# DiffCI MCP server

> Lets AI coding agents identify and run only the specific tests affected by code changes to speed up verification.

- Repository: https://github.com/DiffCI/core
- Page: https://hostedmcp.org/servers/diffci/core
- Transport: stdio, remote
- Stars: 3
- License: MIT
- Latest version: 0.3.45

## Install

### Claude Code

```sh
claude mcp add core -- npx -y @diffci.com/diffci
```

### Cursor (`~/.cursor/mcp.json`)

```json
{
  "mcpServers": {
    "core": {
      "command": "npx",
      "args": [
        "-y",
        "@diffci.com/diffci"
      ]
    }
  }
}
```

### VS Code (`.vscode/mcp.json`)

```json
{
  "servers": {
    "core": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@diffci.com/diffci"
      ]
    }
  }
}
```

### VS Code CLI

```sh
code --add-mcp '{"name":"core","type":"stdio","command":"npx","args":["-y","@diffci.com/diffci"]}'
```

### Claude Desktop (`claude_desktop_config.json`)

```json
{
  "mcpServers": {
    "core": {
      "command": "npx",
      "args": [
        "-y",
        "@diffci.com/diffci"
      ]
    }
  }
}
```

### Codex

```sh
codex mcp add core -- npx -y @diffci.com/diffci
```

### Codex config.toml (`~/.codex/config.toml`)

```toml
[mcp_servers.core]
command = "npx"
args = ["-y", "@diffci.com/diffci"]
```

### Gemini CLI

```sh
gemini mcp add -s user core npx -- -y @diffci.com/diffci
```

### Gemini settings.json (`~/.gemini/settings.json`)

```json
{
  "mcpServers": {
    "core": {
      "command": "npx",
      "args": [
        "-y",
        "@diffci.com/diffci"
      ]
    }
  }
}
```

## FAQ

### Does DiffCI require an account or API key?

No, it works without a DiffCI account, hosted service, or API key.

### What happens if DiffCI cannot determine which tests are affected?

It falls back to running the full test suite whenever the evidence is incomplete.

### Which programming languages are supported?

It supports JavaScript/TypeScript repositories, Vue components, Go modules, Maven reactors, and Python projects using pytest.