@modelcontextprotocol/server-filesystem

Exposes local filesystem read operations through the Model Context Protocol, allowing LLM clients to request file contents, directory listings, and metadata without direct filesystem access. Implements MCP resource handlers that translate client requests into safe filesystem operations with path validation and permission checks, enabling AI agents to inspect codebases, configuration files, and documentation on the host machine.

Implements MCP resource discovery endpoints that allow clients to enumerate available files and directories, including metadata like file size, modification time, and MIME type. Uses the MCP resource listing protocol to expose filesystem structure as queryable resources with optional filtering and pagination, enabling clients to understand what files are accessible before requesting specific content.

Enforces path validation rules to prevent directory traversal attacks and unauthorized access to files outside configured root directories. Implements path normalization (resolving `..` and symlinks), allowlist/denylist filtering, and permission checks before serving any filesystem operation, ensuring that LLM clients cannot escape the intended sandbox or access sensitive system files.

Exposes filesystem operations as MCP tools with structured schemas, allowing LLM clients to invoke read, list, and metadata operations through the MCP tool-calling protocol. Implements request/response marshaling that converts LLM tool calls into filesystem operations and returns results in a format the LLM can parse and reason about, enabling natural language requests like 'read the main.py file' to be translated into filesystem calls.

Supports streaming large file contents through the MCP protocol to avoid loading entire files into memory or LLM context at once. Implements chunked reading and optional compression to efficiently deliver large files (>10MB) without overwhelming the client or exceeding context limits, enabling analysis of large codebases or log files that would otherwise be impractical.

Provides detailed file metadata (size, modification time, permissions, ownership, MIME type) through MCP resources, allowing clients to make informed decisions about which files to read or how to process them. Implements metadata caching and lazy evaluation to avoid expensive stat() calls for every file, enabling efficient filtering and prioritization of large directory trees.

Implements comprehensive error handling for filesystem operations with MCP-compliant error responses, translating OS-level errors (permission denied, file not found, I/O errors) into structured error messages that LLM clients can understand and act upon. Provides detailed error context (error codes, descriptions, suggested remedies) to enable intelligent error recovery and user feedback.

Manages MCP server initialization, configuration loading, and graceful shutdown, implementing standard MCP server patterns for capability negotiation and protocol versioning. Handles configuration of root directories, access rules, and resource schemas at startup, with support for environment variables and configuration files to enable flexible deployment across different environments.