diff --git a/__init__.py b/__init__.py
index 41c6fba7..7482e606 100644
--- a/__init__.py
+++ b/__init__.py
@@ -120,6 +120,7 @@ except Exception as e:
         logger = get_logger("prompt_manager.init")
         logger.error(f"Failed to register API routes: {e}")
     except Exception:
+        # logging failed too; a report must never stop the node loading
         pass
 
 # Shared database, set up with the monitoring system below. Stays None when that
@@ -411,6 +412,7 @@ except Exception as e:
             f"Failed to register the exit signal: {e}"
         )
     except Exception:
+        # logging failed too; a report must never stop the node loading
         pass
 
 try:
@@ -428,6 +430,7 @@ except Exception as e:
             f"Failed to register the background work teardown: {e}"
         )
     except Exception:
+        # logging failed too; a report must never stop the node loading
         pass
 
 __all__ = ["NODE_CLASS_MAPPINGS", "NODE_DISPLAY_NAME_MAPPINGS", "WEB_DIRECTORY"]
diff --git a/database/library_move.py b/database/library_move.py
index 91dc7274..c104ac15 100644
--- a/database/library_move.py
+++ b/database/library_move.py
@@ -590,6 +590,7 @@ class _Move:
             try:
                 os.rmdir(self.plan.target_dir)
             except OSError:
+                # not empty or already gone: the undo leaves it alone
                 pass
 
 
diff --git a/database/managed_connection.py b/database/managed_connection.py
index fb71fc6d..49e58390 100644
--- a/database/managed_connection.py
+++ b/database/managed_connection.py
@@ -35,38 +35,51 @@ from __future__ import annotations
 
 import contextlib
 import logging
+import operator
+import sys
 import threading
 import time
 import weakref
-from typing import Iterable, Iterator, List, Optional
+from collections import deque
+from typing import Any, Callable, Iterable, Iterator, List, Optional
 
 import sqlite3
 
 CLOSED_MESSAGE = "Cannot operate on a closed database."
 # Rows fetched per step when a cursor is iterated: the connection is marked
 # in use once per chunk instead of once per row (iteration costs about what
-# a plain cursor costs). A loop that stops early leaves up to this many rows
-# fetched; ``fetchone``/``fetchmany`` after a partial loop skip them.
+# a plain cursor costs). Prefetched rows belong to the cursor so iteration
+# and explicit fetches always advance the same position.
 ITER_CHUNK = 128
 
 
 class ManagedCursor(sqlite3.Cursor):
     """A cursor whose calls into SQLite count as its connection being in use."""
 
+    def __init__(self, *args: Any, **kwargs: Any) -> None:
+        super().__init__(*args, **kwargs)
+        self._pending = deque()
+        self._closed = False
+
     def execute(self, sql, parameters=(), /):
-        conn = self.connection
-        conn._enter()
-        try:
-            return super().execute(sql, parameters)
-        finally:
-            conn._leave()
+        return self._run_statement(super().execute, sql, parameters)
 
     def executemany(self, sql, seq_of_parameters, /):
+        return self._run_statement(super().executemany, sql, seq_of_parameters)
+
+    def _run_statement(self, operation: Callable, *args: Any) -> ManagedCursor:
         conn = self.connection
         conn._enter()
+        description = self.description
+        completed = False
         try:
-            return super().executemany(sql, seq_of_parameters)
+            result = operation(*args)
+            completed = True
+            return result
         finally:
+            # Argument parsing can fail before SQLite replaces the old statement.
+            if completed or self.description is not description:
+                self._pending.clear()
             conn._leave()
 
     def executescript(self, sql_script, /):
@@ -81,6 +94,8 @@ class ManagedCursor(sqlite3.Cursor):
         conn = self.connection
         conn._enter()
         try:
+            if self._pending and not self._closed:
+                return self._pending.popleft()
             return super().fetchone()
         finally:
             conn._leave()
@@ -89,7 +104,20 @@ class ManagedCursor(sqlite3.Cursor):
         conn = self.connection
         conn._enter()
         try:
-            return super().fetchmany(*args, **kwargs)
+            # Let SQLite validate the original arguments, including version-specific
+            # handling of zero/negative sizes, before touching prefetched rows.
+            rows = super().fetchmany(*args, **kwargs)
+            if not self._pending:
+                return rows
+            size = operator.index(
+                kwargs.get("size", args[0] if args else self.arraysize)
+            )
+            # Python 3.12 reads all rows for size=0; 3.13+ reads none.
+            if size == 0 and sys.version_info >= (3, 13):
+                return rows
+            self._pending.extend(rows)
+            count = len(self._pending) if size <= 0 else min(size, len(self._pending))
+            return [self._pending.popleft() for _ in range(count)]
         finally:
             conn._leave()
 
@@ -97,25 +125,31 @@ class ManagedCursor(sqlite3.Cursor):
         conn = self.connection
         conn._enter()
         try:
-            return super().fetchall()
+            rows = super().fetchall()
+            pending = list(self._pending)
+            self._pending.clear()
+            return pending + rows
         finally:
             conn._leave()
 
     def __iter__(self) -> Iterator:
-        return self._chunks()
-
-    def _chunks(self) -> Iterator:
-        while True:
-            rows = self.fetchmany(ITER_CHUNK)
-            if not rows:
-                return
-            yield from rows
+        return self
 
     def __next__(self):
         conn = self.connection
+        pending = self._pending
+        # Buffered Python rows need no SQLite lock, but retirement and cursor
+        # close must still stop an iterator obtained before either operation.
+        if conn._retired or self._closed:
+            raise sqlite3.ProgrammingError(CLOSED_MESSAGE)
+        if pending:
+            return pending.popleft()
         conn._enter()
         try:
-            return super().__next__()
+            pending.extend(super().fetchmany(ITER_CHUNK))
+            if not pending:
+                raise StopIteration
+            return pending.popleft()
         finally:
             conn._leave()
 
@@ -126,7 +160,10 @@ class ManagedCursor(sqlite3.Cursor):
         except sqlite3.ProgrammingError:
             return super().close()  # the connection is closed or closing
         try:
-            return super().close()
+            result = super().close()
+            self._pending = deque()
+            self._closed = True
+            return result
         finally:
             conn._leave()
 
@@ -293,6 +330,9 @@ class ManagedConnection(sqlite3.Connection):
             cursors = list(self._cursors)
         try:
             for cursor in cursors:
+                if isinstance(cursor, ManagedCursor):
+                    cursor._pending = deque()
+                    cursor._closed = True
                 with contextlib.suppress(sqlite3.Error):
                     sqlite3.Cursor.close(cursor)
             super().close()
diff --git a/database/operations.py b/database/operations.py
index 51607876..2e1dca0b 100644
--- a/database/operations.py
+++ b/database/operations.py
@@ -34,7 +34,7 @@ from .history_reads import HistoryReadOperations
 from .health import HealthOperations, iter_consistency_issues
 from .duplicate_copies import DuplicateCopyOperations
 from .workflow_storage import WorkflowStorageOperations
-from .category_import import CategoryImportOperations, EmptyReplacement  # noqa: F401
+from .category_import import CategoryImportOperations
 from .image_categories import ImageCategoryOperations
 from .workflow_documents import (
     DocumentReader,
diff --git a/database/safety_backup.py b/database/safety_backup.py
index ad212a14..5ce36619 100644
--- a/database/safety_backup.py
+++ b/database/safety_backup.py
@@ -46,6 +46,7 @@ def remove_quietly(*paths):
             if path and os.path.exists(path):
                 os.remove(path)
         except OSError:
+            # cleanup after a failure must not replace that failure
             pass
 
 
diff --git a/database/vocabulary.py b/database/vocabulary.py
index 971112bd..206d13f6 100644
--- a/database/vocabulary.py
+++ b/database/vocabulary.py
@@ -66,7 +66,6 @@ def _tag_rows(page: str, order: str = "page.id") -> str:
     )
 
 
-_TAG_PAGE = _tag_rows("SELECT id,name FROM tags WHERE id>? ORDER BY id LIMIT ?")
 # #444 tag sorts: sort -> (key expression on tags/counted, direction). Ties and
 # "created" follow the id, so every order is total and keyset pages are exact.
 TAG_SORTS = {
diff --git a/py/api/admin.py b/py/api/admin.py
index 64768544..3488a056 100644
--- a/py/api/admin.py
+++ b/py/api/admin.py
@@ -176,7 +176,7 @@ def _physical_file_key(path, stat):
     volumes on Windows) falls back to the resolved, case-folded path.
     """
     if stat.st_ino:
-        return ("inode", stat.st_dev, stat.st_ino)
+        return ("inode", (stat.st_dev, stat.st_ino))
     return ("path", os.path.normcase(os.path.realpath(str(path))))
 
 
@@ -539,6 +539,7 @@ def _diagnose_output_dirs(configured_dirs, public_path=None):
 
         candidates.append(folder_paths.get_output_directory())
     except ImportError:
+        # outside ComfyUI there is no output folder to add
         pass
 
     output_dirs = []
diff --git a/py/api/annotation_suggest.py b/py/api/annotation_suggest.py
index 9411640b..bb676d92 100644
--- a/py/api/annotation_suggest.py
+++ b/py/api/annotation_suggest.py
@@ -13,7 +13,6 @@ import math
 from ..tagging_defaults import (  # noqa: F401 - re-exported for the route
     LLM_MODEL_TYPES as LLM_MODELS,
     MAX_INSTRUCTION_BYTES,
-    MAX_INSTRUCTION_CHARS,
     MODEL_TYPES,
     WD14_MODEL_TYPES as WD14_MODELS,
     validate_template,
diff --git a/py/api/autotag_routes.py b/py/api/autotag_routes.py
index 388e5e3a..9e82d30d 100644
--- a/py/api/autotag_routes.py
+++ b/py/api/autotag_routes.py
@@ -424,6 +424,7 @@ class AutotagRoutesMixin:
         title = f"Tagging model download · {label}"
         _download_titles.clear()
         _download_titles[owner] = title
+        admitted = False
         try:
             job = self._jobs.start(
                 MODEL_DOWNLOAD_JOB_KIND,
@@ -439,13 +440,13 @@ class AutotagRoutesMixin:
                     self._run_model_download, service, model_type, owner
                 ),
             )
-        except BaseException as refused:
-            # JobBusy, or anything else the registry raised: give the gate back.
-            model_gate.release(owner)
-            _download_titles.pop(owner, None)
-            if isinstance(refused, JobBusy):
-                return None, busy_response(refused)
-            raise
+            admitted = True
+        except JobBusy as refused:
+            return None, busy_response(refused)
+        finally:
+            if not admitted:  # JobBusy, or anything else: give the gate back.
+                model_gate.release(owner)
+                _download_titles.pop(owner, None)
 
         def ended(_task):
             model_gate.release(owner)
@@ -1041,12 +1042,12 @@ class AutotagRoutesMixin:
                 return self._bad_request('existing must be "skip" or "merge"')
             try:
                 options = self._single_options(data, model_type)
+            except OptionError as error:
+                return self._bad_request(str(error))
             except (ValueError, TypeError):
                 return self._bad_request(
                     "general_threshold and character_threshold must be numeric"
                 )
-            except OptionError as error:
-                return self._bad_request(str(error))
             target, error = await self._select_autotag_target(data)
             if error is not None:
                 return error
diff --git a/py/api/backup_restore.py b/py/api/backup_restore.py
index a83ecbfa..ab3d030a 100644
--- a/py/api/backup_restore.py
+++ b/py/api/backup_restore.py
@@ -971,6 +971,7 @@ class BackupRestoreRoutesMixin:
         line = restored_line(staged.summary)
         job.log_line(line)
         job.update(progress=100, status_line=line)
+        return None
 
