What it does. Migrate supported instruction files, skills, agents, and MCP config into Codex project and global files. Part of openai/skills (Skills Catalog for Codex) (openai/skills).

Install

• Codex: $skill-installer installs from this catalog ($migrate-to-codex invokes it); other agents: npx skills add openai/skills --skill migrate-to-codex.
• Raw file: curl -sL https://raw.githubusercontent.com/openai/skills/HEAD/skills/.curated/migrate-to-codex/SKILL.md

SKILL.md (verbatim)

name: migrate-to-codex
description: Migrate supported instruction files, skills, agents, and MCP config into Codex project and global files.

Migrate to Codex

Autonomy

Keep going until the selected migration is completely done: run the migrator, inspect the report, fix migrated Codex instructions/skills/agents/MCP config, and re-run checks without stopping to ask for confirmation of the next step. If the user has selected a target, do not ask before creating, editing, replacing, or deleting generated Codex artifacts in that target (AGENTS.md, .codex/, .agents/, or ~/.codex/). Preserve unrelated existing Codex config entries in .codex/config.toml or ~/.codex/config.toml, such as notify, projects, marketplaces, or unrelated MCP servers; do not ask about them unless they fail validation or directly conflict with the migration. Do not edit source Claude Code files (.claude/, ~/.claude/, .mcp.json, or .claude.json), unrelated project code, secrets, or another repository.

Migration Order

Run the migration in this order for each selected global or project source:

1. Start by using Codex's built-in TODO/task list tool. Do not create MIGRATION_TODOS.md or any TODO file unless the user explicitly asks. The TODO list input has a plan array whose items each have step and status; use statuses pending, in_progress, and completed. Make the TODOs specific to the selected artifacts. Before finishing, update the TODO list so every finished step is marked completed and no step remains in_progress. Use literal source → Codex target labels, for example:

   • Inspect .claude/commands → Codex skills/prompts
   • Inspect .claude/agents → .codex/agents
   • Inspect .mcp.json → .codex/config.toml MCP servers
   • Inspect .claude/settings.json hooks → .codex/hooks.json
   • Migrate safe selected artifacts → Codex files
   • Validate generated .codex/config.toml
   • Validate generated .codex/agents
   • Report migrated artifacts and manual-review items

2. Read references/differences.md (and refresh Codex docs if its Docs last checked date is old).

3. Scan and inspect before writing:

   • --scan-only lists active and inactive source surfaces.
   • --plan prints staged Codex artifact paths and report rows.
   • --doctor summarizes readiness, manual-review work, and validation risks.

4. Convert surfaces in the same order the CLI uses:

   • instructions: CLAUDE.md / AGENTS.md to AGENTS.md
   • plugins: report Claude plugin trees and marketplaces as manual migration work
   • hooks: rewrite supported Claude hooks into .codex/hooks.json and enable [features].codex_hooks = true
   • skills and commands: write Codex skills under .agents/skills/
   • config: write .codex/config.toml from Claude model/sandbox settings and MCP servers, including personality = "friendly" when config is generated
   • subagents: write Codex custom agents under .codex/agents/

5. Dry-run, then write the selected target. Use --replace only when orphan generated skills or agents should be deleted.

6. Inspect the terminal output and .codex/migrate-to-codex-report.txt after real runs.

7. Review generated artifacts in this order: AGENTS.md, .agents/skills/, .codex/config.toml, .codex/hooks.json, .codex/agents/, then report-only plugin items.

8. Run --validate-target against each target after edits.

9. Re-run checks and --dry-run after edits.

10. Return the final migration report as one markdown table per scope that has rows. The tables cover only the non-native follow-up migration work you performed, such as skills created from slash commands, subagents, MCP servers, hooks, unsupported/local plugin notes, and manual-review caveats. Include programmatic native import rows for config, instructions, skills, or supported plugins only if you personally migrated them in this follow-up run.

    If only one scope has rows, render only the table with no heading. If multiple scopes have rows, render one heading before each table. Use **User Config** for user-scope rows. For project-scope rows, use the actual project folder name as the heading, for example **northstar-support-portal**; do not use Current Project as the heading. Do not add prose before or after the table output.

    Use exactly these columns:

    northstar-support-portal

    Status	Item	Notes
    Added	Slash command pr-review	Converted into a Codex skill
    Added	Subagent release-lead	Added as a Codex subagent
    Check before using	Hook PreToolUse	Converted, but some Claude hook behavior differs in Codex
    Not Added	Hook Notification	Codex does not have an equivalent notification hook
    Not Added	Plugin team-macros	Plugin needs manual setup

    Status must be Added, Check before using, or Not Added. Use Added when a Codex-facing artifact was created or changed and needs no special review. Use Check before using when a Codex-facing artifact was created or changed but the migration changed semantics, inferred behavior, preserved tool rules as guidance, or dropped unsupported behavior. Use Not Added when a source artifact was detected but no Codex-facing artifact was created. Item combines the artifact type and concrete item name in one cell. Artifact type must be singular: Skill, Slash command, Subagent, MCP, Hook, or Plugin. Wrap the artifact type in inline code; write the item name as plain text after it. Notes is always required; never leave it empty. Keep notes short, plain, and literal. Avoid internal implementation terms such as runtime expansion. Prefer phrases like Converted into a Codex skill, Added as a Codex subagent, Added to Codex config, Converted into a Codex hook, Converted, but some Claude hook behavior differs in Codex, Codex does not have an equivalent notification hook, Plugin needs manual setup, or Plugin marketplace needs manual setup.

