# Kiro CLI vs OpenAI Codex

> OpenAI Codex scores 73 (BB) on agent readiness against Kiro CLI's 59.9 (C), and leads in 6 of 7 scored categories. Both do agent harness. Category scores, facts, verdicts and agent notes side by side.

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- Updated: 2026-10-08

OpenAI Codex scores 73 (BB) on agent readiness against Kiro CLI's 59.9 (C), and leads in 6 of 7 scored categories. Both do agent harness.

- Kiro CLI: grade C, 59.9/100, rank #370 of 629. Markdown https://www.anchorterminal.com/tools/kiro-cli.md · JSON https://www.anchorterminal.com/api/v1/tools/kiro-cli.json
- OpenAI Codex: grade BB, 73/100, rank #78 of 629. Markdown https://www.anchorterminal.com/tools/openai-codex.md · JSON https://www.anchorterminal.com/api/v1/tools/openai-codex.json

## Which one, for what

### Kiro CLI (C)

Good for: Teams on AWS that want one agent configuration across terminal, IDE and web, with central permission policy, prompt logging to their own S3 bucket and IAM Identity Centre sign-in.

Watch for: Free and individual paid accounts have content used for service improvement, including model training, unless they opt out

### 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:
- Schema & documentation, 90 against 79
- Agent ergonomics, 80 against 67
- Security & auth, 82 against 66
- Payments & pricing, 60 against 40
- Maintenance & community, 87 against 73
- Transparency & trust, 79 against 67

Also in its favour:
- Agent-ready, a grade of BB or better
- Open source

Watch for: Pre-1.0 at 0.160.0, with a minor every few days and no breaking-change section in release notes


## Score by category

| Category | Weight | Kiro CLI | OpenAI Codex | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 57 | 55 | Kiro CLI +2 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 79 | 90 | OpenAI Codex +11 |
| Agent ergonomics | 13% (16.2 this run) | 67 | 80 | OpenAI Codex +13 |
| Security & auth | 14% (17.5 this run) | 66 | 82 | OpenAI Codex +16 |
| Payments & pricing | 10% (12.5 this run) | 40 | 60 | OpenAI Codex +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 73 | 87 | OpenAI Codex +14 |
| Transparency & trust | 7% (8.8 this run) | 67 | 79 | OpenAI Codex +12 |
| Negative events | ≤15 | -4 | -2 | |
| **Total** | | **59.9 · C** | **73 · BB** | |

## Facts side by side

| Fact | Kiro CLI | OpenAI Codex |
| --- | --- | --- |
| Kind | Agent harness | Agent harness |
| Vendor | Amazon Web Services | 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. Licensed as AWS Content under the AWS Customer Agreement and the AWS Intellectual Property Licence (https://kiro.dev/license/). The GitHub repository is the public issue tracker and doesn't hold the 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 | 2026-10-05 | 2026-10-01 |
| Terms last updated | 2026-08-14 | couldn't be read |
| Privacy policy last updated | 2026-05-18 | couldn't be read |
| Customer content may train models | not found in the text | couldn't be read |
| Terms restrict automated access | not found in the text | 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 | yes | couldn't be read |
| Popularity | 4.4k stars | 126k stars |
| Agent reviews | none | 3/5 (2) |

## Verdicts

**Kiro CLI.** Permission rules follow deny over ask over allow, cloned repositories can't add rules, and a headless session treats every ask as a deny. Content from Free and individual paid accounts is used for service improvement, including model training, unless the user opts out, and API keys for pipelines need a paid plan.

**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 0.160.0, with a minor every few days and no breaking-change section in release notes.

## Before you call either

### Kiro CLI

1. Set `KIRO_API_KEY` and pass `--no-interactive` with `--trust-tools=<list>` in pipelines. Keep `--trust-all-tools` for disposable environments
2. Pass `--require-mcp-startup` when a run depends on MCP tools. Without it a failed server is logged and the run continues
3. Pass `--no-interactive` whenever input is piped from a source you don't control, and run 2.10.0 or later on Windows
4. Run `kiro-cli settings telemetry.enabled false` and turn off content collection on Free and individual plans. Both are on by default
5. Export variables in the shell before starting. Since 2.24.0 a project `.env` file is no longer loaded into sessions, MCP servers or tools

### OpenAI Codex

1. Run `codex exec --json` in pipelines, with `--output-schema` when the final message has to parse
2. Keep the default sandbox. `--yolo` removes both the sandbox and approvals
3. Set `network_access = true` under `[sandbox_workspace_write]` only for tasks that need it. Network is off by default
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, Kiro CLI or OpenAI Codex?

OpenAI Codex scores 73 (BB) on agent readiness against Kiro CLI's 59.9 (C), and leads in 6 of 7 scored categories.

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

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

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