# mcp URL: /milo-cli/api/milo/mcp/ Section: milo Description: MCP server — expose CLI commands as tools via JSON-RPC on stdin/stdout. --- > For a complete page index, fetch /milo-cli/llms.txt. Open LLM text (/milo-cli/api/milo/mcp/index.txt) Share with AI Ask Claude (https://claude.ai/new?q=Please%20help%20me%20understand%20this%20documentation%3A%20%2Fmilo-cli%2Fapi%2Fmilo%2Fmcp%2Findex.txt) Ask ChatGPT (https://chatgpt.com/?q=Please%20help%20me%20understand%20this%20documentation%3A%20%2Fmilo-cli%2Fapi%2Fmilo%2Fmcp%2Findex.txt) Ask Gemini (https://gemini.google.com/app?q=Please%20help%20me%20understand%20this%20documentation%3A%20%2Fmilo-cli%2Fapi%2Fmilo%2Fmcp%2Findex.txt) Ask Copilot (https://copilot.microsoft.com/?q=Please%20help%20me%20understand%20this%20documentation%3A%20%2Fmilo-cli%2Fapi%2Fmilo%2Fmcp%2Findex.txt) Module # `mcp` MCP server — expose CLI commands as tools via JSON-RPC on stdin/stdout. 1Class18Functions ## Classes `_CLIHandler` 8 ▼ MCPHandler implementation for a single CLI (leaf server). MCPHandler implementation for a single CLI (leaf server). #### Methods `initialize` 1 `dict[str, Any]` ▼ `def initialize(self, params: dict[str, Any]) -> dict[str, Any]` ##### Parameters Name Type Description `params` `—` ##### Returns `dict[str, Any]` `list_tools` 1 `dict[str, Any]` ▼ `def list_tools(self, params: dict[str, Any]) -> dict[str, Any]` ##### Parameters Name Type Description `params` `—` ##### Returns `dict[str, Any]` `call_tool` 1 `dict[str, Any]` ▼ `def call_tool(self, params: dict[str, Any]) -> dict[str, Any]` ##### Parameters Name Type Description `params` `—` ##### Returns `dict[str, Any]` `list_resources` 1 `dict[str, Any]` ▼ `def list_resources(self, params: dict[str, Any]) -> dict[str, Any]` ##### Parameters Name Type Description `params` `—` ##### Returns `dict[str, Any]` `read_resource` 1 `dict[str, Any]` ▼ `def read_resource(self, params: dict[str, Any]) -> dict[str, Any]` ##### Parameters Name Type Description `params` `—` ##### Returns `dict[str, Any]` `list_prompts` 1 `dict[str, Any]` ▼ `def list_prompts(self, params: dict[str, Any]) -> dict[str, Any]` ##### Parameters Name Type Description `params` `—` ##### Returns `dict[str, Any]` `get_prompt` 1 `dict[str, Any]` ▼ `def get_prompt(self, params: dict[str, Any]) -> dict[str, Any]` ##### Parameters Name Type Description `params` `—` ##### Returns `dict[str, Any]` Internal Methods 1 ▼ `__init__` 2 ▼ `def __init__(self, cli: CLI, cached_tools: list[dict[str, Any]] | None = None) -> None` ##### Parameters Name Type Description `cli` `—` `cached_tools` `—` Default:`None` ## Functions `_to_text` 1 `str` ▼ Convert a result to text for MCP content responses. `def _to_text(result: Any) -> str` ##### Parameters Name Type Description `result` `Any` ##### Returns `str` `run_mcp_server` 1 `None` ▼ Run MCP JSON-RPC server on stdin/stdout. Implements the MCP protocol (initiali… `def run_mcp_server(cli: CLI) -> None` Run MCP JSON-RPC server on stdin/stdout. Implements the MCP protocol (initialize, tools/list, tools/call, resources/list, resources/read, prompts/list, prompts/get). ##### Parameters Name Type Description `cli` `CLI` `_classify_exception` 1 `tuple[int, dict[str, Any…` ▼ Map an exception to a JSON-RPC error code and optional data payload. Returns (… `def _classify_exception(exc: Exception) -> tuple[int, dict[str, Any] | None]` Map an exception to a JSON-RPC error code and optional data payload. Returns (code, data) where: - MiloError with validation/config codes -> -32602 (Invalid params) - MiloError with not-found codes -> -32601 (Method not found) - All others -> -32603 (Internal error) with traceback in data When the MiloError carries`argument` or `constraint`context, those fields are included in the data payload so callers can tell agents which parameter failed and what constraint was violated. ##### Parameters Name Type Description `exc` `Exception` ##### Returns `tuple[int, dict[str, Any] | None]` `_milo_error_data` 1 `dict[str, Any]` ▼ Build the structured data payload for a MiloError. `def _milo_error_data(exc: Any) -> dict[str, Any]` ##### Parameters Name Type Description `exc` `Any` ##### Returns `dict[str, Any]` `_constraint_example` 1 `Any` ▼ Derive an example value from a JSON-Schema-style constraint dict. Never uses u… `def _constraint_example(constraint: dict[str, Any]) -> Any` Derive an example value from a JSON-Schema-style constraint dict. Never uses user input. Returns`None`when no safe example applies. ##### Parameters Name Type Description `constraint` `dict[str, Any]` ##### Returns `Any` `_builtin_resources` 0 `list[dict[str, Any]]` ▼ Built-in MCP