diff --git a/CHANGELOG.md b/CHANGELOG.md
index dd0b9f1e..869655de 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -122,6 +122,14 @@
   looked exactly like one where the feature was switched off.
 
 ### Fixed
+- **Updating FunPack in the app installs the dependencies the update needs.** It pulled new
+  code and never new requirements, so a release that added one left the node pack unable to
+  import with nothing said. When an update touches `requirements.txt`, pip runs against the
+  interpreter ComfyUI is using — never a bare `pip`, which in a venv installs somewhere else
+  entirely — before the restart, and a failure names the command to run by hand rather than
+  turning a completed update into an error. Update and branch switch also moved off the event
+  loop; a fetch over a tunnel plus an install was freezing every stream in the meantime.
+
 - **A LoRA that matches by name but not by shape now says so.** Key matching proves a LoRA is
   *for* a model, not that its weights fit it; a mismatched pair is dropped during the merge,
   which was visible only as one generic warning per key while FunPack's own status line still
diff --git a/movie_editor/backend/git_update.py b/movie_editor/backend/git_update.py
index b5768214..f3ccfb7d 100644
--- a/movie_editor/backend/git_update.py
+++ b/movie_editor/backend/git_update.py
@@ -4,6 +4,7 @@ from __future__ import annotations
 import re
 import shutil
 import subprocess
+import sys
 from pathlib import Path
 
 REPO_ROOT = Path(__file__).resolve().parents[2]
@@ -154,8 +155,65 @@ def status() -> dict:
                 "codename": funpack_codename(), "detail": str(e)}
 
 
-def pull(branch: str | None = None) -> dict:
-    """Fast-forward pull from origin on the given branch (current if omitted)."""
+REQUIREMENTS = "requirements.txt"
+
+
+def requirements_changed(before: str, after: str) -> bool:
+    """Did this update touch requirements.txt?
+
+    The only honest trigger for installing: running pip on every pull would be slow and
+    surprising, and running it on none leaves an update that added a dependency looking
+    like a broken build instead of an unfinished install.
+    """
+    if not before or not after or before == after:
+        return False
+    proc = _run_git("diff", "--name-only", f"{before}..{after}", "--", REQUIREMENTS)
+    if proc.returncode != 0:
+        # Cannot tell — install rather than skip. A redundant pip run costs seconds; a
+        # skipped one costs a broken node pack and a confusing error.
+        return True
+    return bool((proc.stdout or "").strip())
+
+
+def install_requirements(timeout: int = 900) -> dict:
+    """`pip install -r requirements.txt` into the interpreter ComfyUI is running.
+
+    `sys.executable`, never a bare `pip`: ComfyUI is usually in a venv, and the pip on PATH
+    belongs to whatever else is on it. Installing into the wrong environment succeeds
+    loudly and changes nothing.
+
+    Never raises. A failed install must not turn a completed update into an error — the
+    code IS updated by this point, and the remedy is a command the user can run.
+    """
+    req = REPO_ROOT / REQUIREMENTS
+    if not req.is_file():
+        return {"ran": False, "ok": True, "detail": "no requirements.txt in this checkout"}
+    cmd = [sys.executable, "-m", "pip", "install", "--disable-pip-version-check",
+           "-r", str(req)]
+    try:
+        proc = subprocess.run(cmd, cwd=REPO_ROOT, capture_output=True, text=True,
+                              timeout=timeout)
+    except subprocess.TimeoutExpired:
+        return {"ran": True, "ok": False,
+                "detail": f"pip did not finish within {timeout}s — run it yourself: "
+                          f"pip install -r {req}"}
+    except OSError as e:
+        return {"ran": True, "ok": False, "detail": f"could not run pip: {e}"}
+    if proc.returncode != 0:
+        tail = ((proc.stderr or proc.stdout or "").strip() or "pip failed")[-800:]
+        return {"ran": True, "ok": False,
+                "detail": f"pip install failed — run it yourself:\n"
+                          f"  {sys.executable} -m pip install -r {req}\n\n{tail}"}
+    return {"ran": True, "ok": True, "detail": (proc.stdout or "").strip()[-800:]}
+
+
+def pull(branch: str | None = None, *, install_deps: bool = False) -> dict:
+    """Fast-forward pull from origin on the given branch (current if omitted).
+
+    `install_deps` is OFF by default and turned on by the update route. Running pip is a
+    side effect no caller should acquire by accident just for asking git to move a branch —
+    it has to be asked for at the point that means "the user pressed Update".
+    """
     branch = (branch or _current_branch()).strip()
     if not branch:
         raise GitUpdateError("Could not determine current branch.")
@@ -188,11 +246,17 @@ def pull(branch: str | None = None) -> dict:
             raise GitUpdateError(msg)
         realigned = True
     after = _current_commit()
+    # Dependencies are part of the update. Done BEFORE the response, so the restart the
+    # caller schedules cannot race an install that is still running.
+    deps = None
+    if install_deps and before != after and requirements_changed(before, after):
+        deps = install_requirements()
     return {
         "branch": branch,
         "before": before,
         "after": after,
         "updated": before != after,
+        "requirements": deps,
         # Surfaced so the update reads as what it was, not a silent jump to another commit.
         "realigned": realigned,
         "output": ((pull_proc.stdout or "").strip() if not realigned
@@ -201,7 +265,7 @@ def pull(branch: str | None = None) -> dict:
     }
 
