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SEP-2260: Require Server requests to be associated with a Client request. Model Context Protocol · in the page seps/2260-Require-Server-requests-to-be-associated-with-Client-requests …* ## Abstract This SEP clarifies that `roots/list`, `sampling/createMessage`, and `elicitation/create` requests **MUST** be associated with an originating client-to-server request (e.g., during `too…

SEP-2322: Multi Round-Trip Requests Model Context Protocol · in the page seps/2322-MRTR …chema: ```typescript theme={null} export type InputRequest = CreateMessageRequest | ElicitRequest | ListRootsRequest; export interface InputRequests { [key: string]: InputRequest; } export type…

SEP-2484: Require Conformance Tests for Standards Track SEPs to Reach Final Status Model Context Protocol · in the page seps/2484-conformance-tests-required-for-final-seps …tocol behavior**: behavior a conformant peer can detect by inspecting messages on the wire, transport-observable side effects (HTTP status codes, headers, connection lifecycle, OAuth redirects), or pr…

SEP-2567: Sessionless MCP via Explicit State Handles Model Context Protocol · in the page seps/2567-sessionless-mcp …When a tool call triggers an `elicitation/create` or `sampling/createMessage` round-trip, the server has to correlate the eventual response with the original in-flight tool call — state that today li…

SEP-2575: Make MCP Stateless Model Context Protocol · in the page seps/2575-stateless-mcp …d any log notifications for this request. The client opts in to log messages by explicitly setting a level. Replaces the `logging/setLevel` RPC. Roots are intentionally not included as a per-requ…

SEP-2577: Deprecate Roots, Sampling, and Logging Model Context Protocol · in the page seps/2577-deprecate-roots-sampling-and-logging …, `notifications/roots/list_changed`) * **Sampling** (`sampling/createMessage`, `ClientCapabilities.tasks.requests.sampling`) * **Logging** (`logging/setLevel`, `notifications/message`) These featu…

SEP-2596: Specification Feature Lifecycle and Deprecation Policy Model Context Protocol · in the page seps/2596-spec-feature-lifecycle-and-deprecation …nd `"allServers"` are labeled "soft-deprecated" in [`sampling/createMessage`][sampling-includecontext] and in `schema.ts`, with the note that they "may be removed in future spec releases." * JSON-…

SEP-2640: Skills Extension Model Context Protocol · in the page seps/2640-skills-extension …t never receives the call. The extension introduces no other methods, message types, or schema changes. A server that does not implement this extension simply exposes no `skill://` resources; existing…

SEP-2663: Tasks Extension Model Context Protocol · in the page seps/2663-tasks-extension …// MISSING_REQUIRED_CLIENT_CAPABILITY "code": -32021, // Message provided for example purposes only. The content of this example message is non-normative. "message": "Missing required…

Architecture Model Context Protocol · in the page specification/2024-11-05/architecture/index …andles protocol negotiation and capability exchange * Routes protocol messages bidirectionally * Manages subscriptions and notifications * Maintains security boundaries between servers A host applica…

Overview Model Context Protocol · in the page specification/2024-11-05/basic/index # Overview All messages between MCP clients and servers **MUST** follow the [JSON-RPC 2.0](https://www.jsonrpc.org/specification) specification. The protocol defines three fundamental types of messag…

Transports Model Context Protocol · in the page specification/2024-11-05/basic/transports …unches the MCP server as a subprocess. * The server receives JSON-RPC messages on its standard input (`stdin`) and writes responses to its standard output (`stdout`). * Messages are delimited by new…

Cancellation Model Context Protocol · in the page specification/2024-11-05/basic/utilities/cancellation …ts optional cancellation of in-progress requests through notification messages. Either side can send a cancellation notification to indicate that a previously-issued request should be terminated. ##…

Ping Model Context Protocol · in the page specification/2024-11-05/basic/utilities/ping …client or server can initiate a ping by sending a `ping` request. ## Message Format A ping request is a standard JSON-RPC request with no parameters: ```json theme={null} { "jsonrpc": "2.0", "i…

