/regression-suite

name: regression-suite
description: "Map test coverage to GDD critical paths, find fixed bugs lacking regression tests, flag drift from new features."
argument-hint: "[update | audit | report]"
user-invocable: true
allowed-tools: Read, Glob, Grep, Write, Edit, AskUserQuestion, Bash(bash "*/.claude/skills/regression-suite/../../hooks/yaml-helper.sh" resolve_config *)
model: sonnet

!`bash "${CLAUDE_SKILL_DIR}/../../hooks/yaml-helper.sh" resolve_config --keys automation,workflow,qa.level,system_overrides`

Resolved above — use as-is. No block → defaults in `.claude/docs/config-resolution.md`.

Regression Suite

This skill ensures that every bug fix is backed by a test that would have caught the original bug — and that the regression suite stays current as the game evolves. It also detects when new features have been added without corresponding regression coverage.

A regression suite is not a new test category — it is a **curated list of tests already in `tests/`** that collectively cover the game's critical paths and known failure points. This skill maintains that list.

**Output:** `tests/regression-suite.md`

**When to run:**

• After fixing a bug (confirm a regression test was written or identify gap)
• Before a phase gate — at `qa.level: full`, `/gate-check` requires a regression suite
• As part of sprint close to detect coverage drift

---

Every `AskUserQuestion` call follows `.claude/docs/automation-modes.md` (collaborative asks always · guided major-only · autonomous logs and proceeds; `automation_always_ask` categories always prompt).

**Workflow tier**: `modes.workflow` as resolved above — supplied by `modes.rigor` unless set explicitly — per `.claude/docs/workflow-modes.md`; in `audit` mode consider `workflow_overrides.system_overrides.<system>` per system as each GDD is read. It sets whether GDD critical paths are mapped or coverage is smoke-only — see Step 2c.

**`qa.level`**: controls whether the suite is generated at all. At `minimal`, the regression suite is **not generated** (report that and stop); at `standard`, generate it at Polish-stage entry; at `full`, at Production-stage entry. Distinct axis from `workflow`.

1. Parse Arguments

**Early `qa.level` guard (resolved above):** if `qa.level: minimal`, the regression suite is **not generated** — report "Regression suite not generated at qa.level minimal" and **STOP here, before any scan**, in every mode (`update` / `audit` / `report`). This is the `qa.level` axis; it is distinct from the `workflow`-tier `minimal` branch in Step 2c (which only changes the critical-path *source*, not *whether* the suite runs). Do not enter Step 2c's `minimal` branch on account of `qa.level`. This stop's verdict is **NOT ASSESSED** (Section 7) — tests are not required at this level, and nothing was scanned.

**Modes:**

• `/regression-suite update` — scan new bug fixes this sprint and check

for regression test presence; add new tests to the suite manifest

• `/regression-suite audit` — full audit of all GDD critical paths vs.

existing test coverage; flag paths with no regression test

• `/regression-suite report` — read-only status report (no writes); suitable

for sprint reviews

• No argument — if a sprint is clearly active (sprint plan exists with in-progress stories), run `update`. If ambiguous or no active sprint is detected, use `AskUserQuestion`:
• Prompt: "No subcommand specified. Which mode do you want to run?"
• Options:
• `[A] update — scan new bug fixes this sprint and add missing regression tests`
• `[B] audit — full audit of all GDD critical paths vs. existing test coverage`
• `[C] report — read-only status report (no writes)`

---

2. Load Context

Step 2a — Load existing regression suite

Read `tests/regression-suite.md` if it exists. Extract:

• Total registered regression tests
• Last updated date
• Any tests flagged as `STALE` or `QUARANTINED`

If it does not exist: note "No regression suite found — will create one."

Step 2b — Load test inventory

Glob all test files:

tests/unit/**/*_test.*
tests/integration/**/*_test.*
tests/regression/**/*

For each file, note the system (from directory path) and file name. Do not read test file contents unless needed for name-to-test mapping.

Step 2c — Load GDD critical paths

For `audit` mode: read `design/gdd/systems-index.md` to get all systems, then scope the scan by each system's workflow tier (resolved above):

• **`full`** — read the GDD and map critical paths from all sections.
• **`standard`** — same, from the required sections (Acceptance Criteria, Edge

Cases, and Formulas where the system defines numeric rules). A system pinned higher via `system_overrides` is mapped at its higher tier.

• **`minimal`** — **skip the GDD critical-path scan**. Instead read the latest

smoke-check report in `production/qa/smoke-*.md` and take the critical paths it exercises as the regression scope (Step 3 maps coverage against those, not GDD acceptance criteria). If no smoke report exists, stop with Verdict: **NOT ASSESSED — no smoke report to take critical paths from** — there is no critical-path source at minimal without one; run `/smoke-check` first.

(Tier affects `audit` mode only; `update` and `report` modes are tier-independent.)

Read each GDD by section: find the headings you need with the Grep tool (pattern `^#`, content mode) and Read those ranges with offset and limit. At `full` that is every section, read in ranges, since a whole-file Read over 40 KB is refused.

For each in-scope MVP-tier system's GDD, extract:

• Acceptance Criteria (these define the critical paths)
• Formulas section (formulas must have regression tests)
• Edge Cases section (known edge cases should have regression tests)

For `update` mode: skip full GDD scan. Instead read the current sprint plan and story files to find stories with Status: Complete this sprint.

Step 2d — Load closed bugs

Glob `production/qa/bugs/*.md` and filter for bugs wit