# AGENTS.md

This is the only authoritative agent entry for this repository.
If another `AGENTS.md` file says something different, follow this file.

## Canonical numbering

- `1 = 内酯羰基碳`
- `2 = 相邻酯氧`
- `3..N = 从 2 位出发沿环唯一图遍历顺序继续编号`

For 16-membered rings, the mirror mapping is fixed:

- `3 → 16`
- `4 → 15`
- `5 → 14`
- `6 → 13`
- `7 → 12`
- `8 → 11`
- `9 → 10`

This numbering is deterministic and is not a visual clockwise / anticlockwise toggle.
它不是视觉顺时针，也不是视觉逆时针切换。
The public API does not expose `clockwise` or `anticlockwise` parameters.

## Practical rule

- Use canonical numbering in code, reports, and validation outputs.
- Convert to literature-style mirrored labels only when you are comparing against a source that numbers the ring from the opposite direction.
- Keep bridge / fused multi-anchor cases explicit; do not silently reinterpret them as a direction choice.

## Entry points

- `README.md` is the progressive disclosure landing page.
- `docs/index.md` is the documentation landing page.
- `docs/user-guide/ring-numbering.md` is the canonical numbering reference.
- `docs/development/project-structure.md` is the repository layout reference.
- `docs/project-docs/AGENTS.md` points back here and should never override this file.