protect-mcp

Intercepts and logs all MCP protocol messages (requests, responses, errors) flowing through the gateway without blocking or modifying the actual execution path. Implements a transparent proxy pattern that sits between the MCP client and server, capturing full message payloads including tool calls, parameters, and responses for audit and debugging purposes without introducing latency into the critical path.

Enforces granular authorization rules on a per-tool basis before MCP tool calls are executed, allowing administrators to define which tools are callable, by whom, and under what conditions. Implements a policy evaluation layer that intercepts tool invocation requests, matches them against a policy ruleset, and either permits or denies execution based on tool name, caller identity, or other contextual attributes.

Generates cryptographically signed receipts for completed tool invocations using Ed25519 digital signatures, creating a tamper-proof audit trail that proves a specific tool was called with specific parameters at a specific time. Each receipt contains the tool invocation details and is signed with a private key, allowing verification that the receipt has not been modified and was issued by the authorized gateway.

Acts as a transparent wrapper around MCP server processes, intercepting the MCP protocol communication between client and server without requiring modifications to either endpoint. Implements a process-level proxy that launches the target MCP server as a child process and mediates all stdin/stdout communication, allowing policies and logging to be applied uniformly across any MCP server implementation.

Provides mechanisms to verify the authenticity and integrity of Ed25519-signed receipts generated by the gateway, allowing external systems or auditors to confirm that a receipt was legitimately issued and has not been tampered with. Verification uses the public key corresponding to the gateway's signing key to validate the signature and confirm the receipt contents.