# MCP Integration — Colibri as the Agent Coordination Hub **LIVE VS PLANNED.** The building blocks are all real and in the repos today (Hermes speaks MCP both directions; `colibri-mcp` exists; the board + poller/worker loop and the cross-host bridge are live). What is **not yet wired** is the one setup step this document describes: pointing each Hermes at `colibri-mcp` so the two instances coordinate through the shared board. Sections are tagged `[LIVE]`, `[SETUP]` (the work to do), or `[PLANNED]`. --- ## 1. What MCP is — and what "connect two Hermes" actually means MCP (Model Context Protocol) is a **client → server tool-calling** protocol over JSON-RPC. A client (an agent's LLM loop) connects to a server that advertises **tools** and **resources**; the client calls them and gets results. It is **not** a peer-to-peer chat bus and **not** a message queue. So "connect two Hermes instances" has two distinct meanings: - **(a) Tool sharing** — Hermes A invokes Hermes B's *own* tools (B's browser, B's files) by treating B as an MCP server. Point-to-point. - **(b) Coordination** — the two instances hand work back and forth and share state. Our fleet already does **(b)** through the Colibri board (register-agent → poll → execute → done; see [`CAPABILITY-ROUTING.md`](./CAPABILITY-ROUTING.md)). The simplest, highest-leverage MCP move is therefore to make MCP the **in-conversation interface to that board**, not to wire the two Hermes mouth-to-mouth. > **Expectation-set:** this gives each Hermes's LLM conversational read/write access to > the shared board. It is **not** a live two-way chat between the instances. The > **board is the shared state they meet at** — durable, inspectable, restart-safe. --- ## 2. [LIVE] What already exists **Hermes is both an MCP server and an MCP client.** - **Server** — `hermes mcp serve` (`mcp_serve.py`, FastMCP over stdio) exposes Hermes tools/conversations to any MCP client. Client config shape: ```json { "mcpServers": { "hermes": { "command": "hermes", "args": ["mcp", "serve"] } } } ``` - **Client** — Hermes consumes external MCP servers from its `mcp_servers` config (`hermes_cli/mcp_config.py`, managed via the `hermes mcp` subcommand; loaded by `tui_gateway/server.py`; refreshable in-session with `reload-mcp`). Each entry is the standard `command` / `args` / `env` (or `url`) shape; presets exist (e.g. Codex). **Colibri ships a ready-made MCP server fronting the board: `colibri-mcp`.** - Crate `crates/colibri-mcp` (binary `colibri-mcp`), a stdio JSON-RPC MCP server that wraps `colibri-client` and talks to the daemon over its Unix socket. - Tool surface (`crates/colibri-mcp/src/lib.rs`): | Tool | Access | Description | |------|--------|-------------| | `colibri_status` | read | Daemon status (agents, sessions) | | `colibri_snapshot` | read | Glasspane snapshot (pane states) | | `colibri_list_tasks` | read | Tasks by status | | `colibri_list_skills` | read | Registered skills catalog | | `colibri_create_task` | write-gated | Create a task | | `colibri_intake_task` | write-gated | Submit intake task with `required_capabilities` | | `colibri_set_cost_mode` | write-gated | Switch cost mode (fast/smart/max) | - Environment (`crates/colibri-mcp/src/main.rs`): - `COLIBRI_MCP_SOCKET` — daemon socket path (override) - `COLIBRI_DAEMON_SOCKET` — fallback socket path - `COLIBRI_MCP_WRITE=1` — enable the write-gated tools - `COLIBRI_MCP_EXTERNAL_CONFIG` / `COLIBRI_MCP_EXTERNAL_CALL=1` — proxy external MCP servers (see §6) - Default daemon socket on FreeBSD: `/var/run/colibri/colibri.sock` (from the `colibri_daemon` rc.d). `colibri-mcp socket-path` prints the resolved path. **Cross-host reach is already solved** — `colibri-mcp` connects to a daemon socket; a *remote* daemon is reached via the `socat` bridge on `100.72.229.63:9190` (Tailscale-only; see CAPABILITY-ROUTING `[LIVE] Cross-host topology`). osa-local instances just use the local socket. --- ## 3. Architecture — hub-and-spoke, not mesh ``` Hermes-osa-cli ──MCP──┐ ┌──MCP── Hermes-osa-web ▼ ▼ colibri-mcp (stdio JSON-RPC, one per Hermes) │ │ └────► colibri-daemon / board (SQLite) ◄────┘ ▲ poller (2 min) / worker (5 min) loop │ executes tasks assigned by agent UUID ``` Each Hermes configures Colibri **once**. Adding a third agent is one more spoke — no N×N wiring. The instances never connect to each other directly; they meet at the board. **Flow:** Hermes A's LLM calls `colibri_create_task {required_capabilities:["freebsd"]}` → the daemon's scheduler assigns it to a matching agent's UUID → that agent's poll loop (`scripts/colibri_poll.py`) picks up its own tasks, executes, and marks done (`scripts/colibri_task_done.py`) → A reads the result with `colibri_list_tasks`. This layers cleanly on the coordination model already built: | Layer | Role | Source of truth | |-------|------|-----------------| | `colibri-mcp` tools | conversational read/write to the board (this doc) | — | | poller / worker loop | autonomous execution of assigned tasks | scripts (PR #83) | | board (SQLite) | shared state: agents, tasks, lifecycle | `colibri-store` | --- ## 4. [SETUP] Wiring it up (config, not code) Per Hermes instance on osa: 1. **Provide the binary.** Build or stage `colibri-mcp`: ```sh cargo build --release -p colibri-mcp # target/release/colibri-mcp ``` Confirm it reaches the daemon: `colibri-mcp socket-path`. 2. **Register the server** in each Hermes's `mcp_servers` config (via `hermes mcp add` or the config file), giving the two instances distinct agent identities: ```yaml mcp_servers: colibri: command: /usr/local/bin/colibri-mcp env: COLIBRI_MCP_SOCKET: /var/run/colibri/colibri.sock COLIBRI_MCP_WRITE: "1" # enable create/intake ``` 3. **Reload tools** — `reload-mcp` in each Hermes; confirm the `colibri_*` tools appear. 4. **Validate end-to-end** — from cli-Hermes, create a `freebsd` task; confirm web-Hermes's loop runs it and the task flips to `done`. > Keep the two instances on **separate `HERMES_HOME`** (shared `.env` is fine, shared > state home is not — single-writer rule). Give them distinguishing capability tags if > a task must land on a specific one (e.g. `web-ui` vs `cli`). --- ## 5. [LIVE] Security - **Write tools are gated** by `COLIBRI_MCP_WRITE=1`. Leave it unset for read-only agents; set it only where an instance should create/assign work. - **Socket, not network.** `colibri-mcp` talks to the daemon's Unix socket; the only network surface is the bridge, bound to the Tailscale IP with a `pf` rule — never `0.0.0.0`. - **License:** `colibri-mcp` is AGPL-3.0-only; keep that in mind for any redistribution. --- ## 6. [PLANNED] Beyond coordination - **External MCP proxying.** `colibri-mcp` can host *third-party* MCP servers (`COLIBRI_MCP_EXTERNAL_CONFIG` + `COLIBRI_MCP_EXTERNAL_CALL=1`), jail-wrapped on FreeBSD (`colibri-mcp` `external.rs` → `colibri_daemon::spawner::jail_wrap`). This lets the hub aggregate outside tools behind one MCP endpoint, confined per the capability/isolation model. - **Tool-sharing mode (Option A).** If a real need arises for one Hermes to call another's *own* tools, expose the target with `hermes mcp serve` and add it as a spoke — but prefer the board for coordination; reserve direct tool-sharing for genuine capability borrowing, and accept the point-to-point cost. --- ## 7. Rejected alternative: direct Hermes ↔ Hermes mesh Connecting A's client straight to B's `hermes mcp serve` was considered and **not chosen** for coordination: it is a mesh (N×N config), stdio transport would have A *spawn a new* B rather than reach the running one, and it bypasses the board that already gives us durable, inspectable shared state. The hub (Option B above) reuses everything and scales by adding spokes. --- _See [`CAPABILITY-ROUTING.md`](./CAPABILITY-ROUTING.md) for the routing engine and cross-host transport, and [`../AGENTS.md`](../AGENTS.md) for the agent matrix._