X Discussion: YC President Garry Tan Open-Sources Harness Evals: 7 Model-Harness Setups All Pass 71-79% of 20 Tasks, With Cost the Real Gap: OpenClaw About $0.44 per Solved Task, Claude Code $0.22, Codex $0.17
Garry Tan (@garrytan), President and CEO of Y Combinator, posted on X at 18:09 UTC on 2026-11-08 that out of curiosity he is doing open-source eval work on harnesses with frontier models, attaching a screenshot of early results; he then shared the GitHub repo garrytan/g-harness-evals (MIT). The repo holds the model (Opus 5.5 or GPT-6.1 Sol) and tasks fixed and swaps only the harness (system prompt, tools, memory). The screenshot says 7 setups all passed 71-79% of the same 20 coding tasks, and 14 of the 20 tasks scored the same in every setup, so the test was too easy to separate them; a harder Terminal-Bench rerun is in progress. Cost differs a lot: on Opus, OpenClaw about $0.44 per solved task, Claude Code $0.22, Hermes $0.24 and QM $0.19; on Sol, Codex is cheapest and fastest at $0.17. At capture the post had about 312 likes, 84 replies, 117 bookmarks and about 41,767 impressions. The repo discloses conflicts: QM is a YC project and YC is an investor in Hermes.

Key Takeaways
- Original post: Garry Tan (bio "President & CEO @ycombinator") posted at 18:09 UTC on 2026-11-08; about 312 likes, 16 reposts, 10 quotes, 84 replies, 117 bookmarks and 41,767 impressions at capture
- Method (repo README): fix the model (Opus 5.5 or GPT-6.1 Sol) and 20 public tasks, swap only the harness; metrics are pass rate, cost per solved task and time per trial
- Pass rate: all 7 setups land at 71-79%; on Opus, Claude Code 76.3%, Hermes 78.8%, OpenClaw 76.3%, QM 72.5%; 95% ranges overlap and the author says they cannot be told apart
- Cost and speed: on Opus, OpenClaw $0.44 per solved task and 99.4 s per trial vs Claude Code $0.22 and 40.1 s; on Sol, Codex $0.17 and 30.1 s (author figures, descriptive, no significance test)
- Framing: a discussion around a personally run open-source eval, not an official vendor benchmark; the author discloses QM is a YC project, YC invests in Hermes, and gstack/gbrain are his own projects








