Simple Coding Rules (Lerim)

This file defines general coding rules for Lerim. Follow these rules unless Isaac explicitly asks to change them.

1) One clear path per feature

For each feature, prefer one clear execution path. Avoid parallel/duplicate implementations for the same behavior.

2) Keep code minimal

Prefer fewer functions and fewer layers. Avoid helper chains when one function can express the flow clearly. Choose names that describe one clear action.

3) Use strict schemas

Use strict typed models (Pydantic/enums) for important inputs/outputs. Do not add alias or legacy compatibility layers unless explicitly requested.

4) Fail fast on missing requirements

If a package, key, or required config is missing, raise an error. Do not add silent fallback behavior.

5) Config from TOML layers, API keys from env

Runtime config comes from TOML layers (default.toml → user → project → local → LERIM_CONFIG). Only API keys use environment variables. Keep config branching short and readable. Do not add hidden defaults that mask misconfiguration.

6) Real tests over mock-only checks

Each file should be runnable in isolation when practical. __main__ self-tests should run real paths (no mock/stub self-test flow). Validate quality of outputs, not only counts/status.

7) Remove old paths when replacing logic

When a new path replaces an old one, remove obsolete code. Do not keep dead compatibility code "just in case."

8) Keep docs and rules in sync

When behavior changes, update the related docs and AGENTS.md references in the same change.