Built an open-source local runtime firewall for coding agents (secret redaction + token budget caps)

[ASHISH PATIL (ashp15205)]

Hey everyone! 👋

I built Guardian-Runtime, a local-first reverse proxy designed to protect developer workstations when using AI coding tools (Cursor, Claude Code, Aider).

What problem does it solve?

Autonomous coding agents index local repositories and can accidentally leak .env credentials, AWS keys, or internal code to external LLMs. Additionally, infinite agent retry loops can burn through API budgets in minutes.

How it works:

It runs 100% locally on localhost:8080 (zero cloud dependencies):

• 🛡️ Reversible Secret Vaulting: Scans code prompts locally; replaces secrets with temporary tokens on outbound requests, and restores the real keys on response so generated code never breaks.
• 💰 FinOps Circuit-Breaker: Compresses token payload bloat by ~50% and enforces hard daily spend caps to prevent runaway loops.
• ⚡ Sub-15ms Latency: In-memory scanning with no external telemetry.

👉 GitHub Repository: https://github.com/ashp15205/guardian-runtime

Feedback, issues, and ideas are welcome! ⭐