Progress Model Context Protocol · in the page specification/2024-11-05/basic/utilities/progress …al progress tracking for long-running operations through notification messages. Either side can send progress notifications to provide updates about operation status. ## Progress Flow When a party w…

Roots Model Context Protocol · in the page specification/2024-11-05/client/roots …will emit notifications when the list of roots changes. ## Protocol Messages ### Listing Roots To retrieve roots, servers send a `roots/list` request: **Request:** ```json theme={null} { "json…

Sampling Model Context Protocol · in the page specification/2024-11-05/client/sampling …null} { "capabilities": { "sampling": {} } } ``` ## Protocol Messages ### Creating Messages To request a language model generation, servers send a `sampling/createMessage` request: **Reque…

Specification Model Context Protocol · in the page specification/2024-11-05/index …workflows The protocol uses [JSON-RPC](https://www.jsonrpc.org/) 2.0 messages to establish communication between: * **Hosts**: LLM applications that initiate connections * **Clients**: Connectors wi…

Prompts Model Context Protocol · in the page specification/2024-11-05/server/prompts …mpt templates to clients. Prompts allow servers to provide structured messages and instructions for interacting with language models. Clients can discover available prompts, retrieve their contents, a…

Resources Model Context Protocol · in the page specification/2024-11-05/server/resources …Only list change notifications supported } } } ``` ## Protocol Messages ### Listing Resources To discover available resources, clients send a `resources/list` request. This operation supports…

Tools Model Context Protocol · in the page specification/2024-11-05/server/tools …notifications when the list of available tools changes. ## Protocol Messages ### Listing Tools To discover available tools, clients send a `tools/list` request. This operation supports [pagination…

Completion Model Context Protocol · in the page specification/2024-11-05/server/utilities/completion …lf does not mandate any specific user interaction model. ## Protocol Messages ### Requesting Completions To get completion suggestions, clients send a `completion/complete` request specifying what…

Logging Model Context Protocol · in the page specification/2024-11-05/server/utilities/logging …(MCP) provides a standardized way for servers to send structured log messages to clients. Clients can control logging verbosity by setting minimum log levels, with servers sending notifications conta…

Architecture Model Context Protocol · in the page specification/2025-03-26/architecture/index …andles protocol negotiation and capability exchange * Routes protocol messages bidirectionally * Manages subscriptions and notifications * Maintains security boundaries between servers A host applica…

Authorization Model Context Protocol · in the page specification/2025-03-26/basic/authorization …: MCP Request with Access Token Note over C,M: Begin standard MCP message exchange ``` ### Server Metadata Discovery For server capability discovery: * MCP clients *MUST* follow the OAuth 2.0 A…

Overview Model Context Protocol · in the page specification/2025-03-26/basic/index …ey components that work together: * **Base Protocol**: Core JSON-RPC message types * **Lifecycle Management**: Connection initialization, capability negotiation, and session control * **Server Feat…

Transports Model Context Protocol · in the page specification/2025-03-26/basic/transports # Transports MCP uses JSON-RPC to encode messages. JSON-RPC messages **MUST** be UTF-8 encoded. The protocol currently defines two standard transport mechanisms for client-server communication: 1.…

Cancellation Model Context Protocol · in the page specification/2025-03-26/basic/utilities/cancellation …ts optional cancellation of in-progress requests through notification messages. Either side can send a cancellation notification to indicate that a previously-issued request should be terminated. ##…

Ping Model Context Protocol · in the page specification/2025-03-26/basic/utilities/ping …client or server can initiate a ping by sending a `ping` request. ## Message Format A ping request is a standard JSON-RPC request with no parameters: ```json theme={null} { "jsonrpc": "2.0", "i…

Progress Model Context Protocol · in the page specification/2025-03-26/basic/utilities/progress …al progress tracking for long-running operations through notification messages. Either side can send progress notifications to provide updates about operation status. ## Progress Flow When a party w…

Key Changes Model Context Protocol · in the page specification/2025-03-26/changelog …tprotocol/specification/pull/185)) ## Other schema changes * Added `message` field to `ProgressNotification` to provide descriptive status updates * Added support for audio data, joining the existin…

