Sam & Claude
c68953b107
New docs/MCP-INTEGRATION.md: how the two Hermes instances connect via MCP using colibri-mcp as the hub-and-spoke front-end to the shared board, rather than a direct mesh. Grounded in actual code: - Hermes is both MCP server (hermes mcp serve) and client (mcp_servers config) - colibri-mcp tool surface + env vars (COLIBRI_MCP_SOCKET/WRITE), socket transport - ties into the live board + poller/worker loop and the socat cross-host bridge - LIVE/SETUP/PLANNED tags; security, rejected mesh alternative, external-MCP future Cross-linked from CAPABILITY-ROUTING.md. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
177 lines
8.2 KiB
Markdown
177 lines
8.2 KiB
Markdown
# 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._
|