Module framing 

Newline-delimited JSON-RPC framing for the stdio binding.

Bounded newline-delimited JSON-RPC over a byte stream (SDK-017 R1, the stdio binding SDK-014 R2 names): one message per line, no embedded newline, a line over the limit refused by name and drained so the next line is read whole.

Enums

FrameError

Why a line could not be read as a message.

Incoming

A message read from the host.

Constants

INVALID_PARAMS

JSON-RPC’s invalid-params code.

INVALID_REQUEST

JSON-RPC’s invalid-request code.

METHOD_NOT_FOUND

JSON-RPC’s method-not-found code.

PARSE_ERROR

JSON-RPC’s parse error code.

UNSUPPORTED_PROTOCOL_VERSION

MCP 2026-07-28’s unsupported-protocol-version code.

Functions

error

An error response for id (null when the request’s id could not be read), with optional data.

parse

A JSON value as a JSON-RPC 2.0 request or notification.

read_message

Reads one line of at most limit bytes. Ok(None) is the host closing its end. A line over the limit is drained to its newline and refused.

result

A result response for id.

write_message

Writes one message as one line and flushes it. The message is serialised by serde_json, which never emits a raw newline inside a string.