Skip to content

mcp_protocol_reference.md

Latest commit

 

History

History
225 lines (153 loc) · 4.04 KB

mcp_protocol_reference.md

File metadata and controls

225 lines (153 loc) · 4.04 KB

ZCP MCP Protocol Reference

This document describes the MCP-facing surface implemented by ZCP. Use it as a wire reference, not as the first conceptual introduction.

Lifecycle

Supported lifecycle methods:

  • initialize
  • initialized
  • ping

initialize returns MCP-shaped data including:

  • protocolVersion
  • serverInfo
  • capabilities

When auth metadata is configured on the native runtime, that information is also reflected through the exposed metadata surfaces.

Tools

Supported tool methods:

  • tools/list
  • tools/call
  • notifications/tools/list_changed

Supported tool metadata projection includes:

  • name
  • title
  • description
  • inputSchema
  • outputSchema
  • annotations
  • icons
  • execution
  • _meta

tools/call can return:

  • normal inline content
  • structured content
  • task objects when task-augmented invocation is requested and supported

Resources

Supported resource methods:

  • resources/list
  • resources/templates/list
  • resources/read
  • resources/subscribe
  • resources/unsubscribe
  • notifications/resources/updated
  • notifications/resources/list_changed

ZCP projects text-like, JSON-like, and binary handler outputs into MCP-compatible resource content.

Prompts

Supported prompt methods:

  • prompts/list
  • prompts/get
  • notifications/prompts/list_changed

Prompt results can be returned as:

  • plain string content
  • {role, content} messages
  • richer content block objects

Completion

Supported completion methods:

  • official completion/complete
  • compatibility alias completions/complete

Completion responses include:

  • values
  • total
  • hasMore

Logging

Supported logging methods and notifications:

  • logging/setLevel
  • notifications/message

Supported levels:

  • debug
  • info
  • notice
  • warning
  • error
  • critical
  • alert
  • emergency

Roots

Supported roots methods and notifications:

  • roots/list
  • notifications/roots/list_changed

Progress

Supported progress notification:

  • notifications/progress

Progress tokens are accepted from common MCP metadata locations, including:

  • params.meta.progressToken
  • params.meta.progress_token
  • params._meta.progressToken

Sampling

Supported method:

  • sampling/createMessage

Supported normalized request fields include:

  • messages
  • systemPrompt
  • modelPreferences
  • includeContext
  • temperature
  • maxTokens
  • stopSequences
  • metadata
  • tools
  • toolChoice

Elicitation

Supported elicitation methods:

  • official elicitation/create
  • compatibility alias elicitation/request

ZCP accepts MCP-style form and URL requests while still preserving a backward compatible alias path for native callers that have not migrated.

Tasks

Supported task methods:

  • tasks/create
  • tasks/list
  • tasks/get
  • tasks/result
  • tasks/cancel
  • notifications/tasks/status

Supported task states include:

  • queued
  • working
  • input_required
  • completed
  • failed
  • cancelled

Task-augmented tools/call is also supported for tools that declare task support.

Transports

Current MCP-facing transports:

  • stdio
  • streamable HTTP on /mcp
  • websocket on /ws

Current native transport:

  • JSON-RPC on /zcp

Streamable HTTP Details

/mcp supports:

  • GET for SSE streaming
  • POST for JSON-RPC and streamed responses
  • DELETE for explicit session teardown

Compatibility behavior includes:

  • mcp-session-id
  • support for the configured native session header
  • SSE id
  • Last-Event-ID replay against a bounded buffer

Authorization Metadata

When OAuth is enabled, the server can expose:

  • authorization server metadata
  • protected resource metadata
  • authorization endpoint
  • token endpoint
  • registration endpoint
  • revocation endpoint

Use authorization_guide.md for deployment guidance and this document only for surface reference.

Notes On Parity

This document describes what the implementation exposes today. It does not claim that every edge case or experimental feature is fully exhausted. For the strict remaining gap list, use mcp_gap_todo.md.