firecrawl-fastmcp

Provides a decorator-based framework for rapidly defining MCP (Model Context Protocol) servers in TypeScript, using class-based handlers and metadata annotations to reduce boilerplate. Decorators map resource definitions, tool handlers, and prompt templates to MCP protocol messages, automatically generating the underlying request/response serialization and routing logic without manual protocol implementation.

Implements Server-Sent Events (SSE) as the underlying transport layer for MCP communication, enabling real-time streaming of tool results, resource updates, and prompt responses from server to client without WebSocket overhead. Uses HTTP long-polling semantics with automatic reconnection and message buffering to maintain session state across network interruptions.

Automatically generates MCP tool schemas (JSON Schema format) from TypeScript function signatures and type annotations, eliminating manual schema duplication. Introspects parameter types, optional fields, and descriptions to produce validated tool definitions that enforce type safety at both definition and invocation time.

Allows declarative definition of MCP resources (documents, data sources, or endpoints) that clients can discover and request. Supports both static resource definitions and dynamic content generation through handler functions, with automatic MIME type detection and content streaming for large payloads.

Provides a declarative system for defining reusable prompt templates within the MCP server, with parameter injection and variable substitution. Templates can be discovered by clients and instantiated with runtime parameters, enabling Claude to request pre-built prompts optimized for specific tasks without constructing them from scratch.

Implements a middleware pattern for intercepting and transforming MCP requests and responses before they reach handlers or are sent to clients. Supports chaining multiple middleware functions for cross-cutting concerns like logging, authentication, rate limiting, and response transformation without modifying handler code.

Provides a framework for consistent error handling across tool calls and resource requests, with structured error responses that include error codes, messages, and optional context. Automatically serializes errors into MCP-compliant error objects that clients can parse and handle programmatically.

Provides a context object that flows through middleware and handlers, enabling type-safe storage and retrieval of request-scoped state (user identity, permissions, request metadata). Uses TypeScript generics to enforce type safety on context properties without runtime overhead.

Provides hooks for server startup, shutdown, and configuration initialization, enabling setup of external resources (database connections, API clients) before the server accepts requests. Supports async initialization with dependency injection patterns for managing resource lifecycles.

Implements MCP protocol handshake and capability negotiation, allowing servers to advertise supported features (tools, resources, prompts) and clients to discover what the server provides. Supports version negotiation and optional feature flags for backward compatibility.