resources provided by the milo runtime. `def _builtin_resources() -> list[dict[str, Any]]` ##### Returns `list[dict[str, Any]]` `_stats_resource` 1 `dict[str, Any]` ▼ Return server statistics as an MCP resource. `def _stats_resource(logger: RequestLogger) -> dict[str, Any]` ##### Parameters Name Type Description `logger` `RequestLogger` ##### Returns `dict[str, Any]` `_pipeline_timeline_resource` 0 `dict[str, Any]` ▼ Return the active pipeline's execution timeline as an MCP resource. `def _pipeline_timeline_resource() -> dict[str, Any]` ##### Returns `dict[str, Any]` `_list_tools` 1 `list[dict[str, Any]]` ▼ Generate MCP tools/list response from all commands including groups. Group com… `def _list_tools(cli: CLI) -> list[dict[str, Any]]` Generate MCP tools/list response from all commands including groups. Group commands use dot-notation names:`site.build`, `site.config.show`. Includes outputSchema when return type annotations are available. Skips commands that fail to import with a warning. ##### Parameters Name Type Description `cli` `CLI` ##### Returns `list[dict[str, Any]]` `_tool_title` 1 `str` ▼ Derive a human-readable title for a tool. Uses the handler's docstring first l… `def _tool_title(cmd: CommandDef | LazyCommandDef) -> str` Derive a human-readable title for a tool. Uses the handler's docstring first line if available and different from the description. Falls back to a title-cased command name. ##### Parameters Name Type Description `cmd` `CommandDef | LazyCommandDef` ##### Returns `str` `_output_schema` 1 `dict[str, Any] | None` ▼ Generate outputSchema from handler return type annotation. Returns None for la… `def _output_schema(cmd: CommandDef | LazyCommandDef) -> dict[str, Any] | None` Generate outputSchema from handler return type annotation. Returns None for lazy commands that haven't been resolved (avoids imports). ##### Parameters Name Type Description `cmd` `CommandDef | LazyCommandDef` ##### Returns `dict[str, Any] | None` `_call_tool` 2 `dict[str, Any]` ▼ Handle tools/call by dispatching to the command handler. Routes through the CL… `def _call_tool(cli: CLI, params: dict[str, Any]) -> dict[str, Any]` Handle tools/call by dispatching to the command handler. Routes through the CLI's middleware stack when present, so middleware can intercept MCP-originated calls just like CLI-originated ones. If the handler returns a generator yielding Progress objects, each Progress is emitted as a`notifications/progress`JSON-RPC notification before the final result is returned. ##### Parameters Name Type Description `cli` `CLI` `params` `dict[str, Any]` ##### Returns `dict[str, Any]` `_tool_error_response` 3 `dict[str, Any]` ▼ Build the ``tools/call`` error response with structured context. MiloError sub… `def _tool_error_response(exc: Exception, tool_name: str, cli: CLI) -> dict[str, Any]` Build the`tools/call`error response with structured context. MiloError subclasses contribute their`argument`, `constraint`, `suggestion`, and `errorCode` fields. Plain `TypeError` messages about missing or unexpected keyword arguments are parsed so agents see which argument was wrong, and the`schema`field points them at the tool's declared parameter schema for repair. ##### Parameters Name Type Description `exc` `Exception` `tool_name` `str` `cli` `CLI` ##### Returns `dict[str, Any]` `_tool_schema` 2 `dict[str, Any] | None` ▼ Return the input schema for a named tool, if known. `def _tool_schema(cli: CLI, tool_name: str) -> dict[str, Any] | None` ##### Parameters Name Type Description `cli` `CLI` `tool_name` `str` ##### Returns `dict[str, Any] | None` `_list_resources` 1 `list[dict[str, Any]]` ▼ Generate MCP resources/list response from registered resources. `def _list_resources(cli: CLI) -> list[dict[str, Any]]` ##### Parameters Name Type Description `cli` `CLI` ##### Returns `list[dict[str, Any]]` `_read_resource` 2 `dict[str, Any]` ▼ Handle resources/read by calling the resource handler. `def _read_resource(cli: CLI, params: dict[str, Any]) -> dict[str, Any]` ##### Parameters Name Type Description `cli` `CLI` `params` `dict[str, Any]` ##### Returns `dict[str, Any]` `_list_prompts` 1 `list[dict[str, Any]]` ▼ Generate MCP prompts/list response from registered prompts. `def _list_prompts(cli: CLI) -> list[dict[str, Any]]` ##### Parameters Name Type Description `cli` `CLI` ##### Returns `list[dict[str, Any]]` `_get_prompt` 2 `dict[str, Any]` ▼ Handle prompts/get by calling the prompt handler. `def _get_prompt(cli: CLI, params: dict[str, Any]) -> dict[str, Any]` ##### Parameters Name Type Description `cli` `CLI` `params` `dict[str, Any]` ##### Returns `dict[str, Any]`