 
-def checkout(branch: str, *, pull_after: bool = True) -> dict:
+def checkout(branch: str, *, pull_after: bool = True, install_deps: bool = False) -> dict:
     """Switch branch, optionally pull, return combined result."""
     branch = (branch or "").strip()
     if not branch:
@@ -219,9 +283,14 @@ def checkout(branch: str, *, pull_after: bool = True) -> dict:
             raise GitUpdateError((co.stderr or co.stdout or "git checkout failed").strip())
     result = {"branch": branch, "before_branch": before_branch, "before": before_commit}
     if pull_after:
-        pulled = pull(branch)
+        pulled = pull(branch, install_deps=install_deps)
         result.update(pulled)
     else:
         result["after"] = _current_commit()
         result["updated"] = result["before"] != result["after"]
+        # A branch switch alone can cross a requirements change just as a pull can — the
+        # checkout above already moved the working tree onto the other branch's files.
+        if install_deps and result["updated"] and requirements_changed(before_commit,
+                                                                      result["after"]):
+            result["requirements"] = install_requirements()
     return result
diff --git a/movie_editor/frontend/git_actions.js b/movie_editor/frontend/git_actions.js
index fee4117a..483a7d6b 100644
--- a/movie_editor/frontend/git_actions.js
+++ b/movie_editor/frontend/git_actions.js
@@ -53,9 +53,10 @@
     const msg = _restartOverlay(`Pulling origin/${branch}…\nComfyUI will restart when the pull finishes.`);
     try {
       const res = await API().gitUpdate(branch);
-      msg.textContent = res.updated
-        ? `Updated ${res.before} → ${res.after}.\nRestarting ComfyUI…`
-        : "Already up to date.\nRestarting ComfyUI…";
+      const deps = _reportRequirements(res);
+      msg.textContent = (res.updated
+        ? `Updated ${res.before} → ${res.after}.${deps}\nRestarting ComfyUI…`
+        : "Already up to date.\nRestarting ComfyUI…");
     } catch (e) {
       window.FunPackRestart?.removeOverlay?.();
       alert("Update failed: " + (e.message || e));
@@ -64,6 +65,19 @@
     _waitForComfyReload(msg, Date.now());
   }
 
+  // An update that changed requirements.txt installs them before restarting. A FAILED
+  // install is the one outcome the user has to act on — the code is updated and the node
+  // pack will not import — so it interrupts rather than scrolling past in an overlay.
+  function _reportRequirements(res) {
+    const r = res && res.requirements;
+    if (!r || !r.ran) return "";
+    if (r.ok) return "\nDependencies installed.";
+    alert("FunPack updated, but installing its dependencies failed.\n\n"
+          + (r.detail || "")
+          + "\n\nFunPack may not load until this is run.");
+    return "\nDependency install FAILED — see the message above.";
+  }
+
   async function switchBranch() {
     const gs = await _ensureStatus();
     if (!gs) return;
@@ -85,9 +99,10 @@
         const msg = _restartOverlay(`Switching to ${branch}…\nComfyUI will restart when ready.`);
         try {
           const res = await API().gitCheckout(branch);
-          msg.textContent = res.updated
-            ? `Switched to ${branch} (${res.before} → ${res.after}).\nRestarting ComfyUI…`
-            : `On ${branch}, already up to date.\nRestarting ComfyUI…`;
+          const deps = _reportRequirements(res);
+          msg.textContent = (res.updated
+            ? `Switched to ${branch} (${res.before} → ${res.after}).${deps}\nRestarting ComfyUI…`
+            : `On ${branch}, already up to date.\nRestarting ComfyUI…`);
         } catch (e) {
           window.FunPackRestart?.removeOverlay?.();
           alert("Branch switch failed: " + (e.message || e));
diff --git a/movie_editor/server.py b/movie_editor/server.py
index 3c7220c4..120612b8 100644
--- a/movie_editor/server.py
+++ b/movie_editor/server.py
@@ -2496,13 +2496,26 @@ if web is not None and PromptServer is not None:
     async def _git_status(_req):
         return web.json_response(git_update.status())
 