 
 async def _outlive_cancel(future):
diff --git a/py/api/duplicate_files.py b/py/api/duplicate_files.py
index 34e15ed4..9a844253 100644
--- a/py/api/duplicate_files.py
+++ b/py/api/duplicate_files.py
@@ -574,12 +574,13 @@ class DuplicateFilesMixin:
             return _fail_job(job, "sources-changed", SOURCES_CHANGED)
         ok, backup = await self._safety_backup_step(job, db, backup_on)
         if not ok:
-            return
+            return None
         try:
             await self._remove_duplicates(job, db, plan, backup)
         finally:
             if backup:
                 await self._prune_backup_pool(job, db)
+        return None
 
     async def _remove_duplicates(self, job, db, plan, backup):
         targets = plan.payload["targets"]
diff --git a/py/api/duplicate_spellings.py b/py/api/duplicate_spellings.py
index 7157e994..1e6d2aff 100644
--- a/py/api/duplicate_spellings.py
+++ b/py/api/duplicate_spellings.py
@@ -27,7 +27,7 @@ def _identity(path):
     except OSError:
         return None
     if info.st_ino:
-        return ("inode", info.st_dev, info.st_ino)
+        return ("inode", (info.st_dev, info.st_ino))
     return ("path", os.path.normcase(os.path.realpath(str(path))))
 
 
diff --git a/py/api/image_delete.py b/py/api/image_delete.py
index 862cda26..b81b8497 100644
--- a/py/api/image_delete.py
+++ b/py/api/image_delete.py
@@ -330,12 +330,13 @@ class ImageDeleteMixin:
             return _fail_job(job, "sources-changed", SOURCES_CHANGED)
         ok, backup = await self._safety_backup_step(job, db, backup_on)
         if not ok:
-            return
+            return None
         try:
             await self._delete_images(job, db, targets, mode, backup)
         finally:
             if backup:
                 await self._prune_backup_pool(job, db)
+        return None
 
     async def _delete_images(self, job, db, targets, mode, backup):
         job.update(total=len(targets), status_line=TITLES[mode])
diff --git a/py/api/image_tag_jobs.py b/py/api/image_tag_jobs.py
index c16751b0..33b679c6 100644
--- a/py/api/image_tag_jobs.py
+++ b/py/api/image_tag_jobs.py
@@ -531,6 +531,7 @@ class ImageTagJobsMixin:
         run = AutotagRun(
             model_type, existing, options, keep_in_memory, backup_on, owner
         )
+        admitted = False
         try:
             job = self._jobs.start(
                 AUTOTAG_BATCH_JOB_KIND,
@@ -541,11 +542,12 @@ class ImageTagJobsMixin:
                 groups=AUTOTAG_GROUP_NAMES,
                 runner=functools.partial(self._run_autotag_batch, run),
             )
-        except BaseException as refused:
-            model_gate.release(owner)
-            if isinstance(refused, JobBusy):
-                return None, _busy_refusal(refused)
-            raise
+            admitted = True
+        except JobBusy as refused:
+            return None, _busy_refusal(refused)
+        finally:
+            if not admitted:
+                model_gate.release(owner)
         job.task.add_done_callback(lambda _task: model_gate.release(owner))
         return job, None
 
diff --git a/py/api/images.py b/py/api/images.py
index 2ded1782..afa4f319 100644
--- a/py/api/images.py
+++ b/py/api/images.py
@@ -39,10 +39,8 @@ from .thumbnail_encode import (
     PREVIEW_HELD,
     EncoderClosed,
     PreviewWriteHeld,
-    replace_unless_held,
     run_encoder,
     sweep_stray_temps,
-    temp_sibling,
     thumbnail_frame,
     writer_settings,
     write_thumbnail,
@@ -339,11 +337,6 @@ def _thumbnail_batch_size(workers):
     return max(4, workers * 2)
 
 
-# Preview files are written by thumbnail_encode in the configured format
-# (thumbnail_settings, #317); these names stay importable from here.
-_temp_sibling = temp_sibling
-_replace_unless_held = replace_unless_held
-
 # A preview that could not be replaced (#249 S5 M6). Windows refuses to rename
 # over a file another process has open (WinError 5 or 32), such as a preview
 # the gallery is serving; the old preview stays and the file counts as an error.
@@ -396,6 +389,7 @@ def _video_placeholder_image(thumbnail_size):
             font=font,
         )
     except (OSError, AttributeError):
+        # a placeholder without its label still works
         pass
     return img
 
@@ -499,6 +493,7 @@ def _preview_names(folders, folder):
                     except OSError:
                         continue
         except OSError:
+            # an unreadable folder lists as empty; nothing there to cache
             pass
         folders[folder] = names
     return names
diff --git a/py/api/job_routes.py b/py/api/job_routes.py
index 82dcbfcb..ce013446 100644
--- a/py/api/job_routes.py
+++ b/py/api/job_routes.py
@@ -250,7 +250,7 @@ class JobRoutesMixin:
         try:
             await response.write(_summary_event(job))
             async with contextlib.aclosing(job.events()) as events:
-                async for _payload in events:
+                async for _ in events:
                     await response.write(_summary_event(job))
             # The last event is published before the job takes its final state.
             await response.write(_summary_event(job))
diff --git a/py/api/library_location.py b/py/api/library_location.py
index 8c4ec324..17d172c7 100644
--- a/py/api/library_location.py
+++ b/py/api/library_location.py
@@ -207,6 +207,7 @@ class LibraryLocationRoutesMixin:
         try:
             size = os.path.getsize(location.db_path)
         except OSError:
+            # no library file yet: report size 0
             pass
         return {
             "path": self._library_public_path(location.db_path),
@@ -373,6 +374,7 @@ class LibraryLocationRoutesMixin:
         line += ". Logs move at the next restart."
         job.log_line(line)
         job.update(progress=100, status_line=line)
+        return None
 
     @staticmethod
     def _fail_library_move(job, code, message):
diff --git a/py/api/log_cleanup.py b/py/api/log_cleanup.py
index f6248388..c1c2cd41 100644
--- a/py/api/log_cleanup.py
+++ b/py/api/log_cleanup.py
@@ -205,3 +205,4 @@ class LogCleanupMixin:
             line += f", {failed} could not be deleted"
         job.log_line(line)
         job.update(processed=len(files), progress=100, status_line=line)
+        return None
diff --git a/py/api/lora_import_routes.py b/py/api/lora_import_routes.py
index a09ec689..f6eec8c6 100644
--- a/py/api/lora_import_routes.py
+++ b/py/api/lora_import_routes.py
@@ -436,7 +436,7 @@ class LoraImportRoutesMixin:
             job.log_line(f"{CANCELLED} {CACHE_NOTE}")
             job.update(status_line=CANCELLED)
             job.finish("cancelled")
-            return
+            return None
         except Exception:
             self.logger.exception("LoRA import staging failed")
             return _fail_job(job, "import-failed", f"{FAILED} {CACHE_NOTE}")
@@ -455,10 +455,10 @@ class LoraImportRoutesMixin:
             job.log_line(f"{CANCELLED} {CACHE_NOTE}")
             job.update(status_line=CANCELLED)
             job.finish("cancelled")
-            return
+            return None
         ok, _backup = await self._safety_backup_step(job, db, backup_on)
         if not ok:
-            return
+            return None
         # I1: the files are listed and fingerprinted again right before the
         # replace, so a file changed, removed or added while the downloads ran
         # (LoraManager refreshing its CivitAI info) aborts with nothing deleted.
@@ -466,6 +466,7 @@ class LoraImportRoutesMixin:
             return _fail_job(job, "plan-changed", f"{SOURCE_CHANGED} {CACHE_NOTE}")
         job.update(status_line="Replacing the LoRA collection", progress=95)
         await self._replace_in_job(job, db, plan, staged)
+        return None
 
     def _count_downloads(self, job, staged):
         downloaded = staged.stats.get("downloaded", 0)
@@ -518,3 +519,4 @@ class LoraImportRoutesMixin:
             staged.stats.get("download_errors", 0),
         )
         job.update(progress=100, processed=job.total, status_line=line)
+        return None
diff --git a/py/api/lora_integration.py b/py/api/lora_integration.py
index 3531d4a2..86370f5b 100644
--- a/py/api/lora_integration.py
+++ b/py/api/lora_integration.py
@@ -536,6 +536,7 @@ class LoraIntegrationMixin:
                 except asyncio.CancelledError:
                     interrupted = True
                 except Exception:
+                    # the await after this loop raises it for the caller
                     pass
             if interrupted:
                 raise asyncio.CancelledError
diff --git a/py/api/maintenance.py b/py/api/maintenance.py
index e7d34020..d93a8973 100644
--- a/py/api/maintenance.py
+++ b/py/api/maintenance.py
@@ -673,6 +673,7 @@ class MaintenanceRoutesMixin:
         line = _changed_line(plan.operation, result["changed"], result.get("marks", 0))
         job.log_line(line)
         job.update(progress=100, status_line=f"{line} · {backup_note(backup)}")
+        return None
 
     def _maintenance_rows(self, operation, described):
         """Outcome rows for the changed records (root-relative paths only)."""
diff --git a/py/api/thumbnail_auto.py b/py/api/thumbnail_auto.py
index 05af0c2d..5cd662b7 100644
--- a/py/api/thumbnail_auto.py
+++ b/py/api/thumbnail_auto.py
@@ -533,6 +533,7 @@ class AutoThumbnailer:
             try:
                 process.kill()
             except OSError:
+                # the process has already exited
                 pass
         if worker is None:
             return True
diff --git a/py/api/thumbnail_encode.py b/py/api/thumbnail_encode.py
index bcbee3ef..f7a6ca54 100644
--- a/py/api/thumbnail_encode.py
+++ b/py/api/thumbnail_encode.py
@@ -158,6 +158,7 @@ def _unlink_quietly(path):
     try:
         Path(path).unlink()
     except FileNotFoundError:
+        # already gone, which is what was wanted
         pass
     except OSError as exc:
         logger.debug(f"Could not remove temp file {Path(path).name}: {exc}")
@@ -221,6 +222,7 @@ def shutdown_encoders():
         try:
             process.kill()
         except OSError:
+            # the process has already exited
             pass
 
