opencode
Use the opencode CLI as an engine; it signs in itself.
In short
opencode is a command-line agent with its own sign-in and a long model list. Thesivor detects it and runs it with a permission config that allows edits only inside the agent's workspace.
1Install and sign in
Install the CLI and sign in once.
2Re-scan in Settings
Settings → AI engines lists it with the models opencode models reports. Pick one for the tier you want.
For technical users
Invocation: opencode run --format json --model <provider/model> --dir <agent-work> --pure "<prompt>", with a permission config that allows edits, denies bash and web fetch, and allows external directories only inside the run folder. The prompt is passed as an argument (this version has no stdin mode), so very large prompts are bounded by the OS argument limit (about 1 MB on macOS). A minimal environment is passed (the XDG_* variables it documents); Thesivor's keys are never included.