# fastest_mcp v0.3.0 - Table of Contents

> Production-grade Model Context Protocol (MCP) SDK for Elixir and Phoenix. Complete server and client support for MCP 2026-07-28 and 2025-11-25, with OAuth authentication, MCP Apps, Tasks, Streamable HTTP, stdio, strict validation, observability, and a FastMCP-inspired DSL.

## Pages

- Start Here
  - [Changelog](changelog.md)
  - [FastestMCP](readme.md)
  - [Onboarding](onboarding.md)

- Explanation
  - [Why FastestMCP](why-fastest-mcp.md)
  - [Protocol Versions](protocol-versions.md)
  - [Protocol Extensions](extensions.md)
  - [Phoenix Deployment](phoenix-deployment.md)
  - [Compatibility and Scope](compatibility-and-scope.md)

- Features
  - [Components](components.md)
  - [Tools](tools.md)
  - [Resources](resources.md)
  - [Prompts](prompts.md)
  - [Context](context.md)
  - [Dependency Injection](dependency-injection.md)
  - [Lifespan](lifespan.md)
  - [Transports](transports.md)
  - [Client](client.md)
  - [Sampling and Interaction](sampling-and-interaction.md)
  - [Pagination](pagination.md)
  - [Progress](progress.md)
  - [Logging](logging.md)
  - [Telemetry](telemetry.md)
  - [Dynamic Component Manager](component-manager.md)
  - [Auth](auth.md)
  - [Middleware](middleware.md)
  - [Tasks](background-tasks.md)
  - [Providers and Mounting](providers-and-mounting.md)
  - [Transforms](transforms.md)
  - [Versioning and Visibility](versioning-and-visibility.md)
  - [Testing](testing.md)
  - [Runtime State and Storage](runtime-state-and-storage.md)
  - [Schema Validation](schema-validation.md)

## Modules

- Core API
  - [FastestMCP](FastestMCP.md): The high-level API.
  - [FastestMCP.ApplicationSession](FastestMCP.ApplicationSession.md): Application-owned state shared across MCP requests.
  - [FastestMCP.Apps](FastestMCP.Apps.md): MCP-facing helpers for the MCP Apps extension.
  - [FastestMCP.BackgroundTask](FastestMCP.BackgroundTask.md): Handle returned for submitted background tasks.
  - [FastestMCP.Context](FastestMCP.Context.md): Explicit request context passed to handlers.
  - [FastestMCP.InputRequiredResult](FastestMCP.InputRequiredResult.md): Handler result for a modern MCP multi round-trip request (MRTR).
  - [FastestMCP.Lifespan](FastestMCP.Lifespan.md): Small server lifespan helper for startup and shutdown state.
  - [FastestMCP.PeerTask](FastestMCP.PeerTask.md): Handle for a task owned by the connected MCP peer.
  - [FastestMCP.RequestContext](FastestMCP.RequestContext.md): Immutable snapshot of request metadata exposed through `FastestMCP.Context`.
  - [FastestMCP.Root](FastestMCP.Root.md): A client-declared MCP filesystem root.
  - [FastestMCP.Server](FastestMCP.Server.md): Immutable server definition.
  - [FastestMCP.ServerModule](FastestMCP.ServerModule.md): Module-based API for application-owned MCP servers.

