@modelcontextprotocol/server-basic-preact

Bootstraps a Model Context Protocol server instance that binds Preact as the rendering framework for server-side UI components. Uses MCP's server initialization pattern to establish bidirectional communication channels between LLM clients and the Preact component tree, enabling declarative UI composition for tool interfaces. The server registers Preact components as MCP resources that can be dynamically rendered and updated based on client requests.

Allows developers to define MCP tools as Preact components with props mapping to tool parameters and component output mapping to tool results. The server introspects component signatures to auto-generate MCP tool schemas, eliminating manual schema duplication. Tool invocation triggers component rendering with parameters as props, and the rendered output is serialized back as the MCP tool result.

Exposes Preact components as MCP resources that clients can request and receive as rendered output. The server maintains a registry of component-based resources, handles client resource requests by rendering the corresponding component with optional query parameters, and returns the rendered output (HTML, text, or structured data) as the resource content. Supports dynamic resource generation based on client context.

Implements MCP's message protocol (requests, responses, notifications) with hooks into Preact component lifecycle. Server receives MCP requests, routes them to appropriate component handlers, executes component render cycles, and sends responses back to clients. Supports both synchronous component rendering and async operations (API calls, database queries) within component lifecycle hooks, with proper error handling and timeout management.

Provides TypeScript-first tool parameter binding by leveraging Preact component prop types to define and validate tool parameters. The server uses TypeScript's type system to auto-generate parameter schemas, validate incoming tool calls against those types, and provide IDE autocomplete for tool parameters. Type mismatches are caught at development time and runtime, with clear error messages for parameter validation failures.

Enables state management within MCP server tools using Preact hooks (useState, useReducer, useContext). State is scoped to individual tool invocations or shared across multiple tools via context providers. The server manages hook state lifecycle, ensuring proper cleanup between tool calls and supporting stateful tool interactions across multiple client requests. Integrates with MCP's request-response model to persist state across related tool calls.

Supports composing multiple Preact components into tool chains where the output of one tool (component) becomes the input to the next. The server manages data flow between composed components, handles error propagation through the chain, and provides a unified interface for executing multi-step tool sequences. Component composition follows Preact's component nesting patterns, making tool chains declarative and reusable.

Manages separate execution contexts and sessions for multiple concurrent MCP clients connecting to the same server. Each client gets an isolated context with its own state, resource namespace, and tool invocation history. The server routes requests to the correct client context, maintains session metadata (client ID, connection time, request count), and handles client disconnection with proper cleanup. Supports session persistence for reconnecting clients.