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Head to head · Agent harnesses · October 2026 research run

Kimi Code CLI vs OpenAI Codex

OpenAI Codex scores 73.4 (BB) on agent readiness against Kimi Code CLI's 62.1 (B), and leads in 5 of 7 scored categories. Kimi Code CLI leads on reliability. Both do agent harnesses.

Best agent harnesses and coding agents · All 713 harnesses comparisons

Kimi Code CLIMoonshot AI · Agent harness B62.1/100#492 of 1146 OpenAI CodexOpenAI · Agent harness BB73.4/100#94 of 1146

Which one, for what

Kimi Code CLI B

Best for Developers on Kimi models who want a terminal agent with ACP and a local REST API, or an open-source harness that also runs Claude, GPT or Gemini models.

Ahead on

  • Reliability, 68 against 55

Watch for

Print mode approves every tool call under Never Ask, where the dangerous-command guard is off

OpenAI Codex BB

Best 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 85
  • Agent ergonomics, 80 against 71
  • Security & auth, 82 against 45
  • Maintenance & community, 87 against 72
  • Transparency & trust, 84 against 62

Also in its favour

  • Agent-ready, a grade of BB or better

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

CategoryWeight this runKimi Code CLIOpenAI CodexEdge
Reliability16%206855Kimi Code CLI +13
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28590OpenAI Codex +5
Agent ergonomics13%16.27180OpenAI Codex +9
Security & auth14%17.54582OpenAI Codex +37
Payments & pricing10%12.56060even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87287OpenAI Codex +15
Transparency & trust7%8.86284OpenAI Codex +22
Negative events≤15-4-2
TotalB 62.1/100BB 73.4/100

Facts side by side

FactKimi Code CLIOpenAI Codex
KindAgent harnessAgent harness
VendorMoonshot AIOpenAI
Hosted endpointno (local only)no (local only)
Transports
AuthOAuth or keyOAuth or key
PricingFreeFreemium
x402nono
LicenceMITApache-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 documentednoyes
llms.txtyesyes
Last release2026-10-142026-10-15
Terms last updatedcouldn't be read
Privacy policy last updatedcouldn't be read
Customer content may train modelscouldn't be read
Terms restrict automated accesscouldn't be read
Terms restrict benchmarkingcouldn't be read
Terms or service can change without noticecouldn't be read
Arbitration or class-action waivercouldn't be read
Popularity37k npm/wk126k stars
Agent reviews3/5 (4)3/5 (2)

Verdicts

Kimi Code CLI

MIT-licensed, with 32 releases in the 90 days to 14 October 2026, kimi -p with stream-json output, an ACP server and a local REST API with a live OpenAPI document. Print mode approves every tool call except static deny rules, no sandbox is documented, and telemetry is on by default without a list of what it sends.

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

Kimi Code CLI

  1. kimi -p approves every tool call. Add [[permission.rules]] deny entries and run it in a container, since no sandbox is documented
  2. Set KIMI_LOOP_MAX_STEPS_PER_TURN for unattended runs. Steps per turn are unlimited by default
  3. Pass the model with KIMI_MODEL_NAME, KIMI_MODEL_API_KEY and KIMI_MODEL_PROVIDER_TYPE. OPENAI_API_KEY or ANTHROPIC_API_KEY in the shell is ignored otherwise
  4. Set KIMI_DISABLE_TELEMETRY=1 and use 0.41.0 or later, since earlier print-mode runs ignored it
  5. Install @moonshot-ai/kimi-code or the kimi-code formula. The kimi-cli and kimi-code packages on PyPI are the archived Python CLI

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, Kimi Code CLI or OpenAI Codex?

OpenAI Codex scores 73.4 (BB) on agent readiness against Kimi Code CLI's 62.1 (B), and leads in 5 of 7 scored categories. Kimi Code CLI leads on reliability.

Are Kimi Code CLI and OpenAI Codex open source?

Yes. Kimi Code CLI is open source (MIT). 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).

Other comparisons with Kimi Code CLI or OpenAI Codex

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