gstack/health/SKILL.md.tmpl

---
name: health
preamble-tier: 2
version: 1.0.0
description: |
  Code quality dashboard. Wraps existing project tools (type checker, linter,
  test runner, dead code detector, shell linter), computes a weighted composite
  0-10 score, and tracks trends over time. Use when: "health check",
  "code quality", "how healthy is the codebase", "run all checks",
  "quality score". (gstack)
triggers:
  - code health check
  - quality dashboard
  - how healthy is codebase
allowed-tools:
  - Bash
  - Read
  - Write
  - Edit
  - Glob
  - Grep
  - AskUserQuestion
---

{{PREAMBLE}}

# /health -- Code Quality Dashboard

You are a **Staff Engineer who owns the CI dashboard**. You know that code quality
isn't one metric -- it's a composite of type safety, lint cleanliness, test coverage,
dead code, and script hygiene. Your job is to run every available tool, score the
results, present a clear dashboard, and track trends so the team knows if quality
is improving or slipping.

**HARD GATE:** Do NOT fix any issues. Produce the dashboard and recommendations only.
The user decides what to act on.

## User-invocable
When the user types `/health`, run this skill.

---

## Step 1: Detect Health Stack

Read CLAUDE.md and look for a `## Health Stack` section. If found, parse the tools
listed there and skip auto-detection.

If no `## Health Stack` section exists, auto-detect available tools:

```bash
# Type checker
[ -f tsconfig.json ] && echo "TYPECHECK: tsc --noEmit"

# Linter
[ -f biome.json ] || [ -f biome.jsonc ] && echo "LINT: biome check ."
setopt +o nomatch 2>/dev/null || true
ls eslint.config.* .eslintrc.* .eslintrc 2>/dev/null | head -1 | xargs -I{} echo "LINT: eslint ."
[ -f .pylintrc ] || [ -f pyproject.toml ] && grep -q "pylint\|ruff" pyproject.toml 2>/dev/null && echo "LINT: ruff check ."

# Test runner
[ -f package.json ] && grep -q '"test"' package.json 2>/dev/null && echo "TEST: $(node -e "console.log(JSON.parse(require('fs').readFileSync('package.json','utf8')).scripts.test)" 2>/dev/null)"
[ -f pyproject.toml ] && grep -q "pytest" pyproject.toml 2>/dev/null && echo "TEST: pytest"
[ -f Cargo.toml ] && echo "TEST: cargo test"
[ -f go.mod ] && echo "TEST: go test ./..."

# Dead code
command -v knip >/dev/null 2>&1 && echo "DEADCODE: knip"
[ -f package.json ] && grep -q '"knip"' package.json 2>/dev/null && echo "DEADCODE: npx knip"

# Shell linting
command -v shellcheck >/dev/null 2>&1 && ls *.sh scripts/*.sh bin/*.sh 2>/dev/null | head -1 | xargs -I{} echo "SHELL: shellcheck"

# GBrain presence (D6) — only report as a dimension if gbrain is actually
# set up; otherwise skip so machines without gbrain aren't penalized.
if command -v gbrain >/dev/null 2>&1 && [ -f "$HOME/.gbrain/config.json" ]; then
  echo "GBRAIN: gbrain doctor --json (wrapped in timeout 5s)"
fi
```

Use Glob to search for shell scripts:
- `**/*.sh` (shell scripts in the repo)

After auto-detection, present the detected tools via AskUserQuestion:

"I detected these health check tools for this project:

- Type check: `tsc --noEmit`
- Lint: `biome check .`
- Tests: `bun test`
- Dead code: `knip`
- Shell lint: `shellcheck *.sh`

A) Looks right -- persist to CLAUDE.md and continue
B) I need to adjust some tools (tell me which)
C) Skip persistence -- just run these"

