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Migrate To Codex

OpenAIOfficialPublished by OpenAI

  • Skill
  • Workflow
  • Automation and integrations
  • Apache-2.0
  • Low risk
  • Has scripts

From the author

Migrate supported instruction files, skills, agents, and MCP config into Codex project and global files.
— the description by OpenAI

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

The migrate-to-codex skill provides a structured, automated procedure to migrate existing Claude Code setups into the Codex ecosystem. It handles the conversion of instruction files, slash commands, skills, agents, and MCP server configurations. The tool follows a rigorous process involving scanning, planning, dry-running, and validating the migration to ensure artifacts are correctly mapped while preserving project-specific configurations. It includes a self-healing loop to resolve manual migration requirements and ensures that generated Codex artifacts are validated against target standards.

What it does

  • Converts Claude Code instruction files into Codex-compatible formats.
  • Migrates slash commands and skills into the Codex skill structure.
  • Updates MCP server configurations for use in Codex.
  • Generates a migration report detailing added items and manual review requirements.
  • Validates generated Codex artifacts to ensure configuration integrity.
  • Provides a dry-run mode to preview changes before applying them.

When to use it

  • When transitioning a development environment from Claude Code to Codex.
  • When you need to port custom skills or agents to a new Codex project.
  • When updating global or project-level configurations to align with Codex standards.
  • When you need to verify the readiness of existing Claude artifacts for Codex.

Advantages

  • Automates complex migration steps, reducing manual effort.
  • Provides clear reporting on what was successfully migrated and what requires manual attention.
  • Includes a self-healing loop to iteratively resolve migration issues.
  • Ensures project-specific configurations are preserved during the transition.
  • Validates targets post-migration to prevent configuration errors.

Usage examples

“Run a scan to see what Claude artifacts are available for migration.”
The tool lists active and inactive source surfaces from the specified Claude directory.
“Perform a dry-run migration of my project settings to Codex.”
The tool generates a plan and reports potential changes without modifying any files.
“Execute the full migration of my global Claude configuration to Codex.”
The tool migrates instructions, skills, and MCP configs, creating a report of the results.
“Validate the Codex target after my migration.”
The tool checks the generated Codex files for errors and reports any remaining manual fixes.

Install

  1. Download the skill as a ZIP:

    https://mp-staging.autogineer.com/agent-skills/openai/migrate-to-codex/download
  2. Unzip it into the cross-client skills folder of your project:

    mkdir -p .agents/skills && unzip migrate-to-codex.zip -d .agents/skills

Documentation by OpenAI

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

    StatusItemNotes
    AddedSlash command pr-reviewConverted into a Codex skill
    AddedSubagent release-leadAdded as a Codex subagent
    Check before usingHook PreToolUseConverted, but some Claude hook behavior differs in Codex
    Not AddedHook NotificationCodex does not have an equivalent notification hook
    Not AddedPlugin team-macrosPlugin 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.

Files

scripts/utils/util.py

from __future__ import annotations

import glob
import json
import re
from collections.abc import Mapping, Sequence
from dataclasses import dataclass
from pathlib import Path
from typing import TypeAlias


YamlScalar: TypeAlias = str | bool | int | float | None
YamlValue: TypeAlias = YamlScalar | Sequence[YamlScalar]
TomlScalar: TypeAlias = str | bool | int | float | None
TomlValue: TypeAlias = object


def detected_json_keys(content: str, keys: Sequence[str]) -> tuple[str, ...]:
    return tuple(key for key in keys if re.search(rf'"{re.escape(key)}"\s*:', content))


def strip_jsonc_comments(content: str) -> str:
    lines: list[str] = []
    for line in content.splitlines():
        in_string = False
        escaped = False
        result: list[str] = []
        index = 0
        while index < len(line):
            char = line[index]
            if escaped:
                result.append(char)
                escaped = False
                index += 1
                continue
            if char == "\\" and in_string:
                result.append(char)
                escaped = True
                index += 1
                continue
            if char == '"':
                in_string = not in_string
                result.append(char)
                index += 1
                continue
            if (
                not in_string
                and char == "/"
                and index + 1 < len(line)
                and line[index + 1] == "/"
            ):
                break
            result.append(char)
            index += 1
        lines.append("".join(result))
    return "\n".join(lines)


