# run-codegen

> Claude/Codex skill by [@zakariaf](https://omgskills.com/library/zakariaf/index.md) · 61 stars · Updated 2026-09-23

Runs the deterministic build\_runner codegen pass (drift\_dev, freezed, json\_serializable, riverpod\_generator) as one pinned command with --delete-conflicting-outputs, always before flutter analyze, never hand-editing or force-committing generated \*.g.dart / \*.freezed.dart / \*.drift.dart output, watch only in local dev. Use when regenerating codegen, fixing "missing part file" / "conflicting outputs" / undefined generated-class analyzer errors, after editing a drift table or DAO, a freezed value object, a riverpod Notifier or provider, or a json\_serializable model, or after a fresh git clone, branch switch, or pull.

Tags: agent-skills, ai-agents, best-practices, claude-code, codex, coding-agent, cursor, dart, dartlang, developer-tools, drift, flutter, flutter-architecture, github-copilot, go-router, llm, material-design, mvvm, riverpod, skills

## Install

```sh
git clone https://github.com/zakariaf/Flutter-Skills /tmp/Flutter-Skills && ln -s /tmp/Flutter-Skills/skills/run-codegen ~/.claude/skills/run-codegen
```

## From README

Run codegen (buildrunner) A deterministic, low-freedom runbook: regenerate all annotation-driven code in one pass, then analyze. Run the pinned command exactly as written — do not modify it, add flags, or hand-edit generated files. Applies whenever a source file carries a codegen annotation (@freezed, @JsonSerializable, @riverpod, @DriftDatabase, a drift table) and its .g.dart / .freezed.dart / .drift.dart part is missing or stale. Non-negotiable rules Run codegen BEFORE flutter analyze. A fresh clone, branch switch, or freshly edited annotated file has no generated part on disk. Analyzing that tree produces misleading "missing part file" and undefined-class errors that describe the missing output, not a real code defect — regenerate, then analyze. Use the pinned command verbatim, always with --delete-conflicting-outputs. Without it, buildrunner refuses to overwrite an output it did not write this run and fails with a wall of "conflicting outputs" text.

## Links

- HTML page: https://omgskills.com/library/zakariaf/flutter-skills/skills/run-codegen/
- GitHub: https://github.com/zakariaf/Flutter-Skills
- Author: [@zakariaf](https://omgskills.com/library/zakariaf/index.md)

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