Harnesses

The harness is the runtime that executes your agent loop. Swap one line to switch runtimes.

executor:
  harness: claude

Supported harnesses

Harness	Runtime	Best for
`claude`	Claude Code	Claude Code out of the box. Add tools, policies, and prompts to customize.
`codex`	Codex	Codex out of the box. Add tools, policies, and prompts to customize.
`pi`	Pi	Headless multi-model worker that runs on any gateway model. Ideal for review, exploration, and read-heavy tasks delegated by a supervisor agent.

More harness integrations are on the way.

Tools, policies, and other config stay the same across harnesses. Just change the harness value in your YAML, or override it at runtime:

omni run agent.yaml --harness codex

See Models & Credentials for how to set up API keys and choose models.