Compare
Codex CLI vs Claude.ai (web app)
Side-by-side comparison of Codex CLI and Claude.ai (web app) for SKILL.md agent skills — install model, shell access, native support, skill count and best use cases.
Comparison
At a glance
| Dimension | Codex | Claude.ai |
|---|---|---|
| Vendor | OpenAI | Anthropic |
| Native SKILL.md support | Yes | Yes |
| Verified skills indexed | 45 | 32 |
| Install model | Local folder | Upload via Settings |
| Shell / Bash access | Yes | Sandboxed |
| Tagline | OpenAI's coding agent CLI. Adopted the SKILL.md spec verbatim in Dec 2025. | The Claude web app. Upload skills as zips via Settings → Features. Pro/Max/Team/Enterprise. |
Both
5
Skills verified to work on both Codex and Claude.ai.
Only Codex
40
Indexed for Codex CLI but not yet verified on Claude.ai (web app).
Only Claude.ai
27
Indexed for Claude.ai (web app) but not yet verified on Codex CLI.
Verdict
Which should you pick?
Both support SKILL.md natively, so the choice is about ecosystem fit. Pick Codex CLI for OpenAI integrations and the workflows it makes easiest; pick Claude.ai (web app) for Anthropic integrations and its specific surface.
Many teams use both — Skills with the SKILL.md spec are portable, and 5 of the skills indexed here are verified on both agents. Browse the per-agent rankings to see which Skills lead on each platform: Skills for Codex CLI · Skills for Claude.ai (web app).
FAQ
Common questions
Which is better for SKILL.md skills, Codex CLI or Claude.ai (web app)?
Both support SKILL.md natively. Codex CLI has 45 verified skills indexed here; Claude.ai (web app) has 32. 5 skills work on both.
Can I use the same Skill on Codex CLI and Claude.ai (web app)?
5 of the skills indexed here work on both. The SKILL.md spec is shared, so most skills run cleanly on both — the exceptions are skills that depend on agent-specific tools (Bash, Workflows, MCP patterns).
How do I install a Skill on Codex CLI?
Drop the Skill folder under `~/.codex/skills/` for user-wide or `.codex/skills/` for project-scoped. Codex loads SKILL.md the same way Claude Code does.
How do I install a Skill on Claude.ai (web app)?
Settings → Features → Skills. Upload the Skill folder as a ZIP. The Skill becomes available in all your Claude.ai conversations.
Which agent should I pick for cross-platform skill use?
Both support skills natively. Pick by ecosystem fit: Codex CLI for OpenAI customers, Claude.ai (web app) for Anthropic customers.
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