Customizing harnesses
Partly builtSome of this works today; the page says which parts.
Harness settings live in the sandbox, so they persist like any other files. Use the file API to add instructions:
harebox new --name custom
harebox file write current --path /home/user/AGENTS.md --raw "Run the tests before finishing."
Bring your own harness by implementing the Harness port, with ID, Models and Run. The Shell harness is the smallest example, at services/harness/harness.go.