def load_jsonc_object(content: str, json_object: callable) -> Mapping[str, object]:
    without_comments = strip_jsonc_comments(content)
    without_trailing_commas = re.sub(r",\s*([}\]])", r"\1", without_comments)
    return json_object(json.loads(without_trailing_commas))


def parse_jsonc_mapping_text(text: str) -> Mapping[str, object] | None:
    """Return the top-level JSON object, or None if the text is not a JSON object."""
    try:
        without_comments = strip_jsonc_comments(text)
        without_trailing_commas = re.sub(r",\s*([}\]])", r"\1", without_comments)
        parsed = json.loads(without_trailing_commas)
    except (json.JSONDecodeError, TypeError, ValueError):
        return None
    if isinstance(parsed, Mapping):
        return parsed
    return None


@dataclass(frozen=True)
class JsonMappingFileRead:
    exists: bool
    ok: bool
    data: Mapping[str, object]


def read_json_mapping_file(path: Path) -> JsonMappingFileRead:
    """Read a JSON/JSONC file. ``ok`` is False when the file exists but could not be parsed."""
    if not path.is_file():
        return JsonMappingFileRead(exists=False, ok=True, data={})
    text = path.read_text()
    parsed = parse_jsonc_mapping_text(text)
    if parsed is None:
        return JsonMappingFileRead(exists=True, ok=False, data={})
    return JsonMappingFileRead(exists=True, ok=True, data=parsed)


@dataclass(frozen=True)
class TomlMultilineString:
    value: str


def parse_yaml_mapping(content: str) -> dict[str, YamlValue]:
    """Parse the small YAML-frontmatter subset used by Claude metadata."""
    result: dict[str, YamlValue] = {}
    current_key: str | None = None

    for raw_line in content.splitlines():
        if not raw_line.strip():
            continue

        if raw_line.startswith("  - ") and current_key:
            current_value = result.setdefault(current_key, [])
            if not isinstance(current_value, list):
                current_value = [current_value]
                result[current_key] = current_value
            current_value.append(parse_yaml_value(raw_line[4:].strip()))
            continue

        key, separator, value = raw_line.partition(":")
        if not separator:
            continue

        current_key = key.strip()
        value = value.strip()
        result[current_key] = parse_yaml_value(value) if value else []

    return result


def parse_yaml_value(value: str) -> YamlValue:
    if value in {"true", "True"}:
        return True
    if value in {"false", "False"}:
        return False
    if value in {"null", "Null", "~"}:
        return None
    if value.startswith("[") and value.endswith("]"):
        return tuple(
            parse_yaml_value(item)
            for item in split_delimited_values(value[1:-1])
            if item
        )
    if value.startswith('"') and value.endswith('"'):
        try:
            return json.loads(value)
        except json.JSONDecodeError:
            return value[1:-1]
    if value.startswith("'") and value.endswith("'"):
        return value[1:-1].replace("''", "'")
    return value


def split_delimited_values(content: str) -> tuple[str, ...]:
    values: list[str] = []
    token: list[str] = []
    quote: str | None = None
    escaped = False
    for char in content:
        if escaped:
            token.append(char)
            escaped = False
            continue
        if char == "\\" and quote == '"':
            token.append(char)
            escaped = True
            continue
        if quote:
            token.append(char)
            if char == quote:
                quote = None
            continue
        if char in {"'", '"'}:
            token.append(char)
            quote = char
            continue
        if char == ",":
            values.append("".join(token).strip())
            token = []
            continue
        token.append(char)
    values.append("".join(token).strip())
    return tuple(values)


def format_yaml_mapping(values: Mapping[str, YamlValue]) -> str:
    return "\n".join(
        f"{key}: {format_yaml_value(value)}" for key, value in values.items()
    )


def format_yaml_value(value: YamlValue) -> str:
    if isinstance(value, bool):
        return "true" if value else "false"
    if value is None:
        return "null"
    if isinstance(value, Sequence) and not isinstance(value, (str, bytes)):
        return "[" + ", ".join(format_yaml_value(item) for item in value) + "]"
    return json.dumps(str(value))


