Add Gmail as an MCP tool (read, search, send, label, draft) using OneCLI-managed OAuth. The agent gets Gmail tools in every enabled group; OneCLI injects real tokens at request time so no raw credentials are ever in the container or on disk in usable form.
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Add Gmail as an MCP tool (read, search, send, label, draft) using OneCLI-managed OAuth. The agent gets Gmail tools in every enabled group; OneCLI injects real tokens at request time so no raw credentials are ever in the container or on disk in usable form.
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</> SKILL.md
add-gmail-tool.SKILL.md
---name: add-gmail-tool
description: Add Gmail as an MCP tool (read, search, send, label, draft) using OneCLI-managed OAuth. The agent gets Gmail tools in every enabled group; OneCLI injects real tokens at request time so no raw credentials are ever in the container or on disk in usable form.
---# Add Gmail Tool (OneCLI-native)
This skill wires the [`@gongrzhe/server-gmail-autoauth-mcp`](https://www.npmjs.com/package/@gongrzhe/server-gmail-autoauth-mcp) stdio MCP server into selected agent groups. The MCP server reads stub credentials containing the `onecli-managed` placeholder; the OneCLI gateway intercepts outbound calls to `gmail.googleapis.com` and injects the real OAuth bearer from its vault.
Tools exposed (from `gmail-mcp@1.1.11`, surfaced to the agent as `mcp__gmail__<name>`): `search_emails`, `read_email`, `send_email`, `draft_email`, `delete_email`, `modify_email`, `batch_modify_emails`, `batch_delete_emails`, `download_attachment`, `list_email_labels`, `create_label`, `update_label`, `delete_label`, `get_or_create_label`, `list_filters`, `get_filter`, `create_filter`, `create_filter_from_template`, `delete_filter`.
**Why this pattern:** v2's invariant is that containers never receive raw API keys — OneCLI is the sole credential path (see CHANGELOG v2.0.0). The stub-file pattern satisfies this: the container sees `"onecli-managed"` placeholders, the gateway swaps them in flight.
## Phase 1: Pre-flight
### Verify OneCLI has Gmail connected
```bash
onecli apps get --provider gmail
```
Expected: `"connection": { "status": "connected" }` with scopes including `gmail.readonly`, `gmail.modify`, `gmail.send`.
> Open the OneCLI web UI at http://127.0.0.1:10254, go to Apps → Gmail, and click Connect. Sign in with the Google account you want the agent to act as.
### Verify stub credentials exist
```bash
ls -la ~/.gmail-mcp/gcp-oauth.keys.json ~/.gmail-mcp/credentials.json 2>&1
If either file exists but does **not** contain `onecli-managed`, **STOP** and tell the user — these are real OAuth credentials from a previous non-OneCLI install. Back them up, then delete before proceeding. The OneCLI migration normally handles this; if it didn't, something is wrong.
`~/.gmail-mcp` must sit under an `allowedRoots` entry (e.g. `/home/<user>`). If it doesn't, tell the user to run `/manage-mounts` first or add their home directory.
### Check agent secret-mode
For each target agent group, confirm OneCLI will inject Gmail secrets into its container. Find the OneCLI agent ID that matches the group's `agentGroupId`:
```bash
onecli agents list
```
If that agent's `secretMode` is `all`, you're done — Gmail secrets (identified by OneCLI's Gmail hostPattern) will auto-inject. If it's `selective`, explicitly assign the Gmail secrets using the safe merge pattern (`set-secrets` replaces the entire list — always read first):
### Copy the skill's tests into the container tree
Both integration points this skill relies on live in the container (Bun) tree — the Dockerfile package install and the dynamic allow-pattern derivation in `claude.ts` — so the guards go there. `cp` overwrites, so re-running is safe.
- `gmail-dockerfile.test.ts` asserts the `GMAIL_MCP_VERSION` ARG and the pinned `pnpm install -g` line are present — the `gmail-mcp` binary is a Dockerfile-installed CLI, not importable or typed, so this structural guard is what goes red if the install is dropped.
- `gmail-allow-pattern.test.ts` asserts `claude.ts` still spreads `Object.keys(this.mcpServers).map(mcpAllowPattern)` into `allowedTools` — the derivation that makes registering `gmail` (Phase 3) enough to expose `mcp__gmail__*`.
### Add MCP server to Dockerfile
Edit `container/Dockerfile`. Find the pinned-version ARG block:
```dockerfile
ARG CLAUDE_CODE_VERSION=2.1.154
ARG AGENT_BROWSER_VERSION=latest
ARG VERCEL_VERSION=52.2.1
ARG BUN_VERSION=1.3.12
```
Add a new line:
```dockerfile
ARG GMAIL_MCP_VERSION=1.1.11
```
Then find the last pnpm global-install `RUN` block (the one that installs `@anthropic-ai/claude-code`) and add a new block directly after it (before the `# ---- ncl CLI wrapper` section):
Pinned version matters — `minimumReleaseAge` in `pnpm-workspace.yaml` gates trunk installs, and CLAUDE.md requires a fixed ARG version for all Node CLIs installed into the image.
**Why the `zod-to-json-schema` pin:** `@gongrzhe/server-gmail-autoauth-mcp@1.1.11` has loose deps (`zod-to-json-schema: ^3.22.1`, `zod: ^3.22.4`). pnpm resolves `zod-to-json-schema` to the latest 3.25.x, which imports `zod/v3` — a subpath that only exists in `zod>=3.25`. But `zod` resolves to `3.24.x` (highest satisfying `^3.22.4` without breaking peer ranges). Result: `ERR_PACKAGE_PATH_NOT_EXPORTED` at import time. Pinning `zod-to-json-schema` to a pre-v3-subpath version avoids it. Re-check if you bump `GMAIL_MCP_VERSION`.
