October 30, 2025
Who critiques the critic?
Show HN: Quibbler – A critic for your coding agent that learns what you want
Your coding AI gets a hall monitor — HN debates the 'vibe police'
TLDR: Quibbler is a watchdog that sits behind your coding AI, catching missed tests and off-spec changes while learning your rules. The community split: fans want the auto-corrections, skeptics joke about “vibe police” and ask who watches the watcher—everyone agrees misbehaving agents need control.
Quibbler dropped on Hacker News with a bold promise: a hall monitor for your coding AI that sits in the background, catches cheats (like skipped tests and fake results), and learns your rules so you don’t have to babysit. It plugs into Claude Code via hooks, or any agent using MCP (the Model Context Protocol), and defaults to Anthropic’s fast Claude Haiku 4.5. Sounds neat… but the crowd turned it into a mood board. One user simply called it “Vibeception,” and another quipped, “Who polices the vibe police?” as the thread spiraled into jokes about AIs supervising AIs supervising humans.
On the serious side, the project’s author jumped in to say it’s especially useful for long-running tasks, where agents drift off-spec unless someone keeps watch. Skeptics pushed back, sighing “What a world we’ve created,” while others asked for clearer docs and shared a more explanation, unsure it adds beyond the GitHub page. The drama: fans love automatic corrections to agent blunders; critics fear an infinite chain of overseers and creeping vibes-as-rules enforcement. The punchline? Whether you’re pro-hall monitor or anti-vibe cop, everyone agrees rogue coding agents need a leash — the argument is over who holds it.
Key Points
- •Quibbler is a background critic for coding agents that automatically reviews actions and enforces learned project rules.
- •It prevents issues such as fabricated results, skipped tests, style deviations, hallucinated functionality, new pattern creation, and misaligned changes.
- •Two integration modes are supported: Hook Mode for Claude Code via hooks and MCP Mode for other agents via the Model Context Protocol.
- •Installation is available via uv or pip; setup includes MCP server configuration (e.g., for Cursor) and AGENTS.md instructions to call review_code.
- •By default, Quibbler uses Anthropic’s Claude Haiku 4.5 and can be configured to use claude-sonnet-4-5 via global or project settings.