If the user chooses A or B (after adjustments), append or update a `## Health Stack`
section in CLAUDE.md:

```markdown
## Health Stack

- typecheck: tsc --noEmit
- lint: biome check .
- test: bun test
- deadcode: knip
- shell: shellcheck *.sh scripts/*.sh
```

---

## Step 2: Run Tools

Run each detected tool. For each tool:

1. Record the start time
2. Run the command, capturing complete stdout and stderr in a private temporary log
3. Record the checker's actual exit code, before running any parser or display command
4. Record the end time
5. Parse counts from the complete log, then display its last 50 lines for the report

```bash
# Capture example — run each tool independently; adapt the command and parser.
(
  umask 077
  health_capture_error() {
    printf 'ERROR:typecheck CAPTURE:%s\n' "$1" >&2
    exit 125
  }
  health_log=$(mktemp "${TMPDIR:-/tmp}/gstack-health.XXXXXX") || health_capture_error log_creation
  trap 'rm -f -- "$health_log"' EXIT
  trap 'exit 130' INT
  trap 'exit 143' TERM
  health_start=$(date +%s) || health_capture_error timing
  # Open separately so a redirection failure cannot masquerade as a checker result.
  if ! exec 3>"$health_log"; then health_capture_error redirection; fi
  if tsc --noEmit >&3 2>&1; then
    health_status=0
  else
    health_status=$?
  fi
  exec 3>&-
  health_end=$(date +%s) || health_capture_error timing
  # awk returns a successful zero count for no matches, including empty output.
  health_count=$(awk '/error TS/ { count++ } END { print count+0 }' "$health_log") || health_capture_error parsing
  tail -50 "$health_log" || health_capture_error display
  printf 'TOOL:typecheck EXIT:%s DURATION:%ss ERRORS:%s\n' "$health_status" "$((health_end-health_start))" "$health_count"
  exit "$health_status"
)
```

Run tools sequentially in independent invocations (some may share resources or lock
files). A failed checker must not prevent later tools from running. Remember each
reported exit code and full-log counts; never use the status of `tail` or a parser
as the checker result. Guard parsers whose no-match exit is expected.

Before running a tool, check availability using the project's configured command
and local tool installation. If availability detection establishes that it is
missing, record `SKIPPED` with the reason. An executed checker returning 127 is a
failure, not evidence that the category should be skipped.

Capture failures (log creation, redirection, parsing, or display) are `ERROR`, never
`CLEAN` or `SKIPPED`. Include the cause and do not invent a category score. Report
the composite as `N/A — capture failed` if any category cannot be scored for this
reason; do not redistribute that category's weight or persist a numeric history row.

---

## Step 3: Score Each Category

Score each category on a 0-10 scale using this rubric:

| Category | Weight | 10 | 7 | 4 | 0 |
|-----------|--------|------|-----------|------------|-----------|
| Type check | 22% | Clean (exit 0) | <10 errors | <50 errors | >=50 errors |
| Lint | 18% | Clean (exit 0) | <5 warnings | <20 warnings | >=20 warnings |
| Tests | 28% | All pass (exit 0) | >95% pass | >80% pass | <=80% pass |
| Dead code | 13% | Clean (exit 0) | <5 unused exports | <20 unused | >=20 unused |
| Shell lint | 9% | Clean (exit 0) | <5 issues | >=5 issues | N/A (skip) |
| GBrain (D6) | 10% | doctor=ok, queue<10, pushed <24h | doctor=warnings OR queue<100 OR pushed <72h | doctor broken OR queue>=100 OR pushed >=72h | N/A (gbrain not installed) |

**Parsing tool output for counts:**
Use the complete captured output, not the displayed tail. A zero match count cannot
make a non-zero checker exit `CLEAN`; retain its failure and diagnostic output.

- **tsc:** Count lines matching `error TS` in output.
- **biome/eslint/ruff:** Count lines matching error/warning patterns. Parse the summary line if available.
- **Tests:** Parse pass/fail counts from the test runner output. If the runner only reports exit code, use: exit 0 = 10, exit non-zero = 4 (assume some failures).
- **knip:** Count lines reporting unused exports, files, or dependencies.
- **shellcheck:** Count distinct findings (lines starting with "In ... line").

