diff --git a/pm/plugin_declarations.py b/pm/plugin_declarations.py
index 169b7136437b8..8d38d636155f5 100644
--- a/pm/plugin_declarations.py
+++ b/pm/plugin_declarations.py
@@ -170,12 +170,14 @@ def read_python_declaration(plugin_dir: Path) -> PythonDeclaration:
         text = None
     if text is not None:
         files.append(project)
-        if "GENERATED by pm" not in text:
-            document = tomllib.loads(text)
-            specs = document.get("project", {}).get("dependencies", [])
+        document = tomllib.loads(text) if "GENERATED by pm" not in text else {}
+        # A pyproject with no [project] table only configures tools (ruff, pytest);
+        # the manifest still declares the dependencies.
+        if "project" in document:
+            specs = document["project"].get("dependencies", [])
             if not isinstance(specs, list) or any(not isinstance(v, str) for v in specs):
                 raise ValueError(f"invalid project.dependencies: {project}")
-            requires_python = document.get("project", {}).get("requires-python")
+            requires_python = document["project"].get("requires-python")
             if requires_python is not None and not isinstance(requires_python, str):
                 raise ValueError(f"invalid project.requires-python: {project}")
             return PythonDeclaration(tuple(files), project, tuple(specs), manifest, requires_python)
diff --git a/pm/workspace.py b/pm/workspace.py
index 2f54fcf43b221..82c12eb8763c4 100644
--- a/pm/workspace.py
+++ b/pm/workspace.py
@@ -248,6 +248,25 @@ def _member_key(identity: Path) -> str:
     return f"{name}-{digest}"
 
 
+def _installable_project(document: dict) -> bool:
+    """Drop what Hermes never installs from a plugin's pyproject; True when it changed.
+
+    Hermes never installs a plugin's extras, and uv syncs a member's default ``dev``
+    group into Hermes's own environment. Resolving them anyway made a plugin's
+    pytest/ruff pins conflict with core's.
+    """
+    project = document.get("project", {})
+    changed = False
+    if "optional-dependencies" in project and "optional-dependencies" not in project.get("dynamic", []):
+        del project["optional-dependencies"]
+        changed = True
+    for table, key in ((document, "dependency-groups"), (document.get("tool", {}).get("uv", {}), "dev-dependencies")):
+        if key in table:
+            del table[key]
+            changed = True
+    return changed
+
+
 def _workspace_member(plugin_dir: Path, root: Path, *, identity: Path) -> Path:
     """Keep workspace members with their generation, not a temporary install clone."""
     import json
@@ -272,6 +291,7 @@ def _workspace_member(plugin_dir: Path, root: Path, *, identity: Path) -> Path:
         changed = declaration.install_requirements != declaration.requirements
         if changed:
             document["project"]["dependencies"] = list(declaration.install_requirements)
+        changed = _installable_project(document) or changed
         for sources in document.get("tool", {}).get("uv", {}).get("sources", {}).values():
             for spec in sources if isinstance(sources, list) else [sources]:
                 if not isinstance(spec, dict) or "path" not in spec:
diff --git a/pyproject.toml b/pyproject.toml
index a16898701ee23..8f8781aa8d16d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -787,6 +787,28 @@ uvicorn = false
 vercel = false
 websockets = false
 youtube-transcript-api = false
+# Catalog plugins floored on a release younger than the 14-day window
+# (temporary). Each cutoff is the upload time of the OLDEST release the
+# plugin accepts, so exactly that release gets through and anything newer
+# still waits. A line is dead once its date is 14 days old: delete it then.
+# The lasting fix is upstream (exact pin + the plugin's own exemption, see
+# the developer guide's "Dependency security policy").
+# birkin-mnemosyne 0.4.0: catalog birkin-mnemosyne; dead after 2026-10-14
+birkin-mnemosyne = "2026-09-30T10:47:28Z"
+# cortexlayer 0.1.2: catalog cortexlayer; dead after 2026-10-09
+cortexlayer = "2026-09-25T14:28:59Z"
+# evalroute 0.9.0: catalog evalroute; dead after 2026-10-19
+evalroute = "2026-10-05T04:51:25Z"
+# gonogo-eval 0.3.0: catalog gonogo, thomas; dead after 2026-10-12
+gonogo-eval = "2026-09-28T21:07:00Z"
+# hermes-mnemostack 1.0.3: catalog mnemostack; dead after 2026-10-11
+hermes-mnemostack = "2026-09-27T19:26:09Z"
+# loreconvo 0.10.15: catalog loreconvo; dead after 2026-10-18
+loreconvo = "2026-10-04T17:35:24Z"
+# mnemosyne-hermes 0.7.3: catalog mnemosyne; dead after 2026-10-07
+mnemosyne-hermes = "2026-09-23T23:42:51Z"
+# mnemosyne-memory 4.0.0b3: catalog mnemosyne; dead after 2026-10-07
+mnemosyne-memory = "2026-09-23T23:41:58Z"
 
