Vectimus – Cedar policy enforcement for AI coding agents

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Vectimus – Cedar policy enforcement for AI coding agents

Hey HN. I built Vectimus because coding agents keep doing things they shouldn't and there's no runtime governance layer for the developer workstation. The problem: Claude Code, Cursor, Gemini CLI and GitHub Copilot let agents execute shell commands, write files and call MCP servers. Most developers disable the permission prompts because they slow you down. But that means the agent can rm -rf /, read your .env, push to production or call a compromised MCP server with nothing watching. Vectimus intercepts every tool call and evaluates it against 78 Cedar policies containing 369 rules before execution. Cedar is the policy language AWS chose for AgentCore Policy (GA this month). Evaluation runs locally via a persistent daemon in under 10ms. Zero network calls. Zero telemetry. Every evaluation produces an Ed25519-signed receipt so you have cryptographic proof of what was allowed and denied. Every policy maps to a real incident. CVE-2025-6514 compromised 437,000+ developer environments through a malicious MCP OAuth proxy. The GitHub MCP server was hijacked via a crafted issue to exfiltrate private repo data. A Terraform agent destroyed production infrastructure. These happened. How it hooks in: Claude Code intercepts shell commands, file writes, MCP calls and web fetches. Cursor governs shell commands, file reads/writes and MCP tool calls at the editor level. Copilot intercepts terminal commands, file edits, deletes and git pushes. Gemini CLI uses Gemini's native hook system. MCP servers are blocked by default and allowlisted per-project with input inspection. Observe mode lets you see what would be blocked before you enforce. I also built Sentinel ( https://github.com/vectimus/sentinel ), a three-agent pipeline that scans for new agentic AI security incidents daily, drafts Cedar policies, replays the incident in a sandbox to prove the policy catches it, then opens a PR. The pipeline is governed by Vectimus. Every finding and policy draft is public. All 10 OWASP Agentic Top 10 categories covered. Compliance annotations for SOC 2, NIST AI RMF, NIST CSF 2.0, EU AI Act, ISO 27001, CIS Controls and SLSA. Apache 2.0. Solo founder, built in Ireland. Happy to go deep on the Cedar policy design, the hook architecture, the signed receipts or the OWASP mapping.