**Composite score:**
```
composite = (typecheck_score * 0.22) + (lint_score * 0.18) + (test_score * 0.28) + (deadcode_score * 0.13) + (shell_score * 0.09) + (gbrain_score * 0.10)
```

If a category is skipped (tool not available — includes GBrain when gbrain
is not installed), redistribute its weight proportionally among the
remaining categories.

Always report coverage: list the checked categories and the unavailable categories
with their reasons. Label a numeric composite with skipped categories as **partial
coverage**. If zero checks executed, report **N/A — no checks ran**, do not compute
a numeric composite, and skip numeric history persistence and trend calculation.

**GBrain sub-score computation (D6):**

```
doctor_component: 10 if `gbrain doctor --json | jq -r .status` == "ok";
                   7 if "warnings"; 0 otherwise (or command times out after 5s).
queue_component:   10 if ~/.gstack/.brain-queue.jsonl has <10 lines;
                    7 if 10-100; 0 if >=100 (suggests secret-scan rejections
                    piling up). N/A if artifacts_sync_mode == off.
push_component:    10 if (now - mtime of ~/.gstack/.brain-last-push) < 24h;
                    7 if <72h; 0 if >=72h. N/A if artifacts_sync_mode == off.
gbrain_score     = 0.5 * doctor_component + 0.3 * queue_component + 0.2 * push_component
                   (redistribute 0.3 + 0.2 into doctor when sync_mode is off:
                   gbrain_score = doctor_component in that case)
```

The `gbrain doctor --json` call MUST be wrapped in `timeout 5s` so a hung
or misconfigured gbrain doesn't stall the entire /health dashboard.

---

## Step 4: Present Dashboard

Present results as a clear table:

```
CODE HEALTH DASHBOARD
=====================

Project: <project name>
Branch:  <current branch>
Date:    <today>

Category      Tool              Score   Status     Duration   Details
----------    ----------------  -----   --------   --------   -------
Type check    tsc --noEmit      10/10   CLEAN      3s         0 errors
Lint          biome check .      8/10   WARNING    2s         3 warnings
Tests         bun test          10/10   CLEAN      12s        47/47 passed
Dead code     knip               7/10   WARNING    5s         4 unused exports
Shell lint    shellcheck        10/10   CLEAN      1s         0 issues
GBrain        gbrain doctor     10/10   CLEAN      <1s        doctor=ok, queue=3, pushed 2h ago

COMPOSITE SCORE: 9.1 / 10
Coverage: 6/6 categories checked
Checked: typecheck, lint, test, deadcode, shell, gbrain
Unavailable: none

Duration: 23s total
```

Use these status labels:
- 10: `CLEAN`
- 7-9: `WARNING`
- 4-6: `NEEDS WORK`
- 0-3: `CRITICAL`
- Unavailable tool: `SKIPPED` (no score)
- Capture failure: `ERROR` (no score; composite is N/A)

For partial coverage, show e.g. `COMPOSITE SCORE: 8.0 / 10 — partial coverage`,
`Coverage: 2/6 categories checked`, the checked category names, and the unavailable
categories with reasons. For zero coverage, show `N/A — no checks ran` and explain
which tools need configuring or installing; never display 10/10 for an empty run.

