Phase 3b: FastMCP "ai service" for claude.ai cooking mode

A standalone MCP server (no Django import) exposing 7 tools over
Streamable HTTP, backed by the Django REST API via the caine token.

- mcp_server/: client.py (httpx wrapper over /api/), server.py (the
  tools + FastMCP app + main), __main__.py, tests.py.
- Tools: get_pantry, set_item_state, add_to_pantry, what_can_i_cook,
  get_recipes, log_cook (suggests, never mutates), create_meta_recipe
  (brainstorm -> commit). Each description says when to call it.
- deploy/food-mcp.service: systemd unit (own process, runs .venv python
  -m mcp_server, loads /var/lib/food/.env).
- deploy/food.tomflux.xyz.nginx: current config + an authless
  /mcp/<secret>/ location proxying to 127.0.0.1:8765 (the URL secret is
  the credential; SSE-friendly buffering/timeout).
- pyproject: [dependency-groups] mcp = [fastmcp, httpx]; deploy with
  `uv sync --group mcp`.

Verified: 7 tools register on fastmcp 3.x, run() accepts transport/
host/port/path, 6 FoodClient unit tests pass (httpx MockTransport).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

9 files changed, 449 insertions, 8 deletions

diff --git a/deploy/food-mcp.service b/deploy/food-mcp.service
new file mode 100644
index 0000000..0bef140
--- /dev/null
+++ b/deploy/food-mcp.service
@@ -0,0 +1,18 @@
+[Unit]
+Description=Food MCP service (FastMCP — claude.ai connector)
+After=network.target food.service
+
+[Service]
+Type=simple
+User=openclaw
+Group=openclaw
+WorkingDirectory=/var/lib/food
+Environment="PATH=/var/lib/food/.venv/bin:/usr/bin"
+# FOOD_API_TOKEN (the caine DRF token), optional FOOD_API_BASE / FOOD_MCP_PORT.
+EnvironmentFile=-/var/lib/food/.env
+ExecStart=/var/lib/food/.venv/bin/python -m mcp_server
+Restart=on-failure
+RestartSec=5
+
+[Install]
+WantedBy=multi-user.target
diff --git a/deploy/food.tomflux.xyz.nginx b/deploy/food.tomflux.xyz.nginx
new file mode 100644
index 0000000..0d4a357
--- /dev/null
+++ b/deploy/food.tomflux.xyz.nginx
@@ -0,0 +1,71 @@
+# nginx config for food.tomflux.xyz
+# Adds the MCP location to the existing web-app server block.
+#
+# The MCP connector is "authless" from claude.ai's side — the long secret in the
+# URL path IS the credential. Only that exact prefix is proxied to the FastMCP
+# service; everything else under /mcp/ falls through to the catch-all 301.
+# Generate the secret once and keep it out of git, e.g.:
+#     python -c "import secrets; print(secrets.token_urlsafe(32))"
+# then replace REPLACE_WITH_LONG_SECRET below and in the claude.ai connector URL:
+#     https://food.tomflux.xyz/mcp/REPLACE_WITH_LONG_SECRET/
+
+server {
+    server_name food.tomflux.xyz;
+
+    location /app/ {
+        proxy_pass http://127.0.0.1:8042;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;
+    }
+
+    location /accounts/ {
+        proxy_pass http://127.0.0.1:8042;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;
+    }
+
+    location /static/ {
+        proxy_pass http://127.0.0.1:8042;
+    }
+
+    # --- MCP server (claude.ai cooking-mode connector) ---
+    # Trailing slashes on both sides strip the secret prefix, so the FastMCP
+    # service (serving at "/") sees clean paths.
+    location /mcp/REPLACE_WITH_LONG_SECRET/ {
+        proxy_pass http://127.0.0.1:8765/;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header X-Forwarded-Proto $scheme;
+        proxy_buffering off;            # MCP Streamable HTTP / SSE
+        proxy_read_timeout 3600s;
+    }
+
+    location / {
+        return 301 /app/;
+    }
+
+    # Block API and admin from external access (MCP reaches the API over
+    # localhost, so this does not affect it).
+    location /api/ { return 404; }
+    location /admin/ { return 404; }
+
+    listen 443 ssl; # managed by Certbot
+    ssl_certificate /etc/letsencrypt/live/dav.jihakuz.xyz/fullchain.pem; # managed by Certbot
+    ssl_certificate_key /etc/letsencrypt/live/dav.jihakuz.xyz/privkey.pem; # managed by Certbot
+    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
+    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot
+}
+
+server {
+    if ($host = food.tomflux.xyz) {
+        return 301 https://$host$request_uri;
+    } # managed by Certbot
+
+    server_name food.tomflux.xyz;
+    listen 80;
+    return 404; # managed by Certbot
+}
diff --git a/mcp.md b/mcp.md
index 06449fb..42a491d 100644
--- a/mcp.md
+++ b/mcp.md
@@ -8,7 +8,7 @@
 > Decisions locked in `plan.md §3` and `requirements.md §7`: a **separate
 > FastMCP "ai service"** (a pattern Tom already runs elsewhere) that talks to
 > the existing Django REST API, hosted on the same box at
-> **`food.jihakuz.xyz/mcp`**, behind nginx, **bearer-token** auth.
+> **`food.tomflux.xyz/mcp`**, behind nginx, **bearer-token** auth.
 
