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Code Relay

Code Relay

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github.comDeveloper Tools0Updated 8w ago
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About Code Relay

Code Relay is an MCP integration for coding agents that lets development happen on one machine and verification on another. It binds runbooks to a branch and source commit, then returns structured receipts to inform repair iterations.

Key features

  1. 01Branch-bound project setup
  2. 02Exact-commit verification in isolated worktrees
  3. 03Checkpoint execution on a self-hosted runner
  4. 04Allowlisted validation commands with limits
  5. 05Structured receipts for verification results

Use cases

  1. 01Verify code in a Linux or production-like environment
  2. 02Run model code on a CUDA/GPU machine
  3. 03Test integrations or devices unavailable locally

MCP support

Code Relay runs as a local MCP server over stdio. It exposes tools for project binding, checkpoint management, runbook publishing, status checks, receipt retrieval, and analysis.

Configuration

Local server config is the same for every client. Copy it into your client’s MCP config file.

mcp.json · Universal config
{
  "mcpServers": {
    "zarcherlot-code-relay": {
      "command": "npx",
      "args": [
        "-y",
        "code-relay-mcp"
      ]
    }
  }
}
Run commandnpx -y code-relay-mcp

Local servers need a runtime on your machine (e.g. Node.js 18+). Config file locations differ by client; see your client’s docs.

Packages
npmcode-relay-mcp3.1.0

Tools

No tool list yet

Local servers expose tools only once running on your machine, and the maintainer has not provided a tool list.

Details

From the project README

README image Code Relay

English · Chinese

Build. Prove. Relay.

Code Relay lets your coding agent develop on one machine and prove the result on another.

Relay is an MCP-based coding-agent integration for cross-machine development and verification. AI on the Dev Host implements the request; the Target Host runs the real validation; a structured receipt comes back to guide the next repair iteration. It works with Codex, Claude Code, Cursor, VS Code, and other MCP-capable coding agents.

When Relay is useful

  • Different environments — develop on Windows or macOS, verify on Linux, a private network, or a production-like host.
  • Special hardware — send model code to a CUDA/GPU machine, or verify a camera, serial device, or sensor where it is connected.
  • Real integrations — exercise payment callbacks, queues, databases, browsers, or internal services that cannot be reproduced locally.
  • AI-driven iteration — return concrete expected/actual results so the coding agent can repair, republish, and retry.

What Relay provides

  • Branch-scoped project binding and short-lived join links.
  • Exact source-commit verification in an isolated worktree.
  • Checkpoint execution through a code-relay-checkpoint GitHub Actions self-hosted runner.
  • Safe, allowlisted validation commands with bounded output and timeouts.
  • Structured receipt.json and human-readable receipts for passed, failed, and blocked runs.

Quick start

AI client installation

Let your coding agent read and follow the instructions:

https://raw.githubusercontent.com/zarcherlot/code-relay/main/install.md
npm fallback
npx -y code-relay-mcp@latest install --client codex

Replace codex with claude-code, cursor, vscode, or generic as needed.

MCP server details

Code Relay is a local MCP server that communicates over stdio. The npm package starts the server with:

npx -y [email protected]

The server implements the MCP JSON-RPC surface directly in Go (without a third-party MCP SDK). It supports initialize, ping, tools/list, and tools/call, and exposes these tools:

ToolPurpose
bind_projectBind a repository and branch to a relay role.
create_checkpoint_inviteCreate a short-lived checkpoint join link.
join_checkpointJoin a branch-scoped checkpoint subscription.
watcher_statusRead local watcher state.
stop_watcherStop the local watcher.
doctorRun non-mutating local health checks.
publish_runbookValidate and publish a runbook.
statusRead runbook and receipt status.
fetch_receiptLoad and validate a runbook receipt.
analyzeAnalyze a receipt and determine the next state.

The implementation and transport loop are in internal/relay/mcp.go.

How it works

Dev Host sends a runbook through Code Relay to a Target Host; the Target Host runs a checkpoint and returns a receipt with evidence

the Dev Host sends a repository- and branch-bound runbook through Relay; the Target Host checks the exact source commit in its real environment and returns a Receipt recording the Checkpoint result.

Every runbook is bound to a repository, branch, and source commit. The Target Host acts as the Checkpoint, and the resulting receipt records passed, failed, or blocked verification for the next iteration.

Documentation

License

Code Relay is released under the MIT License.

Comments

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