feat(mcp): note CRUD tools (list/get/create/update/delete)

Five tools wrapping services/notes.py with is_task=False. Signatures
mirror the existing fable-mcp note tool contracts so Claude usage is
unchanged.

Key behavior the tests pin down:
  - list_notes repackages (rows, total) tuple into {notes, total}
  - tag=""/search_text="" are "no filter" sentinels
  - update_note ONLY sends non-default fields to the service (the
    main risk: a default empty string overwriting real data)
  - tags=[] is an explicit clear; tags=None is "leave unchanged"
  - project_id=0 on create => orphan; on update => leave unchanged
    (preserved limitation from existing fable-mcp)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/fabledassistant/mcp/tools/__init__.py

@@ -4,9 +4,10 @@ Each tool module exposes a `register(mcp)` function that attaches its tools
 to a FastMCP instance. `register_all(mcp)` is the single entry point called
 from `mcp.server.build_mcp_server`.
 """
-from fabledassistant.mcp.tools import search
+from fabledassistant.mcp.tools import notes, search
 
 
 def register_all(mcp) -> None:
     """Register every tool module's tools on the given FastMCP instance."""
     search.register(mcp)
+    notes.register(mcp)

src/fabledassistant/mcp/tools/notes.py

@@ -0,0 +1,133 @@
+"""Note CRUD MCP tools.
+
+Thin wrappers over services/notes.py with is_task=False. Signatures mirror
+the existing fable-mcp contracts exactly so client behavior is preserved.
+
+Sentinel conventions (inherited from existing fable-mcp tools):
+  - `tag: str = ""` / `search_text: str = ""` — empty means "no filter"
+  - `project_id: int = 0` — on create: orphan note (no project); on update:
+    "leave unchanged" (there is no "remove from project" through this tool,
+    which is a pre-existing limitation)
+  - `title: str = ""` / `body: str = ""` on update — empty means "leave unchanged"
+  - `tags: list[str] | None = None` — None means "leave unchanged"; [] clears
+"""
+from __future__ import annotations
+
+from fabledassistant.mcp._context import current_user_id
+from fabledassistant.services import notes as notes_svc
+
+
+async def fable_list_notes(
+    limit: int = 20,
+    offset: int = 0,
+    tag: str = "",
+    search_text: str = "",
+) -> dict:
+    """List notes (non-task documents) stored in Fable.
+
+    Optionally filter by a single tag (plain string, no # prefix) or a keyword
+    search against title and body. Results are ordered by last-updated descending.
+
+    Use fable_search for semantic/meaning-based lookup instead of exact keyword search.
+    """
+    uid = current_user_id()
+    rows, total = await notes_svc.list_notes(
+        uid,
+        q=search_text or None,
+        tags=[tag] if tag else None,
+        is_task=False,
+        limit=max(1, min(limit, 100)),
+        offset=max(0, offset),
+    )
+    return {"notes": [n.to_dict() for n in rows], "total": total}
+
+
+async def fable_get_note(note_id: int) -> dict:
+    """Fetch the full content of a single Fable note by its ID.
+
+    Returns id, title, body (markdown), tags, project_id, created_at, updated_at.
+    """
+    uid = current_user_id()
+    note = await notes_svc.get_note(uid, note_id)
+    if note is None:
+        raise ValueError(f"note {note_id} not found")
+    return note.to_dict()
+
+
+async def fable_create_note(
+    title: str,
+    body: str = "",
+    tags: list[str] | None = None,
+    project_id: int = 0,
+) -> dict:
+    """Create a new note in Fable.
+
+    Args:
+        title: Note title (required).
+        body: Markdown content. Supports [[wikilinks]] to other notes by title.
+        tags: List of plain-string tags without # prefix, e.g. ["python", "ideas"].
+        project_id: Associate with a project (use 0 for no project / orphan note).
+
+    Returns the created note object including its assigned id.
+    """
+    uid = current_user_id()
+    note = await notes_svc.create_note(
+        uid,
+        title=title,
+        body=body,
+        tags=tags,
+        project_id=project_id or None,
+    )
+    return note.to_dict()
+
+
+async def fable_update_note(
+    note_id: int,
+    title: str = "",
+    body: str = "",
+    tags: list[str] | None = None,
+    project_id: int = 0,
+) -> dict:
+    """Update an existing Fable note. Only explicitly provided fields are changed.
+
+    Args:
+        note_id: ID of the note to update.
+        title: New title, or omit to leave unchanged.
+        body: New markdown body, or omit to leave unchanged.
+        tags: Replaces the full tag list. Pass [] to clear all tags. Omit to leave unchanged.
+        project_id: New project association. Omit (or pass 0) to leave unchanged.
+    """
+    uid = current_user_id()
+    fields: dict = {}
+    if title:
+        fields["title"] = title
+    if body:
+        fields["body"] = body
+    if tags is not None:
+        fields["tags"] = tags
+    if project_id:
+        fields["project_id"] = project_id
+    note = await notes_svc.update_note(uid, note_id, **fields)
+    if note is None:
+        raise ValueError(f"note {note_id} not found")
+    return note.to_dict()
+
+
+async def fable_delete_note(note_id: int) -> str:
+    """Permanently delete a Fable note by ID. This cannot be undone."""
+    uid = current_user_id()
+    deleted = await notes_svc.delete_note(uid, note_id)
+    if not deleted:
+        raise ValueError(f"note {note_id} not found")
+    return f"Note {note_id} deleted."
+
+
+def register(mcp) -> None:
+    for fn in (
+        fable_list_notes,
+        fable_get_note,
+        fable_create_note,
+        fable_update_note,
+        fable_delete_note,
+    ):
+        mcp.tool(name=fn.__name__)(fn)