Phab Arc

phab-arc-mcp is a small MCP stdio server for reviewing Phabricator revisions.

What This Server Exposes

The public MCP surface is intentionally small:

• review-phab
• inline-comments-phab

What review-phab Does

review-phab is the tool you call when you want an AI reviewer to review a Differential properly.

You give it a revision ID like D35297. It fetches the revision title, summary, changed files, raw diff, and the linked Maniphest task context, then packages all of that together with the review prompt the model should use.

From a user point of view, this means you do not have to manually open the revision, copy the diff, inspect related tasks, and explain the background before asking for a review. The tool gives the model the code changes and the surrounding context in one shot.

That makes reviews more useful because the model can judge the change against the actual task being solved, not just the raw code diff. It can use the overall repository context to reason about likely bugs, regressions, and edge cases, and it can also check whether the revision actually does what the linked task says it should do. In practice.

After that, inline-comments-phab can take the review findings and create draft inline comments directly on the Differential.

Important details:

• comments are created as draft inlines, not published comments

Installation

Requirements

1. Node.js 18 or newer
2. npm
3. access to a Phabricator instance with the Conduit API enabled
4. a Conduit API token for an account that can read the revisions and tasks you want to review

1. Clone the repository

git clone https://github.com/wxomi/node-chat.git
cd mcp-phab

2. Install dependencies

npm install

3. Build the server

npm run build

This produces the MCP server entrypoint at dist/server.js.

4. Configure environment variables

Set these before starting the server or before wiring it into your MCP client:

• PHAB_API_TOKEN
  • required
  • primary token variable used by the server
• CONDUIT_TOKEN
  • optional alias for PHAB_API_TOKEN
• PHAB_CONDUIT_TOKEN
  • optional alias for PHAB_API_TOKEN
• PHAB_CONDUIT_URI
  • optional
  • default: https://phab.instahyre.com/
  • should point to the base URL of your Phabricator instance
• PHAB_ARC_TIMEOUT_MS
  • optional
  • default: 30000
  • request timeout in milliseconds

Example:

export PHAB_CONDUIT_URI="https://phabricator.example.com/"
export PHAB_API_TOKEN="api-xxxxxxxxxxxxxxxx"
export PHAB_ARC_TIMEOUT_MS="30000"

If you do not set PHAB_CONDUIT_URI, the server will try https://phab.instahyre.com/.

5. Start the server manually (optional)

You usually do not need this step when using the server through an MCP client. In the normal setup, the MCP client launches the stdio server process for you using its mcpServers configuration.

Run the built server manually only if you want to verify that the binary starts correctly:

npm start

For local development without building on every change:

npm run dev

The server uses stdio transport, so manual npm start is optional and is not a required installation step.

Setup In An MCP Client

Codex / MCP config using the built server

{
  "mcpServers": {
    "phab-arc-mcp": {
      "command": "node",
      "args": ["/absolute/path/to/phab-arc-mcp/dist/server.js"],
      "env": {
        "PHAB_CONDUIT_URI": "https://phab.instahyre.com/",
        "PHAB_API_TOKEN": "api-xxxxxxxxxxxxxxxx"
      }
    }
  }
}

Setup Checklist

Use this to verify the installation quickly:

1. npm install completes successfully
2. npm run build creates dist/server.js
3. your MCP client is configured with PHAB_API_TOKEN
4. PHAB_CONDUIT_URI points to the correct Phabricator base URL
5. the MCP client can see the review-phab and inline-comments-phab tools

Example Usage

Step 1: get review context

Call review-phab with:

{
  "revision_id": "D35297"
}

Notes

• This server talks to Phabricator over the Conduit HTTP API.
• A valid API token is required for every tool call.
• Comments created by inline-comments-phab are draft inlines and are not published automatically.