 
@@ -359,10 +361,12 @@ def thumbnail_frame(img, edge):
     try:
         img.seek(0)
     except (EOFError, AttributeError, ValueError):
+        # not seekable or a single frame: use the current one
         pass
     try:
         img.draft("RGB", (edge, edge))  # JPEG: decode at a reduced scale
     except (AttributeError, ValueError, OSError):
+        # draft is only a speedup; the full decode below still works
         pass
     frame = img.convert("RGB") if img.mode != "RGB" else img.copy()
     frame.thumbnail((edge, edge), Image.Resampling.LANCZOS)
diff --git a/py/api/workflow_storage.py b/py/api/workflow_storage.py
index 753c197b..fde4be76 100644
--- a/py/api/workflow_storage.py
+++ b/py/api/workflow_storage.py
@@ -275,3 +275,4 @@ class WorkflowStorageRoutesMixin:
         job.record_counted("changed", 1)
         job.log_line(line)
         job.update(progress=100, status_line=line)
+        return None
diff --git a/py/config_store.py b/py/config_store.py
index 949423a3..0664f026 100644
--- a/py/config_store.py
+++ b/py/config_store.py
@@ -109,6 +109,7 @@ def _write_atomically(path: str, payload: bytes) -> None:
         try:
             os.unlink(temp_path)
         except OSError:
+            # nothing to clean up; the original error is raised below
             pass
         raise
 
diff --git a/py/lora_manager_layout.py b/py/lora_manager_layout.py
index d05abe59..dba820b3 100644
--- a/py/lora_manager_layout.py
+++ b/py/lora_manager_layout.py
@@ -642,6 +642,7 @@ def layout_summary(layout: LoraManagerLayout, home: Path) -> Dict:
             relative = Path(settings_file).relative_to(home)
             settings_file = os.path.join("~", str(relative))
         except ValueError:
+            # outside the home folder: show the full path
             pass
     return {
         "source": layout.source,
diff --git a/py/lora_utils.py b/py/lora_utils.py
index da71a3c9..4c8f6de2 100644
--- a/py/lora_utils.py
+++ b/py/lora_utils.py
@@ -585,6 +585,7 @@ def _read_capped(resp, cap: int) -> Optional[bytes]:
             if int(declared) > cap:
                 return None
         except ValueError:
+            # a bad header says nothing; the read below enforces the cap
             pass
 
     chunks = []
@@ -707,6 +708,7 @@ def _save_atomically(image, local_path: Path) -> None:
         try:
             os.remove(temp)
         except OSError:
+            # nothing to clean up; the original error is raised below
             pass
         raise
 
diff --git a/tests/browser/activity-concept.spec.mjs b/tests/browser/activity-concept.spec.mjs
index 9dd4e646..443a6c0e 100644
--- a/tests/browser/activity-concept.spec.mjs
+++ b/tests/browser/activity-concept.spec.mjs
@@ -6,7 +6,6 @@ import { THEMES, seedConcept, openConcept, openProduction, diffInventory, mutate
 // app.js 1428–1432) and its backup box with the concept's System `.notice`; the differences are D55. The job view
 // has no concept counterpart: it is compared with the approved mockup `activity-scan.html` (a local, ignored file),
 // whose structure and CSS values are restated below (D56). Each comparison is shown to notice a mutation.
-const workspace = '/prompt_manager/workspace';
 
 test.beforeEach(async ({ page, request, browserName }) => {
     await startCoverage(page, browserName);
diff --git a/tests/browser/slow_reset_watch.py b/tests/browser/slow_reset_watch.py
index e3b453b6..3ff6a85f 100644
--- a/tests/browser/slow_reset_watch.py
+++ b/tests/browser/slow_reset_watch.py
@@ -109,6 +109,7 @@ class ResetWatch:
             stream.write(text)
             stream.flush()
         except (OSError, ValueError):
+            # the stream closed; a watcher must not fail the server
             pass
 
 
diff --git a/tests/browser/workspace-saved-views.spec.mjs b/tests/browser/workspace-saved-views.spec.mjs
index 1b216a4d..69258546 100644
--- a/tests/browser/workspace-saved-views.spec.mjs
+++ b/tests/browser/workspace-saved-views.spec.mjs
@@ -233,7 +233,7 @@ test('a view stored under older rules still lists and opens with its usable valu
 // D153 (#447): the workspace no longer offers "Highest rated"; the API still stores such a view as it was saved.
 test('a view saved under Highest rated opens on Recently added on Images and the Library', async ({ page, request }) => {
     const images = await create(request, { page: 'images', name: 'Rated cats', state: { ...IMAGE_DEFAULTS, q: 'cat', sort: 'rating' } });
-    const library = await create(request, { page: 'library', name: 'Rated dogs', state: { q: 'dog', category: '', sort: 'rating', tags: [], tag_mode: 'all', folder: '' } });
+    await create(request, { page: 'library', name: 'Rated dogs', state: { q: 'dog', category: '', sort: 'rating', tags: [], tag_mode: 'all', folder: '' } });
     expect((await listed(request)).map(view => view.state.sort)).toEqual(['rating', 'rating']);
     const listings = [];
     page.on('request', item => {
diff --git a/tests/browser/workspace-sticky-chrome.spec.mjs b/tests/browser/workspace-sticky-chrome.spec.mjs
index 88323a0f..eec48a2b 100644
--- a/tests/browser/workspace-sticky-chrome.spec.mjs
+++ b/tests/browser/workspace-sticky-chrome.spec.mjs
@@ -60,7 +60,7 @@ async function openReview(page, request, items = 30) {
 const inViewport = (rect, page) => rect.top >= 0 && rect.bottom <= page.viewportSize().height;
 
 test.beforeEach(async ({ page, browserName }) => { await startCoverage(page, browserName); });
-test.afterEach(async ({ page, browserName }, testInfo) => { await saveCoverage(page, browserName, testInfo); });
+test.afterEach(async ({ page, browserName }) => { await saveCoverage(page, browserName); });
 
 for (const viewport of [null, PHONE]) {
     const label = viewport ? ' at 390px' : '';
diff --git a/tests/browser/workspace-system-diagnostics.spec.mjs b/tests/browser/workspace-system-diagnostics.spec.mjs
index 2f4cc07a..8f8cf38c 100644
--- a/tests/browser/workspace-system-diagnostics.spec.mjs
+++ b/tests/browser/workspace-system-diagnostics.spec.mjs
@@ -11,7 +11,6 @@ const REPORT_URL = '/prompt_manager/system/diagnostics';
 const LOGS_URL = '/prompt_manager/logs';
 const CONFIG_URL = '/prompt_manager/logs/config';
 const PREVIEW_URL = '/prompt_manager/maintenance/preview';
-const APPLY_URL = '/prompt_manager/maintenance/apply';
 const TEST_LINK_URL = '/prompt_manager/diagnostics/test-link';
 const CHANGED = 'The log files changed since the review; nothing was deleted. Review again.';
 const KEY = 'sk-s12-browser-SECRET-0123456789';
diff --git a/tests/js/legacy-refusals.test.js b/tests/js/legacy-refusals.test.js
index 78d15c9b..23f6cf0e 100644
--- a/tests/js/legacy-refusals.test.js
+++ b/tests/js/legacy-refusals.test.js
@@ -21,14 +21,6 @@ function jsonResponse(status, body) {
         json: async () => body };
 }
 
-function sseResponse(frames) {
-    const bytes = new TextEncoder().encode(frames.map(frame => `data: ${JSON.stringify(frame)}\n\n`).join(''));
-    let sent = false;
-    return { ok: true, status: 200, body: { getReader: () => ({
-        read: async () => (sent ? { done: true } : (sent = true, { done: false, value: bytes })),
-    }) } };
-}
-
 function load(file, className, fetchUrl, extra = {}, dom = elements()) {
     const timers = [];
     const notifications = [];
@@ -63,8 +55,6 @@ function load(file, className, fetchUrl, extra = {}, dom = elements()) {
     return { page, dom, timers, notifications, storage };
 }
 
-const BUSY = 'Scan for metadata already running';
-
 test('admin settings save shows why config.json refused it', async () => {
     const message = 'config.json cannot be read, so nothing was saved. Fix or remove the file, then save again.';
     const { page, notifications } = load('admin.js', 'PromptAdmin',
diff --git a/tests/test_api_admin.py b/tests/test_api_admin.py
index 755a5369..98f424cc 100644
--- a/tests/test_api_admin.py
+++ b/tests/test_api_admin.py
@@ -2584,7 +2584,7 @@ class TestActivityJobs(AdminAPITestCase):
     async def test_cancel_after_first_batch_keeps_partial_counts(self):
         """Review M7: the real scan stops at the batch boundary, keeping batch 1."""
         import threading
-        from unittest import mock
+        import unittest.mock as mock
 
         from py.api import admin
 
diff --git a/tests/test_api_autotag.py b/tests/test_api_autotag.py
index 4b009ba8..1ef568b2 100644
--- a/tests/test_api_autotag.py
+++ b/tests/test_api_autotag.py
@@ -600,6 +600,33 @@ class TestAutotagSingleEdgeCases(AutotagAPITestCase):
             {"path": str(image), "general_threshold": "high"},
         )
         self.assertEqual(resp.status, 400)
+        self.assertEqual(
+            (await resp.json())["error"],
+            "general_threshold and character_threshold must be numeric",
+        )
+
+    async def test_invalid_single_options_report_the_validation_error(self) -> None:
+        image = self._make_image(self.output_dir)
+        cases = (
+            (
+                {"model_type": "wd14-vit", "general_threshold": 2},
+                "general_threshold must be between 0 and 1",
+            ),
+            (
+                {"model_type": "gguf", "prompt": "x" * 4001},
+                "instructions must be at most 4000 characters",
+            ),
+        )
+        for options, message in cases:
+            with self.subTest(options=options["model_type"]):
+                resp = await self._post_json(
+                    "/prompt_manager/autotag/single",
+                    {"path": str(image), **options},
+                )
+                self.assertEqual(resp.status, 400)
+                self.assertEqual(
+                    await resp.json(), {"success": False, "error": message}
+                )
 
     async def test_prompt_lookup_failure_still_returns_tags(self):
         image = self._make_image(self.output_dir)
@@ -1151,7 +1178,9 @@ class TestModelStatus(AutotagAPITestCase):
         )
         # Kept fields legacy pages and the workspace read.
         for model in models.values():
-            self.assertTrue({"name", "description", "size", "downloaded"} <= set(model))
+            self.assertLessEqual(
+                {"name", "description", "size", "downloaded"}, set(model)
+            )
         self.assertTrue(data["model_loaded"])
         self.assertEqual(data["loaded_model_type"], "wd14-vit")
 
diff --git a/tests/test_api_core.py b/tests/test_api_core.py
index 7d7d1958..96f17862 100644
--- a/tests/test_api_core.py
+++ b/tests/test_api_core.py
@@ -351,8 +351,6 @@ class TestLongJobLock(unittest.TestCase):
         self.api = PromptManagerAPI(db=database)
 
     def _run(self, coro):
-        import asyncio
-
         return asyncio.run(coro)
 
     def test_second_acquire_is_refused_until_first_releases(self):
@@ -825,8 +823,6 @@ class TestInstanceHelpers(FolderPathsFixture):
         self.addCleanup(setattr, GalleryConfig, "MONITORING_DIRECTORIES", orig_dirs)
 
     def _run(self, coro):
-        import asyncio
-
         return asyncio.run(coro)
 
     def test_run_in_executor_with_kwargs(self):
diff --git a/tests/test_api_diagnostics_report.py b/tests/test_api_diagnostics_report.py
index 8b6ef318..be8b3c7d 100644
--- a/tests/test_api_diagnostics_report.py
+++ b/tests/test_api_diagnostics_report.py
@@ -16,7 +16,7 @@ import re
 import sqlite3
 import sys
 import unittest
-from unittest import mock
+import unittest.mock as mock
 from unittest.mock import MagicMock
 
