Module mcp 

MCP message taxonomy (spec v2025-11-25).

See PIPELINE.md §Types. Method identity is a cheap enum — one string match per message. Grouping by feature area (Tools, Resources, …) matches the spec table and lets middlewares pattern-match at the granularity they need.

Every method enum has an Unknown(String) tail variant so non-spec methods forward unchanged instead of failing classification.

Structs

McpMessage

Shallow envelope paired with its classification. Used inside McpRequest (client direction) and Response::McpBuffered (server direction).

Enums

ClientKind

Kind of message the client is sending. Computed at intake from method + id + result/error presence.

ClientMethod

ClientNotifMethod

CompletionMethod

LifecycleMethod

LoggingMethod

MessageKind

Direction discriminator for an McpMessage.

PromptsMethod

ResourcesMethod

ServerKind

Kind of message the server is sending. Appears in response bodies (streamable-HTTP chunks or legacy SSE frames).

ServerMethod

ServerNotifMethod

TasksMethod

Task lifecycle methods. Used by both directions (client asks the server about tasks; server can also request task state from the client).

ToolsMethod

Functions

classify_client

Classify a client→server envelope. Assumes the envelope came from JsonRpcEnvelope::parse, which already rejected malformed shapes.

classify_server

Classify a server→client envelope.