Living Brain, from ChatAndBuild, stores context outside any one model so the same knowledge can be written in ChatGPT and pulled back in Claude, Cursor, Codex, or a custom agent. It is for people who already move between those tools, and for developers who want that memory inside their own agent systems. This launch opens the layer through an API, TypeScript and Python SDKs, a CLI, and a hosted MCP server, including sign-in inside ChatGPT and Claude that does not require an API key. Notes, links, files, meeting transcripts, and chat turns are compiled into pages that keep their sources and version history, with related material grouped as it arrives rather than reassembled on every question. Scoring policies decide what is worth keeping, where it belongs, what it connects to, and whether it should come back into the next task. Founder and CEO Christel Buchanan, previously an early international hire at Twitter, posted the launch on 4 November 2026. ChatAndBuild is one of 25 companies in the Google for Startups Accelerator Southeast Asia 2026 cohort. On its latest internal LoCoMo run, Living Brain reports 92.2% judged accuracy across 1,540 questions, a 464 millisecond median retrieval time, and about 9,400 context tokens per question versus about 26,000 for a full-conversation baseline. On LongMemEval-S, the company reports about 22.6 times fewer tokens per question than a 116,000-token full-context baseline, and 95% lower cost per task. The site labels both sets of results as internal evaluations. API use is prepaid from $5 and metered at $8 per million input tokens and $0.50 per million output tokens.