 _mock_server = MagicMock()
diff --git a/tests/test_api_duplicate_safety.py b/tests/test_api_duplicate_safety.py
index 8ae50edb..402b48ab 100644
--- a/tests/test_api_duplicate_safety.py
+++ b/tests/test_api_duplicate_safety.py
@@ -381,7 +381,7 @@ class TestAnotherMount(SafetyTestCase):
         self.assertTrue(other.is_file() and keeper.is_file())
 
     async def test_a_volume_without_file_ids_is_named_truthfully(self):
-        keeper, other, patches = self.mount("x.png", "x.png")
+        self.mount("x.png", "x.png")
 
         def zero(path, *args, **kwargs):
             return _fake_stat(self.real_stat(path), st_dev=0, st_ino=0)
diff --git a/tests/test_api_images.py b/tests/test_api_images.py
index c1772f66..580fb12a 100644
--- a/tests/test_api_images.py
+++ b/tests/test_api_images.py
@@ -3713,7 +3713,7 @@ class TestSharedListing(ImageAPITestCase):
 
     async def test_a_root_read_again_after_the_roots_change_listens_again(self):
         make_png(self.output_dir / "a.png")
-        record = await self._listed()
+        await self._listed()
         self.api.reset_gallery_roots_cache()
         record = await self._listed()  # still configured: read and walked
         self._interval(0)
diff --git a/tests/test_api_maintenance.py b/tests/test_api_maintenance.py
index 749a3af3..f700aa64 100644
--- a/tests/test_api_maintenance.py
+++ b/tests/test_api_maintenance.py
@@ -675,7 +675,7 @@ class TestBackupPoolAndDiskSpace(ApplyTestCase):
         self.assertEqual(len(backups), MAX_SAFETY_BACKUPS)
         self.assertNotIn(restore_style[0], backups)
         self.assertNotIn(restore_style[1], backups)
-        self.assertTrue(set(maintenance_style) <= set(backups))
+        self.assertLessEqual(set(maintenance_style), set(backups))
         # A restore prunes the same pool, maintenance backups included.
         self.old_backup("prompts.db.backup_20020101_000000", 3000)
         _prune_safety_backups(self.api.db.model.db_path)
diff --git a/tests/test_browser_fast_reset.py b/tests/test_browser_fast_reset.py
index c23fae43..971c40ba 100644
--- a/tests/test_browser_fast_reset.py
+++ b/tests/test_browser_fast_reset.py
@@ -11,7 +11,7 @@ import time
 import types
 import unittest
 from pathlib import Path
-from unittest import mock
+import unittest.mock as mock
 
 try:
     from tests.open_handles import assert_closed
diff --git a/tests/test_browser_malloc_tuning.py b/tests/test_browser_malloc_tuning.py
index d578fc9c..4345f064 100644
--- a/tests/test_browser_malloc_tuning.py
+++ b/tests/test_browser_malloc_tuning.py
@@ -6,7 +6,7 @@ Large frees then go back to the OS instead of fragmenting per-thread arenas.
 import ctypes
 import sys
 import unittest
-from unittest import mock
+import unittest.mock as mock
 
 from tests.browser import malloc_tuning
 
diff --git a/tests/test_browser_slow_reset_watch.py b/tests/test_browser_slow_reset_watch.py
index 569983b8..3d211c65 100644
--- a/tests/test_browser_slow_reset_watch.py
+++ b/tests/test_browser_slow_reset_watch.py
@@ -46,7 +46,6 @@ class TestResetWatch(unittest.TestCase):
         self.assertFalse(is_reset_path("/__test__/reset/extra"))
 
     def test_a_stalled_reset_reports_state_and_stacks_while_it_waits(self):
-        stream = io.StringIO()
         reported = threading.Event()
 
         class Stream(io.StringIO):
diff --git a/tests/test_bulk_library_delete.py b/tests/test_bulk_library_delete.py
index 7fce13e1..7c1aa7b5 100644
--- a/tests/test_bulk_library_delete.py
+++ b/tests/test_bulk_library_delete.py
@@ -385,8 +385,8 @@ class TestArchivedReaders(LibraryDeleteCase):
 
     def setUp(self):
         super().setUp()
-        self.kept, _kn, _kp = self.paired("Kept cat", "kept blur")
-        self.gone, _gn, _gp = self.paired("Gone cat", "gone blur")
+        self.kept, _, _ = self.paired("Kept cat", "kept blur")
+        self.gone, _, _ = self.paired("Gone cat", "gone blur")
         for pid, category, tag in ((self.kept, "keep", "k"), (self.gone, "gone", "g")):
             self.db.update_prompt_metadata(pid, category=category, tags=[tag])
         self.apply([self.gone])
@@ -642,7 +642,7 @@ class TestPairedDelete(LibraryDeleteCase):
         # The negatives stay, and the image file stays on disk.
         self.assertTrue((self.root / "owl.png").exists())
         texts = [row[0] for row in rows(self.db, "SELECT text FROM prompts")]
-        self.assertTrue({"dark", "fog", "Bystander"} <= set(texts))
+        self.assertLessEqual({"dark", "fog", "Bystander"}, set(texts))
 
     def test_a_negative_used_by_another_positive_is_archived_never_deleted(self):
         shared = save(self.db, "Shared")
diff --git a/tests/test_cached_runs.py b/tests/test_cached_runs.py
index bd52416c..ed726220 100644
--- a/tests/test_cached_runs.py
+++ b/tests/test_cached_runs.py
@@ -14,7 +14,7 @@ import threading
 import types
 import unittest
 from collections import namedtuple
-from unittest import mock
+import unittest.mock as mock
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
diff --git a/tests/test_database_migrations.py b/tests/test_database_migrations.py
index 544d0fb9..47a67b13 100644
--- a/tests/test_database_migrations.py
+++ b/tests/test_database_migrations.py
@@ -140,8 +140,10 @@ class TestIdempotentMigrations(MigrationTestCase):
     def test_stale_prompts_new_from_a_failed_rebuild_does_not_block_startup(self):
         self._legacy_db(
             [
-                "INSERT INTO prompts (text, hash, workflow_name)"
-                " VALUES ('a', 'h1', 'wf')",
+                (
+                    "INSERT INTO prompts (text, hash, workflow_name)"
+                    " VALUES ('a', 'h1', 'wf')"
+                ),
                 "CREATE TABLE prompts_new (id INTEGER PRIMARY KEY, junk TEXT)",
                 "INSERT INTO prompts_new (junk) VALUES ('leftover')",
             ]
@@ -157,10 +159,14 @@ class TestIdempotentMigrations(MigrationTestCase):
         # DROP TABLE prompts with foreign keys ON cascades into generated_images
         self._legacy_db(
             [
-                "INSERT INTO prompts (text, hash, workflow_name)"
-                " VALUES ('a', 'h1', 'wf')",
-                "INSERT INTO generated_images (prompt_id, image_path, filename)"
-                " VALUES (1, '/out/a.png', 'a.png')",
+                (
+                    "INSERT INTO prompts (text, hash, workflow_name)"
+                    " VALUES ('a', 'h1', 'wf')"
+                ),
+                (
+                    "INSERT INTO generated_images (prompt_id, image_path, filename)"
+                    " VALUES (1, '/out/a.png', 'a.png')"
+                ),
             ]
         )
 
@@ -172,11 +178,15 @@ class TestIdempotentMigrations(MigrationTestCase):
     def test_rebuild_keeps_library_state_rows(self):
         self._legacy_db(
             [
-                "INSERT INTO prompts (text, hash, workflow_name)"
-                " VALUES ('a', 'h1', 'wf')",
-                "CREATE TABLE prompt_library_state (prompt_id INTEGER PRIMARY KEY,"
-                " title TEXT, FOREIGN KEY(prompt_id) REFERENCES prompts(id)"
-                " ON DELETE CASCADE)",
+                (
+                    "INSERT INTO prompts (text, hash, workflow_name)"
+                    " VALUES ('a', 'h1', 'wf')"
+                ),
+                (
+                    "CREATE TABLE prompt_library_state (prompt_id INTEGER PRIMARY KEY,"
+                    " title TEXT, FOREIGN KEY(prompt_id) REFERENCES prompts(id)"
+                    " ON DELETE CASCADE)"
+                ),
                 "INSERT INTO prompt_library_state VALUES (1, 'kept')",
             ]
         )
@@ -232,43 +242,59 @@ class TestIdempotentMigrations(MigrationTestCase):
         byte_id = "6a1b2c3d-4e5f-4a6b-8c9d-0e1f2a3b4c5d"
         self._legacy_db(
             [
-                "INSERT INTO prompts (text, hash, workflow_name)"
-                " VALUES ('a', 'h1', 'wf')",
-                "CREATE TABLE tags (id INTEGER PRIMARY KEY AUTOINCREMENT,"
-                " name TEXT NOT NULL UNIQUE)",
+                (
+                    "INSERT INTO prompts (text, hash, workflow_name)"
+                    " VALUES ('a', 'h1', 'wf')"
+                ),
+                (
+                    "CREATE TABLE tags (id INTEGER PRIMARY KEY AUTOINCREMENT,"
+                    " name TEXT NOT NULL UNIQUE)"
+                ),
                 "INSERT INTO tags (id, name) VALUES (3, 'img-only')",
-                "CREATE TABLE media_annotation_metadata (singleton_id INTEGER"
-                " PRIMARY KEY CHECK(singleton_id=1), schema_version INTEGER NOT"
-                " NULL CHECK(schema_version=1), image_index_revision INTEGER NOT"
-                " NULL DEFAULT 0 CHECK(image_index_revision>=0))",
+                (
+                    "CREATE TABLE media_annotation_metadata (singleton_id INTEGER"
+                    " PRIMARY KEY CHECK(singleton_id=1), schema_version INTEGER NOT"
+                    " NULL CHECK(schema_version=1), image_index_revision INTEGER NOT"
+                    " NULL DEFAULT 0 CHECK(image_index_revision>=0))"
+                ),
                 "INSERT INTO media_annotation_metadata VALUES (1, 1, 4)",
-                "CREATE TABLE media_annotation_files (id TEXT PRIMARY KEY"
-                " CHECK(length(id)=36), locator TEXT NOT NULL UNIQUE,"
-                " created_at TEXT NOT NULL)",
+                (
+                    "CREATE TABLE media_annotation_files (id TEXT PRIMARY KEY"
+                    " CHECK(length(id)=36), locator TEXT NOT NULL UNIQUE,"
+                    " created_at TEXT NOT NULL)"
+                ),
                 f"INSERT INTO media_annotation_files VALUES ('{file_id}',"
                 " '/out/a.png', '2026-10-22T00:00:00.000000+00:00')",
-                "CREATE TABLE media_annotation_bytes (id TEXT PRIMARY KEY"
-                " CHECK(length(id)=36), file_id TEXT NOT NULL REFERENCES"
-                " media_annotation_files(id) ON DELETE CASCADE, sha256 TEXT NOT"
-                " NULL CHECK(length(sha256)=64 AND sha256 NOT GLOB"
-                " '*[^0-9a-f]*'), size INTEGER NOT NULL CHECK(size>=0), mtime_ns"
-                " INTEGER NOT NULL, verified_at TEXT NOT NULL, first_seen_at TEXT"
-                " NOT NULL, tag_revision INTEGER NOT NULL DEFAULT 0"
-                " CHECK(tag_revision>=0), UNIQUE(file_id, sha256))",
-                "CREATE INDEX idx_media_annotation_bytes_fingerprint ON"
-                " media_annotation_bytes(file_id, size, mtime_ns)",
+                (
+                    "CREATE TABLE media_annotation_bytes (id TEXT PRIMARY KEY"
+                    " CHECK(length(id)=36), file_id TEXT NOT NULL REFERENCES"
+                    " media_annotation_files(id) ON DELETE CASCADE, sha256 TEXT NOT"
+                    " NULL CHECK(length(sha256)=64 AND sha256 NOT GLOB"
+                    " '*[^0-9a-f]*'), size INTEGER NOT NULL CHECK(size>=0), mtime_ns"
+                    " INTEGER NOT NULL, verified_at TEXT NOT NULL, first_seen_at TEXT"
+                    " NOT NULL, tag_revision INTEGER NOT NULL DEFAULT 0"
+                    " CHECK(tag_revision>=0), UNIQUE(file_id, sha256))"
+                ),
+                (
+                    "CREATE INDEX idx_media_annotation_bytes_fingerprint ON"
+                    " media_annotation_bytes(file_id, size, mtime_ns)"
+                ),
                 f"INSERT INTO media_annotation_bytes VALUES ('{byte_id}',"
                 f" '{file_id}', '{'a' * 64}', 3, 1700000000000000000,"
                 " '2026-10-22T00:00:00.000000+00:00',"
                 " '2026-10-22T00:00:00.000000+00:00', 2)",
-                "CREATE TABLE media_image_tags (byte_id TEXT NOT NULL REFERENCES"
-                " media_annotation_bytes(id) ON DELETE CASCADE, tag_id INTEGER"
-                " NOT NULL REFERENCES tags(id) ON DELETE CASCADE, position"
-                " INTEGER NOT NULL CHECK(position>=0), PRIMARY KEY(byte_id,"
-                " tag_id))",
+                (
+                    "CREATE TABLE media_image_tags (byte_id TEXT NOT NULL REFERENCES"
+                    " media_annotation_bytes(id) ON DELETE CASCADE, tag_id INTEGER"
+                    " NOT NULL REFERENCES tags(id) ON DELETE CASCADE, position"
+                    " INTEGER NOT NULL CHECK(position>=0), PRIMARY KEY(byte_id,"
+                    " tag_id))"
+                ),
                 "CREATE INDEX idx_media_image_tags_tag ON media_image_tags(tag_id)",
-                "CREATE UNIQUE INDEX idx_media_image_tags_position ON"
-                " media_image_tags(byte_id, position)",
+                (
+                    "CREATE UNIQUE INDEX idx_media_image_tags_position ON"
+                    " media_image_tags(byte_id, position)"
+                ),
                 f"INSERT INTO media_image_tags VALUES ('{byte_id}', 3, 0)",
             ]
         )
@@ -367,18 +393,28 @@ class TestIdempotentMigrations(MigrationTestCase):
     def test_image_table_is_rebuilt_with_uniqueness_by_full_path(self):
         self._legacy_db(
             [
-                "INSERT INTO prompts (text, hash, workflow_name)"
-                " VALUES ('a', 'h1', 'wf')",
+                (
+                    "INSERT INTO prompts (text, hash, workflow_name)"
+                    " VALUES ('a', 'h1', 'wf')"
+                ),
                 # same basename in two folders: both must survive
-                "INSERT INTO generated_images (prompt_id, image_path, filename)"
-                " VALUES (1, '/out/2026-01-01/a.png', 'a.png')",
-                "INSERT INTO generated_images (prompt_id, image_path, filename)"
-                " VALUES (1, '/out/2026-01-02/a.png', 'a.png')",
+                (
+                    "INSERT INTO generated_images (prompt_id, image_path, filename)"
+                    " VALUES (1, '/out/2026-01-01/a.png', 'a.png')"
+                ),
+                (
+                    "INSERT INTO generated_images (prompt_id, image_path, filename)"
+                    " VALUES (1, '/out/2026-01-02/a.png', 'a.png')"
+                ),
                 # two spellings of one file: only the newest row survives
-                "INSERT INTO generated_images (prompt_id, image_path, filename)"
-                " VALUES (1, '/out/x/../b.png', 'b.png')",
-                "INSERT INTO generated_images (prompt_id, image_path, filename)"
-                " VALUES (1, '/out/b.png', 'b.png')",
+                (
+                    "INSERT INTO generated_images (prompt_id, image_path, filename)"
+                    " VALUES (1, '/out/x/../b.png', 'b.png')"
+                ),
+                (
+                    "INSERT INTO generated_images (prompt_id, image_path, filename)"
+                    " VALUES (1, '/out/b.png', 'b.png')"
+                ),
             ]
         )
 