The Gmail allow-pattern is derived automatically. `container/agent-runner/src/providers/claude.ts` builds `allowedTools` from each group's `mcpServers` map (`Object.keys(this.mcpServers).map(mcpAllowPattern)`), so registering `gmail` in Phase 3 exposes `mcp__gmail__*` to the agent.
### Rebuild the container image
```bash
./container/build.sh
```
Must complete cleanly. The new `pnpm install -g` layer is ~60s first time (cached on rebuild).
## Phase 3: Wire Per-Agent-Group
For each agent group that should have Gmail (ask the user — typically their personal DM and CLI agents, sometimes shared household agents), persist two changes to the **central DB** (`data/v2.db`): the `mcpServers.gmail` entry and an `additionalMounts` entry for `.gmail-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.
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 `.gmail-mcp` mount
Register the mount with the host-only `ncl groups config add-mount` verb. For each chosen `<group-id>`:
```bash
ncl groups config add-mount \
--id <group-id> \
--host "$HOME/.gmail-mcp" \
--container .gmail-mcp
```
`--host` is the host path, `--container` is the in-container path (relative, lands at `/workspace/extra/.gmail-mcp`). No `--ro` — the MCP server writes refreshed token state back into the mount. The verb is idempotent (a re-run skips if the mount is already present) and operator-only (host-side; rejected from inside a container), so run it from a host operator shell when applying this skill.
**Why the container path is relative:** `mount-security` rejects absolute `containerPath` values. Additional mounts are prefixed with `/workspace/extra/`, so `containerPath: ".gmail-mcp"` lands at `/workspace/extra/.gmail-mcp`. The MCP server's `GMAIL_OAUTH_PATH` / `GMAIL_CREDENTIALS_PATH` env vars point at that absolute location inside the container.
**Why this can't be `groups/<folder>/container.json`:** post-migration `014-container-configs`, `materializeContainerJson` in `src/container-config.ts` rewrites that file from the DB on every spawn. Anything hand-edited there is silently overwritten on next restart.
(cd container/agent-runner && bun test src/providers/gmail-dockerfile.test.ts src/providers/gmail-allow-pattern.test.ts)
```
All must be clean before proceeding. `gmail-dockerfile.test.ts` confirms the package install is wired into the image; `gmail-allow-pattern.test.ts` confirms the allow-pattern derivation that exposes `mcp__gmail__*`. A failure means one drifted.
> In your `<agent-name>` chat, send: **"list my gmail labels"** or **"search my inbox for invoices from last month"**.
>
> The agent should use `mcp__gmail__list_labels` / `mcp__gmail__search`. The first call may take a second or two while the MCP server starts and OneCLI does the token exchange.
- `command not found: gmail-mcp` → image wasn't rebuilt or PATH doesn't include `/pnpm` (should — `ENV PATH="$PNPM_HOME:$PATH"` in Dockerfile).
- `ENOENT: no such file or directory, open '/workspace/extra/.gmail-mcp/credentials.json'` → mount is missing. Check `~/.config/nanoclaw/mount-allowlist.json` includes a parent of `~/.gmail-mcp`.
- `401 Unauthorized` from `gmail.googleapis.com` → OneCLI isn't injecting. Check the agent's secret mode (`onecli agents secrets --id <agent-id>`) and that the Gmail app is connected (`onecli apps get --provider gmail`).
- Agent says "I don't have Gmail tools" → the `gmail` 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 (rebuild with `./container/build.sh`, with `--no-cache` if suspicious).
## Removal
See [REMOVE.md](REMOVE.md) for the idempotent removal procedure (delete the copied tests, unregister the MCP server per group, drop the mount, remove the Dockerfile install, rebuild, and optionally drop the stubs and disconnect OneCLI).
## Notes
- **Stub format is OneCLI-prescribed.** The `access_token: "onecli-managed"` pattern with `expiry_date: 99999999999999` tells the Google auth client the token is valid; OneCLI intercepts the outgoing Gmail API call and rewrites `Authorization: Bearer onecli-managed` to the real token. `expiry_date: 0` (refresh-interception) is an alternative the OneCLI docs describe — both work but OneCLI's own `migrate` command writes the far-future variant, which is what this skill assumes.
- **Scopes are set at OAuth connect time.** If the agent needs scopes beyond what's currently connected (e.g. the user later wants `calendar.readonly` for combined email/calendar workflows), disconnect and reconnect Gmail in the OneCLI web UI with the expanded scope set.
- **This is tool-only.** Inbound email as a channel (emails trigger the agent) is a separate piece of work — it needs a `src/channels/gmail.ts` adapter that polls the inbox and routes to a messaging group. The pre-v2 qwibitai skill had this; it has not been ported to v2's channel architecture as of v2.0.0.
## Credits & references
- **MCP server:** [`@gongrzhe/server-gmail-autoauth-mcp`](https://github.com/GongRzhe/Gmail-MCP-Server) by GongRzhe — MIT-licensed.
- **OneCLI credential stubs:** pattern documented at `https://onecli.sh/docs/guides/credential-stubs/gmail.md`.
- **Skill pattern:** modeled on [`add-atomic-chat-tool`](../add-atomic-chat-tool/SKILL.md) and [`add-vercel`](../add-vercel/SKILL.md).
- **Addresses:** [issue #1500](https://github.com/nanocoai/nanoclaw/issues/1500) (proxy Gmail/Calendar OAuth tokens through credential proxy) for the Gmail side.
- **Related PRs:** [#1810](https://github.com/nanocoai/nanoclaw/pull/1810) (pre-install Gmail/Notion MCP) overlaps on the "install the MCP server in the image" idea but bundles many unrelated changes; this skill is the focused OneCLI-native version.
