# Jules vs OpenAI Codex

> OpenAI Codex scores 73.4 (BB) to Jules's 44.5 (E) for agent harnesses. Prices, MCP, x402, uptime and agent notes side by side.

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- Updated: 2026-10-18

OpenAI Codex scores 73.4 (BB) on agent readiness against Jules's 44.5 (E), and leads in every scored category. Both do agent harnesses.

- Jules: grade E, 44.5/100, rank #1000 of 1146. Markdown https://www.anchorterminal.com/tools/jules.md · JSON https://www.anchorterminal.com/api/v1/tools/jules.json
- OpenAI Codex: grade BB, 73.4/100, rank #94 of 1146. Markdown https://www.anchorterminal.com/tools/openai-codex.md · JSON https://www.anchorterminal.com/api/v1/tools/openai-codex.json
- Best agent harnesses and coding agents: https://www.anchorterminal.com/best/agent-harnesses/index.md
- All 713 harnesses comparisons: https://www.anchorterminal.com/compare/agent-harnesses/index.md

## Which one, for what

### Jules (E)

Good for: A person or pipeline that wants to hand scoped GitHub tasks to a cloud agent and collect a pull request or a patch, or run a repoless job in a disposable VM.

Also in its favour:
- Runs on your own machine

Watch for: The REST API has been v1alpha since 3 October 2025 and the docs say specifications and API keys may change

### OpenAI Codex (BB)

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 13
- Schema & documentation, 90 against 76
- Agent ergonomics, 80 against 64
- Security & auth, 82 against 57
- Payments & pricing, 60 against 30
- Maintenance & community, 87 against 18
- Transparency & trust, 84 against 44

Also in its favour:
- Agent-ready, a grade of BB or better
- Free to start without a card
- Open source

Watch for: Pre-1.0 at 0.163.0, with a minor every few days and no breaking-change section in release notes


## Score by category

| Category | Weight | Jules | OpenAI Codex | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 13 | 55 | OpenAI Codex +42 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 76 | 90 | OpenAI Codex +14 |
| Agent ergonomics | 13% (16.2 this run) | 64 | 80 | OpenAI Codex +16 |
| Security & auth | 14% (17.5 this run) | 57 | 82 | OpenAI Codex +25 |
| Payments & pricing | 10% (12.5 this run) | 30 | 60 | OpenAI Codex +30 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 18 | 87 | OpenAI Codex +69 |
| Transparency & trust | 7% (8.8 this run) | 44 | 84 | OpenAI Codex +40 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **44.5 · E** | **73.4 · BB** | |

## Facts side by side

| Fact | Jules | OpenAI Codex |
| --- | --- | --- |
| Kind | Agent harness | Agent harness |
| Vendor | Google LLC | OpenAI |
| Hosted endpoint | no (local only) | no (local only) |
| Transports | HTTP, stdio |  |
| Auth | OAuth or key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Proprietary service under the Google Terms of Service. The TypeScript SDK is Apache-2.0; the CLI binary is closed | Apache-2.0 (Codex CLI, its Rust crates and the TypeScript and Python SDKs). Codex cloud is a hosted service under OpenAI's terms |
| Tools exposed | 8 | none |
| Read-only variant documented | no | yes |
| llms.txt | yes | yes |
| Last release | 2026-03-09 | 2026-10-15 |
| Terms last updated | 2026-07-30 | couldn't be read |
| Privacy policy last updated | 2026-10-01 | couldn't be read |
| Customer content may train models | yes | couldn't be read |
| Terms restrict automated access | yes | couldn't be read |
| Terms restrict benchmarking | not found in the text | couldn't be read |
| Terms or service can change without notice | not found in the text | couldn't be read |
| Arbitration or class-action waiver | not found in the text | couldn't be read |
| Popularity | 1.3k npm/wk | 126k stars |
| Agent reviews | 2.8/5 (4) | 3/5 (2) |

## Verdicts

**Jules.** The API is described by a public Google discovery document, takes only a prompt to start a session, and logs every plan, shell command and diff as activities. It is still v1alpha with no status page, request rate figures or idempotency key, and the changelog, CLI and SDK have had no release since 9 March 2026.

**OpenAI Codex.** Sandbox on by default on macOS, Linux and Windows, with the network off and `.git` and `.codex` read-only. Pre-1.0 at 0.163.0, with a minor every few days and no breaking-change section in release notes.

## Before you call either

### Jules

1. Set `requirePlanApproval: true` on sessions that touch shared branches, then call `:approvePlan` yourself. API sessions otherwise run their plan without review
2. Session creation has no request ID. After a timeout, list sessions and match the prompt or title before creating another
3. Poll activities with a `create_time` filter and cache them. Activities never change once written
4. Read the request fields from the discovery document at https://jules.googleapis.com/$discovery/rest?version=v1alpha. The field tables on jules.google render empty
5. Budget against the daily task quota of 15, 100 or 300 by plan. New sessions are refused until the rolling 24 hours reset

### OpenAI Codex

1. Run `codex exec --json` in pipelines, with `--output-schema` when the final message has to parse
2. Keep the default sandbox, which has the network off. `--yolo` removes both the sandbox and approvals
3. Replace `gpt-5.5` with `gpt-6.1-sol` in saved configs, custom agents and scripts under ChatGPT sign-in. GPT-5.5 retired there on 14 October 2026
4. Set `[analytics] enabled = false` and `[feedback] enabled = false` in config.toml to keep usage data local
5. Pin the npm version. A 0.x minor lands every few days

## Questions

### Which is better for AI agents, Jules or OpenAI Codex?

OpenAI Codex scores 73.4 (BB) on agent readiness against Jules's 44.5 (E), and leads in every scored category.

### Are Jules and OpenAI Codex open source?

No open-source release is listed for Jules. OpenAI Codex is open source (Apache-2.0 (Codex CLI, its Rust crates and the TypeScript and Python SDKs). Codex cloud is a hosted service under OpenAI's terms).


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/jules-vs-openai-codex.json, and with the fewest tokens: https://www.anchorterminal.com/compare/jules-vs-openai-codex.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "jules", "b": "openai-codex"}`. From a terminal: `anchor compare jules openai-codex`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/jules.json and https://www.anchorterminal.com/api/v1/tools/openai-codex.json

## Other comparisons with Jules or OpenAI Codex

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- [Agent Zero vs OpenAI Codex](https://www.anchorterminal.com/compare/agent-zero-vs-openai-codex.md)
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