 [tool.setuptools]
 # Root single-file modules are derived by setup.py at build time from the
diff --git a/tests/pm/test_workspace.py b/tests/pm/test_workspace.py
index 21406f3819aeb..6c88679a02607 100644
--- a/tests/pm/test_workspace.py
+++ b/tests/pm/test_workspace.py
@@ -60,6 +60,51 @@ def test_missing_explicit_seed_cannot_silently_resolve_new_versions(layout):
     assert not (tmp / "env").exists()
 
 
+def _plugin_pyproject(tmp: Path, name: str, body: str) -> Path:
+    directory = tmp / name
+    directory.mkdir()
+    (directory / "pyproject.toml").write_text(body, encoding="utf-8")
+    (directory / "plugin.yaml").write_text(f"name: {name}\n", encoding="utf-8")
+    return directory
+
+
+def test_plugin_extras_and_dev_groups_never_constrain_hermes(layout):
+    """Hermes installs neither a plugin's extras nor its dev group, so their pins (here an
+    unsatisfiable one against core's ``base-dep==1.0``) must not make the plugin uninstallable."""
+    import tomllib
+
+    tmp, core, _, _ = layout
+    plugin = _plugin_pyproject(tmp, "pinned-dev", (
+        '[project]\nname = "pinned-dev"\nversion = "1"\nrequires-python = ">=3.11"\n'
+        'dependencies = ["member-dep==1.0"]\n'
+        '[project.optional-dependencies]\ndev = ["base-dep==9.9"]\n'
+        '[dependency-groups]\ndev = ["other-dep==9.9"]\n[tool.uv]\npackage = false\n'))
+    root = tmp / "workspace"
+    ws.lock_and_sync([plugin], [], root=root, source=core, seed_lock=core / "uv.lock",
+                     environment=managed_environment(tmp / "env"))
+    locked = {p["name"]: p["version"] for p in tomllib.loads((root / "uv.lock").read_text())["package"]}
+    assert locked["base-dep"] == "1.0" and locked["member-dep"] == "1.0"
+
+
+def test_tool_config_pyproject_leaves_the_manifest_in_charge_of_dependencies(layout):
+    """A pyproject holding only tool settings (ruff, pytest) is not a package definition:
+    the plugin's manifest dependencies still install, instead of uv refusing a [project]
+    table PM had to invent."""
+    import tomllib
+
+    tmp, core, _, _ = layout
+    plugin = tmp / "lint-only"
+    plugin.mkdir()
+    (plugin / "pyproject.toml").write_text("[tool.ruff]\nline-length = 100\n", encoding="utf-8")
+    (plugin / "plugin.yaml").write_text("name: lint-only\npython_dependencies:\n  - member-dep==1.0\n",
+                                        encoding="utf-8")
+    root = tmp / "workspace"
+    ws.lock_and_sync([plugin], [], root=root, source=core, seed_lock=core / "uv.lock",
+                     environment=managed_environment(tmp / "env"))
+    locked = {p["name"] for p in tomllib.loads((root / "uv.lock").read_text())["package"]}
+    assert "member-dep" in locked
+
+
 class _TimedIndex:
     """A PEP 691 JSON index with per-file ``upload-time``.
 
diff --git a/uv.lock b/uv.lock
index 5389dde571a2d..3b0d67814667b 100644
--- a/uv.lock
+++ b/uv.lock
@@ -14,106 +14,114 @@ exclude-newer = "0001-01-01T00:00:00Z" # This has no effect and is included for
 exclude-newer-span = "P14D"
 
