605 pages for supported.

Authorization Model Context Protocol · in the page specification/2025-03-26/basic/authorization …irements Authorization is **OPTIONAL** for MCP implementations. When supported: * Implementations using an HTTP-based transport **SHOULD** conform to this specification. * Implementations using an S… Lifecycle Model Context Protocol · in the page specification/2025-03-26/basic/lifecycle …se by sending an `initialize` request containing: * Protocol version supported * Client capabilities * Client implementation information ```json theme={null} { "jsonrpc": "2.0", "id": 1, "meth… Transports Model Context Protocol · in the page specification/2025-03-26/basic/transports …header, listing both `application/json` and `text/event-stream` as supported content types. 3. The body of the POST request **MUST** be one of the following: * A single JSON-RPC *request*, *noti… Roots Model Context Protocol · in the page specification/2025-03-26/client/roots …"id": 1, "error": { "code": -32601, "message": "Roots not supported", "data": { "reason": "Client does not have roots capability" } } } ``` ## Security Considerations 1.… Resources Model Context Protocol · in the page specification/2025-03-26/server/resources …e={null} { "capabilities": { "resources": {} // Neither feature supported } } ``` ```json theme={null} { "capabilities": { "resources": { "subscribe": true // Only subscriptions s… Completion Model Context Protocol · in the page specification/2025-03-26/server/utilities/completion …r common failure cases: * Method not found: `-32601` (Capability not supported) * Invalid prompt name: `-32602` (Invalid params) * Missing required arguments: `-32602` (Invalid params) * Internal err… Architecture Model Context Protocol · in the page specification/2025-06-18/architecture/index …negotiation system where clients and servers explicitly declare their supported features during initialization. Capabilities determine which protocol features and primitives are available during a ses… Authorization Model Context Protocol · in the page specification/2025-06-18/basic/authorization …irements Authorization is **OPTIONAL** for MCP implementations. When supported: * Implementations using an HTTP-based transport **SHOULD** conform to this specification. * Implementations using an S… Lifecycle Model Context Protocol · in the page specification/2025-06-18/basic/lifecycle …se by sending an `initialize` request containing: * Protocol version supported * Client capabilities * Client implementation information ```json theme={null} { "jsonrpc": "2.0", "id": 1, "meth… Transports Model Context Protocol · in the page specification/2025-06-18/basic/transports …header, listing both `application/json` and `text/event-stream` as supported content types. 3. The body of the POST request **MUST** be a single JSON-RPC *request*, *notification*, or *response*. 4… Elicitation Model Context Protocol · in the page specification/2025-06-18/client/elicitation …"maximum": 100 } }, "required": ["propertyName"] } ``` ### Supported Schema Types The schema is restricted to these primitive types: 1. **String Schema** ```json theme={null} {… Roots Model Context Protocol · in the page specification/2025-06-18/client/roots …"id": 1, "error": { "code": -32601, "message": "Roots not supported", "data": { "reason": "Client does not have roots capability" } } } ``` ## Security Considerations 1.… Resources Model Context Protocol · in the page specification/2025-06-18/server/resources …e={null} { "capabilities": { "resources": {} // Neither feature supported } } ``` ```json theme={null} { "capabilities": { "resources": { "subscribe": true // Only subscriptions s… Completion Model Context Protocol · in the page specification/2025-06-18/server/utilities/completion …r common failure cases: * Method not found: `-32601` (Capability not supported) * Invalid prompt name: `-32602` (Invalid params) * Missing required arguments: `-32602` (Invalid params) * Internal err… Architecture Model Context Protocol · in the page specification/2025-11-25/architecture/index …negotiation system where clients and servers explicitly declare their supported features during initialization. Capabilities determine which protocol features and primitives are available during a ses… Authorization Model Context Protocol · in the page specification/2025-11-25/basic/authorization …irements Authorization is **OPTIONAL** for MCP implementations. When supported: * Implementations using an HTTP-based transport **SHOULD** conform to this specification. * Implementations using an S… Overview Model Context Protocol · in the page specification/2025-11-25/basic/index …mas MAY include a `$schema` field to specify a different dialect 3. **Supported dialects**: Implementations MUST support at least 2020-12 and SHOULD document which additional dialects they support 4.