diff --git a/tests/test_diagnostics_config.py b/tests/test_diagnostics_config.py
index 2fca7ac4..e3cfb3e1 100644
--- a/tests/test_diagnostics_config.py
+++ b/tests/test_diagnostics_config.py
@@ -182,7 +182,7 @@ class TestAdminEndpointsUseConfigPath(unittest.TestCase):
                 self.assertIsNone(warning)
                 self.assertEqual(os.path.dirname(snapshot), folder)
                 with open(snapshot, "rb") as handle:
-                    self.assertTrue(handle.read(16) == b"SQLite format 3\x00")
+                    self.assertEqual(handle.read(16), b"SQLite format 3\x00")
             finally:
                 os.unlink(snapshot)
         finally:
diff --git a/tests/test_execution_history_events.py b/tests/test_execution_history_events.py
index 76a1474f..f2742e6b 100644
--- a/tests/test_execution_history_events.py
+++ b/tests/test_execution_history_events.py
@@ -31,6 +31,20 @@ def message(kind, job_id=JOB, **fields):
     return (kind, {"prompt_id": job_id, **fields})
 
 
+def hash_recording_kind():
+    """A str subclass for event kinds, and the list of hashes taken of it."""
+    hashed = []
+
+    class OversizedKind(str):
+        __eq__ = str.__eq__
+
+        def __hash__(self):
+            hashed.append(len(self))
+            return str.__hash__(self)
+
+    return OversizedKind, hashed
+
+
 def finish(messages, completed=True):
     return make_finish(SESSION, 0, EPOCH, Status("success", completed, messages), 500)
 
@@ -346,13 +360,10 @@ class ExecutionHistoryEventsTests(unittest.TestCase):
         self.assertLessEqual(len(encode_command(command)), 2048)
 
     def test_oversized_unknown_kind_is_ignored_without_hashing(self):
-        class OversizedKind(str):
-            def __hash__(self):
-                raise AssertionError("Oversized event kind must not be hashed")
-
+        kind_class, hashed = hash_recording_kind()
         command = finish(
             [
-                message(OversizedKind("x" * 1_000_000)),
+                message(kind_class("x" * 1_000_000)),
                 message("execution_success", timestamp=300),
             ]
         )
@@ -361,19 +372,16 @@ class ExecutionHistoryEventsTests(unittest.TestCase):
             (result.outcome, result.reason), ("succeeded", "terminal_success")
         )
         self.assertLessEqual(len(encode_command(command)), 2048)
+        self.assertEqual(hashed, [], "Oversized event kind must not be hashed")
 
     def test_encoder_rejects_oversized_kind_without_hashing(self):
-        class OversizedKind(str):
-            def __hash__(self):
-                raise AssertionError("Oversized event kind must not be hashed")
-
+        kind_class, hashed = hash_recording_kind()
         command = finish([message("execution_success")])
-        event = LifecycleEvent(
-            OversizedKind("x" * 1_000_000), JOB, None, None, None, None
-        )
+        event = LifecycleEvent(kind_class("x" * 1_000_000), JOB, None, None, None, None)
         with self.assertRaises(ValueError):
             encode_command(
                 replace(
                     command, evidence=TerminalEvidence((event,), False, False, False)
                 )
             )
+        self.assertEqual(hashed, [], "Oversized event kind must not be hashed")
diff --git a/tests/test_execution_output_capture.py b/tests/test_execution_output_capture.py
index 4bf86b9d..423bc26f 100644
--- a/tests/test_execution_output_capture.py
+++ b/tests/test_execution_output_capture.py
@@ -17,7 +17,7 @@ class Hostile:
         raise AssertionError("host scalar coercion")
 
     def __bool__(self):
-        raise AssertionError("host truth test")
+        raise TypeError("host truth test")
 
     def __eq__(self, other):
         raise AssertionError("host equality")
diff --git a/tests/test_exit_cancel.py b/tests/test_exit_cancel.py
index e3fb5ba5..5eeab498 100644
--- a/tests/test_exit_cancel.py
+++ b/tests/test_exit_cancel.py
@@ -24,7 +24,7 @@ import tempfile
 import textwrap
 import threading
 import unittest
-from unittest import mock
+import unittest.mock as mock
 
 ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 sys.path.insert(0, ROOT)
diff --git a/tests/test_exit_window_threads.py b/tests/test_exit_window_threads.py
index 1323f4db..30e39bdd 100644
--- a/tests/test_exit_window_threads.py
+++ b/tests/test_exit_window_threads.py
@@ -26,7 +26,7 @@ import types
 import unittest
 from concurrent.futures import ThreadPoolExecutor
 from pathlib import Path
-from unittest import mock
+import unittest.mock as mock
 
 from py.api import thumbnail_auto
 from utils import image_monitor, parallel
diff --git a/tests/test_file_prompt.py b/tests/test_file_prompt.py
index c4dadfed..8b525659 100644
--- a/tests/test_file_prompt.py
+++ b/tests/test_file_prompt.py
@@ -7,7 +7,7 @@ I/O: history comes in through ``lookup``.
 
 import json
 import unittest
-from unittest import mock
+import unittest.mock as mock
 
 from database.run_attribution import RecordedOutput
 from tests.test_pair_scan import flux_graph, sampled_graph
diff --git a/tests/test_focused_node.py b/tests/test_focused_node.py
index 5e9a2ef1..3e7bbd8f 100644
--- a/tests/test_focused_node.py
+++ b/tests/test_focused_node.py
@@ -2,7 +2,7 @@
 
 import logging
 import unittest
-from unittest import mock
+import unittest.mock as mock
 
 from prompt_manager import PromptManager, PromptManagerFocused
 from utils.prompt_graph import positive_prompt_nodes, run_prompt_nodes
diff --git a/tests/test_gallery_listing.py b/tests/test_gallery_listing.py
index ca796bfe..0e2ebf7f 100644
--- a/tests/test_gallery_listing.py
+++ b/tests/test_gallery_listing.py
@@ -312,7 +312,7 @@ class RootContainsTests(unittest.TestCase):
         root = os.path.normcase(os.path.realpath(tempfile.gettempdir()))
         inside = os.path.join(root, "x.png")
         self.assertTrue(root_contains(root, inside))
-        self.assertTrue(root_contains(root, inside.upper()) == (os.name == "nt"))
+        self.assertEqual(root_contains(root, inside.upper()), os.name == "nt")
 
 
 if __name__ == "__main__":
diff --git a/tests/test_init_package.py b/tests/test_init_package.py
index 43661084..01ab75b5 100644
--- a/tests/test_init_package.py
+++ b/tests/test_init_package.py
@@ -527,7 +527,7 @@ class TestPackageLoggerIsolation(unittest.TestCase):
         def log_from_background_thread():
             try:
                 logging.getLogger("prompt_manager.late_emitter").warning(message)
-            except BaseException as error:
+            except Exception as error:
                 errors.append(error)
 
         self.handler.addFilter(pause_before_handler_lock)
diff --git a/tests/test_library.py b/tests/test_library.py
index 24540f24..e7585639 100644
--- a/tests/test_library.py
+++ b/tests/test_library.py
@@ -143,8 +143,6 @@ class TestLibrary(unittest.TestCase):
             self.db.get_library_positive(positive, variant_limit=201)
 
     def test_sorts_keysets_survive_anchor_deletion_and_insertions_without_writes(self):
-        import sqlite3
-
         a = self.save("Alpha", rating=2, tags=["tag"])
         b = self.save("beta", rating=5)
         c = self.save("charlie")
diff --git a/tests/test_library_delete_routes.py b/tests/test_library_delete_routes.py
index 1582cbc7..4e3b1bf0 100644
--- a/tests/test_library_delete_routes.py
+++ b/tests/test_library_delete_routes.py
@@ -297,7 +297,7 @@ class TestLibraryDeleteRoutes(LibraryDeleteRouteCase):
         )
         page = await response.json()
         self.assertEqual(page["archived_total"], 3)
-        self.assertTrue(set(item["id"] for item in page["items"]) <= set(kept))
+        self.assertLessEqual(set(item["id"] for item in page["items"]), set(kept))
         response = await self.client.request(
             "GET",
             "/prompt_manager/library?limit=2&shelf=archived"
diff --git a/tests/test_library_location_wiring.py b/tests/test_library_location_wiring.py
index d2fa31af..a0087b30 100644
--- a/tests/test_library_location_wiring.py
+++ b/tests/test_library_location_wiring.py
@@ -135,6 +135,7 @@ class TestLogsAndCache(_EnvCase):
 
