asgeirtj/system_prompts_leaks
A maintained archive of extracted system prompts from 100+ AI products — Claude Fable 5, Claude Code, ChatGPT 5.5, Gemini, Cursor — useful for studying how vendors actually instruct their agents.
**The gist** The repo collects extracted system prompts from roughly **100+** models and products across **Anthropic, OpenAI, Google, xAI**, Microsoft, Meta, and Mistral — including Claude Fable 5, Claude Code, ChatGPT 5.5, and Cursor — organized by vendor with a recently-updated index. It sits at **49.5k stars** with **599 commits** and updates as recent as July 2026.
**Why it matters** Vendor system prompts are the closest thing to a reference library for **prompting** and harness design: how labs structure tool instructions, refusal rules, and formatting constraints. Reading how **Claude Code** or **Cursor** is instructed can directly inform the system prompt of your own agent.
**The gist** The repo collects extracted system prompts from roughly **100+** models and products across **Anthropic, OpenAI, Google, xAI**, Microsoft, Meta, and Mistral — including Claude Fable 5, Claude Code, ChatGPT 5.5, and Cursor — organized by vendor with a recently-updated index. It sits at **49.5k stars** with **599 commits** and updates as recent as July 2026. **Why it matters** Vendor system prompts are the closest thing to a reference library for **prompting** and harness design: how labs structure tool instructions, refusal rules, and formatting constraints. Reading how **Claude Code** or **Cursor** is instructed can directly inform the system prompt of your own agent. **Watch out** Nothing here is verified: prompts are obtained via **extraction-style prompting**, the repo states **no validation methodology**, and vendors revise prompts constantly — treat any entry as a possibly **stale or partial** reconstruction.