Compare
Claude.ai (web app) vs Codex CLI
Side-by-side comparison of Claude.ai (web app) and Codex CLI for SKILL.md agent skills — install model, shell access, native support, skill count and best use cases.
Comparison
At a glance
| Dimension | Claude.ai | Codex |
|---|---|---|
| Vendor | Anthropic | OpenAI |
| Native SKILL.md support | Yes | Yes |
| Verified skills indexed | 32 | 45 |
| Install model | Upload via Settings | Local folder |
| Shell / Bash access | Sandboxed | Yes |
| Tagline | The Claude web app. Upload skills as zips via Settings → Features. Pro/Max/Team/Enterprise. | OpenAI's coding agent CLI. Adopted the SKILL.md spec verbatim in Dec 2025. |
Both
5
Skills verified to work on both Claude.ai and Codex.
Only Claude.ai
27
Indexed for Claude.ai (web app) but not yet verified on Codex CLI.
Only Codex
40
Indexed for Codex CLI but not yet verified on Claude.ai (web app).
Verdict
Which should you pick?
Both support SKILL.md natively, so the choice is about ecosystem fit. Pick Claude.ai (web app) for Anthropic integrations and the workflows it makes easiest; pick Codex CLI for OpenAI 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 Claude.ai (web app) · Skills for Codex CLI.
FAQ
Common questions
Which is better for SKILL.md skills, Claude.ai (web app) or Codex CLI?
Both support SKILL.md natively. Claude.ai (web app) has 32 verified skills indexed here; Codex CLI has 45. 5 skills work on both.
Can I use the same Skill on Claude.ai (web app) and Codex CLI?
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 Claude.ai (web app)?
Settings → Features → Skills. Upload the Skill folder as a ZIP. The Skill becomes available in all your Claude.ai conversations.
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.
Which agent should I pick for cross-platform skill use?
Both support skills natively. Pick by ecosystem fit: Claude.ai (web app) for Anthropic customers, Codex CLI for OpenAI customers.
More comparisons