t3-code-mcp

An MCP gateway that lets MCP clients interact with T3 Code agents: find projects and threads, start tasks, check progress, retrieve results, and respond to requests for input.

It connects to one configured T3 Code environment and supports local stdio and remote Streamable HTTP connections for desktop assistants, hosted clients, and custom integrations.

The original idea was to pair it with GPTVoice's tool calls to start tasks and get agent updates by voice while on the go.

flowchart LR
    User[You] <--> Client[Any compatible MCP client]
    Client <-->|MCP over stdio or Streamable HTTP| Gateway[t3-code-mcp]
    Gateway <-->|Authenticated HTTP and WebSocket RPC| T3[T3 Code and its coding agents]
    Gateway <-->|Native T3 MCP, forwarded tools| T3
    Gateway -->|Read-only Git status and revision comparison| Workspace[T3-selected workspace]

What you can do

• See the open queue of threads that are not working by default, review every project and thread on request, triage what needs attention, and read full thread timelines.

• Inspect structured Git status, bounded uncommitted diffs, and committed base-to-head comparisons in T3-selected workspaces.

• Start recoverable one-call tasks, find them after reconnecting, review their changes, and cancel them.

• Steer, queue, interrupt, fork, configure, and organize threads, manage schedules and pull request watches, and upload attachments, through T3's own native MCP tools that the gateway forwards.

• Answer approval and input requests.

• Record redacted tool, transport, upstream, Git, and journal activity for later review through t3_audit_log.

• Connect through local stdio or authenticated Streamable HTTP.

The gateway supports T3 orchestration protocols 1 and 2. Protocol 2, introduced by upstream PR #2829, uses HTTP snapshot reads and authenticated WebSocket RPC for thread control. Protocol 1 retains HTTP dispatch for older deployments. The recorded live integration target is v0.0.41-nightly.20260910.1507. V2 has source-contract and local fixture coverage. A candidate protocol transition acceptance passed on 2026-10-06 in an isolated V1 to V2 upgrade and rollback. It did not verify the full V2 surface or an installed service, so live verification of the deployed V2 build is still required. See orchestrator compatibility. See usage and tool behavior for examples, supported tools, and current limits.

Related MCP server: VoxMesh

Security

Write access lets a client control your T3 coding agent with that agent's machine permissions. Both thread creation and composite task start require the caller to choose a runtime mode explicitly. The client can answer approval requests without independent human verification. Read-only access still exposes thread content and project information.

Start with MCP_READ_ONLY=true, connect only trusted clients, and review the security and access risks before enabling remote access or control tools.

Quick start

Install Cargo and Rust 1.88 or newer. The package commands and TypeScript reference checks also need Node.js 22.13 or newer and pnpm 11.16.0.

Run from the repository root:

pnpm install
pnpm build
cp .env.example .env
chmod 600 .env

Edit .env: set T3_ACCESS_TOKEN, a separate random MCP_BEARER_TOKEN, and MCP_READ_ONLY=true. Set T3_HTTP_BASE_URL if T3 is not at http://127.0.0.1:3773.

For HTTP, set MCP_TRANSPORT=http and start the gateway:

set -a
. ./.env
set +a
pnpm start

pnpm build produces rust/target/release/t3-code-mcp. start and serve run that release binary. dev builds and runs the Rust debug binary. The CLI reads exported environment variables. pnpm build:reference builds the TypeScript reference used by compatibility checks.

Connect your MCP client to http://127.0.0.1:8787/mcp with Authorization: Bearer <MCP_BEARER_TOKEN>. This address is local to the gateway machine; remote clients need an authenticated tunnel or HTTPS proxy. For a local client that launches the process, use MCP_TRANSPORT=stdio instead.

Run native-login with a T3 pairing code to enable the forwarded native tools; see native T3 login. Request connection status, list projects, and read an existing thread to verify the connection. Follow the configuration and client connection guide for all environment variables and the first write-enabled check.

The gateway writes its append-only redacted usage trail to audit.jsonl in T3_MCP_DATA_DIR; a future agent can query the bounded history with t3_audit_log. For offline aggregate analysis without T3 credentials, run pnpm usage-summary --file ./data/audit.jsonl --since <ISO> --until <ISO>. See usage analysis for metric definitions and task briefs for precise launch/continuation examples.

Documentation

V1 integration references

These references record the V1 limits checked on 2026-09-11. Several are addressed by the new V2 orchestrator. See orchestrator compatibility for the gateway behavior after that upgrade.