MCP Integration¶

Agent Code Review includes an MCP (Model Context Protocol) server for native integration with Claude Code and other MCP-compatible clients.

Overview¶

The MCP server exposes code review functionality as tools that Claude can use directly within Claude Code. This enables AI-assisted code reviews without leaving your development environment.

Configuration¶

Claude Code¶

Add the following to your Claude Code MCP configuration:

macOS/LinuxWindows

Edit ~/.config/claude-code/mcp.json:

{
  "mcpServers": {
    "code-review": {
      "command": "acr",
      "args": ["serve"]
    }
  }
}

Edit %APPDATA%\claude-code\mcp.json:

{
  "mcpServers": {
    "code-review": {
      "command": "acr.exe",
      "args": ["serve"]
    }
  }
}

With Environment Variables¶

If you need to pass authentication via environment variables:

{
  "mcpServers": {
    "code-review": {
      "command": "acr",
      "args": ["serve"],
      "env": {
        "GITHUB_TOKEN": "ghp_xxxxxxxxxxxx"
      }
    }
  }
}

Tip

For GitHub App authentication, ensure the config file exists at ~/.config/gogithub/app.json or set the environment variables before starting Claude Code.

Available Tools¶

The MCP server exposes six tools:

review_pr¶

Post a code review to a GitHub pull request.

Parameters:

Name	Type	Required	Description
`owner`	string	Yes	Repository owner
`repo`	string	Yes	Repository name
`pr_number`	integer	Yes	Pull request number
`event`	string	Yes	`APPROVE`, `REQUEST_CHANGES`, or `COMMENT`
`body`	string	Yes	Review body (markdown)

Example Usage in Claude:

"Review PR #123 in plexusone/agent-code-review and approve it with the message 'LGTM!'"

comment_pr¶

Add a general comment to a pull request.

Parameters:

Name	Type	Required	Description
`owner`	string	Yes	Repository owner
`repo`	string	Yes	Repository name
`pr_number`	integer	Yes	Pull request number
`body`	string	Yes	Comment body (markdown)

Example Usage:

"Add a comment to PR #123 thanking the contributor"

line_comment¶

Add a comment on a specific line in the PR diff.

Parameters:

Name	Type	Required	Description
`owner`	string	Yes	Repository owner
`repo`	string	Yes	Repository name
`pr_number`	integer	Yes	Pull request number
`commit_id`	string	Yes	Commit SHA to comment on
`path`	string	Yes	File path relative to repo root
`line`	integer	Yes	Line number in the diff
`body`	string	Yes	Comment body (markdown)

Example Usage:

"Add a line comment on main.go line 42 suggesting a better variable name"

get_pr_diff¶

Fetch the diff for a pull request.

Parameters:

Name	Type	Required	Description
`owner`	string	Yes	Repository owner
`repo`	string	Yes	Repository name
`pr_number`	integer	Yes	Pull request number

Returns: The unified diff as text.

Example Usage:

"Get the diff for PR #123 so I can review it"

get_pr¶

Get pull request metadata.

Parameters:

Name	Type	Required	Description
`owner`	string	Yes	Repository owner
`repo`	string	Yes	Repository name
`pr_number`	integer	Yes	Pull request number

Returns: PR details including title, author, state, branches, and commit count.

Example Usage:

"What's the status of PR #123?"

list_prs¶

List open pull requests in a repository.

Parameters:

Name	Type	Required	Description
`owner`	string	Yes	Repository owner
`repo`	string	Yes	Repository name

Returns: List of open PRs with number, title, author, and branch.

Example Usage:

"List the open PRs in plexusone/agent-code-review"

Workflow Example¶

A typical code review workflow in Claude Code:

List PRs — "Show me open PRs in my-org/my-repo"
Get Diff — "Get the diff for PR #42"
Analyze — Claude reviews the code changes
Post Review — "Approve PR #42 with a summary of your findings"

Troubleshooting¶

Server Not Starting¶

Check that acr is in your PATH:

which acr

If not found, ensure the Go bin directory is in your PATH:

export PATH=$PATH:$(go env GOPATH)/bin

Authentication Errors¶

Verify authentication is configured:

# Test with CLI
acr list -o owner -r repo

If this works, the MCP server will use the same authentication.

Debug Mode¶

Run the server manually to see output:

acr serve

The server communicates via stdin/stdout using JSON-RPC. Any errors will be returned in the response.