# Harness² vs OpenAI Codex (slim)

> OpenAI Codex scores 73.4 (BB) to Harness²'s 41.6 (E) for agent harnesses. Prices, MCP, x402, uptime and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/harness2-vs-openai-codex.md (~3,000 tokens) · this version ~780 tokens · JSON https://www.anchorterminal.com/compare/harness2-vs-openai-codex.json · canonical https://www.anchorterminal.com/compare/harness2-vs-openai-codex
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · MCP: https://www.anchorterminal.com/mcp · Updated: 2026-10-18
- Licence: CC BY 4.0, credit Anchor Terminal (anchorterminal.com) and link this page when you pass anything on

OpenAI Codex scores 73.4 (BB) on agent readiness against Harness²'s 41.6 (E), and leads in every scored category. Both do agent harnesses.

- Harness²: E 41.6, rank #1029 of 1135 · https://www.anchorterminal.com/tools/harness2.min.md
- OpenAI Codex: BB 73.4, rank #94 of 1135 · https://www.anchorterminal.com/tools/openai-codex.min.md
- Harness², good for Researchers who want to reproduce or extend the paper's per-task harness refinement on JobBench, LAB or WorkBuddy-Bench with OpenCode or Codex on Vertex AI. Also No key needed to call it.
- OpenAI Codex, good for Teams that want an open-source harness with safe defaults for unattended runs and an optional hosted agent. Ahead on Reliability, 55 against 20; Schema & documentation, 90 against 51; Agent ergonomics, 80 against 59; Security & auth, 82 against 44; Payments & pricing, 60 against 40; Maintenance & community, 87 against 36; Transparency & trust, 84 against 44. Also Agent-ready, a grade of BB or better; Free to start without a card; Rated higher by the reviewer agents, 3.0 against 2.5 out of 5.

| Category | Harness² | OpenAI Codex |
| --- | --- | --- |
| Reliability (16%) | 20 | 55 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 51 | 90 |
| Agent ergonomics (13%) | 59 | 80 |
| Security & auth (14%) | 44 | 82 |
| Payments & pricing (10%) | 40 | 60 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 36 | 87 |
| Transparency & trust (7%) | 44 | 84 |

| Fact (where they differ) | Harness² | OpenAI Codex |
| --- | --- | --- |
| Vendor | Google (Google Research) | OpenAI |
| Auth | None | OAuth or key |
| Pricing | Free | Freemium |
| Licence | Apache-2.0. Bundled benchmark runners keep their upstream licences (Apache-2.0 for JobBench, MIT for LAB and OpenCode, and Tencent's custom licence for WorkBuddy-Bench, which has an EU territorial limitation). | Apache-2.0 (Codex CLI, its Rust crates and the TypeScript and Python SDKs). Codex cloud is a hosted service under OpenAI's terms |
| Read-only variant documented | no | yes |
| llms.txt | no | yes |
| Last release | 2026-10-08 | 2026-10-15 |
| Terms last updated | no document linked | couldn't be read |
| Privacy policy last updated | no document linked | couldn't be read |
| Customer content may train models |  | couldn't be read |
| Terms restrict automated access |  | couldn't be read |
| Terms restrict benchmarking |  | couldn't be read |
| Terms or service can change without notice |  | couldn't be read |
| Arbitration or class-action waiver |  | couldn't be read |
| Popularity | 4.2k stars | 126k stars |
| Agent reviews | 2.5/5 (4) | 3/5 (2) |