+    # install_deps is opt-in on the library side: pressing Update is what means "install
+    # what this update needs", and no other caller of pull()/checkout() should acquire a
+    # pip run by accident.
+    def _pull_with_deps(branch):
+        return git_update.pull(branch, install_deps=True)
+
+    def _checkout_with_deps(branch):
+        return git_update.checkout(branch, pull_after=True, install_deps=True)
+
     @routes.post(UI_PREFIX + "/api/git/update")
     async def _git_update(req):
         import asyncio
         body = await req.json() if req.can_read_body else {}
         branch = body.get("branch")
         try:
-            result = git_update.pull(str(branch).strip() if branch else None)
+            # to_thread: git fetch over a tunnel takes seconds, and a requirements install
+            # can take a minute. Inline, both freeze the one event loop ComfyUI has —
+            # stalling every playing /result stream and the whole editor API meanwhile.
+            result = await asyncio.to_thread(
+                _pull_with_deps, str(branch).strip() if branch else None)
         except git_update.GitUpdateError as e:
             return web.json_response({"detail": str(e)}, status=400)
         asyncio.get_event_loop().call_later(0.7, _restart_comfy)
@@ -2516,7 +2529,7 @@ if web is not None and PromptServer is not None:
         if not branch:
             return web.json_response({"detail": "Branch name is required."}, status=400)
         try:
-            result = git_update.checkout(branch, pull_after=True)
+            result = await asyncio.to_thread(_checkout_with_deps, branch)
         except git_update.GitUpdateError as e:
             return web.json_response({"detail": str(e)}, status=400)
         asyncio.get_event_loop().call_later(0.7, _restart_comfy)
diff --git a/movie_editor/tests/test_git_update.py b/movie_editor/tests/test_git_update.py
index 281d5079..290e21a5 100644
--- a/movie_editor/tests/test_git_update.py
+++ b/movie_editor/tests/test_git_update.py
@@ -1,5 +1,7 @@
 """Git update helpers for the Movie Editor."""
 