Roots Model Context Protocol · in the page specification/2025-03-26/client/roots …will emit notifications when the list of roots changes. ## Protocol Messages ### Listing Roots To retrieve roots, servers send a `roots/list` request: **Request:** ```json theme={null} { "json…

Sampling Model Context Protocol · in the page specification/2025-03-26/client/sampling …null} { "capabilities": { "sampling": {} } } ``` ## Protocol Messages ### Creating Messages To request a language model generation, servers send a `sampling/createMessage` request: **Reque…

Specification Model Context Protocol · in the page specification/2025-03-26/index …workflows The protocol uses [JSON-RPC](https://www.jsonrpc.org/) 2.0 messages to establish communication between: * **Hosts**: LLM applications that initiate connections * **Clients**: Connectors wi…

Prompts Model Context Protocol · in the page specification/2025-03-26/server/prompts …mpt templates to clients. Prompts allow servers to provide structured messages and instructions for interacting with language models. Clients can discover available prompts, retrieve their contents, a…

Resources Model Context Protocol · in the page specification/2025-03-26/server/resources …Only list change notifications supported } } } ``` ## Protocol Messages ### Listing Resources To discover available resources, clients send a `resources/list` request. This operation supports…

Tools Model Context Protocol · in the page specification/2025-03-26/server/tools …notifications when the list of available tools changes. ## Protocol Messages ### Listing Tools To discover available tools, clients send a `tools/list` request. This operation supports [pagination…

Completion Model Context Protocol · in the page specification/2025-03-26/server/utilities/completion …l} { "capabilities": { "completions": {} } } ``` ## Protocol Messages ### Requesting Completions To get completion suggestions, clients send a `completion/complete` request specifying what…

Logging Model Context Protocol · in the page specification/2025-03-26/server/utilities/logging …(MCP) provides a standardized way for servers to send structured log messages to clients. Clients can control logging verbosity by setting minimum log levels, with servers sending notifications conta…

Architecture Model Context Protocol · in the page specification/2025-06-18/architecture/index …andles protocol negotiation and capability exchange * Routes protocol messages bidirectionally * Manages subscriptions and notifications * Maintains security boundaries between servers A host applica…

Overview Model Context Protocol · in the page specification/2025-06-18/basic/index …ey components that work together: * **Base Protocol**: Core JSON-RPC message types * **Lifecycle Management**: Connection initialization, capability negotiation, and session control * **Authorizati…

Transports Model Context Protocol · in the page specification/2025-06-18/basic/transports # Transports MCP uses JSON-RPC to encode messages. JSON-RPC messages **MUST** be UTF-8 encoded. The protocol currently defines two standard transport mechanisms for client-server communication: 1.…

Cancellation Model Context Protocol · in the page specification/2025-06-18/basic/utilities/cancellation …ts optional cancellation of in-progress requests through notification messages. Either side can send a cancellation notification to indicate that a previously-issued request should be terminated. ##…

Ping Model Context Protocol · in the page specification/2025-06-18/basic/utilities/ping …client or server can initiate a ping by sending a `ping` request. ## Message Format A ping request is a standard JSON-RPC request with no parameters: ```json theme={null} { "jsonrpc": "2.0", "i…

Progress Model Context Protocol · in the page specification/2025-06-18/basic/utilities/progress …al progress tracking for long-running operations through notification messages. Either side can send progress notifications to provide updates about operation status. ## Progress Flow When a party w…

Elicitation Model Context Protocol · in the page specification/2025-06-18/client/elicitation …l} { "capabilities": { "elicitation": {} } } ``` ## Protocol Messages ### Creating Elicitation Requests To request information from a user, servers send an `elicitation/create` request: ##…

Roots Model Context Protocol · in the page specification/2025-06-18/client/roots …will emit notifications when the list of roots changes. ## Protocol Messages ### Listing Roots To retrieve roots, servers send a `roots/list` request: **Request:** ```json theme={null} { "json…