quality-tiers

name	quality-tiers
description	Module rigor tier system and uniform coverage thresholds.

Converted rule

Source: legacy Claude rule quality-tiers.

Module Rigor Tiers

This rule defines the T1–T4 module rigor tier system used by all CI gates in this repository. The tier system source of truth is docs/ci.research.md section 1; the file quality-tiers.yml at the repository root maps every project to a tier. Adding a project without a tier classification fails CI.

Tiers

• T1 — Critical. Behavior bugs cause silent data loss, model drift, or security holes. Examples (No-COM architecture): classifier engines (SpamBayes, Triage), ToDo ID allocator and hierarchy operations, Graph extended-properties adapter, auth/token handling, host-agnostic command bus.
• T2 — Core. Bugs cause feature regressions but not data loss. Examples: TaskMaster.Domain, TaskMaster.Application, mail-item DTOs, settings store abstraction, schema definitions.
• T3 — Adapters & UI. Glue around APIs the team does not own. Examples: Outlook task pane UI, Office.js wrappers, Microsoft Graph SDK wrappers, persistence I/O.
• T4 — Scaffolding. Examples: DI wiring, bootstrap, build scripts, dev tooling, generated code, manifests.

Source of Truth

• quality-tiers.yml at repo root maps every project to one tier.
• The CI pipeline's tier-classification stage validates that every project entry has a tier and that no unclassified project exists. Adding a project without a tier classification fails CI.

Uniform-vs-Tier-Dependent Gate Matrix

Per Authoritative Decision #2, line and branch coverage thresholds are uniform across all tiers. Other gates remain tier-dependent.

Uniform across all tiers (T1–T4)

• Format check: 100% pass.
• Lint errors: 0.
• Type errors: 0.
• Architecture violations: 0.
• Line coverage: >= 85%.
• Branch coverage: >= 75%.
• No regression on changed lines.

Tier-dependent

Gate	T1	T2	T3	T4
Untyped escape hatches (any/dynamic)	0	0	<= 5 per file, justified	unlimited
Property test density	>= 1 per pure function	>= 1 per pure function	none	none
Mutation score	>= 75%	trend-only	none	none
Contract breaking changes	major bump required	major bump required	n/a	n/a
Determinism (retry rate)	< 0.5%	< 1%	< 2%	n/a
Golden tests	required for classifier-output modules	optional	none	none
Full E2E suite scope	all critical paths	core paths	adapter smoke	none

Rationale (uniform coverage thresholds)

High test coverage is a fundamental quality-control design choice that enables autonomous agentic development and trust in the work product. For that reason, line coverage >= 85% and branch coverage >= 75% apply uniformly across T1–T4; tier-specific lower coverage floors are not used in this repository.