tool-surface-discipline

# Tool-surface discipline Authority: `docs/standard/STANDARD.md` criterion 4; CLAUDE.md "Tool-description quality", "Codex tool-surface benchmark", "Tier-switch pricing"; `tests/test_schema_budget.py`, `tests/test_counter_surface_stability.py`, `tests/test_description_smells.py`; `scripts/surface_diff.py`. The principle in three sentences: the published `counter` surface is byte-pinned and a reworded description is a full-rate cache write for every user; `core_compact` has a hard token ceiling the tree sits within a few tokens of; a new tool is paid for on every request by every user whether or not they call it. A surface change is ANY of: a tool added, removed or renamed; an argument added, removed or retyped; a description reworded; a tier or profile membership moved; a Counter front-door change; an always-visible control added. `scripts/surface_diff.py` sees names only (`docs/workflows/FINDINGS.md` W-1); descriptions are diffed from `_build_tools_list()` dumps. Every surface change carries: README tool reference, CLAUDE.md Key Files (invariant) or KEY-FILES.md (description), CHANGELOG naming the tool, and `benchmarks/schema_baseline.json` regenerated with the token delta stated (DoD 4). The `schema.core_compact_ceiling` verdict decides whether a description may grow; the answer is usually to trim.