The Redis URL That Leaked Its Own Password Into AI Agent Context

Short summary

ContextOS, a context-pack builder for AI coding agents, had a secret-detection gap: Redis URLs using the standard no-username format (redis://:password@host) bypassed redaction because the regex required at least one character before the colon. The fix was a single regex change from + to *, plus two regression tests covering the empty-username case. The broader lesson is that test suites which only exercise known formats create coverage gaps disguised as passing tests.

• •Redis URLs with empty usernames bypassed ContextOS secret redaction, exposing passwords to AI agents
• •Fix: change regex quantifier from + to * in the username segment, plus two regression tests
• •Key lesson: test coverage that only checks formats you already knew about will always look complete

Generated with AI, which can make mistakes.