arcana-codex-plugins/plugins/staged-implementation

Staged Implementation

Staged Implementation is a Codex plugin that bundles four skills for chunked implementation work:

• planner plans scoped chunks, writes implementer prompts, reviews diffs, and clarifies frozen contracts.
• implementer executes one scoped implementation prompt without widening the task.
• validator verifies implemented behavior against the plan, prompt, checklist, review findings, or frozen contracts.
• orchestrator coordinates the planner, implementer, and validator loop across multiple chunks.

Use this plugin when a feature or fix is too large or contract-heavy to handle as one open-ended coding pass.

Plugin Structure

staged-implementation/
  .codex-plugin/
    plugin.json
  skills/
    planner/
      SKILL.md
    orchestrator/
      SKILL.md
    implementer/
      SKILL.md
    validator/
      SKILL.md

Recommended Marketplace Layout

Codex installs plugins from a marketplace catalog. To publish this from Git, put the plugin inside a marketplace repository:

codex-plugins/
  .agents/
    plugins/
      marketplace.json
  plugins/
    staged-implementation/
      .codex-plugin/
        plugin.json
      skills/
        planner/
        orchestrator/
        implementer/
        validator/

Example .agents/plugins/marketplace.json:

{
  "name": "my-codex-plugins",
  "interface": {
    "displayName": "My Codex Plugins"
  },
  "plugins": [
    {
      "name": "staged-implementation",
      "source": {
        "source": "local",
        "path": "./plugins/staged-implementation"
      },
      "policy": {
        "installation": "AVAILABLE",
        "authentication": "ON_INSTALL"
      },
      "category": "Productivity"
    }
  ]
}

Install From Git

Add the marketplace repository:

codex plugin marketplace add ssh://git@your-git-server/path/codex-plugins.git --ref main

Install the plugin:

codex plugin add staged-implementation@my-codex-plugins

Start a new Codex session after installation so the bundled skills are available.

Usage

Invoke a specific skill when you know the role you want:

Use $planner to write the next implementer prompt for this feature.
Use $implementer with docs/prompts/chunk-03.md.
Use $validator to verify this chunk against the frozen API contract.
Use $orchestrator to run the staged implementation loop for this checklist.

The usual flow is:

1. Use planner to freeze scope, contracts, validation, and the next chunk.
2. Use implementer to execute only that chunk.
3. Use validator when runtime, UI, API, integration, or regression evidence is needed.
4. Use orchestrator when you want Codex to coordinate the loop across chunks.

Notes

• The skills are intentionally separate. Keeping the roles separate makes the boundaries clearer and reduces accidental scope widening.
• validator reports evidence and risk. planner or orchestrator decides whether a chunk is accepted.
• orchestrator may commit accepted chunks only when the user explicitly authorizes commits.
• If the same skill names also exist as standalone local skills, Codex may show duplicates. After the plugin is installed and verified, remove or disable the standalone copies if you want only the plugin version.

Development

Validate the plugin manifest:

python3 /path/to/plugin-creator/scripts/validate_plugin.py /path/to/staged-implementation

Validate an individual skill:

python3 /path/to/skill-creator/scripts/quick_validate.py /path/to/staged-implementation/skills/planner

When updating an installed local plugin, bump or cache-bust the plugin version and reinstall it from the marketplace so Codex picks up the new files.