 [options.exclude-newer-package]
-agent-client-protocol = false
+elevenlabs = false
+langfuse = "2026-09-09T16:01:26Z"
+setuptools = false
+modal = false
+pyyaml = false
+dingtalk-stream = false
+maturin = false
+numpy = false
+pvporcupine = false
+google-auth = false
 aiohttp = false
-aiohttp-socks = false
-aiosqlite = false
-alibabacloud-dingtalk = false
+starlette = false
+mistralai = false
+firecrawl-py = false
+parallel-web = false
+markdown = false
+opentelemetry-sdk = false
+prompt-toolkit = false
+fastapi = false
 anthropic = false
+pathspec = false
+ruff = false
+defusedxml = false
+websockets = false
+exa-py = false
+mcp = false
+python-olm = false
+wheel = false
+pytest = false
+pillow = false
+setuptools-rust = false
+tenacity = false
+sherpa-onnx-core = "2026-09-10T15:58:47Z"
+pyjwt = false
+slack-bolt = false
+fal-client = false
 asyncpg = false
-azure-identity = false
 boto3 = false
-brotlicffi = false
-browser-harness = false
+ruamel-yaml = false
+sherpa-onnx = "2026-09-10T17:00:04Z"
+huggingface-hub = false
+pytest-asyncio = false
+google-cloud-pubsub = false
+slack-sdk = false
+discord-py = false
+rich = false
+faster-whisper = false
 certifi = false
-concurrent-log-handler = false
-croniter = false
-cryptography = false
-daytona = false
-ddgs = "2026-08-26T21:52:34Z"
 debugpy = false
-defusedxml = false
-dingtalk-stream = false
-discord-py = false
+ddgs = "2026-08-26T21:52:34Z"
+packaging = false
+unpaddedbase64 = false
+youtube-transcript-api = false
+h2 = false
+birkin-mnemosyne = "2026-09-30T10:47:28Z"
+gonogo-eval = "2026-09-28T21:07:00Z"
+mnemosyne-memory = "2026-09-23T23:41:58Z"
 edge-tts = false
-elevenlabs = false
-exa-py = false
-fal-client = false
-fastapi = false
-faster-whisper = false
-fire = false
+microsoft-teams-apps = false
+aiohttp-socks = false
+sentencepiece = false
+opentelemetry-exporter-otlp-proto-http = false
+croniter = false
+browser-harness = false
+azure-identity = false
+lark-oapi = false
 firecrawl-anydoc = false
-firecrawl-py = false
 google-api-python-client = false
-google-auth = false
-google-auth-httplib2 = false
-google-auth-oauthlib = false
-google-cloud-pubsub = false
-h2 = false
-httplib2 = false
-httpx = false
-httpx2 = false
-huggingface-hub = false
-jinja2 = false
-langfuse = "2026-09-09T16:01:26Z"
-lark-oapi = false
-markdown = false
-maturin = false
-mautrix = false
-mcp = false
+brotlicffi = false
 mem0ai = false
-microsoft-teams-apps = false
-mistralai = false
-modal = false
+qrcode = false
+soundfile = "2026-06-06T08:58:48Z"
+vercel = false
+hermes-mnemostack = "2026-09-27T19:26:09Z"
+evalroute = "2026-10-05T04:51:25Z"
+aiosqlite = false
+tzdata = false
+python-dotenv = false
+daytona = false
+uvicorn = false
+loreconvo = "2026-10-04T17:35:24Z"
+mnemosyne-hermes = "2026-09-23T23:42:51Z"
 nemo-relay = false
-neutts = "2026-07-22T14:54:23Z"
-numpy = false
-openai = false
-opentelemetry-exporter-otlp-proto-http = false
-opentelemetry-sdk = false
-packaging = false
-parallel-web = false
-pathspec = false
-pillow = false
+requests = false
+httplib2 = false
+httpx = false
 piper-tts = "2026-09-04T16:47:32Z"
-prompt-toolkit = false
-psutil = false
-pvporcupine = false
 pyasn1 = false
+snowballstemmer = false
+concurrent-log-handler = false
+cryptography = false
 pydantic = false
-pyjwt = false
-pytest = false
-pytest-asyncio = false
-python-dotenv = false
+agent-client-protocol = false
+fire = false
+httpx2 = false
+google-auth-oauthlib = false
 python-multipart = false
-python-olm = false
+ty = false
+openai = false
+google-auth-httplib2 = false
+neutts = "2026-07-22T14:54:23Z"
+mautrix = false
+psutil = false
 python-telegram-bot = false
-pyyaml = false
-qrcode = false
-requests = false
-rich = false
-ruamel-yaml = false
-ruff = false
-sentencepiece = false
-setuptools = false
-setuptools-rust = false
-sherpa-onnx = "2026-09-10T17:00:04Z"
-sherpa-onnx-core = "2026-09-10T15:58:47Z"
-slack-bolt = false
-slack-sdk = false
-snowballstemmer = false
+jinja2 = false
 sounddevice = false
-soundfile = "2026-06-06T08:58:48Z"
-starlette = false
-tenacity = false
-ty = false
-tzdata = false
-unpaddedbase64 = false
-uvicorn = false
-vercel = false
-websockets = false
-wheel = false
-youtube-transcript-api = false
+alibabacloud-dingtalk = false
+cortexlayer = "2026-09-25T14:28:59Z"
 
 [manifest]
 overrides = [