Code as Agent Harness
a clean articulation of the shift from prompt engineering toward harness/system design, reliability coming from execution, verification, and environment structure, not just smarter base models.
What it is: How To AI thread summarizing the Stanford + Meta “Code as Agent Harness” paper.
Gist: the core claim is that reliable agents should externalize reasoning into executable code instead of relying on free-form natural-language chain-of-thought. In this framing, code becomes the agent harness: scripts hold state, tests/verifiers provide feedback, execution logs become memory, and the environment constrains behavior through real runtime errors rather than vague self-talk.
Newsletter angle: “the important unit of agent capability is the harness, not the prompt” or “code is becoming the runtime substrate for agent reasoning.”
Note: extracted via FXTwitter note-tweet payload; saved as a secondary summary/interpretation of the paper rather than a direct read of the paper itself.