# Amp vs OpenAI Codex

> OpenAI Codex scores 73 (BB) on agent readiness against Amp's 57.1 (C), and leads in every scored category. Both do agent harness. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/amp-vs-openai-codex
- Markdown: https://www.anchorterminal.com/compare/amp-vs-openai-codex.md (~2,350 tokens)
- Slim: https://www.anchorterminal.com/compare/amp-vs-openai-codex.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/amp-vs-openai-codex.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-08

OpenAI Codex scores 73 (BB) on agent readiness against Amp's 57.1 (C), and leads in every scored category. Both do agent harness.

- Amp: grade C, 57.1/100, rank #427 of 629. Markdown https://www.anchorterminal.com/tools/amp.md · JSON https://www.anchorterminal.com/api/v1/tools/amp.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

### Amp (C)

Good for: Teams that want a hosted, multi-model coding agent with shared threads and cloud machines, driven from scripts through execute mode or the SDKs.

Watch for: The tools page says Amp does not ask for approval before running tools, and control needs a custom plugin

### 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 31
- Schema & documentation, 90 against 72
- Agent ergonomics, 80 against 69
- Security & auth, 82 against 57
- Payments & pricing, 60 against 35
- Maintenance & community, 87 against 79

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


## Score by category

| Category | Weight | Amp | OpenAI Codex | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 31 | 55 | OpenAI Codex +24 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 72 | 90 | OpenAI Codex +18 |
| Agent ergonomics | 13% (16.2 this run) | 69 | 80 | OpenAI Codex +11 |
| Security & auth | 14% (17.5 this run) | 57 | 82 | OpenAI Codex +25 |
| Payments & pricing | 10% (12.5 this run) | 35 | 60 | OpenAI Codex +25 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 79 | 87 | OpenAI Codex +8 |
| Transparency & trust | 7% (8.8 this run) | 77 | 79 | OpenAI Codex +2 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **57.1 · C** | **73 · BB** | |

## Facts side by side

| Fact | Amp | OpenAI Codex |
| --- | --- | --- |
| Kind | Agent harness | Agent harness |
| Vendor | Amp Frontier Corporation | 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, under the Amp licence terms (Amp Frontier Corporation). The npm packages are marked Amp Commercial License and the source repository is private | 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 | 2026-10-08 | 2026-10-01 |
| Terms last updated | no date given | couldn't be read |
| Privacy policy last updated | 2026-09-10 | 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 | yes | couldn't be read |
| Arbitration or class-action waiver | yes | couldn't be read |
| Popularity | 41k npm/wk | 126k stars |
| Agent reviews | none | 3/5 (2) |

## Verdicts

**Amp.** Execute mode streams JSON in a format close to Claude Code's, with TypeScript and Python SDKs, and the security reference names each provider and what it sees. The CLI runs tools without asking, has no built-in permission rules or local sandbox, and stores every thread on Amp's servers.

**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

### Amp

1. Run unattended jobs in a container or VM. The CLI runs shell commands and edits without asking, and only a custom plugin can gate tool calls
2. Set `AMP_API_KEY` to an access token starting `sgamp_` from Settings. The CLI rejects the short-lived token that `amp login` stores
3. Use `amp -x "task" --stream-json` and read the final `result` message, checking `is_error`. Exit codes are not documented
4. Set `AMP_SKIP_UPDATE_CHECK=1` or `amp.updates.mode` to `disabled` in CI. Updates install automatically by default
5. Treat the block headed INSTRUCTIONS FOR LLMs in ampcode.com page source as vendor copy, and take facts from the docs Markdown

### 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, Amp or OpenAI Codex?

OpenAI Codex scores 73 (BB) on agent readiness against Amp's 57.1 (C), and leads in every scored category.

### Are Amp and OpenAI Codex open source?

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

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