ai-coord-mcp

A shared coordination layer between multiple AI coding assistants — not an orchestrator.

This MCP server never launches, manages, or talks to any AI process. It only exposes a task queue, a per-task message thread, and progress reporting, all persisted as human-readable JSON on disk. Claude Code and OpenCode (or any other MCP-capable client) are launched manually, in separate terminals, and both point their MCP config at this server. Claude typically plays coordinator (creates/reviews tasks); OpenCode plays implementer (claims/updates/completes them) — but the server has no opinion about that, it just stores state.

Claude Code (Sonnet)                    OpenCode (DeepSeek/Qwen/etc.)
        │                                        │
        │ create_task, list_tasks,                │ claim_task, update_progress,
        │ approve_task, request_revision           │ complete_task, post_message
        ▼                                        ▼
              ai-coord-mcp  (this server)
                       │
                       ▼
              .ai/coordination/*.json  (on disk)

Design

• Transport: stdio. Each client spawns its own copy of this server as a subprocess. "The same server" means the same storage directory (COORDINATION_DIR), not one process. Every tool call re-reads the relevant JSON file from disk before mutating it; writes go through temp-file-then-rename (writeJsonAtomic) so a reader never sees a half-written file; a cross-process mutex (withLock, src/storage/lock.ts) built on mkdir guards concurrent writers, with stale-lock reclaim after 10s and an ownership token per holder.

• IDs: sequential task-0001, task-0002, … assigned under a short-lived lock. Validated against /^task-\d{4,}$/ before being joined into any filesystem path.

• Optimistic concurrency: every task carries a version counter. Pass expected_version to any mutating tool to get a ConflictError instead of a silent overwrite.

• Not implemented: binary attachments (the files field is path references only, not stored content), archiving (the archive/ directory exists but nothing writes to it), typed branch/commit fields (use the metadata convention below instead), structured Definition-of-Done / verify_command (use expected_output instead), task relationships / parent_id/blocks (use tags to group instead), MCP Resources / resources/subscribe (use wait_for_task instead).

Status model:

pending --claim_task--> claimed --update_progress--> in_progress
   ^                        |                              |
   |                        |     both claimed and in_progress can complete_task--> completed
   |                        |                                                            |
   |                        └──────────────────────cancel_task─────────────────┐  approve_task│request_revision
   |                                                                            |         |         |
   └───────────────reopen_task (from cancelled/completed/approved)◄────────────┘         ▼         ▼
                                                                                    approved   revision_requested
                                                                                               (loops back through
                                                                                                update_progress →
                                                                                                in_progress again)

update_progress auto-advances claimed or revision_requested to in_progress on its first call in that cycle — there's no separate "start_task" tool.

Related MCP server: MCP Agent Mail

Storage layout

.ai/coordination/
  tasks/task-0001.json       one file per task (includes its own audit history[])
  messages/task-0001.json    array of {id, taskId, author, timestamp, content}
  progress/task-0001.json    latest snapshot + full history of updates
  archive/                   reserved, unused
  .locks/                    transient lock directories, safe to delete if empty

Everything is plain JSON — cat .ai/coordination/tasks/task-0001.json works fine while the server is running.

Setup

cd ai-coord-mcp
pnpm install
pnpm run build

Both Claude Code and OpenCode need to point at the same COORDINATION_DIR (an absolute path) so they share state regardless of which directory each was launched from.

Claude Code — add to .mcp.json (project) or via claude mcp add:

{
  "mcpServers": {
    "ai-coord": {
      "command": "node",
      "args": ["/absolute/path/to/ai-coord-mcp/dist/index.js"],
      "env": {
        "COORDINATION_DIR": "/absolute/path/to/shared/.ai/coordination"
      }
    }
  }
}

OpenCode — add the equivalent entry to its MCP config (opencode.json / ~/.config/opencode/config.json, depending on your OpenCode version):

{
  "mcp": {
    "ai-coord": {
      "type": "local",
      "command": ["node", "/absolute/path/to/ai-coord-mcp/dist/index.js"],
      "environment": {
        "COORDINATION_DIR": "/absolute/path/to/shared/.ai/coordination"
      }
    }
  }
}

If COORDINATION_DIR is unset, the server defaults to <cwd>/.ai/coordination — only safe if you know both clients will be launched from the same working directory.

Getting started

1. Build the server and wire up COORDINATION_DIR for both clients (Setup above).

2. Launch Claude Code and OpenCode in separate terminals, both in the shared repo.

3. In Claude Code, create a task:

   Create a task: title "Sort inventory list", description "Implement stable sort by SKU for the inventory panel, keep the existing filter hooks working", expected_output "inventory.ts updated, existing tests still pass, new test for empty list". → calls create_task, returns task-0001 (status pending).

4. In OpenCode:

   Check ai-coord for any pending tasks. → calls claim_next_task, works the task, calls update_progress a few times, then complete_task.

5. Back in Claude Code:

   Review task-0001 and approve or request revision. → reviews the diff, calls approve_task or request_revision (the latter posts feedback to the thread; OpenCode reads it via get_messages and repeats from update_progress).

Tools

All mutating tools accept an optional expected_version — pass the task's current version to get a ConflictError instead of clobbering a concurrent change.

Every status-changing tool above (claim_task through reopen_task) returns the same summary shape as list_tasks — no history[] — so an implementer with a small context window (a local model, say) isn't handed the whole growing transition/note log back on every call. Same for update_progress: it returns the current snapshot, not the growing history[]. get_task/get_progress remain the only tools that return full history.

Workflow conventions

• Waiting for work: use wait_for_task over polling get_task/list_tasks — one call instead of N, blocks server-side without holding a lock, returns timed_out: true as a normal result.

• Picking up work: use claim_next_task over list_tasks({status:"pending"}) + claim_task — same two steps, atomic, retries automatically if another claimer wins the race.

• Git state: no typed branch/commit field. Convention: create_task's metadata carries { baseCommit, branch }; both agents read/write those same keys. expected_output plus this README is the Definition-of-Done contract.

• Implementer loop: claim_next_task (or claim_task on a specific id) → work → a few update_progress calls → complete_task. If revision is requested, get_messages for the feedback, then repeat from update_progress.

• Coordinator loop: create_task → wait_for_task (or check back later) → on completed, review the diff at working_directory → approve_task or request_revision.

Tests

pnpm test

Runs node:test (via tsx) over every src/**/*.test.ts file: the storage layer (atomic writes, cross-process lock semantics including the stale-lock/ownership-token edge case, id generation, message/progress persistence) and the full tool surface (state-machine transitions, TASK_ID schema rejecting malformed/traversal ids, version conflicts) driven through the real registerXxx() functions against a fresh temp COORDINATION_DIR per test file.