Spec Coverage

GetMCP targets the Model Context Protocol specification revision 2025-11-25 with negotiation back to 2025-06-18. This page is the authoritative answer to “does GetMCP support X?” — broken down by spec section. The transport is Streamable HTTP (with an outbound message queue for server-initiated traffic). The legacy plain-SSE transport has been deprecated by the MCP spec and is intentionally not implemented — Streamable HTTP supersedes it. stdio isn’t supported as of now (it’s mostly relevant for locally-spawned subprocesses, which doesn’t fit the WordPress hosting model).

Legend

Symbol	Meaning
✅	Fully implemented per spec
🟡	Partial — handler exists, but the server doesn’t yet emit it from internal events (e.g. a long-running tool won’t auto-fire progress; the emitter is callable from a custom hook)
⚪	Not implemented

Lifecycle

Method	Direction	Status	Notes
`initialize`	Client → Server	✅	Protocol negotiation, capability declaration, server info
`notifications/initialized`	Client → Server	✅	Acknowledges initialization complete
`ping`	Either	✅	Round-trip health check

Tools

Method	Direction	Status	Notes
`tools/list`	Client → Server	✅	Paginated; supports `cursor` continuation
`tools/call`	Client → Server	✅	JSON Schema validation, parameter mapping, response transforms, per-tool rate limits
`notifications/tools/list_changed`	Server → Client	⚪	Server-side tool config changes don’t auto-notify connected clients yet

Resources

Method	Direction	Status	Notes
`resources/list`	Client → Server	✅	Paginated
`resources/templates/list`	Client → Server	✅	URI templates for parameterised resources
`resources/read`	Client → Server	✅	MIME-typed responses
`resources/subscribe`	Client → Server	✅	Subscribes a session to URI-change notifications
`resources/unsubscribe`	Client → Server	✅	Cancels a subscription
`notifications/resources/list_changed`	Server → Client	⚪	Not emitted yet
`notifications/resources/updated`	Server → Client	⚪	Not emitted yet

Prompts

Method	Direction	Status	Notes
`prompts/list`	Client → Server	✅	Paginated
`prompts/get`	Client → Server	✅	Renders parameterised template
`notifications/prompts/list_changed`	Server → Client	⚪	Not emitted yet

Sampling

Method	Direction	Status	Notes
`sampling/createMessage`	Server → Client	✅	Server can ask the client model for a completion (subject to client’s `sampling` capability)

Logging

Method	Direction	Status	Notes
`logging/setLevel`	Client → Server	✅	Per-session log filter
`notifications/message`	Server → Client	🟡	Emitter API is callable — see Server Logging Notifications. Existing tool calls don’t auto-emit; available via the `getmcp_log_message_emit` hook

Completion

Method	Direction	Status	Notes
`completion/complete`	Client → Server	✅	Argument autocomplete for prompt + resource template parameters

Progress & Cancellation

Method	Direction	Status	Notes
`notifications/progress`	Server → Client	🟡	Emitter API in place; built-in `ToolExecutor` is synchronous and doesn’t emit progress mid-run. See Progress Notifications
`notifications/cancelled`	Client → Server	🟡	Handler accepts the cancel flag; the synchronous executor doesn’t poll it. See Cancellation Notifications

Roots

Method	Direction	Status	Notes
`roots/list`	Server → Client	✅	Server can request the client’s local filesystem roots. See Roots List
`notifications/roots/list_changed`	Client → Server	✅	Client signals the user changed their roots; server invalidates its cached copy

Elicitation

Method	Direction	Status	Notes
`elicitation/create`	Server → Client	✅	Server can ask the client for typed user input mid-tool. See Elicitation

Outbound Message Queue

The Streamable HTTP transport doesn’t yet open a long-poll SSE channel for server-initiated traffic. Instead, GetMCP buffers server-initiated messages (roots/list requests, progress notifications, log messages, elicitation requests) in a per-session transient queue and piggy-backs them onto the next HTTP response as a JSON-RPC batch. So if you issue a tools/call, the response body may contain:

[
  { "jsonrpc": "2.0", "id": 7, "result": { "content": [...] } },
  { "jsonrpc": "2.0", "method": "notifications/progress", "params": { ... } },
  { "jsonrpc": "2.0", "id": "srv-12", "method": "roots/list", "params": {} }
]

Clients that already handle JSON-RPC batches (the official SDKs do) will see no change. A future SSE GET handler can drain the same queue without changing the emitter API.

Not Implemented

The following spec methods have no handler today:

notifications/tools/list_changed
notifications/resources/list_changed
notifications/resources/updated
notifications/prompts/list_changed

These are all “the server changed; come refresh” notifications. Clients re-list on their own cadence in practice, so this hasn’t been a blocker. Open a discussion at github.com/InfiWebs/getmcp if you need them prioritised.

The MCP specification is evolving rapidly. GetMCP’s protocol version is set in includes/transport/class-streamable-http.php and pinned to the spec revision it was tested against — initialize will negotiate down for older clients.

Overview

Servers

Tools

Resources

Prompts

Analytics

Settings

Health

MCP Protocol

Legend

Lifecycle

Tools

Resources

Prompts

Sampling

Logging

Completion

Progress & Cancellation

Roots

Elicitation

Outbound Message Queue

Not Implemented

​Legend

​Lifecycle

​Tools

​Resources

​Prompts

​Sampling

​Logging

​Completion

​Progress & Cancellation

​Roots

​Elicitation

​Outbound Message Queue

​Not Implemented

Legend

Lifecycle

Tools

Resources

Prompts

Sampling

Logging

Completion

Progress & Cancellation

Roots

Elicitation

Outbound Message Queue

Not Implemented