---
name: add-gcal-tool
description: Add Google Calendar as an MCP tool (list calendars, list/search/create events, free/busy queries) using OneCLI-managed OAuth. Multi-calendar and multi-account supported. Mirrors /add-gmail-tool's stub pattern — no raw credentials ever reach the container; OneCLI injects real tokens at request time.
---

# Add Google Calendar Tool (OneCLI-native)

This skill wires [`@cocal/google-calendar-mcp`](https://github.com/cocal-com/google-calendar-mcp) into selected agent groups. The MCP server reads stub credentials containing the `onecli-managed` placeholder; the OneCLI gateway intercepts outbound calls to `calendar.googleapis.com` / `oauth2.googleapis.com` and swaps the bearer for the real OAuth token from its vault.

**Why this package (and not gongrzhe's):** `@gongrzhe/server-calendar-autoauth-mcp` only supports the `primary` calendar and exposes 5 tools (no `list_calendars`). `@cocal/google-calendar-mcp` explicitly supports multi-calendar and multi-account, and is actively maintained.

Tools exposed (surfaced as `mcp__calendar__<name>`, exact set depends on version — run `tools/list` against the MCP server to enumerate): `list-calendars`, `list-events`, `search-events`, `create-event`, `update-event`, `delete-event`, `get-event`, `list-colors`, `get-freebusy`, `get-current-time`, plus multi-account management tools.

**Why this pattern:** v2's invariant is that containers never receive raw API keys (CHANGELOG 2.0.0). Same stub pattern `/add-gmail-tool` uses. This skill is deliberately a sibling, not a combined "Google Workspace" skill — installs independently and removes cleanly.

## Phase 1: Pre-flight

### Verify OneCLI has Google Calendar connected

```bash
onecli apps get --provider google-calendar
```

Expected: `"connection": { "status": "connected" }` with scopes including `calendar.readonly` and `calendar.events`.

If not connected, tell the user:

> Open the OneCLI web UI at http://127.0.0.1:10254, go to Apps → Google Calendar, and click Connect. Sign in with the Google account the agent should act as. `calendar.readonly` + `calendar.events` are the minimum useful scopes.

### Verify stub credentials exist

The stub lives at `~/.calendar-mcp/` by convention (shared with `/add-gmail-tool`'s sibling). cocal doesn't default to this path (it uses `~/.config/google-calendar-mcp/tokens.json`) — we override via env vars below so it reads our stubs instead.

```bash
ls -la ~/.calendar-mcp/gcp-oauth.keys.json ~/.calendar-mcp/credentials.json 2>&1
```

If both exist with `onecli-managed`:

```bash
grep -l onecli-managed ~/.calendar-mcp/gcp-oauth.keys.json ~/.calendar-mcp/credentials.json
```

...skip to Phase 2. If either file has real credentials (no `onecli-managed`), **STOP** — back up and delete before proceeding.

If absent, write them:

```bash
mkdir -p ~/.calendar-mcp
cat > ~/.calendar-mcp/gcp-oauth.keys.json <<'EOF'
{
  "installed": {
    "client_id": "onecli-managed.apps.googleusercontent.com",
    "client_secret": "onecli-managed",
    "redirect_uris": ["http://localhost:3000/oauth2callback"]
  }
}
EOF
cat > ~/.calendar-mcp/credentials.json <<'EOF'
{
  "access_token": "onecli-managed",
  "refresh_token": "onecli-managed",
  "token_type": "Bearer",
  "expiry_date": 99999999999999,
  "scope": "https://www.googleapis.com/auth/calendar.readonly https://www.googleapis.com/auth/calendar.events"
}
EOF
chmod 600 ~/.calendar-mcp/*.json
```

### Verify mount allowlist covers the path

```bash
cat ~/.config/nanoclaw/mount-allowlist.json
```

`~/.calendar-mcp` must sit under an `allowedRoots` entry.

### Check agent secret-mode

For each target agent group, confirm OneCLI will inject the Google Calendar token:

```bash
onecli agents list
```

`secretMode: all` is sufficient. If `selective`, explicitly assign the Calendar secret.

## Phase 2: Apply Code Changes

### Check if already applied

```bash
grep -q 'CALENDAR_MCP_VERSION' container/Dockerfile && \
echo "ALREADY APPLIED — skip to Phase 3"
```

### Add MCP server to Dockerfile

Edit `container/Dockerfile`. Find the pinned-version ARG block and add:

```dockerfile
ARG CALENDAR_MCP_VERSION=2.6.1
```

If `/add-gmail-tool` has already been applied, the pnpm global-install block already exists with its `zod-to-json-schema@3.22.5` pin. Just append the calendar package — **the calendar-mcp uses `zod@4.x` and does NOT need that pin**, but it's harmless to share the block:

```dockerfile
RUN --mount=type=cache,target=/root/.cache/pnpm \
    pnpm install -g \
        "@gongrzhe/server-gmail-autoauth-mcp@${GMAIL_MCP_VERSION}" \
        "@cocal/google-calendar-mcp@${CALENDAR_MCP_VERSION}" \
        "zod-to-json-schema@3.22.5"
```

If `/add-gmail-tool` hasn't been applied, install Calendar standalone:

```dockerfile
RUN --mount=type=cache,target=/root/.cache/pnpm \
    pnpm install -g "@cocal/google-calendar-mcp@${CALENDAR_MCP_VERSION}"
```

`container/agent-runner/src/providers/claude.ts` derives the allow-pattern dynamically from each group's `mcpServers` map (`Object.keys(this.mcpServers).map(mcpAllowPattern)`), so registering `calendar` in Phase 3 automatically allows `mcp__calendar__*`.

