suggestions .chip.tag-suggestion > button { min-block-size: 40px; min-inline-size: 40px; }
+    .ca-tools #tag-suggestions .chip.tag-suggestion > button, .ca-tools .skip-chips .chip.tag-suggestion > button { min-block-size: 40px; min-inline-size: 40px; }
 }
 
 /* Needs review (#249 PR F): the concept's Metadata review page (app.js a749–760) in its own classes. */
@@ -492,6 +492,24 @@ pre.prompt-text { font: inherit; font-size: 12px; line-height: 1.75; margin-bloc
 @media (max-width: 700px) {
   #workspace-main .setting-row :is(#send-destination, #renderer) { max-width: 160px !important; /* D106 */ }
 }
+/* D202 (#431): System › Auto-tagging "Skipped tags", a setting whose control (an add input, the chips and the preview
+   line) is wider than a `.setting-row` column: the row's label and description tokens over the full width, the chips
+   in the Tag image dialog's D83 chip markup (an entry that hides no known tag is muted). */
+.setting-block { padding: 17px 0; border-top: 1px solid var(--line); /* D202 */ }
+.setting-block-text label { font-size: 12px; font-weight: 500; display: block; /* D202 */ }
+.setting-block-text p { font-size: 11px; color: var(--ca-muted); margin-top: 4px; max-width: 640px; /* D202 */ }
+.setting-block[aria-invalid="true"] { box-shadow: inset 3px 0 0 var(--red); padding-inline-start: 12px; /* D202 */ }
+.skip-add { display: flex; gap: 8px; margin-top: 12px; max-width: 460px; /* D202 */ }
+.skip-add input { flex: 1; min-width: 0; font-size: 12px; /* D202 */ }
+.skip-problem { color: var(--red); margin-top: 6px; /* D202 */ }
+.skip-problem:empty, .skip-chips:empty { display: none; /* D202 */ }
+.skip-chips .chip.tag-suggestion.none { border-color: var(--line); background: var(--ca-field); color: var(--ca-muted); /* D202 */ }
+.skip-preview { margin-top: 12px; max-width: 760px; /* D202 */ }
+.skip-preview b { font-weight: 500; color: var(--ca-text); /* D202 */ }
+@media (max-width: 700px) {
+    .skip-add { max-width: none; /* D202 */ }
+}
+
 /* D132: at phone width the concept's 120px cap cuts every engine label ("WD14 SwinV2 · ~400 MB"); the Tagging model
    select alone keeps its natural width there (its widest engine label) and, with no room beside the row text, wraps
    under it. Existing tags (#398) never shrinks for its row text and, past the cap, keeps its natural width beside the