Write an agent's ethos.md

Turn the answers from ethos-explore into a durable artifact. The ethos.md is the contract that people and agents read before they build, evaluate, review, or change this agent. Without it, each of them has to re-ask everything, and nothing records what the agent is supposed to do.

Creating or reviewing an ethos.md does not authorize application changes or imply that changes will follow. Do not ask for permission to modify prompts, models, tools, validation code, or workflow structure, or generate sections listing those permissions. Any workflow that later changes the application collects the permissions it needs when that work is undertaken. Keep behavioral constraints and safety boundaries, including approvals the agent needs for its own actions, in Behavior and Constraints. Also retain already-confirmed organizational safety and review policies and their known owners; recording such a restriction does not grant permission to make a change.