modelcontextprotocol.io

Test and debug an MCP server with MCP Inspector, including scripted CLI mode for CI

Cancel an in-flight MCP request correctly, given that cancellation differs between Streamable HTTP and stdio in 2026-07-28

Design stateful MCP tools with explicit handles now that the protocol has no session (2026-07-28)

Paginate MCP list results correctly with opaque cursors (tools/list, resources/list, resources/templates/list, prompts/list)

Report MCP tool failures correctly: tool execution errors with isError versus JSON-RPC protocol errors

Report MCP tool failures correctly: tool execution errors with isError versus JSON-RPC protocol errors

Handle an MCP insufficient_scope 403 and perform step-up authorization without losing previously granted scopes

Validate access token audience on an MCP server and refuse token passthrough when calling upstream APIs

Choose the right OAuth client registration mechanism for an MCP client now that RFC 7591 Dynamic Client Registration is deprecated

Run the MCP client-side OAuth 2.1 authorization flow: PRM discovery, PKCE, the RFC 8707 resource parameter, and RFC 9207 iss validation

Expose an MCP server as an OAuth 2.1 protected resource: serve RFC 9728 Protected Resource Metadata and issue the 401 WWW-Authenticate challenge

Receive MCP list-changed and resource-updated notifications by opening a subscriptions/listen stream (2026-07-28 replacement for the standalone SSE stream)

Handle MCP protocol version negotiation and the MCP-Protocol-Version header correctly under the stateless 2026-07-28 revision

Implement the MCP Streamable HTTP transport server-side under spec revision 2026-07-28 (single POST endpoint, no sessions, no GET stream)

Define MCP tools with outputSchema, structuredContent, and annotations under the 2026-07-28 spec

Detect whether an MCP server speaks the modern stateless revision or the legacy initialize handshake and negotiate a version

Adopt the io.modelcontextprotocol/tasks MCP extension for long-running server operations

Validate the RFC 9207 iss parameter and bind MCP client credentials to the issuing authorization server

Register an MCP client with an authorization server using a Client ID Metadata Document instead of Dynamic Client Registration

Migrate off the deprecated MCP Roots, Sampling and Logging features and adopt per-request log levels

Add MCP CacheableResult caching hints (ttlMs and cacheScope) to list and read results

Migrate a Streamable HTTP MCP server from the 2025-11-25 session handshake to the stateless 2026-07-28 revision

Deliver an MCP elicitation request in form or URL mode under the Multi Round-Trip Requests pattern

Handle an MCP input_required result client-side by gathering inputResponses and retrying the original request

Return an InputRequiredResult from an MCP server to request elicitation, sampling or roots via the Multi Round-Trip Requests pattern

Replace resources/subscribe with subscriptions/listen to receive MCP list-changed and resource-update notifications

Expose an MCP tool parameter as an HTTP header using the x-mcp-header schema annotation

Enforce the required MCP Streamable HTTP request headers and reject header/body mismatches

Write a stateless MCP client that carries protocol version and capabilities in per-request _meta instead of an initialize handshake

Implement the server/discover RPC on an MCP server so clients can select a protocol version and read capabilities in one call

Migrate a Streamable HTTP MCP server from the 2025-11-25 session handshake to the stateless 2026-07-28 revision

Build a FastMCP server with OAuth 2.1 auth for remote Claude agent connections