# Backend Guidelines Index

> Backend, plugin, data-fix, and integration rules for the KCode Kingdee spec template.

---

## Platform Layers

| Platform | Directory | When to Read |
| --- | --- | --- |
| Cosmic / BOS Java | [cosmic-java/](./cosmic-java/index.md) | Cangqiong, Cosmic, Xinghan, Flagship, Java plugin, KSQL, BOS metadata |
| Enterprise C# / IronPython / OpenAPI | [enterprise/](./enterprise/index.md) | K/3 Cloud, Enterprise C# plugin, IronPython script plugin, OpenAPI integration |

---

## Shared First

Before implementing, read these when relevant:

| Topic | File |
| --- | --- |
| Project profile and platform routing | [../shared/project-context.md](../shared/project-context.md) |
| KCode skill routing | [../shared/kcode-skills.md](../shared/kcode-skills.md) |
| Metadata verification | [../shared/metadata-verification.md](../shared/metadata-verification.md) |
| Review gate | [../shared/review-checklist.md](../shared/review-checklist.md) |

---

## Routing Rule

If product family is uncertain or evidence conflicts, stop and ask before writing platform-specific code.