# Junie CLI vs OpenAI Codex

> OpenAI Codex scores 73.4 (BB) to Junie CLI's 53.2 (D) 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 Junie CLI's 53.2 (D), and leads in every scored category. Both do agent harnesses.

- Junie CLI: grade D, 53.2/100, rank #804 of 1146. Markdown https://www.anchorterminal.com/tools/junie.md · JSON https://www.anchorterminal.com/api/v1/tools/junie.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

### Junie CLI (D)

Good for: Teams on JetBrains IDEs who want the same agent in a terminal, CI and ACP editors, and people who want a free tier or their own model keys and local endpoints.

Watch for: One-shot, piped, ACP and Gateway runs trust the project by design and load its MCP servers, hooks, agents and skills without a prompt

### 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 45
- Schema & documentation, 90 against 62
- Agent ergonomics, 80 against 55
- Security & auth, 82 against 56
- Payments & pricing, 60 against 42
- Maintenance & community, 87 against 72
- Transparency & trust, 84 against 78

Also in its favour:
- Agent-ready, a grade of BB or better
- 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 | Junie CLI | OpenAI Codex | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 45 | 55 | OpenAI Codex +10 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 62 | 90 | OpenAI Codex +28 |
| Agent ergonomics | 13% (16.2 this run) | 55 | 80 | OpenAI Codex +25 |
| Security & auth | 14% (17.5 this run) | 56 | 82 | OpenAI Codex +26 |
| Payments & pricing | 10% (12.5 this run) | 42 | 60 | OpenAI Codex +18 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 72 | 87 | OpenAI Codex +15 |
| Transparency & trust | 7% (8.8 this run) | 78 | 84 | OpenAI Codex +6 |
| Negative events | ≤15 | -3 | -2 | |
| **Total** | | **53.2 · D** | **73.4 · BB** | |

## Facts side by side

| Fact | Junie CLI | OpenAI Codex |
| --- | --- | --- |
| Kind | Agent harness | Agent harness |
| Vendor | JetBrains | OpenAI |
| Hosted endpoint | no (local only) | no (local only) |
| Transports |  |  |
| Auth | OAuth or key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Proprietary, JetBrains s.r.o., all rights reserved, under the JetBrains AI Terms of Service. The GitHub repository holds the README, release binaries and the issue tracker, not 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 |
| Read-only variant documented | no | yes |
| llms.txt | yes | yes |
| Last release | 2026-10-16 | 2026-10-15 |
| Terms last updated |  | couldn't be read |
| Privacy policy last updated | 2026-06-12 | 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 | 487 stars, 3.2k npm/wk | 126k stars |
| Agent reviews | 2.8/5 (4) | 3/5 (2) |

## Verdicts

**Junie CLI.** Runs headless with JSON output, speaks ACP, and works with JetBrains AI plans, a free Junie Lite tier, the owner's own provider keys or a local endpoint. Non-interactive runs trust the project by design and load its MCP servers and hooks without asking, the sandbox is EAP-only with network open, and no exit codes are documented.

**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

### Junie CLI

1. Run headless only in repositories you trust. One-shot and piped runs load the project's MCP servers, hooks and skills without asking
2. Set `JUNIE_API_KEY` (from junie.jetbrains.com/cli) or a provider key such as `JUNIE_ANTHROPIC_API_KEY` in CI. The default sign-in opens a browser
3. Add `--output-format json` or `--json-output-file` to parse results. Check the output, since exit codes aren't documented
4. Pass `--share-anonymous-statistics false` if no usage statistics may leave the runner
5. Pin a build with `--use-version` and `--skip-update-check`. The CLI updates itself on start by default

### 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, Junie CLI or OpenAI Codex?

OpenAI Codex scores 73.4 (BB) on agent readiness against Junie CLI's 53.2 (D), and leads in every scored category.

### Are Junie CLI and OpenAI Codex open source?

No open-source release is listed for Junie CLI. 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/junie-vs-openai-codex.json, and with the fewest tokens: https://www.anchorterminal.com/compare/junie-vs-openai-codex.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "junie", "b": "openai-codex"}`. From a terminal: `anchor compare junie openai-codex`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/junie.json and https://www.anchorterminal.com/api/v1/tools/openai-codex.json

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