Module version 

Protocol revision negotiation and MCP 2026-07-28 wire envelopes.

MCP 2025-11-25 uses a connection-scoped initialize handshake. MCP 2026-07-28 is stateless: every request declares its version, client identity, and capabilities in _meta. Keeping this behavior in one module prevents revision checks from leaking into application handlers.

Structs

ConnectResult

Revision-neutral result returned when a client establishes protocol behavior.

DiscoverParams

Parameters for server/discover.

DiscoverResult

Result of the stateless server/discover request.

InputRequiredResult

A modern server response that asks the client to provide in-band input and retry.

ModernRequestContext

Parsed modern request information. It is request-scoped by design.

NegotiatedProtocol

Stable record of the protocol selected for a connection.

RequestMetaObject

Required metadata envelope for a 2026-07-28 request.

ToolHeaderMapping

Enums

CacheScope

Cache sharing policy introduced by MCP 2026-07-28.

OperationResult

A version-neutral operation result for MRTR-aware applications.

ProtocolEra

The lifecycle family selected for an active client.

ProtocolMode

Runtime protocol selection policy.

ResultType

The discriminant present on all modern successful results.

Constants

CLIENT_CAPABILITIES_META_KEY

Reserved request _meta key carrying per-request client capabilities.

CLIENT_INFO_META_KEY

Reserved request _meta key carrying client identity.

HEADER_MISMATCH

MCP-defined header/body mismatch error code.

LEGACY_PROTOCOL_VERSION

Stateful MCP protocol revision retained for production interoperability.

MCP_METHOD_HEADER

Standard HTTP method routing header.

MCP_NAME_HEADER

Standard HTTP resource/name routing header.

MCP_PROTOCOL_VERSION_HEADER

Standard HTTP protocol revision header.

MISSING_REQUIRED_CLIENT_CAPABILITY

MCP-defined missing client capability error code.

MODERN_PROTOCOL_VERSION

Final stateless MCP protocol revision supported by Prism v3.

PROTOCOL_VERSION_META_KEY

Reserved request _meta key carrying the protocol revision.

SERVER_INFO_META_KEY

Reserved result _meta key carrying server identity.

SUPPORTED_PROTOCOL_VERSIONS

Protocol revisions supported by a dual-stack Prism server, in preference order.

UNSUPPORTED_PROTOCOL_VERSION

MCP-defined unsupported revision error code.

Functions

decode_http_header_value

Decode and validate an MCP HTTP routing-header value.

decorate_modern_request

Add or replace the required modern _meta fields without disturbing application-defined metadata.

decorate_modern_result

Convert a handler-produced object into a standards-compliant modern result.

encode_http_header_value

Encode a body string as an MCP HTTP routing-header value.

is_cacheable_method

List/discovery operations that require explicit cache policy in 2026-07-28.

is_legacy_only_method

Methods removed from the stateless 2026 core.

is_method_not_found

Test whether an error is the one safe automatic-downgrade signal.

json_rpc_error_details

Map SDK errors to their JSON-RPC code and structured MCP error data.

modern_request_context

Parse and validate the required modern request envelope.

request_protocol_version

Extract the modern protocol version from a request body for HTTP routing.

request_routing_name

Derive the Mcp-Name header value from the corresponding request field.

tool_call_headers

Build the custom HTTP headers required for one tool call.

tool_header_mappings

Extract and validate x-mcp-header annotations from a tool input schema.

validate_http_headers

Validate standard HTTP routing headers against a modern request body.

validate_tool_call_headers

Validate received Mcp-Param-* values against a tool call body.