Self-Healing Loop

Keep looping until the selected migration is complete:

1. Run --plan or --doctor.
2. Run the migration with --dry-run.
3. Run the migration for real.
4. Fix every generated ## MANUAL MIGRATION REQUIRED block and every manual_fix_required or skipped report row that can be resolved inside Codex artifacts.
5. Run --validate-target.
6. Re-run the migrator and validator until the report and validator have no actionable generated-artifact fixes left.

Do not edit source Claude Code files, unrelated project code, secrets, or another repository during this loop. If a report row requires source-provider changes or product judgment, leave the generated Codex artifact with clear manual guidance instead of changing the source.

Commands

Choose the migrator command.

MIGRATE_TO_CODEX='python3 .codex/skills/migrate-to-codex/scripts/migrate-to-codex.py'

Inspect the migration before writing.

$MIGRATE_TO_CODEX --source ~/.claude/ --scan-only
$MIGRATE_TO_CODEX --source ~/.claude/ --target ~/.codex/ --plan
$MIGRATE_TO_CODEX --source ~/.claude/ --target ~/.codex/ --doctor

Dry-run, then run without --dry-run, for global and project.

$MIGRATE_TO_CODEX --source ~/.claude/ --target ~/.codex/ --dry-run
$MIGRATE_TO_CODEX --source ~/.claude/ --target ~/.codex/
$MIGRATE_TO_CODEX --source ./.claude/ --target ./.codex/ --dry-run
$MIGRATE_TO_CODEX --source ./.claude/ --target ./.codex/

Run the post-migration validator against each target after edits.

$MIGRATE_TO_CODEX --validate-target ~/.codex/
$MIGRATE_TO_CODEX --validate-target ./.codex/

Run $MIGRATE_TO_CODEX --help for flags (--scan-only, --plan, --doctor, --validate-target, defaults, and so on). Deep tables and more links are in references/differences.md.

Other files in this skill

• LICENSE.txt
• agents/openai.yaml
• references/differences.md
• scripts/cli.py
• scripts/migrate-to-codex.py
• scripts/migrate/init.py
• scripts/migrate/agents.py
• scripts/migrate/codex_config.py
• scripts/migrate/common.py
• scripts/migrate/hooks.py
• scripts/migrate/instructions.py
• scripts/migrate/mcps.py
• scripts/migrate/plugins.py
• scripts/migrate/settings.py
• scripts/migrate/skills.py
• scripts/utils/init.py
• scripts/utils/scan.py
• scripts/utils/util.py

references/differences.md (verbatim)

Migration Differences

Summary

This reference covers Claude Code to Codex migration only. It lists migration differences, partial mappings, and unsupported Claude Code behavior. Direct 1:1 mappings are intentionally omitted. When the converter preserves Claude-only semantics as prompt guidance, it also emits a manual_fix_required report row and writes a ## MANUAL MIGRATION REQUIRED block into the generated file.

Docs last checked: 2026-04-20. If today's date is later, re-open the official Codex docs below and the Claude Code docs map before trusting these mappings.

Instructions

Commands

Skills

MCP and config

Subagents

Plugin Marketplaces

Hooks

Planning and validation

Minimal examples

Source skill metadata becomes prompt guidance:

allowed-tools:
  - Read
  - Bash

## MANUAL MIGRATION REQUIRED

Claude `allowed-tools` was preserved as prompt guidance, not a Codex permission boundary.

You're allowed to use these tools:

- Read
- Bash

Source subagent metadata becomes TOML plus prompt guidance:

skills:
  - release-notes
tools:
  - Read
disallowedTools:
  - Bash

sandbox_mode = "workspace-write"
developer_instructions = """
## Skills
- $release-notes

## Tools
You're allowed to use these tools:
- Read

Don't use these tools:
- Bash
"""

Sources

• https://docs.claude.com/en/docs/claude-code/claude_code_docs_map
• https://developers.openai.com/codex/config-reference
• https://developers.openai.com/codex/mcp
• https://developers.openai.com/codex/plugins/
• https://developers.openai.com/codex/plugins/build/
• https://developers.openai.com/codex/skills
• https://developers.openai.com/codex/subagents
• https://developers.openai.com/codex/hooks
• https://code.claude.com/docs/en/skills
• https://code.claude.com/docs/en/sub-agents
• https://code.claude.com/docs/en/hooks
• https://code.claude.com/docs/en/hooks-guide
• https://code.claude.com/docs/en/mcp
• https://code.claude.com/docs/en/settings
• https://code.claude.com/docs/en/plugins
• https://code.claude.com/docs/en/plugin-marketplaces

Back to openai/skills (Skills Catalog for Codex) or Agent skills.