Heimdall

MCP proxy that adds OpenTelemetry observability and policy-based access control to any MCP backend, with trace storage in SQLite, PostgreSQL, or MySQL.

An MCP proxy server that wraps stdio, HTTP, and SSE MCP backends to add OpenTelemetry/OTLP-based observability (compatible with Jaeger, Tempo, and Grafana) and policy-based access control with allow/deny rules. Traces are stored in SQLite, PostgreSQL, or MySQL. Useful for monitoring MCP tool usage and enforcing access policies in multi-user environments.