DiffCI

Fail-closed, change-aware verification for AI coding agents with affected-test guidance.

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What it can do

    What data it sees

    Do you need an account

    No: the server works without sign-in

    Fail-closed, change-aware verification for AI coding agents with affected-test guidance.

    How to connect

    How to connect DiffCI to Claude

    The server address to paste into Claude settings:

    https://diffci.com/mcp/v1

    1. Open Claude (claude.ai or the desktop app).
    2. Go to Settings → Connectors.
    3. Click Add custom connector.
    4. Paste the server address copied below into Remote MCP server URL and click Add.
    5. In a chat, click + → Connectors and switch the new connector on.

    Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.

    Authorization

    After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.

    How to connect DiffCI to ChatGPT

    The server address to paste into ChatGPT settings:

    https://diffci.com/mcp/v1

    1. Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
    2. Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
    3. Open Settings → Connectors and click Create.
    4. Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
    5. Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
    6. In a new chat open + → Apps/Connectors and enable the connector.

    OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.

    Authorization

    On first use ChatGPT opens the service's sign-in window. Sign in and approve access.

    How to connect DiffCI to Cursor

    The server address to paste into Cursor settings:

    https://diffci.com/mcp/v1

    Fastest: click Open in Cursor below and confirm the prompt.

    Manually:

    1. In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
    2. Paste the JSON copied below into ~/.cursor/mcp.json (per project: .cursor/mcp.json in the repo root).
    3. Save the file. The server appears in the MCP list; authorize it there if asked.

    Authorization

    If the service needs sign-in, an authorize button appears next to the server in the MCP list.

    Server tool list (3)

    Raw names from tools/list. Only developers need these.

    diffci_validation_planPlan change-aware CI validation, affected-test selection, test impact analysis, or GitHub Actions workflow checks. Returns a safe local DiffCI command without accessing the checkout or executing it.
    diffci_interpret_reportValidate and summarize a DiffCI observation report, including selective or full mode, affected-test counts, fallbacks, non-interference evidence, and the conservative next action.
    diffci_verify_workflow_textPerform a stateless preliminary safety check of GitHub Actions YAML: dedicated observer job, continue-on-error, dependency isolation, read-only permissions, and immutable DiffCI references.