Agent harnesses

The program around the model is most of the result.

• What a harness does that the model cannot 10 November 2026

  A model returns tokens. The harness runs the tool, feeds the result back, decides when to stop and what to forget. That loop is most of the product.

• Agent harnesses compared on context handling 10 November 2026

  Claude Code, Codex and Gemini CLI all summarise the history when the window fills. What differs is the size of the window and what a full one costs.

• Claude Code vs Codex vs Gemini CLI 10 November 2026

  Three terminal agents, three ways to pay. Claude Code and Codex come with a subscription; Gemini CLI has a free tier of 1,000 requests a day.