- Client and Transport
  - [FastestMCP.Client](FastestMCP.Client.md): Connected MCP client.
  - [FastestMCP.Client.CallbackContext](FastestMCP.Client.CallbackContext.md): Context passed to server-initiated client callbacks.
  - [FastestMCP.Client.OAuth](FastestMCP.Client.OAuth.md): MCP OAuth coordinator for HTTP clients.
  - [FastestMCP.Client.OAuth.AuthorizationHandler](FastestMCP.Client.OAuth.AuthorizationHandler.md): Host boundary for interactive OAuth authorization.
  - [FastestMCP.Client.OAuth.AuthorizationHandler.Request](FastestMCP.Client.OAuth.AuthorizationHandler.Request.md): Information passed to the host authorization callback.
  - [FastestMCP.Client.OAuth.ClientAssertionProvider](FastestMCP.Client.OAuth.ClientAssertionProvider.md): Host boundary for `private_key_jwt` client authentication.
  - [FastestMCP.Client.OAuth.ClientAssertionProvider.Request](FastestMCP.Client.OAuth.ClientAssertionProvider.Request.md): Information passed to the host assertion callback.
  - [FastestMCP.Client.OAuth.EnterpriseManagedProvider](FastestMCP.Client.OAuth.EnterpriseManagedProvider.md): Host boundary for enterprise identity assertions.
  - [FastestMCP.Client.OAuth.EnterpriseManagedProvider.Assertion](FastestMCP.Client.OAuth.EnterpriseManagedProvider.Assertion.md): Identity assertion and IdP token-exchange request details.
  - [FastestMCP.Client.OAuth.EnterpriseManagedProvider.Request](FastestMCP.Client.OAuth.EnterpriseManagedProvider.Request.md): Information passed to the enterprise identity callback.
  - [FastestMCP.Client.OAuth.Error](FastestMCP.Client.OAuth.Error.md): Redacted error returned by the MCP OAuth client coordinator.
  - [FastestMCP.Client.OAuth.TokenStore](FastestMCP.Client.OAuth.TokenStore.md): Storage boundary for MCP OAuth token sets.
  - [FastestMCP.Client.OAuth.TokenStore.Memory](FastestMCP.Client.OAuth.TokenStore.Memory.md): Per-client in-memory OAuth token store.
  - [FastestMCP.Client.ProtocolError](FastestMCP.Client.ProtocolError.md): Raised when a connected peer returns a syntactically valid JSON-RPC message
that does not satisfy the negotiated MCP method schema.
  - [FastestMCP.Client.Request](FastestMCP.Client.Request.md): Opaque handle for an asynchronous connected-client request.
  - [FastestMCP.Client.Task](FastestMCP.Client.Task.md): Connected-client handle for one remote MCP task.
  - [FastestMCP.Client.ToolResult](FastestMCP.Client.ToolResult.md): Stable, protocol-faithful result returned by `FastestMCP.Client.call_tool_result/4`.
  - [FastestMCP.Client.URLElicitation](FastestMCP.Client.URLElicitation.md): A server-initiated URL elicitation presented to a connected client.
  - [FastestMCP.Protocol](FastestMCP.Protocol.md): Central protocol version and capability helpers.
Keep the active MCP protocol baseline in one place so server responses, client
handshakes, and tests do not drift.
  - [FastestMCP.Protocol.Extensions](FastestMCP.Protocol.Extensions.md): Normalization and identifiers for MCP extensions.
  - [FastestMCP.Transport.HTTPApp](FastestMCP.Transport.HTTPApp.md): Embeddable Plug app for FastestMCP's HTTP transport.
  - [FastestMCP.Transport.Stdio](FastestMCP.Transport.Stdio.md): JSON-line stdio transport backed by the shared transport engine.
  - [FastestMCP.Transport.StreamableHTTP](FastestMCP.Transport.StreamableHTTP.md): Minimal HTTP transport slice backed by the shared transport engine.
  - [FastestMCP.Transport.WellKnownHTTP](FastestMCP.Transport.WellKnownHTTP.md): RFC 9728 Protected Resource Metadata plug.

- Runtime Features
  - [FastestMCP.Auth](FastestMCP.Auth.md): Declarative auth wrapper and authenticator contract.
  - [FastestMCP.Auth.ProtectedResource](FastestMCP.Auth.ProtectedResource.md): RFC 9728 Protected Resource Metadata for an HTTP MCP endpoint.
  - [FastestMCP.Auth.Result](FastestMCP.Auth.Result.md): Normalized authentication result attached to the runtime context.
  - [FastestMCP.Auth.StaticToken](FastestMCP.Auth.StaticToken.md): Hermetic bearer-token authenticator for server-side and local testing.
  - [FastestMCP.Authorization](FastestMCP.Authorization.md): Component-level authorization checks layered on top of authentication.
  - [FastestMCP.Authorization.Check](FastestMCP.Authorization.Check.md): Tagged authorization check.
  - [FastestMCP.Authorization.Context](FastestMCP.Authorization.Context.md): Authorization-only view of the runtime context used by authorization checks.

