OpenAI Codex Plugin

The codex plugin integrates OpenAI Codex CLI (codex) and environments into a Repo Nexus Virtual Meta-Repo.

All AI assistants in Repo Nexus share AGENTS.md at the workspace root as the single universal source of truth for routing. When enabled, the codex plugin generates zero-logic User Skill pointers into .codex/skills/ (e.g. rnex-clone-sync/SKILL.md, rnex-batch-exec/SKILL.md, rnex-karpathy-llm-wiki-ingest/SKILL.md).

Operational skills, rules, and subagents remain cleanly encapsulated within .rnex/skills/ and active plugin directories (.rnex/plugins/<plugin-name>/).

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Capabilities

1. Zero-Logic User Skills (.codex/skills/rnex-*/SKILL.md):

   • Generates native SKILL.md bundles prefixed with rnex- in .codex/skills/ with YAML frontmatter for Codex skill discovery.
   • Contains zero inline heuristics—redirects Codex directly to the underlying agentic skill protocols inside .rnex/.

2. Native Instruction Support via CODEX.md & AGENTS.md:

   • OpenAI Codex natively looks for CODEX.md as its primary instruction file; it falls back to AGENTS.md when no CODEX.md exists in the project.
   • When enabled, the Codex plugin automatically synchronizes Repo Nexus routing instructions to CODEX.md (or merges them cleanly if you already have custom instructions).
   • Routing instructions in CODEX.md are permanently maintained across plugin state transitions (such as disabling the plugin), guaranteeing uninterrupted context routing without breaking assistant workflows.

3. Subagent & Skill Execution:

   • Core skills reside under .rnex/skills/.
   • Plugin skills reside under .rnex/plugins/<plugin>/skills/.
   • Subagents reside under .rnex/agents/ and .rnex/plugins/<plugin>/agents/ and are invoked as subagents without external mirroring.

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Enabling the Plugin

Via CLI

# Enable across the workspace in rnex.yaml
rnex plugin enable codex

# Enable locally in .local.rnex.yaml for your workstation only
rnex plugin enable --local codex

Or initialize a new workspace with Codex integration pre-configured:

rnex init --codex

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Configuration Options

Configure options under plugins.codex in rnex.yaml or .local.rnex.yaml:

plugins:
  codex:
    skills: true         # Generate user skills in .codex/skills/ (default: true)
    instructions: true   # Maintain routing instructions in CODEX.md (default: true)
    enabled: true        # Set to false to disable

Option	Type	Default	Description
skills	boolean	true	Generate user skill pointers in .codex/skills/rnex-*/SKILL.md.
instructions	boolean	true	Maintain routing directive in CODEX.md.
enabled	boolean	true	Enable or disable the plugin. Overridable in .local.rnex.yaml.

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Generated Directory Structure

When codex is enabled with functional plugins like karpathy-llm, it generates:

my-workspace/
├── AGENTS.md                          # Universal workspace instructions & routing
├── CODEX.md                           # Codex-specific instructions
├── .codex/
│   └── skills/                        # Zero-logic User Skill pointers
│       ├── rnex-clone-sync/
│       │   └── SKILL.md
│       ├── rnex-batch-exec/
│       │   └── SKILL.md
│       ├── rnex-workspace-status/
│       │   └── SKILL.md
│       ├── rnex-karpathy-llm-wiki-ingest/
│       │   └── SKILL.md
│       └── rnex-karpathy-llm-wiki-lint/
│           └── SKILL.md
├── .rnex/
│   ├── skills/                        # Core workspace agentic skills
│   └── plugins/
│       └── karpathy-llm/              # Scoped plugin skills and rules
└── rnex.yaml

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Disabling & Pruning

To disable the Codex plugin:

rnex plugin disable codex

Repo Nexus automatically performs surgical cleanup:

• Removes auto-generated user skills under .codex/skills/rnex-*.
• Preserves routing instructions in CODEX.md and AGENTS.md.
• Developer-created custom skills and rules under .codex/ are preserved.