 ---
 
@@ -43,7 +43,7 @@ blocks — now grounded instead of guessed.
   claude.ai (cooking mode)
         │  Streamable HTTP, secret in the URL path
         ▼
-  nginx  food.jihakuz.xyz/mcp   (TLS, public)
+  nginx  food.tomflux.xyz/mcp   (TLS, public)
         │  proxy_pass 127.0.0.1:8765
         ▼
   FastMCP "ai service"  (food-mcp.service, localhost only)
@@ -71,7 +71,7 @@ localhost Django**. It holds no database connection of its own.
 
 - **Transport:** Streamable HTTP (the remote-MCP transport claude.ai connectors
   use). FastMCP served over HTTP, bound to `127.0.0.1:8765`.
-- **Public route:** nginx on `food.jihakuz.xyz`, `location /mcp` →
+- **Public route:** nginx on `food.tomflux.xyz`, `location /mcp` →
   `proxy_pass http://127.0.0.1:8765`. TLS via the existing Let's Encrypt setup.
   Note SSE/streaming needs `proxy_buffering off;` and a long
   `proxy_read_timeout` on that location.
@@ -90,7 +90,7 @@ header**, so the original bearer-header plan isn't directly supported. Two ways
 to honour the "tight secret, single user" intent:
 
 - **Recommended — authless connector + secret in the URL path.** Register the
-  connector URL as `https://food.jihakuz.xyz/mcp/<long-random-secret>/`. To
+  connector URL as `https://food.tomflux.xyz/mcp/<long-random-secret>/`. To
   claude.ai it's an authless server; in reality nginx proxies *only* that exact
   secret prefix to the FastMCP service and 404s everything else. The URL **is**
   the bearer-equivalent — it matches Tom's "a tight enough secret, I'm the only
@@ -178,11 +178,17 @@ A small package in this repo, its own process — not bolted into Django:
 ```
 mcp_server/
   __init__.py
-  __main__.py        # FastMCP app; runs streamable-HTTP on 127.0.0.1:8765
+  __main__.py        # entrypoint: from .server import main; main()
+  server.py          # FastMCP app + the @mcp.tool definitions (§5) + main()
   client.py          # thin httpx client around the Django API (caine token)
-  tools.py           # the @mcp.tool definitions from §5
+  tests.py           # FoodClient tests via httpx.MockTransport (no network)
 ```
 
+`main()` runs streamable-HTTP at path `/` on `127.0.0.1:8765`
+(`mcp.run(transport="http", host, port, path="/")`); nginx maps
+`/mcp/<secret>/` → that root. Client tests run with
+`python -m unittest mcp_server.tests` (needs the `mcp` dep group).
+
 - Deps via a uv group so they only install where needed:
   `[dependency-groups] mcp = ["fastmcp", "httpx"]`. Deploy with
   `uv sync --group mcp` on the box that runs the service.
@@ -204,10 +210,10 @@ All out of git; the systemd unit loads the same `.env` the Django service uses.
 1. `uv sync --group mcp` on the box.
 2. Add the three env vars to `/var/lib/food/.env`; generate the bearer token.
 3. Install `deploy/food-mcp.service`, `daemon-reload`, start, enable.
-4. Add the `location /mcp` block to the `food.jihakuz.xyz` nginx config
+4. Add the `location /mcp` block to the `food.tomflux.xyz` nginx config
    (`proxy_buffering off`, long read timeout), `nginx -t`, reload.
 5. In claude.ai, add a custom connector pointing at the **secret URL**
-   `https://food.jihakuz.xyz/mcp/<secret>/` (authless connector — see §4).
+   `https://food.tomflux.xyz/mcp/<secret>/` (authless connector — see §4).
 6. Smoke test: in cooking mode, "what's in my pantry?" → Claude calls
    `get_pantry` and lists real items.
 
