---

name: meta-unify-core description: Core configuration engine for meta-unify plugin. Parses user configuration requests, translates between Claude and Codex formats, and generates appropriate configuration files for both systems. Invoked by meta-unify commands to handle MCP servers, skills, hooks, rules, and instructions. user-invocable: false

Meta-Unify Core Skill

This skill provides the parsing, translation, and generation logic that powers the meta-unify plugin. It is not invoked directly by users but is called by meta-unify commands to perform configuration operations.

Core Capabilities

What This Skill Does

1. Parses Configuration Requests: Interprets natural language or structured requests for adding/modifying MCP servers, skills, hooks, rules, or instructions
2. Translates Between Formats: Converts configuration syntax between Claude Code and Codex formats
3. Generates Configuration Files: Creates or modifies the appropriate files for both systems
4. Validates Output: Ensures generated configurations are syntactically correct before writing

Configuration Types Handled

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File Location Mappings

Quick Reference Table

Notes on Scope Differences

• Codex MCP: Only supports user-scope configuration in config.toml
• Codex Hooks: Not supported; use rules for command-level control
• Codex Rules: Starlark-based files in ~/.codex/rules/ directory

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Format Translation Rules

MCP Servers

Claude (JSON) → Codex (TOML)

Copy// Claude (.mcp.json or ~/.claude.json)
{
  "mcpServers": {
    "server-name": {
      "command": "npx",
      "args": ["@package/server"],
      "env": { "KEY": "value" }
    }
  }
}

Copy# Codex (~/.codex/config.toml)
[mcp_servers.server-name]
command = "npx"
args = ["@package/server"]

[mcp_servers.server-name.env]
KEY = "value"

HTTP Transport

Copy// Claude
{
  "mcpServers": {
    "remote-server": {
      "url": "https://api.example.com/mcp"
    }
  }
}

Copy# Codex
[mcp_servers.remote-server]
url = "https://api.example.com/mcp"

Skills

Both systems use SKILL.md with YAML frontmatter. Key differences:

Translation: Claude-specific fields are omitted from Codex version silently.

Permissions / Rules

Claude (settings.json permissions)

Copy{
  "permissions": {
    "allow": ["Bash(npm run:*)"],
    "ask": ["Bash(git push:*)"],
    "deny": ["Bash(rm -rf:*)"]
  }
}

Codex (Starlark .rules file)

Copyprefix_rule(
    pattern = ["npm", "run"],
    decision = "allow",
)

prefix_rule(
    pattern = ["git", "push"],
    decision = "prompt",
)

prefix_rule(
    pattern = ["rm", "-rf"],
    decision = "forbidden",
)

Instructions

Claude (CLAUDE.md) and Codex (AGENTS.md) use the same markdown format.

Special sections:

• ## Claude Only → Only in CLAUDE.md
• ## Codex Only → Only in AGENTS.md

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Parsing Heuristics

Transport Type Detection

Skill Structure Suggestions

Environment Variable Patterns

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Validation Requirements

Before Writing Configuration

1. JSON Validation (Claude configs)

   • Valid JSON syntax
   • Required keys present
   • Correct structure

2. TOML Validation (Codex configs)

   • Valid TOML syntax
   • Required sections present

3. Starlark Validation (Codex rules)

   • Valid Python-like syntax
   • prefix_rule() calls are correct

4. Command Existence Check (STDIO MCP)

   • Verify command exists in PATH
   • Warn if not found

---

Error Handling

Partial Failure Protocol

When one system succeeds but the other fails:

1. Do NOT roll back the successful write
2. Report clearly which system succeeded and which failed
3. Show the error from the failed system
4. Ask user how to proceed:
   • Keep successful changes
   • Retry failed system
   • Abort and restore

Error Message Format

Copy[meta-unify] ERROR: Failed to write Codex config
  File: ~/.codex/config.toml
  Reason: Invalid TOML syntax - unclosed string at line 15
  Action: Please check the configuration and retry

---

Reference Documentation

For detailed format specifications, see:

• references/claude-formats.md - Complete Claude Code configuration schemas
• references/codex-formats.md - Complete Codex configuration schemas
• references/plugin-formats.md - Claude Code plugin structure and manifest formats

---

Integration Notes

Called By

• /meta-unify:add-mcp - Adding MCP servers
• /meta-unify:add-skill - Creating new skills
• /meta-unify:add-hook - Adding hooks (Claude only)
• /meta-unify:add-rule - Adding permission rules
• /meta-unify:add-plugin - Creating new Claude Code plugins
• /meta-unify:sync - Synchronizing configs between systems

Limitations

• Codex hooks are not supported; suggests rule-based alternatives
• Cannot migrate complex Starlark rules to Claude permissions automatically
• Does not validate MCP server functionality, only syntax