  - [FastestMCP.ComponentManager](FastestMCP.ComponentManager.md): Runtime-owned mutable component store.
  - [FastestMCP.Error](FastestMCP.Error.md): Normalized error used by the operation pipeline and transports.
  - [FastestMCP.Interact](FastestMCP.Interact.md): Friendly interaction helpers built on top of `FastestMCP.Context`.
  - [FastestMCP.Middleware](FastestMCP.Middleware.md): Built-in middleware constructors.
  - [FastestMCP.Middleware.ToolSearch](FastestMCP.Middleware.ToolSearch.md): Bounded, request-scoped tool discovery middleware.
  - [FastestMCP.Operation](FastestMCP.Operation.md): Runtime operation struct passed through middleware and transforms.
  - [FastestMCP.Provider](FastestMCP.Provider.md): Shared wrapper for provider-backed component sources.
  - [FastestMCP.Providers.ApplicationSessions](FastestMCP.Providers.ApplicationSessions.md): Optional tools for creating and terminating application sessions.
  - [FastestMCP.Providers.Proxy](FastestMCP.Providers.Proxy.md): Request-scoped proxy provider for a remote MCP server.
  - [FastestMCP.ResourceSecurity](FastestMCP.ResourceSecurity.md): Lexical screening policy for decoded resource-template parameters.
  - [FastestMCP.Sampling](FastestMCP.Sampling.md): Elixir-native helpers for MCP sampling.
  - [FastestMCP.Schema](FastestMCP.Schema.md): Compile-once JSON Schema validation for FastestMCP.
  - [FastestMCP.Schema.Compiled](FastestMCP.Schema.Compiled.md): An opaque, compiled JSON Schema validator.
  - [FastestMCP.Schema.Error](FastestMCP.Schema.Error.md): A bounded error returned while compiling or validating JSON Schema.
  - [FastestMCP.Schema.HTTPResolver](FastestMCP.Schema.HTTPResolver.md): Opt-in HTTPS resolver for remote JSON Schema resources.
  - [FastestMCP.ServerExtension](FastestMCP.ServerExtension.md): Declarative behavior for an executable MCP server extension.
  - [FastestMCP.ServerExtension.Method](FastestMCP.ServerExtension.Method.md): A single request/response method owned by a server extension.
  - [FastestMCP.SessionStateStore](FastestMCP.SessionStateStore.md): Behaviour for session-scoped state backends.
  - [FastestMCP.SessionStateStore.Memory](FastestMCP.SessionStateStore.Memory.md): In-memory session-state backend.
  - [FastestMCP.TaskBackend](FastestMCP.TaskBackend.md): Behaviour for background-task storage backends.
  - [FastestMCP.TaskBackend.Memory](FastestMCP.TaskBackend.Memory.md): ETS-backed in-memory task backend.

- Prompt, Resource, and Tool Helpers
  - [FastestMCP.Prompts.Message](FastestMCP.Prompts.Message.md): Prompt message helper with content normalization.
  - [FastestMCP.Prompts.Result](FastestMCP.Prompts.Result.md): Canonical prompt result helper.
  - [FastestMCP.Resources.Binary](FastestMCP.Resources.Binary.md): Convenience builder for binary resource content.
  - [FastestMCP.Resources.Content](FastestMCP.Resources.Content.md): Resource content helper with MIME and metadata support.
  - [FastestMCP.Resources.Directory](FastestMCP.Resources.Directory.md): Helper for serving directory listings as JSON resources.
  - [FastestMCP.Resources.File](FastestMCP.Resources.File.md): Helper for serving file-backed resources.
  - [FastestMCP.Resources.HTTP](FastestMCP.Resources.HTTP.md): Helper for serving HTTP-backed resources.
  - [FastestMCP.Resources.Result](FastestMCP.Resources.Result.md): Canonical resource result helper.
  - [FastestMCP.Resources.Text](FastestMCP.Resources.Text.md): Convenience builder for text resource content.
  - [FastestMCP.Tools.Result](FastestMCP.Tools.Result.md): Canonical tool result helper.

