---
title: Codex CLI vs Claude API
slug: codex-vs-claude-api
type: agent-comparison
a: codex
b: claude-api
canonical: https://top-agent-skills.com/compare/codex-vs-claude-api
rubric: 1.0
---

# Codex CLI vs Claude API

Side-by-side for SKILL.md agent Skills: install model, shell access, native support, and how many Skills are verified on each.

## At a glance

| | Codex | Claude API |
| --- | --- | --- |
| Vendor | OpenAI | Anthropic |
| Native SKILL.md support | Yes | Yes |
| Verified skills indexed | 55 | 13 |
| Install model | Local folder | POST /v1/skills |
| Shell / Bash access | Yes | Sandboxed |
| Tagline | OpenAI's coding agent CLI. Adopted the SKILL.md spec verbatim in Dec 2025. | Claude API + Skills SDK. Pre-built skill_id values plus custom uploads via /v1/skills. |

## Overlap

- Verified on both: 9
- Only Codex: 46
- Only Claude API: 4

## 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 API for Anthropic integrations and its specific surface.

Many teams use both — Skills with the SKILL.md spec are portable, and 9 of the skills indexed here are verified on both agents.

Per-agent rankings: https://top-agent-skills.com/skills-for-codex · https://top-agent-skills.com/skills-for-claude-api

## Common questions

**Which is better for SKILL.md skills, Codex CLI or Claude API?**

Both support SKILL.md natively. Codex CLI has 55 verified skills indexed here; Claude API has 13. 9 skills work on both.

**Can I use the same Skill on Codex CLI and Claude API?**

9 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 API?**

POST your Skill zip to /v1/skills. You receive a skill_id. Reference it in your messages request — the model loads the Skill on demand.

**Which agent should I pick for cross-platform skill use?**

Both support skills natively. Pick by ecosystem fit: Codex CLI for OpenAI customers, Claude API for Anthropic customers.

---

_Top Agent Skills. Machine-readable twin of https://top-agent-skills.com/compare/codex-vs-claude-api._