+import sys
+import types
 from types import SimpleNamespace
 
 import pytest
@@ -169,3 +171,117 @@ def test_pull_keeps_the_original_error_when_it_cannot_prove_safety(monkeypatch):
     monkeypatch.setattr(git_update, "_run_git", fake_run)
     with pytest.raises(git_update.GitUpdateError):
         git_update.pull("dev")
+
+
+# ── requirements installed as part of an update ───────────────────────────────
+# The gap this closes: an in-app update pulled new code but never new dependencies, so a
+# release that added one left the node pack unable to import, with nothing said.
+
+def test_requirements_change_is_detected(monkeypatch):
+    from movie_editor.backend import git_update as gu
+    calls = []
+
+    def fake_git(*args, **kw):
+        calls.append(args)
+        return types.SimpleNamespace(returncode=0, stdout="requirements.txt\n", stderr="")
+
+    monkeypatch.setattr(gu, "_run_git", fake_git)
+    assert gu.requirements_changed("aaa", "bbb") is True
+    assert any("diff" in a for a in calls[0])
+
+
+def test_untouched_requirements_are_not_reinstalled(monkeypatch):
+    from movie_editor.backend import git_update as gu
+    monkeypatch.setattr(gu, "_run_git", lambda *a, **k: types.SimpleNamespace(
+        returncode=0, stdout="", stderr=""))
+    assert gu.requirements_changed("aaa", "bbb") is False
+
+
+def test_no_update_means_no_install(monkeypatch):
+    """Same commit before and after: nothing changed, so nothing to install."""
+    from movie_editor.backend import git_update as gu
+    monkeypatch.setattr(gu, "_run_git", lambda *a, **k: pytest.fail("git should not run"))
+    assert gu.requirements_changed("aaa", "aaa") is False
+    assert gu.requirements_changed("", "bbb") is False
+
+
+def test_an_undecidable_diff_installs_rather_than_skips(monkeypatch):
+    """A redundant pip run costs seconds; a skipped one costs a node pack that will not
+    import and an error that does not name its cause."""
+    from movie_editor.backend import git_update as gu
+    monkeypatch.setattr(gu, "_run_git", lambda *a, **k: types.SimpleNamespace(
+        returncode=128, stdout="", stderr="bad object"))
+    assert gu.requirements_changed("aaa", "bbb") is True
+
+
+def test_install_uses_the_running_interpreter(monkeypatch, tmp_path):
+    """Never a bare `pip`: ComfyUI is usually in a venv, and the pip on PATH belongs to
+    whatever else is on it — installing into the wrong environment succeeds and changes
+    nothing."""
+    from movie_editor.backend import git_update as gu
+    seen = {}
+
+    def fake_run(cmd, **kw):
+        seen["cmd"] = cmd
+        return types.SimpleNamespace(returncode=0, stdout="ok", stderr="")
+
+    monkeypatch.setattr(gu.subprocess, "run", fake_run)
+    out = gu.install_requirements()
+    assert out["ran"] and out["ok"]
+    assert seen["cmd"][0] == sys.executable
+    assert seen["cmd"][1:4] == ["-m", "pip", "install"]
+
+
+def test_a_failed_install_reports_the_command_and_never_raises(monkeypatch):
+    """The code IS updated by this point — turning that into an exception would leave the
+    user with a half-finished update and no instructions."""
+    from movie_editor.backend import git_update as gu
+    monkeypatch.setattr(gu.subprocess, "run", lambda cmd, **kw: types.SimpleNamespace(
+        returncode=1, stdout="", stderr="No matching distribution found for gguf"))
+    out = gu.install_requirements()
+    assert out["ran"] is True and out["ok"] is False
+    assert "pip install -r" in out["detail"]
+    assert "No matching distribution" in out["detail"]
+
+
+def test_a_pip_timeout_is_reported_not_raised(monkeypatch):
+    from movie_editor.backend import git_update as gu
+
+    def boom(cmd, **kw):
+        raise gu.subprocess.TimeoutExpired(cmd, 900)
+
+    monkeypatch.setattr(gu.subprocess, "run", boom)
+    out = gu.install_requirements()
+    assert out["ok"] is False and "did not finish" in out["detail"]
+
+
+def test_pull_does_not_install_unless_asked(monkeypatch):
+    """Running pip is a side effect no caller should acquire just for moving a branch.
+    Turning this on by default made the test suite itself shell out to a real pip install
+    and hang — the default has to be off, with the update route opting in."""
+    from movie_editor.backend import git_update as gu
+    monkeypatch.setattr(gu, "install_requirements",
+                        lambda *a, **k: pytest.fail("pip must not run by default"))
+    monkeypatch.setattr(gu, "requirements_changed", lambda *a, **k: True)
+    monkeypatch.setattr(gu, "_is_dirty", lambda: False)
+    monkeypatch.setattr(gu, "_current_branch", lambda: "v4")
+    commits = iter(["aaa", "bbb"])
+    monkeypatch.setattr(gu, "_current_commit", lambda: next(commits))
+    monkeypatch.setattr(gu, "_run_git", lambda *a, **k: _proc(0, ""))
+    out = gu.pull("v4")
+    assert out["updated"] is True
+    assert out["requirements"] is None
+
+
+def test_pull_installs_when_the_route_asks(monkeypatch):
+    from movie_editor.backend import git_update as gu
+    monkeypatch.setattr(gu, "install_requirements",
+                        lambda *a, **k: {"ran": True, "ok": True, "detail": "done"})
+    monkeypatch.setattr(gu, "requirements_changed", lambda *a, **k: True)
+    monkeypatch.setattr(gu, "_is_dirty", lambda: False)
+    monkeypatch.setattr(gu, "_current_branch", lambda: "v4")
+    commits = iter(["aaa", "bbb"])
+    monkeypatch.setattr(gu, "_current_commit", lambda: next(commits))
+    monkeypatch.setattr(gu, "_run_git", lambda *a, **k: _proc(0, ""))
+    out = gu.pull("v4", install_deps=True)
+    assert out["requirements"] == {"ran": True, "ok": True, "detail": "done"}