Brex CrabTrap
#5 in Observability & EvalsBrex · 2× · last seen Jun 30, 2026
77
Momentum
CrabTrap is an Open Source tool developed by Brex for securing productive AI agents. It operates as a framework-agnostic HTTP/HTTPS forward proxy that intercepts every outgoing request from an agent and evaluates it against a natural language security policy using deterministic rules and an LLM-as-a-Judge before forwarding or blocking it. The solution uses TLS interception (MITM with a custom CA), logs all decisions in PostgreSQL, and is deployed as a Docker container with a web UI for policy and audit management. CrabTrap is available free on GitHub under the MIT license.
Momentum trend
19.05.17.08.
Features
| Throughput/Latency | Histograms for judge and approval latency exposed as metrics; default approval timeout 30s, cache TTL 5 min, max 5 cache uses |
| License | MIT License |
| Platform | Docker container (linux/amd64, linux/arm64), runs alongside PostgreSQL |
| Price | Free, open source (MIT license) |
| Protocol Compatibility | HTTP/HTTPS forward proxy, framework-, language-, and API-agnostic via HTTP_PROXY/HTTPS_PROXY, including TLS interception |
| Release Date | First release v0.0.1 on April 17, 2026; public announcement April 21–22, 2026 |
| Supported Models/Providers | Configurable LLM judge provider and model (per-provider circuit-breaker gauge metric) |