             get_logger_manager()._setup_loggers()
         except Exception:
+            # best effort restore in teardown; must not hide the test result
             pass
 
     def test_lora_image_cache_follows_the_data_folder(self):
diff --git a/tests/test_library_move.py b/tests/test_library_move.py
index 9a450fde..868da97d 100644
--- a/tests/test_library_move.py
+++ b/tests/test_library_move.py
@@ -18,7 +18,7 @@ import tempfile
 import threading
 import types
 import unittest
-from unittest import mock
+import unittest.mock as mock
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
diff --git a/tests/test_library_move_review.py b/tests/test_library_move_review.py
index 57f61c31..1d1fd60d 100644
--- a/tests/test_library_move_review.py
+++ b/tests/test_library_move_review.py
@@ -22,7 +22,7 @@ import sqlite3
 import sys
 import threading
 import unittest
-from unittest import mock
+import unittest.mock as mock
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
diff --git a/tests/test_local_inspect_parity.py b/tests/test_local_inspect_parity.py
index e5ab5dde..e8c45d55 100644
--- a/tests/test_local_inspect_parity.py
+++ b/tests/test_local_inspect_parity.py
@@ -1112,10 +1112,10 @@ class LocalProjectionParityTests(unittest.TestCase):
                 self.assertEqual(_canonical_bytes(local), _canonical_bytes(server))
                 seen.update(server["record_formats"].values())
                 seen.add(server["workflow_graph"]["status"])
-        self.assertTrue(
-            {"reserialized-json", "original-text", "invalid", "limited"} <= seen
+        self.assertLessEqual(
+            {"reserialized-json", "original-text", "invalid", "limited"}, seen
         )
-        self.assertTrue({"parsed", "malformed", "limited"} <= seen)
+        self.assertLessEqual({"parsed", "malformed", "limited"}, seen)
 
 
 def _server_evidence(records, file_name=None):
@@ -1287,7 +1287,7 @@ class LocalResolverParityTests(unittest.TestCase):
     def test_local_roles_match_selection_record_sets(self):
         answers = self._compare(selection_cases.selection_cases())
         reasons = {answer["resolution"]["reason"] for answer in answers.values()}
-        self.assertTrue(
+        self.assertLessEqual(
             {
                 "Every sampler branch uses the same prompt pair",
                 "Multiple sampler branches",
@@ -1301,8 +1301,8 @@ class LocalResolverParityTests(unittest.TestCase):
                 "Negative prompt delimiter is absent",
                 "Parameters exceed the length limit",
                 "No A1111 parameters",
-            }
-            <= reasons
+            },
+            reasons,
         )
         # A stage reaching only previews is dropped: one sampler is named.
         self.assertEqual(
@@ -1352,7 +1352,7 @@ class LocalResolverParityTests(unittest.TestCase):
     def test_local_roles_match_golden_record_sets(self):
         answers = self._compare(resolver_cases.golden_cases())
         codes = {answer["resolution"]["reason_code"] for answer in answers.values()}
-        self.assertTrue(
+        self.assertLessEqual(
             {
                 "malformed",
                 "unsupported-node",
@@ -1364,16 +1364,16 @@ class LocalResolverParityTests(unittest.TestCase):
                 "graph-ceiling",
                 "no-sampler",
                 None,
-            }
-            <= codes
+            },
+            codes,
         )
         sources = {
             side["source"]
             for answer in answers.values()
             for side in answer["prompts"].values()
         }
-        self.assertTrue(
-            {"execution", "graph-inferred", "zeroed-conditioning"} <= sources
+        self.assertLessEqual(
+            {"execution", "graph-inferred", "zeroed-conditioning"}, sources
         )
 
     def test_committed_resolver_vectors_are_current(self):
diff --git a/tests/test_lora_database.py b/tests/test_lora_database.py
index 648b8213..8a913f0c 100644
--- a/tests/test_lora_database.py
+++ b/tests/test_lora_database.py
@@ -197,7 +197,7 @@ class TestGetPromptSubfolders(LoraDBTestCase):
 
     def test_subfolders_use_forward_slashes_on_every_platform(self):
         """Clients split folders on "/" whatever separator the OS produced."""
-        from unittest import mock
+        import unittest.mock as mock
 
         import database.operations as operations
 
diff --git a/tests/test_lora_manager_layout.py b/tests/test_lora_manager_layout.py
index 8af50902..adb0f4f2 100644
--- a/tests/test_lora_manager_layout.py
+++ b/tests/test_lora_manager_layout.py
@@ -584,9 +584,6 @@ class CentralizedDiscoveryTests(LayoutTestCase):
     def test_an_unlistable_folder_raises(self):
         layout = self.load()
 
-        def refuse(error):
-            raise error
-
         def failing_walk(top, onerror=None, followlinks=False):
             onerror(PermissionError(13, "denied", top))
             return iter(())
diff --git a/tests/test_managed_connection.py b/tests/test_managed_connection.py
index b33d437a..c5b13542 100644
--- a/tests/test_managed_connection.py
+++ b/tests/test_managed_connection.py
@@ -15,7 +15,7 @@ import tempfile
 import threading
 import unittest
 import weakref
-from unittest import mock
+import unittest.mock as mock
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
@@ -154,6 +154,116 @@ class TestRetire(_Case):
 
 
 class TestCalls(_Case):
+    def test_iteration_and_fetches_share_one_position(self) -> None:
+        conn = self.connect()
+        conn.executemany("INSERT INTO t VALUES (?)", [(x,) for x in range(1, 260)])
+        cursor = conn.execute("SELECT x FROM t ORDER BY x")
+        self.assertIs(iter(cursor), cursor)
+        self.assertEqual(next(cursor), (0,))
+        self.assertEqual(cursor.fetchone(), (1,))
+        self.assertEqual(cursor.fetchmany(2), [(2,), (3,)])
+        self.assertEqual(next(iter(cursor)), (4,))
+        self.assertEqual(cursor.fetchall(), [(x,) for x in range(5, 260)])
+        self.assertEqual(list(cursor), [])
+
+    def test_a_partial_loop_can_resume_without_skipping_rows(self) -> None:
+        cursor = self.connect().execute(
+            "SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3"
+        )
+        for row in cursor:
+            self.assertEqual(row, (1,))
+            break
+        self.assertEqual(list(cursor), [(2,), (3,)])
+
+    def test_an_existing_iterator_refuses_reads_after_retire_or_close(self) -> None:
+        for retire in (False, True):
+            with self.subTest(retire=retire):
+                conn = self.connect()
+                cursor = conn.execute("SELECT 1 UNION ALL SELECT 2")
+                iterator = iter(cursor)
+                self.assertEqual(next(iterator), (1,))
+                if retire:
+                    conn.retire()
+                else:
+                    cursor.close()
+                with self.assertRaises(sqlite3.ProgrammingError):
+                    next(iterator)
+
+    def test_buffered_fetchmany_matches_sqlite_sizes_and_validation(self) -> None:
+        conn = self.connect()
+        conn.executemany("INSERT INTO t VALUES (?)", [(x,) for x in range(1, 260)])
+        conn.commit()
+        with contextlib.closing(sqlite3.connect(self.path)) as plain:
+            for size in (None, 0, 1, 2, 127, 128, 130, 300, -1):
+                with self.subTest(size=size):
+                    cursors = [
+                        c.execute("SELECT x FROM t ORDER BY x") for c in (plain, conn)
+                    ]
+                    for cursor in cursors:
+                        cursor.arraysize = 2
+                        self.assertEqual(next(iter(cursor)), (0,))
+                    results = []
+                    for cursor in cursors:
+                        try:
+                            rows = (
+                                cursor.fetchmany()
+                                if size is None
+                                else cursor.fetchmany(size)
+                            )
+                        except ValueError as error:  # Negative sizes on Python 3.14+.
+                            rows = type(error)
+                        results.append((rows, cursor.fetchall()))
+                    self.assertEqual(*results)
+        for args, kwargs in ((("bad",), {}), ((1, 2), {}), ((), {"unknown": 1})):
+            cursor = conn.execute("SELECT 1 UNION ALL SELECT 2")
+            self.assertEqual(next(iter(cursor)), (1,))
+            with self.assertRaises(TypeError):
+                cursor.fetchmany(*args, **kwargs)
+            self.assertEqual(cursor.fetchone(), (2,))
+
+    def test_reexecuting_a_cursor_matches_sqlite_result_lifetime(self) -> None:
+        conn = self.connect()
+        conn.row_factory = sqlite3.Row
+        for method, args in (
+            ("execute", ("SELECT 9 AS x",)),
+            ("executemany", ("INSERT INTO t VALUES (?)", [(9,)])),
+            ("executescript", ("SELECT 9 AS x;",)),
+        ):
+            with self.subTest(method=method):
+                cursor = conn.execute("SELECT 1 AS x UNION ALL SELECT 2")
+                self.assertEqual(next(iter(cursor))["x"], 1)
+                self.assertIs(getattr(cursor, method)(*args), cursor)
+                if method == "execute":
+                    self.assertEqual(cursor.fetchone()["x"], 9)
+                elif method == "executescript":
+                    self.assertEqual(cursor.fetchone()["x"], 2)
+                self.assertEqual(list(cursor), [])
+
+    def test_failed_execution_matches_sqlite_result_lifetime(self) -> None:
+        conn = self.connect()
+        cases = (
+            ("execute", (None,)),
+            ("execute", ("invalid sql",)),
+            ("execute", ("SELECT ?", ())),
+            ("executemany", (None, [])),
+            ("executemany", ("SELECT 9", [])),
+            ("executescript", (None,)),
+            ("executescript", ("invalid sql;",)),
+        )
+        with contextlib.closing(sqlite3.connect(self.path)) as plain:
+            for method, args in cases:
+                with self.subTest(method=method, args=args):
+                    results = []
+                    for connection in (plain, conn):
+                        cursor = connection.execute("SELECT 1 UNION ALL SELECT 2")
+                        self.assertEqual(next(iter(cursor)), (1,))
+                        with self.assertRaises(
+                            sqlite3.Error if isinstance(args[0], str) else TypeError
+                        ):
+                            getattr(cursor, method)(*args)
+                        results.append(cursor.fetchall())
+                    self.assertEqual(*results)
+
     def test_every_cursor_call_works_and_is_refused_once_retired(self):
         conn = self.connect()
         conn.row_factory = sqlite3.Row
diff --git a/tests/test_media_capture.py b/tests/test_media_capture.py
index f4cc0b53..e4790f1e 100644
--- a/tests/test_media_capture.py
+++ b/tests/test_media_capture.py
@@ -347,7 +347,7 @@ class CaptureStoreTestCase(unittest.TestCase):
         with patch.object(CaptureStore, "_read", rewriting):
             try:
                 cap = store.capture(self.root, "a.png", epoch=EPOCH, scope=SCOPE)
-            except CaptureChanged:
+            except capture_module.CaptureChanged:
                 detected = True
             else:
                 detected = False
diff --git a/tests/test_prompt_attribution.py b/tests/test_prompt_attribution.py
index 7cf3d101..229ff860 100644
--- a/tests/test_prompt_attribution.py
+++ b/tests/test_prompt_attribution.py
@@ -14,7 +14,7 @@ import sys
 import tempfile
 import threading
 import unittest
-from unittest import mock
+import unittest.mock as mock
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
diff --git a/tests/test_prompt_graph.py b/tests/test_prompt_graph.py
index 1e6ffdac..1329d08b 100644
--- a/tests/test_prompt_graph.py
+++ b/tests/test_prompt_graph.py
@@ -4,7 +4,7 @@ import os
 import sys
 import time
 import unittest
-from unittest import mock
+import unittest.mock as mock
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
diff --git a/tests/test_prompt_pair_resolver.py b/tests/test_prompt_pair_resolver.py
index f739d893..2c8f4388 100644
--- a/tests/test_prompt_pair_resolver.py
+++ b/tests/test_prompt_pair_resolver.py
@@ -9,7 +9,7 @@ import tempfile
 import unittest
 from dataclasses import replace
 from pathlib import Path
-from unittest import mock
+import unittest.mock as mock
 
