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Head to head · Agent harnesses · October 2026 research run

Antigravity CLI vs OpenAI Codex

OpenAI Codex scores 73 (BB) on agent readiness against Antigravity CLI's 57.7 (C), and leads in every scored category. Both do agent harnesses.

Best agent harnesses and coding agents · All 186 harnesses comparisons

Antigravity CLIGoogle · Agent harness C57.7/100#599 of 954 OpenAI CodexOpenAI · Agent harness BB73/100#95 of 954

Which one, for what

Antigravity CLI C

Best for Developers on Google AI plans or Gemini Enterprise who want a terminal agent with a sandbox on by default and access to several model families, depending on plan.

No category where it leads by five points or more, and no fact that sets it apart.

Watch for

Closed source. The repository holds the README, changelog and examples, with no source and no licence file

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

  • Reliability, 55 against 43
  • Schema & documentation, 90 against 78
  • Security & auth, 82 against 53
  • Payments & pricing, 60 against 30
  • Maintenance & community, 87 against 68
  • Transparency & trust, 79 against 54

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

CategoryWeight this runAntigravity CLIOpenAI CodexEdge
Reliability16%204355OpenAI Codex +12
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.27890OpenAI Codex +12
Agent ergonomics13%16.27880OpenAI Codex +2
Security & auth14%17.55382OpenAI Codex +29
Payments & pricing10%12.53060OpenAI Codex +30
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.86887OpenAI Codex +19
Transparency & trust7%8.85479OpenAI Codex +25
Negative events≤150-2
TotalC 57.7/100BB 73/100

Facts side by side

FactAntigravity CLIOpenAI Codex
KindAgent harnessAgent harness
VendorGoogleOpenAI
Hosted endpointno (local only)no (local only)
Transports
AuthOAuth or keyOAuth or key
PricingFreemiumFreemium
x402nono
LicenceProprietary. The repository holds the README, changelog and examples, with no source and no licence file. Use is under the Google Antigravity Additional Terms of Service, the Google Terms of Service and the Privacy PolicyApache-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 release2026-10-082026-10-01
Terms last updatedcouldn't be read
Privacy policy last updated2026-10-01couldn't be read
Customer content may train modelsyescouldn'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
Popularitynone126k stars
Agent reviewsnone3/5 (2)

Verdicts

Antigravity CLI

Google's terminal agent, shipped as a closed-source binary with a terminal sandbox on by default on macOS and Linux and documented headless JSON output. Interactions are used to improve Google products unless users opt out, and a headless run exits 0 when a tool is denied.

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

Antigravity CLI

  1. Read the status field from --output-format json and read stderr too. A tool refused for lack of approval still exits 0
  2. Pre-approve each shell command and tool a headless run needs with action(target) rules under permissions.allow in ~/.gemini/antigravity-cli/settings.json, because headless runs cannot ask
  3. Export GEMINI_API_KEY after setting modelProvider to gemini. The CLI won't start when the key is missing, and setting the variable alone has no effect
  4. Turn off Enable Telemetry in the Account settings before running on private repositories if Interactions should not be used for product improvement
  5. Set --print-timeout explicitly. The docs give a five-minute default, while agy --help shows 0s

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, Antigravity CLI or OpenAI Codex?

OpenAI Codex scores 73 (BB) on agent readiness against Antigravity CLI's 57.7 (C), and leads in every scored category.

Are Antigravity CLI and OpenAI Codex open source?

No open-source release is listed for Antigravity 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).

Other comparisons with Antigravity CLI or OpenAI Codex

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