diff --git a/mcp_server/__init__.py b/mcp_server/__init__.py
new file mode 100644
index 0000000..07b8054
--- /dev/null
+++ b/mcp_server/__init__.py
@@ -0,0 +1,6 @@
+"""FastMCP "ai service" for the Food pantry app.
+
+A standalone process (no Django import) that exposes a small set of MCP tools to
+claude.ai cooking mode over Streamable HTTP, backed by the Food Django REST API.
+See mcp.md for the full specification.
+"""
diff --git a/mcp_server/__main__.py b/mcp_server/__main__.py
new file mode 100644
index 0000000..f5f6e40
--- /dev/null
+++ b/mcp_server/__main__.py
@@ -0,0 +1,4 @@
+from .server import main
+
+if __name__ == "__main__":
+    main()
diff --git a/mcp_server/client.py b/mcp_server/client.py
new file mode 100644
index 0000000..d2b9ff0
--- /dev/null
+++ b/mcp_server/client.py
@@ -0,0 +1,75 @@
+"""Thin HTTP client around the Food Django REST API.
+
+Pure HTTP — holds no Django import. Talks to the API over localhost using the
+`caine` DRF token (Authorization: Token <token>). One method per endpoint the
+MCP tools need; all errors surface as `FoodApiError` with a readable message.
+"""
+import os
+
+import httpx
+
+
+class FoodApiError(Exception):
+    """The Django API returned a non-2xx response, or was unreachable."""
+
+
+class FoodClient:
+    def __init__(self, base=None, token=None, http=None):
+        base = (base or os.environ.get("FOOD_API_BASE", "http://127.0.0.1:8042/api")).rstrip("/")
+        token = token or os.environ.get("FOOD_API_TOKEN", "")
+        # `http` is injectable for tests (e.g. httpx.MockTransport).
+        self._http = http or httpx.Client(
+            base_url=base,
+            headers={"Authorization": f"Token {token}"},
+            timeout=30.0,
+        )
+
+    # --- low level ---
+
+    def _request(self, method, path, **kwargs):
+        try:
+            resp = self._http.request(method, path, **kwargs)
+        except httpx.HTTPError as e:
+            raise FoodApiError(f"could not reach the food API: {e}") from e
+        if resp.status_code >= 400:
+            raise FoodApiError(f"{resp.status_code}: {_safe_json(resp)}")
+        return _safe_json(resp)
+
+    def _get(self, path, params=None):
+        return self._request("GET", path, params=params)
+
+    def _post(self, path, json):
+        return self._request("POST", path, json=json)
+
+    # --- endpoints (one per MCP tool need) ---
+
+    def pantry(self):
+        return self._get("/pantry/")
+
+    def set_state(self, ingredient, state, location=None):
+        body = {"ingredient": ingredient, "state": state}
+        if location:
+            body["location"] = location
+        return self._post("/pantry/set-state/", body)
+
+    def bulk_add(self, items):
+        return self._post("/bulk-pantry-add/", {"items": items})
+
+    def what_can_i_cook(self, servings=2):
+        return self._get("/what-can-i-cook/", {"servings": servings})
+
+    def meta_recipes(self):
+        return self._get("/meta-recipes/")
+
+    def log_cook(self, payload):
+        return self._post("/log-cook/", payload)
+
+    def create_meta_recipe(self, payload):
+        return self._post("/create-meta-recipe/", payload)
+
+
+def _safe_json(resp):
+    try:
+        return resp.json()
+    except ValueError:
+        return resp.text
diff --git a/mcp_server/server.py b/mcp_server/server.py
new file mode 100644
index 0000000..cc8fe4a
--- /dev/null
+++ b/mcp_server/server.py
@@ -0,0 +1,168 @@
+"""FastMCP tool definitions for the Food pantry app.
+
+Each tool maps to a Django API call via FoodClient and returns compact,
+Claude-friendly data (names + states, not raw API dumps). Tool descriptions
+state *when* to call them — current models reach for tools conservatively.
+
+Run with `python -m mcp_server` (see __main__.py). FastMCP 2.x.
+"""
+import os
+
+from fastmcp import FastMCP
+
+from .client import FoodClient, FoodApiError
+
+mcp = FastMCP("food-pantry")
+_api = FoodClient()
+
+VALID_STATES = ("in", "low", "out")
+
+
+def _err(e):
+    return {"error": str(e)}
+
+
+@mcp.tool
+def get_pantry(location: str | None = None, include_out: bool = False) -> dict:
+    """List what's in the pantry with each item's state (in / low / out). Call