… Lifecycle Model Context Protocol · in the page specification/2025-11-25/basic/lifecycle …se by sending an `initialize` request containing: * Protocol version supported * Client capabilities * Client implementation information ```json theme={null} { "jsonrpc": "2.0", "id": 1, "meth… Transports Model Context Protocol · in the page specification/2025-11-25/basic/transports …header, listing both `application/json` and `text/event-stream` as supported content types. 3. The body of the POST request **MUST** be a single JSON-RPC *request*, *notification*, or *response*. 4… Tasks Model Context Protocol · in the page specification/2025-11-25/basic/utilities/tasks …`capabilities.tasks.list` controls if the `tasks/list` operation is supported by the party. `capabilities.tasks.cancel` controls if the `tasks/cancel` operation is supported by the party. ### Tool… Elicitation Model Context Protocol · in the page specification/2025-11-25/client/elicitation …ervers **MUST NOT** send elicitation requests with modes that are not supported by the client. ## Protocol Messages ### Elicitation Requests To request information from a user, servers send an `eli… Roots Model Context Protocol · in the page specification/2025-11-25/client/roots …"id": 1, "error": { "code": -32601, "message": "Roots not supported", "data": { "reason": "Client does not have roots capability" } } } ``` ## Security Considerations 1.… Resources Model Context Protocol · in the page specification/2025-11-25/server/resources …e={null} { "capabilities": { "resources": {} // Neither feature supported } } ``` ```json theme={null} { "capabilities": { "resources": { "subscribe": true // Only subscriptions s… Completion Model Context Protocol · in the page specification/2025-11-25/server/utilities/completion …r common failure cases: * Method not found: `-32601` (Capability not supported) * Invalid prompt name: `-32602` (Invalid params) * Missing required arguments: `-32602` (Invalid params) * Internal err… Architecture Model Context Protocol · in the page specification/2026-07-28/architecture/index …lity-based negotiation system where clients and servers declare their supported features on each request. Clients include their capabilities in `_meta.io.modelcontextprotocol/clientCapabilities` on ev… Authorization Server Discovery Model Context Protocol · in the page specification/2026-07-28/basic/authorization/authorization-server-discovery …gh which MCP clients can determine authorization server endpoints and supported capabilities. ## Authorization Server Location MCP servers **MUST** implement the OAuth 2.0 Protected Resource Metadat… Client Registration Model Context Protocol · in the page specification/2026-07-28/basic/authorization/client-registration …ver indicates that it supports them (via `client_id_metadata_document_supported` in OAuth Authorization Server Metadata) 3. Use Dynamic Client Registration as a fallback if the Authorization Server su… Authorization Model Context Protocol · in the page specification/2026-07-28/basic/authorization/index …irements Authorization is **OPTIONAL** for MCP implementations. When supported: * Implementations using an HTTP-based transport **SHOULD** conform to this specification. * Implementations using an S… Authorization Security Considerations Model Context Protocol · in the page specification/2026-07-28/basic/authorization/security-considerations …OAuth 2.0 Authorization Server Metadata**: If `code_challenge_methods_supported` is absent, the authorization server does not support PKCE and MCP clients **MUST** refuse to proceed. * **OpenID Conne… Overview Model Context Protocol · in the page specification/2026-07-28/basic/index …earlier protocol revisions * **Message Patterns**: Messaging patterns supported by the core protocol including request and response, multi round-trip requests (MRTR), and subscribe and notify * **Auth… Multi Round-Trip Requests Model Context Protocol · in the page specification/2026-07-28/basic/patterns/mrtr …ern. The previous pattern of server-initiated requests is no longer > supported. This is a breaking change. > [!NOTE] > > For brevity, the request examples on this page omit the `_meta` request > met… Subscriptions Model Context Protocol · in the page specification/2026-07-28/basic/patterns/subscriptions …ck the acknowledged filter against what it requested and handle any unsupported types gracefully. ## Receiving Notifications All notifications delivered on the stream carry `io.modelcontextprotocol/… stdio Model Context Protocol · in the page specification/2026-07-28/basic/transports/stdio …returns a `DiscoverResult`: the server is modern. Select a mutually supported version from `supportedVersions` and continue. * The server returns a recognized modern JSON-RPC error such as [`Unsup… Streamable HTTP Model Context Protocol · in the page specification/2026-07-28/basic/transports/streamable-http …header listing both `application/json` and `text/event-stream` as supported content types. 