Open-source Codex plugin

GPT-5.6 Model Router

A skills-only Codex plugin that keeps the root task in charge while routing bounded work to Luna, Terra, and Sol agents at the effort level suited to the job.

What it does

Profiles each unit of work before selecting a pinned model, effort, and role.
Runs root-managed waves and an optional, capability-bounded leaf layer.
Raises execution and independent-review floors for consequential work.
Validates structured child events, budgets, scopes, dependencies, and completion.
Fails closed when the requested route cannot be enforced; it never silently substitutes a model.

Local by design

The plugin contains skills, Python scripts, JSON schemas, and managed custom-agent templates. It does not include an MCP server, hosted backend, connector, analytics service, or credential collection.

Setup can write managed agent templates under ~/.codex/agents and, only when explicitly requested, set agents.max_depth = 2 in ~/.codex/config.toml with backup and rollback safeguards.

Install and inspect

The source, release archive, MIT license, implementation notes, and verification suite are public on GitHub.

Last updated: July 19, 2026.