### Install the dependency-guard test

`@cocal/google-calendar-mcp` is a stdio CLI installed in the image, not an imported module, so `tsc` and the runtime tests never reference it — only the Dockerfile edit above proves it is present. Copy the guard test into the host test tree (vitest) so the Dockerfile `ARG` + install line stay covered:

```bash
cp .claude/skills/add-gcal-tool/gcal-dockerfile.test.ts src/gcal-dockerfile.test.ts
pnpm exec vitest run src/gcal-dockerfile.test.ts
```

`cp` overwrites in place, so re-running this skill is safe.

**This is the skill's only in-tree integration test.** The Phase 3 `ncl groups config add-mcp-server` and `add-mount` steps are runtime writes to the central DB — they leave no line in the source tree whose deletion a test could catch, so a registration test is structurally inapplicable. They're verified at runtime instead (Phase 5).

### Rebuild the container image

```bash
./container/build.sh
```

## Phase 3: Wire Per-Agent-Group

For each agent group, persist two changes to the **central DB** (`data/v2.db`): the `mcpServers.calendar` entry and an `additionalMounts` entry for `.calendar-mcp`. Both flow through `materializeContainerJson` on every spawn, so editing `groups/<folder>/container.json` by hand does **not** stick — that file is regenerated from the DB.

### Register the MCP server

For each chosen `<group-id>` (use `ncl groups list` to enumerate):

```bash
ncl groups config add-mcp-server \
  --id <group-id> \
  --name calendar \
  --command google-calendar-mcp \
  --args '[]' \
  --env '{"GOOGLE_OAUTH_CREDENTIALS":"/workspace/extra/.calendar-mcp/gcp-oauth.keys.json","GOOGLE_CALENDAR_MCP_TOKEN_PATH":"/workspace/extra/.calendar-mcp/credentials.json"}'
```

Approval behaviour depends on where you run it: from inside an agent's container `ncl` write verbs are approval-gated (admin approves before it lands); from a host operator shell with full scope, it executes immediately. Either way, the response tells you which path it took.

### Add the `.calendar-mcp` mount

This is a **host-only / operator** verb — it's rejected from inside a container at any `cli_scope`, so run it host-side when you (the operator) apply this skill via `/setup`, `/customize`, or `/manage-mounts`. It's idempotent (skips if the mount is already present).

```bash
ncl groups config add-mount \
  --id <group-id> \
  --host "$HOME/.calendar-mcp" \
  --container .calendar-mcp
```

`--container` is relative (mount-security rejects absolute paths — additional mounts land at `/workspace/extra/<relative>`). No `--ro`: the MCP server may rewrite `credentials.json` on token refresh, so the mount must be read-write.

The mount also needs to be in the external mount allowlist (`~/.config/nanoclaw/mount-allowlist.json`) to take effect at spawn — see the Phase 1 "Verify mount allowlist covers the path" step. A container restart (`ncl groups restart`) is needed for the mount to apply.

**Why this can't be `groups/<folder>/container.json`:** post-migration `014-container-configs`, `materializeContainerJson` in `src/container-config.ts` rewrites that file from the DB on every spawn. Anything hand-edited there is silently overwritten on next restart.

**Same-group-as-gmail tip:** if this group already has the gmail MCP + `.gmail-mcp` mount, both coexist — `ncl groups config add-mcp-server` only updates the named entry, and `add-mount` appends to `additional_mounts` without disturbing existing entries.

## Phase 4: Build and Restart

```bash
pnpm run build
```

Run from your NanoClaw project root:

```bash
source setup/lib/install-slug.sh
launchctl kickstart -k gui/$(id -u)/$(launchd_label)  # macOS
systemctl --user restart $(systemd_unit)              # Linux
```

Kill any existing agent containers so they respawn with the new mcpServers config:

```bash
docker ps -q --filter 'name=nanoclaw-v2-' | xargs -r docker kill
```

## Phase 5: Verify

### Test from a wired agent

> Send: **"list my calendars"** or **"what's on my work calendar next Monday?"**.
>
> First call takes 2–3s while the MCP server starts and OneCLI does the token exchange.

### Check logs if the tool isn't working

```bash
tail -100 logs/nanoclaw.log | grep -iE 'calendar|mcp'
```

Common signals:
- `command not found: google-calendar-mcp` → image not rebuilt.
- `ENOENT ...credentials.json` → mount missing. Check the mount allowlist.
- `401 Unauthorized` from `*.googleapis.com` → OneCLI isn't injecting; verify agent's secret mode and that Google Calendar is connected.
- Agent says "I don't have calendar tools" → the `calendar` MCP server isn't registered in this group's `mcpServers` (re-run the `ncl groups config add-mcp-server` step in Phase 3 for that group and restart it), or the agent-runner image is stale (`./container/build.sh`, `--no-cache` if suspicious).

## Removal

See [REMOVE.md](REMOVE.md) — unregisters the MCP server, drops the `.calendar-mcp` mount, deletes the copied test, reverts the Dockerfile edits, and rebuilds.

## Credits & references

- **MCP server:** [`@cocal/google-calendar-mcp`](https://github.com/cocal-com/google-calendar-mcp) — MIT-licensed, actively maintained, multi-account and multi-calendar.
- **Why not gongrzhe:** `@gongrzhe/server-calendar-autoauth-mcp` only supports the primary calendar with 5 event-level tools. The cocal server supports multi-account and multi-calendar with the full tool surface.
- **Skill pattern:** direct sibling of [`/add-gmail-tool`](../add-gmail-tool/SKILL.md); same OneCLI stub mechanism.