# 38 — Codex-native build workflow

## Goal

Use current Codex capabilities to make the implementation faster and more reliable without coupling DevRunbook's product architecture to a transient Codex UI feature.

## Persistent repository guidance

Codex discovers `AGENTS.md` and `AGENTS.override.md` in layers from global scope through the project path. The implementation repository therefore keeps durable rules in root and, where necessary, directory-specific guidance. One-time milestone instructions remain in the implementation plan rather than being copied into persistent agent guidance.

## Skills and plugins

Skills are the reusable workflow format for Codex and ChatGPT. A skill can contain instructions, resources and reviewed scripts. Plugins distribute skills and connectors. DevRunbook's eventual Skill export should follow the current open agent skills format and may declare MCP dependencies in plugin metadata. This remains an export adapter, not the canonical internal playbook representation.

For building DevRunbook itself, Codex may use installed skills for browser verification, security review, documentation or deployment when they do not weaken repository gates. The build must remain reproducible without a private skill that is absent from the repository.

## MCP and connected tools

MCP servers expose tools, resources and reusable prompts. They are useful for official documentation, Gitea test instances, browser tooling or deployment inspection. Tool output is untrusted external evidence. A connected tool never grants authority to disclose secrets, modify production resources or bypass the approval boundary.

## Subagents

Subagents are appropriate for specialized, bounded tasks. `CODEX_EXECUTION_PROTOCOL.md` defines ownership, file boundaries and integration. The lead agent remains accountable for contract consistency and release evidence.

## Worktrees and handoff

Codex-managed worktrees allow independent tasks in one project. Use them for low-overlap slices and preserve the base commit plus task ownership. Handoff between local and worktree execution does not change the requirement to reconcile state and re-run gates.

## Browser, computer use and visual review

The Codex app can provide browser and computer-use workflows. For this web product, a browser review is mandatory at UI milestone exits. Codex should prefer browser interactions against localhost, backed by Playwright assertions, and record representative screenshots or traces.

## Automations

Automations are useful after the repository is operational for recurring tasks such as dependency review, documentation drift checks or nightly fixture validation. They are not the primary mechanism for the initial build. A scheduled run must never silently publish, migrate production data or change Gitea settings.

## Web search

Current Codex surfaces can use cached or live web search. Live research is appropriate during Milestone 0 for version selection and during integration work for current official API behavior. Record material sources and do not treat search snippets as authoritative over primary documentation.

## Compatibility rule

The build pack never requires one specific Codex surface. The same repository contract must remain usable from the Codex app, CLI and IDE extension. Surface-specific conveniences may accelerate the build but cannot become an undeclared production dependency.