feat(mcp): event CRUD tools

Five new tools (events weren't in fable-mcp before). Split
start_date + start_time inputs combine into a naive datetime that
services/events.py interprets in the user's local timezone.

Sentinels for update:
  - empty strings → leave unchanged
  - duration_minutes=-1 → leave unchanged
  - duration_minutes=0 → set to point event (NULL duration)
  - start_date/start_time must BOTH be set to move the event

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

src/fabledassistant/mcp/tools/__init__.py

@@ -5,7 +5,7 @@ to a FastMCP instance. `register_all(mcp)` is the single entry point called
 from `mcp.server.build_mcp_server`.
 """
 from fabledassistant.mcp.tools import (
-    milestones, notes, projects, search, tasks,
+    events, milestones, notes, projects, search, tasks,
 )
 
 
@@ -16,3 +16,4 @@ def register_all(mcp) -> None:
     tasks.register(mcp)
     projects.register(mcp)
     milestones.register(mcp)
+    events.register(mcp)

src/fabledassistant/mcp/tools/events.py

@@ -0,0 +1,149 @@
+"""Calendar event MCP tools — new in Phase 3.
+
+Events were previously only an internal-LLM tool; the MCP surface didn't have
+them. Wraps services/events.py.
+
+Date/time inputs are split: start_date (YYYY-MM-DD) + start_time (HH:MM) get
+combined into a naive datetime; the service layer interprets it in the user's
+local timezone. duration_minutes=0 ⇒ point event (NULL duration). The
+LLM-era expected_weekday verification check is intentionally not replicated —
+Claude doesn't need it.
+
+For update, sentinels:
+  - title="" / location="" / description="" → leave unchanged
+  - start_date="" / start_time="" → leave unchanged (both must be provided to
+    move the event)
+  - duration_minutes=-1 → leave unchanged; 0 means "set to point event"
+"""
+from __future__ import annotations
+
+from datetime import datetime
+
+from fabledassistant.mcp._context import current_user_id
+from fabledassistant.services import events as events_svc
+
+
+def _combine(start_date: str, start_time: str) -> datetime:
+    """Combine YYYY-MM-DD + HH:MM into a naive datetime."""
+    t = start_time or "00:00"
+    return datetime.fromisoformat(f"{start_date}T{t}:00")
+
+
+def _event_dict(event) -> dict:
+    """Render an Event model to a dict, handling list_events (already dicts)."""
+    return event if isinstance(event, dict) else event.to_dict()
+
+
+async def fable_list_events(date_from: str, date_to: str) -> dict:
+    """List events between date_from and date_to (YYYY-MM-DD, both inclusive at
+    the day level — `date_to` is interpreted as end-of-that-day).
+
+    Recurring events are expanded into individual occurrences within the range.
+    """
+    uid = current_user_id()
+    start = datetime.fromisoformat(date_from)
+    end = datetime.fromisoformat(date_to)
+    rows = await events_svc.list_events(uid, start, end)
+    return {"events": [_event_dict(e) for e in rows], "total": len(rows)}
+
+
+async def fable_create_event(
+    title: str,
+    start_date: str,
+    start_time: str = "00:00",
+    duration_minutes: int = 0,
+    all_day: bool = False,
+    location: str = "",
+    description: str = "",
+) -> dict:
+    """Create a calendar event.
+
+    Args:
+        title: Event title (required).
+        start_date: YYYY-MM-DD.
+        start_time: HH:MM (24-hour). Ignored when all_day=True.
+        duration_minutes: 0 for a point event (no duration); otherwise minutes.
+        all_day: True to make this an all-day event.
+        location: Optional location string.
+        description: Optional longer description.
+    """
+    uid = current_user_id()
+    event = await events_svc.create_event(
+        uid,
+        title=title,
+        start_dt=_combine(start_date, start_time),
+        duration_minutes=duration_minutes or None,
+        all_day=all_day,
+        location=location,
+        description=description,
+    )
+    return event.to_dict()
+
+
+async def fable_get_event(event_id: int) -> dict:
+    """Fetch a single event by ID."""
+    uid = current_user_id()
+    event = await events_svc.get_event(uid, event_id)
+    if event is None:
+        raise ValueError(f"event {event_id} not found")
+    return event.to_dict()
+
+
+async def fable_update_event(
+    event_id: int,
+    title: str = "",
+    start_date: str = "",
+    start_time: str = "",
+    duration_minutes: int = -1,
+    location: str = "",
+    description: str = "",
+) -> dict:
+    """Update an event. Only explicitly provided fields are changed.
+
+    Args:
+        event_id: ID of the event to update.
+        title: New title; omit to leave unchanged.
+        start_date / start_time: BOTH must be set to move the event. Omit either
+            to leave the start_dt unchanged.
+        duration_minutes: -1 leaves unchanged; 0 sets to point event; any
+            positive value sets the duration.
+        location / description: omit to leave unchanged.
+    """
+    uid = current_user_id()
+    fields: dict = {}
+    if title:
+        fields["title"] = title
+    if location:
+        fields["location"] = location
+    if description:
+        fields["description"] = description
+    if start_date and start_time:
+        fields["start_dt"] = _combine(start_date, start_time)
+    if duration_minutes >= 0:
+        # 0 means point event (NULL); positive sets a real duration.
+        fields["duration_minutes"] = duration_minutes or None
+    event = await events_svc.update_event(uid, event_id, **fields)
+    if event is None:
+        raise ValueError(f"event {event_id} not found")
+    return event.to_dict()
+
+
+async def fable_delete_event(event_id: int) -> str:
+    """Permanently delete a calendar event by ID. Cannot be undone."""
+    uid = current_user_id()
+    existing = await events_svc.get_event(uid, event_id)
+    if existing is None:
+        raise ValueError(f"event {event_id} not found")
+    await events_svc.delete_event(uid, event_id)
+    return f"Event {event_id} deleted."
+
+
+def register(mcp) -> None:
+    for fn in (
+        fable_list_events,
+        fable_create_event,
+        fable_get_event,
+        fable_update_event,
+        fable_delete_event,
+    ):
+        mcp.tool(name=fn.__name__)(fn)