+    this before suggesting meals or a shopping list so advice is grounded in
+    what's actually in stock. `location` optionally filters to fridge, cupboard,
+    or freezer. 'out' items are omitted unless `include_out` is true."""
+    try:
+        rows = _api.pantry()
+    except FoodApiError as e:
+        return _err(e)
+
+    items = []
+    counts = {"in": 0, "low": 0, "out": 0}
+    for r in rows:
+        state = r.get("state")
+        if state in counts:
+            counts[state] += 1
+        if location and r.get("location") != location:
+            continue
+        if not include_out and state == "out":
+            continue
+        items.append({
+            "name": r.get("ingredient_name"),
+            "state": state,
+            "location": r.get("location"),
+            "quantity": r.get("quantity"),
+            "unit": r.get("unit"),
+            "expiry": r.get("expiry_date"),
+            "staple": r.get("is_staple"),
+        })
+    return {"items": items, "counts": counts}
+
+
+@mcp.tool
+def set_item_state(ingredient: str, state: str, location: str | None = None) -> dict:
+    """Mark an ingredient In stock / running Low / Out. Call this when the user
+    says they used up, ran low on, or restocked something. `state` must be one
+    of 'in', 'low', 'out'. `location` is optional (fridge/cupboard/freezer)."""
+    if state not in VALID_STATES:
+        return {"error": f"state must be one of {list(VALID_STATES)}"}
+    try:
+        return _api.set_state(ingredient, state, location)
+    except FoodApiError as e:
+        return _err(e)
+
+
+@mcp.tool
+def add_to_pantry(items: list[dict]) -> dict:
+    """Add items the user bought. Each item is {name, location?, quantity?,
+    unit?} — e.g. {"name": "pork mince", "location": "fridge"}. Existing items
+    are restocked (set back to In) rather than duplicated."""
+    payload = [
+        {
+            "ingredient_name": it.get("name") or it.get("ingredient_name"),
+            "location": it.get("location", "fridge"),
+            "quantity": it.get("quantity"),
+            "unit": it.get("unit"),
+        }
+        for it in items
+    ]
+    try:
+        return _api.bulk_add(payload)
+    except FoodApiError as e:
+        return _err(e)
+
+
+@mcp.tool
+def what_can_i_cook(servings: int = 2) -> dict:
+    """Match the pantry against the meta-recipe templates. Returns each recipe
+    as ready / partial / missing with per-slot availability — use it to suggest
+    what the user can make right now."""
+    try:
+        return _api.what_can_i_cook(servings)
+    except FoodApiError as e:
+        return _err(e)
+
+
+@mcp.tool
+def get_recipes() -> dict:
+    """The meta-recipe templates with their swappable slot options. Use this to
+    suggest substitutions — each slot lists the ingredients that can fill it
+    (e.g. a protein slot accepts pork mince OR chicken)."""
+    try:
+        return {"meta_recipes": _api.meta_recipes()}
+    except FoodApiError as e:
+        return _err(e)
+
+
+@mcp.tool
+def log_cook(
+    meta_recipe_id: int | None = None,
+    recipe_id: int | None = None,
+    slot_choices: dict | None = None,
+    servings: int = 2,
+    rating: int | None = None,
+    notes: str = "",
+) -> dict:
+    """Record a cooked meal (and an optional 1-5 rating). Provide exactly one of
+    `meta_recipe_id` or `recipe_id`. Returns `used_ingredients` as SUGGESTIONS
+    only — the pantry is NOT changed. Confirm with the user, then call
+    `set_item_state` for each ingredient they agree to mark low or out."""
+    payload = {
+        "meta_recipe_id": meta_recipe_id,
+        "recipe_id": recipe_id,
+        "slot_choices": slot_choices or {},
+        "servings": servings,
+        "notes": notes,
+    }
+    if rating is not None:
+        payload["rating"] = rating
+    try:
+        return _api.log_cook(payload)
+    except FoodApiError as e:
+        return _err(e)
+
+
+@mcp.tool
+def create_meta_recipe(recipe: dict) -> dict:
+    """Save a meta-recipe the user brainstormed in the chat. `recipe` is the full
+    template:
+
+      {name, method, prep_time_mins?, cook_time_mins?, default_servings?,
+       gear_needed?, tags?,