def render_toml_document(values: Mapping[str, TomlValue]) -> str:
    lines: list[str] = []
    append_toml_entries(lines, values)
    for key, value in values.items():
        if isinstance(value, Mapping):
            append_toml_table(lines, (key,), value)
    return "\n".join(lines).rstrip() + "\n"


def append_toml_table(
    lines: list[str],
    path: tuple[str, ...],
    values: Mapping[str, TomlValue],
) -> None:
    append_blank_line(lines)
    lines.append("[" + ".".join(format_toml_key(path_part) for path_part in path) + "]")
    append_toml_entries(lines, values)

    for key, value in values.items():
        if isinstance(value, Mapping):
            append_toml_table(lines, (*path, key), value)


def append_toml_entries(lines: list[str], values: Mapping[str, TomlValue]) -> None:
    for key, value in values.items():
        if isinstance(value, Mapping):
            continue
        lines.append(f"{format_toml_key(key)} = {format_toml_value(value)}")


def append_blank_line(lines: list[str]) -> None:
    if lines and lines[-1]:
        lines.append("")


def format_toml_key(key: str) -> str:
    if re.fullmatch(r"[A-Za-z0-9_-]+", key):
        return key
    return json.dumps(key)


def format_toml_value(value: TomlValue) -> str:
    if isinstance(value, TomlMultilineString):
        return format_toml_multiline_string(value.value)
    if isinstance(value, bool):
        return "true" if value else "false"
    if value is None:
        return '""'
    if isinstance(value, Sequence) and not isinstance(value, (str, bytes)):
        return "[" + ", ".join(format_toml_value(item) for item in value) + "]"
    return json.dumps(str(value))


def format_toml_multiline_string(value: str) -> str:
    escaped = value.replace("\\", "\\\\").replace('"""', '\\"\\"\\"')
    return f'"""{escaped}"""'


def slugify_name(value: str) -> str:
    result = re.sub(r"[^A-Za-z0-9_-]+", "-", value.strip()).strip("-").lower()
    return result or "migrated-command"


def first_markdown_heading(content: str) -> str | None:
    for line in content.splitlines():
        match = re.match(r"^#\s+(.+?)\s*$", line)
        if match:
            return match.group(1).strip()
    return None


def format_backtick_list(values: Sequence[str]) -> str:
    if not values:
        return ""
    if len(values) == 1:
        return f"`{values[0]}`"
    return ", ".join(f"`{value}`" for value in values[:-1]) + f", and `{values[-1]}`"


def normalize_source_scope_root(
    path: Path, source_scope_markers: Sequence[Path]
) -> Path:
    resolved = path
    for marker in source_scope_markers:
        if resolved.parts[-len(marker.parts) :] == marker.parts:
            return resolved.parents[len(marker.parts) - 1]
    return resolved


def resolve_source_root(source: str) -> Path:
    if not glob.has_magic(source):
        return Path(source)

    matches = [Path(match) for match in glob.glob(source, recursive=True)]
    if not matches:
        raise FileNotFoundError(f"No matches for source pattern: {source}")

    for match in matches:
        if (
            match.is_dir()
            and (match / "global").exists()
            and (match / "project").exists()
        ):
            return match

    static_prefix = source.split("*", 1)[0].rstrip("/")
    return Path(static_prefix)

Requirements and compatibility

Written for: OpenAI Codex

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Needs: Needs an MCP server, Needs Python

Security

What our scanner noticed· Low risk

  • Scripts that your agent may run

This skill includes scripts that your agent may run. Read them before you use it.

A static scan is not a guarantee. Skills are third-party content: review a skill before you let an agent use it.

Attribution and licence

Published by
OpenAI
Publisher
OpenAI (Official)
Source
openai/skills · skills/.curated/migrate-to-codex · commit 49f948f
Licence
Apache License 2.0 (redistribution allowed)
  • ATTRIBUTION.md (written by AutoGineer)
Synced

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Download ZIP

The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download migrate-to-codex.zip