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stdio

For MCP clients that run on the same machine as your project, the plugin provides a command that speaks MCP over standard input and output:

bin/cake mcp server

Claude Code

claude mcp add my-app -- bin/cake mcp server

Run it from the project directory, or give the full path to bin/cake. With DDEV or Docker, wrap the command, for example claude mcp add my-app -- ddev exec bin/cake mcp server.

Identity

There is no HTTP request, so there is no authentication. By default tools see no identity. To run tools as a particular user, give Mcp.stdio.identity a closure that returns the identity:

Configure::write('Mcp.stdio.identity', function (): ArrayObject {
    return new ArrayObject(['id' => 1, 'role' => 'admin']);
});

Mcp.stdio.identity must be a callable. A plain array or ArrayObject there is silently ignored (the command only calls it when it is callable), so tools would see no identity.

Return whatever shape your tools and authorizer expect (see Authentication). The closure runs once when the command starts.

Trusted mode

Mcp.stdio.trusted defaults to true. A trusted stdio session skips per-tool authorization: the developer who starts the command already has access to the code and the database. Set it to false if you want the configured authorizer applied to the identity from stdio.identity.

Only authorization is skipped. Everything else, including tool discovery and dependency injection, works as over HTTP.

Keep STDOUT clean

The protocol uses STDOUT, so anything else written there corrupts the conversation and the client disconnects.

  • The command removes Cake's default console loggers that mirror info logs to STDOUT, keeping only the stderr one for errors and warnings.
  • Tools must never echo, print or var_dump.
  • No Log engine may write to php://stdout. Cake's ConsoleLog writes to stderr by default, which is fine. If you configured a console log with 'stream' => 'php://stdout', change it or scope it away from the mcp scope for this command.
  • Make sure PHP notices and deprecations are not printed to STDOUT (display_errors off for the CLI, or sent to stderr).