+       slots: [{name, required?, max_choices?,
+                options: [{ingredient_name, quantity_per_serving, unit, tags?}]}],
+       base_ingredients: [{ingredient_name, quantity_per_serving, unit}]}
+
+    Pass an `id` to update an existing template (it rebuilds slots/bases).
+    Unknown ingredients are auto-created."""
+    try:
+        return _api.create_meta_recipe(recipe)
+    except FoodApiError as e:
+        return _err(e)
+
+
+def main():
+    host = os.environ.get("FOOD_MCP_HOST", "127.0.0.1")
+    port = int(os.environ.get("FOOD_MCP_PORT", "8765"))
+    # Streamable HTTP at the root path; nginx maps /mcp/<secret>/ -> here.
+    mcp.run(transport="http", host=host, port=port, path="/")
+
+
+if __name__ == "__main__":
+    main()
diff --git a/mcp_server/tests.py b/mcp_server/tests.py
new file mode 100644
index 0000000..cd13383
--- /dev/null
+++ b/mcp_server/tests.py
@@ -0,0 +1,85 @@
+"""Tests for the FoodClient HTTP layer, using httpx.MockTransport (no network,
+no Django, no fastmcp). Run with: python -m unittest mcp_server.tests
+"""
+import json
+import unittest
+
+import httpx
+
+from mcp_server.client import FoodClient, FoodApiError
+
+
+def make_client(handler):
+    transport = httpx.MockTransport(handler)
+    http = httpx.Client(
+        transport=transport,
+        base_url="http://api.test/api",
+        headers={"Authorization": "Token x"},
+    )
+    return FoodClient(http=http)
+
+
+class FoodClientTests(unittest.TestCase):
+    def test_set_state_posts_expected_body(self):
+        captured = {}
+
+        def handler(request):
+            captured["path"] = request.url.path
+            captured["body"] = json.loads(request.content)
+            return httpx.Response(200, json={"state": "out"})
+
+        out = make_client(handler).set_state("noodles", "out", location="cupboard")
+        self.assertEqual(captured["path"], "/api/pantry/set-state/")
+        self.assertEqual(
+            captured["body"],
+            {"ingredient": "noodles", "state": "out", "location": "cupboard"},
+        )
+        self.assertEqual(out["state"], "out")
+
+    def test_set_state_omits_location_when_absent(self):
+        captured = {}
+
+        def handler(request):
+            captured["body"] = json.loads(request.content)
+            return httpx.Response(200, json={})
+
+        make_client(handler).set_state("eggs", "in")
+        self.assertNotIn("location", captured["body"])
+
+    def test_bulk_add_wraps_items(self):
+        captured = {}
+
+        def handler(request):
+            captured["body"] = json.loads(request.content)
+            return httpx.Response(201, json={"added": 1})
+
+        make_client(handler).bulk_add([{"ingredient_name": "eggs"}])
+        self.assertEqual(captured["body"], {"items": [{"ingredient_name": "eggs"}]})
+
+    def test_what_can_i_cook_passes_servings(self):
+        captured = {}
+
+        def handler(request):
+            captured["servings"] = request.url.params.get("servings")
+            return httpx.Response(200, json={"results": []})
+
+        make_client(handler).what_can_i_cook(servings=4)
+        self.assertEqual(captured["servings"], "4")
+
+    def test_error_response_raises(self):
+        def handler(request):
+            return httpx.Response(404, json={"error": "nope"})
+
+        with self.assertRaises(FoodApiError):
+            make_client(handler).set_state("x", "out")
+
+    def test_unreachable_api_raises(self):
+        def handler(request):
+            raise httpx.ConnectError("boom")
+
+        with self.assertRaises(FoodApiError):
+            make_client(handler).pantry()
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/pyproject.toml b/pyproject.toml
index d09d09a..e0340ed 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -14,3 +14,11 @@ dependencies = [
 
 # No [build-system]: this is an application, not an installable package, so uv
 # treats it as a virtual project and won't try to build/install it.
+
+# Optional deps for the MCP "ai service" (deploy with `uv sync --group mcp`).
+# Kept out of the default set so the Django service stays lean.
+[dependency-groups]
+mcp = [
+    "fastmcp>=2",
+    "httpx>=0.27",
+]