mcp - Milo

Classes

_CLIHandler 9 ▼

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]

server_discover 1 dict[str, Any] ▼

def server_discover(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

_client_supports_ui 1 bool ▼

Return whether initialize params negotiate Milo's MCP Apps MIME type.

def _client_supports_ui(params: dict[str, Any]) -> bool

Parameters

Name	Type	Description
`params`	`dict[str, Any]`

Returns

bool

_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 carriesargument or constraintcontext, 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. ReturnsNonewhen 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 2 list[dict[str, Any]] ▼

Generate MCP tools/list response from all commands including groups. Group com…

def _list_tools(cli: CLI, *, include_ui: bool = True) -> 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`
`include_ui`	`bool`	Default:`True`

Returns

list[dict[str, Any]]

_validate_ui_link 3 None ▼

Require every advertised tool UI link to resolve on this server.

def _validate_ui_link(cli: CLI, tool_name: str, resource_uri: str) -> None

Parameters

Name	Type	Description
`cli`	`CLI`
`tool_name`	`str`
`resource_uri`	`str`

_tool_is_hidden 3 bool ▼

Return whether a tool or any group in its dotted path is hidden.

def _tool_is_hidden(cli: CLI, dotted_name: str, command: CommandDef | LazyCommandDef) -> bool

Parameters

Name	Type	Description
`cli`	`CLI`
`dotted_name`	`str`
`command`	`CommandDef \| LazyCommandDef`

Returns

bool

_ensure_public_tool 2 None ▼

Reject unknown or hidden tools before MCP dispatch resolves handlers.

def _ensure_public_tool(cli: CLI, tool_name: str) -> None

Parameters

Name	Type	Description
`cli`	`CLI`
`tool_name`	`str`

_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 anotifications/progressJSON-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 thetools/callerror response with structured context.

MiloError subclasses contribute theirargument, constraint, suggestion, and errorCode fields. Plain TypeError messages about missing or unexpected keyword arguments are parsed so agents see which argument was wrong, and theschemafield 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]]

_list_ui_resources 1 list[dict[str, Any]] ▼

Generate negotiated MCP Apps resources/list entries.

def _list_ui_resources(cli: CLI) -> list[dict[str, Any]]

Parameters

Name	Type	Description
`cli`	`CLI`

Returns

list[dict[str, Any]]

_ui_resource_error 5 ▼

Build a structured MCP Apps boundary error without exposing internals.

def _ui_resource_error(code_name: str, message: str, *, reason: str, uri: str, suggestion: str)

Parameters

Name	Type	Description
`code_name`	`str`
`message`	`str`
`reason`	`str`
`uri`	`str`
`suggestion`	`str`

_read_ui_resource 3 dict[str, Any] ▼

Read a negotiated MCP Apps HTML resource as text or a base64 blob.

def _read_ui_resource(cli: CLI, params: dict[str, Any], *, enabled: bool) -> dict[str, Any]

Parameters

Name	Type	Description
`cli`	`CLI`
`params`	`dict[str, Any]`
`enabled`	`bool`

Returns

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]