3. The client **MUST** include the [request metadata headers](#request-metadata) on each POST request.… Versioning and Compatibility Model Context Protocol · in the page specification/2026-07-28/basic/versioning …requested version Server-->>Client: result else version unsupported Server-->>Client: UnsupportedProtocolVersionError Note over Client,Server: Client retries with a mutuall… Key Changes Model Context Protocol · in the page specification/2026-07-28/changelog …(`io.modelcontextprotocol/serverInfo`). Version mismatches return `UnsupportedProtocolVersionError` ([SEP-2575](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2575)). 3. Add `serv… Elicitation Model Context Protocol · in the page specification/2026-07-28/client/elicitation …ervers **MUST NOT** send elicitation requests with modes that are not supported by the client. ## Protocol Messages ### Elicitation Requests Servers **MAY** request information from a user during t… Schema Reference Model Context Protocol · in the page specification/2026-07-28/schema …does not support the requested version, it MUST return an <a href="#unsupportedprotocolversionerror" class="tsd-kind-interface">UnsupportedProtocolVersionError</a>.</p> </div></section> <section class… Discovery Model Context Protocol · in the page specification/2026-07-28/server/discover # Discovery `server/discover` lets a client query a server's supported protocol versions, capabilities, and identity before sending any other requests. Servers **MUST** implement it. ## Request The… Completion Model Context Protocol · in the page specification/2026-07-28/server/utilities/completion …r common failure cases: * Method not found: `-32601` (Capability not supported) * Invalid prompt name: `-32602` (Invalid params) * Missing required arguments: `-32602` (Invalid params) * Internal err… Architecture Model Context Protocol · in the page specification/draft/architecture/index …lity-based negotiation system where clients and servers declare their supported features on each request. Clients include their capabilities in `_meta.io.modelcontextprotocol/clientCapabilities` on ev… Authorization Server Discovery Model Context Protocol · in the page specification/draft/basic/authorization/authorization-server-discovery …gh which MCP clients can determine authorization server endpoints and supported capabilities. ## Authorization Server Location MCP servers **MUST** implement the OAuth 2.0 Protected Resource Metadat… Client Registration Model Context Protocol · in the page specification/draft/basic/authorization/client-registration …ver indicates that it supports them (via `client_id_metadata_document_supported` in OAuth Authorization Server Metadata) 3. Use Dynamic Client Registration as a fallback if the Authorization Server su… Authorization Model Context Protocol · in the page specification/draft/basic/authorization/index …irements Authorization is **OPTIONAL** for MCP implementations. When supported: * Implementations using an HTTP-based transport **SHOULD** conform to this specification. * Implementations using an S… Authorization Security Considerations Model Context Protocol · in the page specification/draft/basic/authorization/security-considerations …OAuth 2.0 Authorization Server Metadata**: If `code_challenge_methods_supported` is absent, the authorization server does not support PKCE and MCP clients **MUST** refuse to proceed. * **OpenID Conne… Overview Model Context Protocol · in the page specification/draft/basic/index …earlier protocol revisions * **Message Patterns**: Messaging patterns supported by the core protocol including request and response, multi round-trip requests (MRTR), and subscribe and notify * **Auth… Multi Round-Trip Requests Model Context Protocol · in the page specification/draft/basic/patterns/mrtr …ern. The previous pattern of server-initiated requests is no longer > supported. This is a breaking change. > [!NOTE] > > For brevity, the request examples on this page omit the `_meta` request > met… Subscriptions Model Context Protocol · in the page specification/draft/basic/patterns/subscriptions …ck the acknowledged filter against what it requested and handle any unsupported types gracefully. ## Receiving Notifications All notifications delivered on the stream carry `io.modelcontextprotocol/… stdio Model Context Protocol · in the page specification/draft/basic/transports/stdio …returns a `DiscoverResult`: the server is modern. Select a mutually supported version from `supportedVersions` and continue. * The server returns a recognized modern JSON-RPC error such as [`Unsup… Streamable HTTP Model Context Protocol · in the page specification/draft/basic/transports/streamable-http …header listing both `application/json` and `text/event-stream` as supported content types. 3. The client **MUST** include the [request metadata headers](#request-metadata) on each POST request.…