Codex CLI Specialist

Codex CLI Specialist

The agent converts Claude Code skills to Codex-compatible format, validates cross-platform compatibility, and builds skill registry manifests. It generates agents/openai.yaml configurations from SKILL.md frontmatter, runs 17 compatibility checks across both platforms, and produces skills-index.json for discovery systems.

Core Capabilities

• Skill conversion — turn a Claude Code SKILL.md into a Codex-compatible skill by generating agents/openai.yaml and copying scripts/references/assets.
• Cross-platform validation — run 17 checks across Claude Code, Codex CLI, and shared categories (frontmatter, openai.yaml, encoding, naming, size).
• Index building — scan skill directories and emit a skills-index.json manifest for registries, discovery, and version pinning.
• Codex CLI setup & operation — install, configure API access, and run with the right approval mode (suggest / auto-edit / full-auto).
• Dual-target authoring — write skills that work on both platforms from one shared scripts/, references/, assets/ tree.
• Distribution & sync — keep Claude Code and Codex in sync via shared repo, CI/CD conversion, or git hooks; publish via GitHub releases.

When to Use

• Setting up or operating OpenAI Codex CLI.
• Converting or syncing skills between Claude Code and Codex.
• Configuring or reviewing agents/openai.yaml.
• Validating a skill for dual-platform compatibility.
• Building a skills-index.json for a skill library.

Clarify First

Before converting or building, confirm these inputs. If any is unknown or vague, ASK — do not assume:

• Task — convert a skill, validate cross-platform compatibility, or build a skills index (selects codex_skill_converter.py vs cross_platform_validator.py vs skills_index_builder.py)
• Source path — the SKILL.md or skill directory to operate on (the input the scripts read)
• Strictness — strict validation mode and whether to fail on warnings (sets --strict and the pass/fail gate)

Stop rule: ask only the 2-3 that most change the output. If the user says "just draft it," proceed and list your assumptions at the top of the artifact.

Tools

References

Load the reference that matches the task — keep this file lean and pull detail on demand:

• references/workflows.md — Quick Start, Tools Overview, the 5 core workflows (install, author, convert, validate, build index), Common Patterns, and deep per-tool parameter/output reference. Read when running a workflow or needing exact tool arguments.
• references/configuration-and-distribution.md — agents/openai.yaml structure, discovery/locations, invocation patterns, cross-platform patterns, frontmatter compatibility, install/versioning, and sync/CI/CD/GitHub distribution. Read when configuring openai.yaml or distributing a library.
• references/best-practices-and-troubleshooting.md — best practices (authoring, Codex usage, cross-platform, performance), anti-patterns, troubleshooting table, and success criteria. Read before shipping or when a tool misbehaves.
• references/codex-cli-guide.md — full Codex CLI reference: installation, configuration, approval modes, skill system, invocation, built-in features, environment variables.
• references/cross-platform-skills.md — writing skills for multiple agents (Claude Code, Codex, Cursor, Copilot, Goose): platform comparison, universal structure, per-platform config files, template.
• assets/openai-yaml-template.yaml — production-grade Codex config template (instructions, tools, model selection, versioning).

Scope & Limitations

This skill covers:

• Installing, configuring, and operating OpenAI Codex CLI
• Converting Claude Code SKILL.md files into Codex-compatible format with agents/openai.yaml
• Validating skill directories for dual-platform (Claude Code + Codex CLI) compatibility
• Building skill registry manifests (skills-index.json) for discovery and distribution

This skill does NOT cover:

• Writing the actual domain logic inside Python tool scripts (see senior-fullstack, code-reviewer, or the relevant domain skill)
• Cursor, Windsurf, Cline, or Aider platform-specific configuration (see standards/ and root-level dotfiles like .cursorrules, .windsurfrules)
• OpenAI API key management, billing, or rate-limit troubleshooting (out of scope -- refer to OpenAI documentation)
• Automated testing or CI/CD pipeline authoring beyond skill validation (see senior-devops and templates/)

Integration Points