Headroom: a live gauge of your AI chat's remaining context, so you know before the AI starts forgetting. Free & open source. Built after DeepSeek started contradicting decisions settled 20 rounds earlier — no platform shows remaining context. Tokens from a 6-writing-system model calibrated against real tokenizers. Text is read, counted, discarded — no server, no API keys. ChatGPT · Gemini · DeepSeek · Kimi · Qwen · Qianwen · Doubao · github.com/ZM-BAD/headroom