 from utils import inspection_semantics
 from utils import prompt_pair_resolver as resolver
diff --git a/tests/test_prompt_usage.py b/tests/test_prompt_usage.py
index 41bcc7b6..4c85b637 100644
--- a/tests/test_prompt_usage.py
+++ b/tests/test_prompt_usage.py
@@ -286,7 +286,7 @@ class TestNodeRecordsCachedRunReceipt(UsageTestCase):
     }
 
     def _node(self):
-        from unittest import mock
+        import unittest.mock as mock
 
         from prompt_manager_text import PromptManagerText
 
diff --git a/tests/test_queue_observers.py b/tests/test_queue_observers.py
index e42b520e..44577a75 100644
--- a/tests/test_queue_observers.py
+++ b/tests/test_queue_observers.py
@@ -13,19 +13,19 @@ class FakeQueue:
     def __init__(self):
         self.result = ((0, "job", {}, {}, [], {}), 0)
         self.calls = []
-        self.failure = None
+        self.failures = ()
         self.done_result = object()
 
     def get(self, *args, **kwargs):
         self.calls.append(("get", args, kwargs))
-        if self.failure:
-            raise self.failure
+        for failure in self.failures:
+            raise failure
         return self.result
 
     def task_done(self, *args, **kwargs):
         self.calls.append(("done", args, kwargs))
-        if self.failure:
-            raise self.failure
+        for failure in self.failures:
+            raise failure
         return self.done_result
 
 
@@ -46,7 +46,7 @@ class QueueObserversTests(unittest.TestCase):
         self.assertIsNone(host.get())
         self.assertEqual(seen, [original])
         for error in (queue.Empty(), RuntimeError("host failure")):
-            host.failure = error
+            host.failures = (error,)
             with self.assertRaises(type(error)) as raised:
                 host.get(timeout=sentinel)
             self.assertIs(raised.exception, error)
@@ -59,7 +59,7 @@ class QueueObserversTests(unittest.TestCase):
         self.assertIs(host.task_done(0, sentinel, status=sentinel), host.done_result)
         self.assertEqual(seen, [((0, sentinel), {"status": sentinel})])
         error = ValueError("host failure")
-        host.failure = error
+        host.failures = (error,)
         with self.assertRaises(ValueError) as raised:
             host.task_done(1)
         self.assertIs(raised.exception, error)
diff --git a/tests/test_restore_plans.py b/tests/test_restore_plans.py
index f5825169..b9be6087 100644
--- a/tests/test_restore_plans.py
+++ b/tests/test_restore_plans.py
@@ -357,7 +357,7 @@ class TestRestoreAdmission(RestoreTestCase):
         gate.set()
         await health.task
 
-        restore, release = self.gated_job("restore", "exclusive", RESTORE_JOB_TITLE)
+        self.gated_job("restore", "exclusive", RESTORE_JOB_TITLE)
         resp = await self.client.post("/prompt_manager/system/health")
         refusal = await resp.json()
         self.assertEqual((resp.status, refusal["code"]), (409, "busy"))
@@ -369,7 +369,7 @@ class TestRestoreAdmission(RestoreTestCase):
         self.assertEqual(body["running"]["title"], "Move library")
 
         self.api._jobs.list()[0].finish()
-        body = await self.preview(self.upload(["restored"]))
+        await self.preview(self.upload(["restored"]))
         self.gated_job("restore", "exclusive", RESTORE_JOB_TITLE)
         resp = await self.client.post("/prompt_manager/system/library/move")
         self.assertEqual(resp.status, 409)
diff --git a/tests/test_review_image_links_tool.py b/tests/test_review_image_links_tool.py
index 0e52fdf0..9d698500 100644
--- a/tests/test_review_image_links_tool.py
+++ b/tests/test_review_image_links_tool.py
@@ -116,7 +116,7 @@ class ReviewToolTests(ToolFixture):
         self.assertEqual(code, 0)
         (verdict,) = json.loads(out.split("--apply, for")[0])
         self.assertEqual(verdict["verdict"], "manual")
-        code, _out = self.run_tool("--ids", str(self.guessed[0]), "--apply")
+        self.run_tool("--ids", str(self.guessed[0]), "--apply")
         self.assertEqual(self.links(), before)
 
     def test_prompt_selection_and_text_report(self):
diff --git a/tests/test_review_inspection.py b/tests/test_review_inspection.py
index ea0774a1..e42bd307 100644
--- a/tests/test_review_inspection.py
+++ b/tests/test_review_inspection.py
@@ -337,7 +337,7 @@ class TestDefaultProfileStillDecides(InspectionTestCase):
                 side_effect=AssertionError("inspection choices were asked"),
             ),
         ):
-            _item, (status, data) = await self._apply("cat")
+            _, (status, data) = await self._apply("cat")
         self.assertEqual(status, 200, data)
         # The saver anchor check (#390): with the file's name, nothing matches.
         self.assertEqual([c[1] for c in calls], ["two.png"])
@@ -383,7 +383,7 @@ class TestApplyInspectionCandidate(InspectionTestCase):
             return real(metadata, file_name)
 
         with patch.object(review_capture, "resolve_inspection", side_effect=spy):
-            _item, (status, data) = await self._apply("make it night")
+            _, (status, data) = await self._apply("make it night")
 
         self.assertEqual(status, 200, data)
         self.assertEqual(len(calls), 1)
@@ -566,7 +566,7 @@ class TestVersionChanges(InspectionTestCase):
         self.assertNotEqual(item["resolver_version"], old["resolver_version"])
         self.assertEqual(job["scope"]["review_items"], 1)
         self.assertEqual(self._pending(), 1)
-        _item, (status, data) = await self._apply("make it night")
+        _, (status, data) = await self._apply("make it night")
         self.assertEqual(status, 200, data)
         self.assertEqual(self._linked_text(path), "make it night")
 
@@ -885,7 +885,7 @@ class TestInspectionResolverVersion(InspectionTestCase):
             await self._scan("all")
             (item,) = self._items()
             self.assertNotEqual(item["id"], old["id"])
-            _item, (status, data) = await self._apply("add a red hat")
+            _, (status, data) = await self._apply("add a red hat")
 
         self.assertEqual(status, 200, data)
         self.assertEqual(self._linked_text(path), "add a red hat")
diff --git a/tests/test_review_saver_anchor.py b/tests/test_review_saver_anchor.py
index c61d8112..227cda50 100644
--- a/tests/test_review_saver_anchor.py
+++ b/tests/test_review_saver_anchor.py
@@ -169,7 +169,7 @@ class TestInspectionItemsAnchor(InspectionTestCase):
         path = self._write("branch_1_00001_.png", graph=branch_graph(*PROMPTS))
         await self._scan()
 
-        _item, (status, data) = await self._apply("add a red hat")
+        _, (status, data) = await self._apply("add a red hat")
 
         self.assertEqual(status, 200, data)
         self.assertEqual(self._linked_text(path), "add a red hat")
@@ -316,7 +316,7 @@ class TestDefaultItemsAnchor(InspectionTestCase):
         with patch.object(review_capture, "_captured_inspection", return_value=None):
             await self._scan()
 
-        _item, (status, data) = await self._apply("cat")
+        _, (status, data) = await self._apply("cat")
 
         self.assertEqual(status, 200, data)
         self.assertEqual(self._linked_text(path), "cat")
diff --git a/tests/test_run_attribution.py b/tests/test_run_attribution.py
index 63d2199b..6ecc9868 100644
--- a/tests/test_run_attribution.py
+++ b/tests/test_run_attribution.py
@@ -7,7 +7,7 @@ import threading
 import time
 import unittest
 from pathlib import Path
-from unittest import mock
+import unittest.mock as mock
 
 from database.run_attribution import (
     RecordedOutput,
@@ -86,11 +86,10 @@ class RecordedRuns:
 
 
 class TestStoredRunPrompt(RecordedRuns, unittest.TestCase):
-    setUp = history_tests.HistoryDatabaseTests.setUp
     close_databases = history_tests.HistoryDatabaseTests.close_databases
     database = history_tests.HistoryDatabaseTests.database
 
-    def setUp(self):  # noqa: F811 - the shared temp dir and database list first
+    def setUp(self):  # the shared temp dir and database list first
         history_tests.HistoryDatabaseTests.setUp(self)
         self.db = self.database()
         self.output = str(Path(self.temp.name) / "output")
diff --git a/tests/test_save_to_library.py b/tests/test_save_to_library.py
index 3d8bee47..0a28a15c 100644
--- a/tests/test_save_to_library.py
+++ b/tests/test_save_to_library.py
@@ -10,7 +10,7 @@ import os
 import sys
 import unittest
 from pathlib import Path
-from unittest import mock
+import unittest.mock as mock
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
diff --git a/tests/test_scanned_prompts.py b/tests/test_scanned_prompts.py
index c256e6c2..009bb4b7 100644
--- a/tests/test_scanned_prompts.py
+++ b/tests/test_scanned_prompts.py
@@ -7,7 +7,7 @@ import threading
 import unittest
 from concurrent.futures import ThreadPoolExecutor
 from pathlib import Path
-from unittest import mock
+import unittest.mock as mock
 
 try:
     from tests.open_handles import assert_closed
diff --git a/tests/test_thumbnail_jobs.py b/tests/test_thumbnail_jobs.py
index cda1832f..a74680e5 100644
--- a/tests/test_thumbnail_jobs.py
+++ b/tests/test_thumbnail_jobs.py
@@ -894,7 +894,7 @@ class TestLegacyStreamOnTheJob(ThumbnailJobCase):
         self.assertEqual(resp.status, 200)
         await self._wait(first)
         job = self.api._jobs.active("thumbnails")
-        _subscribed, state["left"] = self._watch_subscribers(job)
+        _, state["left"] = self._watch_subscribers(job)
         resp.close()  # the gallery tab went away
         closed.set()
         await self._wait(state["left"])  # the server saw the client go
diff --git a/tests/test_trash_freedesktop.py b/tests/test_trash_freedesktop.py
index 10f88741..22b2ca91 100644
--- a/tests/test_trash_freedesktop.py
+++ b/tests/test_trash_freedesktop.py
@@ -12,7 +12,7 @@ import stat
 import sys
 import tempfile
 import unittest
-from unittest import mock
+import unittest.mock as mock
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
diff --git a/tests/test_trash_macos.py b/tests/test_trash_macos.py
index 3b2cb185..7ede45c3 100644
--- a/tests/test_trash_macos.py
+++ b/tests/test_trash_macos.py
@@ -12,7 +12,7 @@ import sys
 import tempfile
 import unittest
 from types import SimpleNamespace
-from unittest import mock
+import unittest.mock as mock
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
diff --git a/tests/test_utils_logging_config.py b/tests/test_utils_logging_config.py
index d64ee51e..4d1cf609 100644
--- a/tests/test_utils_logging_config.py
+++ b/tests/test_utils_logging_config.py
@@ -998,7 +998,7 @@ class TestConfiguration(IsolatedLoggerTestCase):
         def log_from_background_thread() -> None:
             try:
                 self.manager.logger.info(message)
-            except BaseException as error:
+            except Exception as error:
                 errors.append(error)
 
         # Allow this record through the fixture's normal main-thread filter.
diff --git a/tests/test_utils_video_metadata.py b/tests/test_utils_video_metadata.py
index f8918780..84222d93 100644
--- a/tests/test_utils_video_metadata.py
+++ b/tests/test_utils_video_metadata.py
@@ -15,7 +15,7 @@ import subprocess
 import sys
 import tempfile
 import unittest
-from unittest import mock
+import unittest.mock as mock
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
diff --git a/tests/test_workspace_system_fixture.py b/tests/test_workspace_system_fixture.py
index 23189560..58f68fed 100644
--- a/tests/test_workspace_system_fixture.py
+++ b/tests/test_workspace_system_fixture.py
@@ -8,7 +8,7 @@ import tempfile
 import types
 import unittest
 from pathlib import Path
-from unittest import mock
+import unittest.mock as mock
 
 from aiohttp import web
 from aiohttp.test_utils import TestClient, TestServer
diff --git a/tools/repair_foreign_links.py b/tools/repair_foreign_links.py
index fe75611d..f710999e 100644
--- a/tools/repair_foreign_links.py
+++ b/tools/repair_foreign_links.py
@@ -506,8 +506,10 @@ def markdown(plan, prompt_texts):
         "",
         f"## Relink ({sum(i['action'] == 'relink' for i in rows)})",
         "",
-        "| row | file | linked prompt | linked text | target | target hash "
-        "| target text |",
+        (
+            "| row | file | linked prompt | linked text | target | target hash "
+            "| target text |"
+        ),
         "|---:|---|---:|---|---|---|---|",
     ]
     for item in (i for i in rows if i["action"] == "relink"):
diff --git a/utils/diagnostics.py b/utils/diagnostics.py
index 61172ece..e532e9d3 100644
--- a/utils/diagnostics.py
+++ b/utils/diagnostics.py
@@ -386,14 +386,9 @@ class GalleryDiagnostics:
         except ImportError:
             self.logger.error("   [FAIL] PIL (Pillow): NOT AVAILABLE")
 
-        # Check sqlite3
-        try:
-            import sqlite3
-
-            dependencies["sqlite3"] = True
-            self.logger.info(f"   [PASS] sqlite3: {sqlite3.sqlite_version}")
-        except ImportError:
-            self.logger.error("   [FAIL] sqlite3: NOT AVAILABLE")
+        # sqlite3 is imported at the top of this module, so it is always here.
+        dependencies["sqlite3"] = True
+        self.logger.info(f"   [PASS] sqlite3: {sqlite3.sqlite_version}")
 
         all_deps_ok = all(dependencies.values())
 
diff --git a/utils/execution_history_writer.py b/utils/execution_history_writer.py
index 248b49de..715bfdad 100644
--- a/utils/execution_history_writer.py
+++ b/utils/execution_history_writer.py
@@ -398,6 +398,7 @@ class HistoryWriter:
                         try:
                             command = self._queue.get_nowait()
                         except queue.Empty:
+                            # no command waiting; the loop below handles command None
                             pass
                 if probe:
                     try:
diff --git a/utils/image_monitor.py b/utils/image_monitor.py
index 5b016c7b..452bf104 100644
--- a/utils/image_monitor.py
+++ b/utils/image_monitor.py
@@ -1048,8 +1048,8 @@ class ImageGenerationHandler(FileSystemEventHandler):
                 with Image.open(image_path) as img:
                     file_info["dimensions"] = list(img.size)
                     file_info["format"] = img.format
-            except Exception:
-                pass
+            except Exception as error:
+                self.logger.debug(f"No dimensions for {image_path}: {error}")
 
             return file_info
         except Exception as e:
@@ -1424,8 +1424,8 @@ class ImageMonitor:
         if self.observer is not None:
             try:
                 observer_alive = self.observer.is_alive()
-            except Exception:
-                pass
+            except Exception as error:
+                self.logger.debug(f"Could not read the observer state: {error}")
         return {
             "running": self.observer is not None,
             "monitored_directories": self.monitored_directories,
diff --git a/utils/library_location.py b/utils/library_location.py
index 4a69b6ab..0e637992 100644
--- a/utils/library_location.py
+++ b/utils/library_location.py
@@ -466,6 +466,7 @@ def ensure_private_dir(path: str) -> str:
             try:
                 os.chmod(path, 0o700)
             except OSError:
+                # the folder exists; a filesystem without modes keeps its own
                 pass
     return path
 
diff --git a/utils/media_capture.py b/utils/media_capture.py
index b826bc85..c978305b 100644
--- a/utils/media_capture.py
+++ b/utils/media_capture.py
@@ -181,6 +181,7 @@ def _unlink_quietly(path: str) -> None:
     try:
         os.unlink(path)
     except FileNotFoundError:
+        # already gone, which is what was wanted
         pass
     except OSError as error:
         logger.warning("Capture file %s could not be removed: %s", path, error)
@@ -390,6 +391,7 @@ class CaptureStore:
         try:
             os.rmdir(self.directory)
         except FileNotFoundError:
+            # already gone, which is what was wanted
             pass
         except OSError as error:
             logger.warning(
diff --git a/utils/trash.py b/utils/trash.py
index 7fcf5121..309c6207 100644
--- a/utils/trash.py
+++ b/utils/trash.py
@@ -339,6 +339,7 @@ class FreedesktopBackend:
         try:
             os.mkdir(name, 0o700, dir_fd=parent_fd)
         except FileExistsError:
+            # the folder already exists; the checks below still vet it
             pass
         except OSError as error:
             raise TrashRefused(NO_TRASH, str(error)) from error
diff --git a/utils/trash_macos.py b/utils/trash_macos.py
index 4ce422da..0a7644a6 100644
--- a/utils/trash_macos.py
+++ b/utils/trash_macos.py
@@ -114,6 +114,7 @@ def inside_any_root(path: str, roots) -> bool:
             if _identity(current) in identities:
                 return True
         except OSError:
+            # an unreadable folder cannot be a trash; try its parent
             pass
         parent = os.path.dirname(current)
         if parent == current:
diff --git a/utils/workspace_keys.py b/utils/workspace_keys.py
index 5087c53b..cdc37ab6 100644
--- a/utils/workspace_keys.py
+++ b/utils/workspace_keys.py
@@ -88,6 +88,7 @@ def _unlink(path: str) -> None:
     try:
         os.unlink(path)
     except OSError:
+        # best effort cleanup; the next sweep removes a leftover temp
         pass
 
 
@@ -105,6 +106,7 @@ def _sweep_temps(directory: str) -> None:
                 if os.stat(path).st_mtime < cutoff:
                     os.unlink(path)
             except OSError:
+                # best effort: a later sweep removes what this one could not
                 pass
 
 
@@ -116,6 +118,7 @@ def _tighten(path: str) -> None:
         if stat.S_IMODE(os.stat(path).st_mode) & 0o077:
             os.chmod(path, 0o600)
     except OSError:
+        # best effort: the key still works with its old mode
         pass
 
 
diff --git a/web/comfy/prompt_manager.js b/web/comfy/prompt_manager.js
index ddd36e5e..6d875c04 100644
--- a/web/comfy/prompt_manager.js
+++ b/web/comfy/prompt_manager.js
@@ -354,8 +354,6 @@ app.registerExtension({
             if (textWidget) {
               // Store reference to the widget for the closure
               const widgetRef = textWidget;
-              const originalSerializeValue = textWidget.serializeValue;
-
               // Override serializeValue - use arrow function to capture widgetRef
               textWidget.serializeValue = (nodeId, widgetIndex) => {
                 // Always return the current DOM value using our stored reference
diff --git a/web/js/admin.js b/web/js/admin.js
index 16039261..a3b4b7c4 100644
--- a/web/js/admin.js
+++ b/web/js/admin.js
@@ -2391,8 +2391,6 @@ Seed: ${this.currentMetadata.seed || 'Unknown'}`;
                     // Extract relative path from the full path
                     // The image_path might be absolute, we need to serve it via the API
                     const path = image.image_path;
-                    // Try to get filename for serving
-                    const filename = image.filename || path.split(/[/\\]/).pop();
                     // Use the image ID if available, otherwise use the path-based serve endpoint
                     if (image.id) {
                         return ApiClient.resolveUrl(`/prompt_manager/images/${image.id}/file`);
diff --git a/web/js/gallery.js b/web/js/gallery.js
index acb4b9a5..b889023b 100644
--- a/web/js/gallery.js
+++ b/web/js/gallery.js
@@ -607,7 +607,6 @@
                     button: true,
                     backdrop: true,
                     navbar: true,
-                    title: true,
                     // IMPORTANT: Use original images for viewing, not thumbnails
                     url: 'data-original',  // Tell ViewerJS to use data-original attribute
                     toolbar: {
diff --git a/web/js/workspace/file-inspector.mjs b/web/js/workspace/file-inspector.mjs
index 4135152c..97a4f0c6 100644
--- a/web/js/workspace/file-inspector.mjs
+++ b/web/js/workspace/file-inspector.mjs
@@ -1,7 +1,6 @@
 import { createScope, createButton } from '../shared/toolkit/core.js';
 import { mountPromptBlocks, promptRoles } from './prompt-blocks.mjs';
 import { createInspectionController } from './inspection-state.mjs';
-import { createSendButton } from './prompt-sender.mjs';
 import { createWorkspaceIcon } from './icons.mjs';
 import { navigateTo } from './state.mjs';
 import { showWorkspaceToast } from './toast.mjs';
diff --git a/web/js/workspace/local-resolver-support.mjs b/web/js/workspace/local-resolver-support.mjs
index 7e062cdb..aa7e0271 100644
--- a/web/js/workspace/local-resolver-support.mjs
+++ b/web/js/workspace/local-resolver-support.mjs
@@ -1,7 +1,7 @@
 // Tables, evidence reader, bounds and outcome lines for local-resolver.mjs (#249 local Inspect, PR L3 Tasks 8-9):
 // the constants of utils/prompt_pair_resolver.py and utils/inspection_outcomes.py, utils/pair_execution.py
 // `read_pair_execution` and the semantics table check of utils/inspection_semantics.py. No DOM.
-import { PyFloat, PyValueError, isDict, isList, isInt, pyJsonLoads, pyLen, pySlice, pyStrip, pyTruthy, pyEqualsOne, pyStr, pyGet } from './py-json.mjs';
+import { PyValueError, isDict, isList, isInt, pyJsonLoads, pyLen, pySlice, pyTruthy, pyEqualsOne, pyGet } from './py-json.mjs';
 
 /** The semantics table is unusable: the server's `SemanticsError`. */
 export class SemanticsError extends Error {
diff --git a/web/js/workspace/local-resolver.mjs b/web/js/workspace/local-resolver.mjs
index 435b1a2a..9ce727f7 100644
--- a/web/js/workspace/local-resolver.mjs
+++ b/web/js/workspace/local-resolver.mjs
@@ -41,7 +41,6 @@ import {
     UNVERIFIABLE_CODES,
     Unresolved,
     ZEROED_SOURCE,
-    compileSemantics,
     explained,
     isLink,
     nodeRef,