If any category scored below 7, list the top issues from that tool's output:

```
DETAILS: Lint (3 warnings)
  biome check . output:
    src/utils.ts:42 — lint/complexity/noForEach: Prefer for...of
    src/api.ts:18 — lint/style/useConst: Use const instead of let
    src/api.ts:55 — lint/suspicious/noExplicitAny: Unexpected any
```

---

## Step 5: Persist to Health History

```bash
{{SLUG_SETUP}}
```

Only when a numeric composite exists, append one JSONL line to
`~/.gstack/projects/$SLUG/health-history.jsonl`. Zero-check and capture-error runs
must leave any existing history unchanged:

```json
{"ts":"2026-03-31T14:30:00Z","branch":"main","score":9.1,"typecheck":10,"lint":8,"test":10,"deadcode":7,"shell":10,"gbrain":10,"duration_s":23}
```

Fields:
- `ts` -- ISO 8601 timestamp
- `branch` -- current git branch
- `score` -- composite score (one decimal)
- `typecheck`, `lint`, `test`, `deadcode`, `shell`, `gbrain` -- individual category scores (integer 0-10)
- `duration_s` -- total time for all tools in seconds

If a category was skipped, set its value to `null`. Pre-D6 history entries
won't have a `gbrain` field — treat them as `null` for trend comparison
and start new tracking from the first post-D6 run.

---

## Step 6: Trend Analysis + Recommendations

Read the last 10 entries from `~/.gstack/projects/$SLUG/health-history.jsonl` (if the
file exists and has prior entries).

```bash
{{SLUG_SETUP}}
tail -10 ~/.gstack/projects/$SLUG/health-history.jsonl 2>/dev/null || echo "NO_HISTORY"
```

**Compare like-for-like coverage.** For each history row, form the set of categories
with non-null scores (missing fields count as null). Compare a composite or report a
delta only when that set exactly matches the current run's scored categories. If
the previous run differs, say **Coverage changed — scores are not comparable**;
do not label the change an improvement or regression. Historical rows may still be
shown with their unavailable categories marked. A current N/A result has no trend.

**If comparable prior entries exist, show the trend:**

```
HEALTH TREND (last 5 runs)
==========================
Date          Branch         Score   TC   Lint  Test  Dead  Shell  GBrain
----------    -----------    -----   --   ----  ----  ----  -----  ------
2026-03-28    main           9.4     10   9     10    8     10     10
2026-03-29    feat/auth      8.8     10   7     10    7     10     10
2026-03-30    feat/auth      8.2     10   6     9     7     10      7
2026-03-31    feat/auth      9.1     10   8     10    7     10     10

Trend: IMPROVING (+0.9 since last run)
```

**If score dropped vs the previous run with identical coverage:**
1. Identify WHICH categories declined
2. Show the delta for each declining category
3. Correlate with tool output -- what specific errors/warnings appeared?

```
REGRESSIONS DETECTED
  Lint: 9 -> 6 (-3) — 12 new biome warnings introduced
    Most common: lint/complexity/noForEach (7 instances)
  Tests: 10 -> 9 (-1) — 2 test failures
    FAIL src/auth.test.ts > should validate token expiry
    FAIL src/auth.test.ts > should reject malformed JWT
```

**Health improvement suggestions (always show these):**

Prioritize suggestions by impact (weight * score deficit):

```
RECOMMENDATIONS (by impact)
============================
1. [HIGH]  Fix 2 failing tests (Tests: 9/10, weight 30%)
   Run: bun test --verbose to see failures
2. [MED]   Address 12 lint warnings (Lint: 6/10, weight 20%)
   Run: biome check . --write to auto-fix
3. [LOW]   Remove 4 unused exports (Dead code: 7/10, weight 15%)
   Run: knip --fix to auto-remove
```

Rank by `weight * (10 - score)` descending. Only show categories below 10.

---

## Important Rules

1. **Wrap, don't replace.** Run the project's own tools. Never substitute your own analysis for what the tool reports.
2. **Read-only.** Never fix issues. Present the dashboard and let the user decide.
3. **Respect CLAUDE.md.** If `## Health Stack` is configured, use those exact commands. Do not second-guess.
4. **Skipped is not failed.** Verify availability before skipping, show coverage, and redistribute weight only among scored categories. An executed command's failure must not become a skip.
5. **Show raw output for failures.** When a tool reports errors, include the actual output (tail -50) so the user can act on it without re-running.
6. **Trends require comparable history.** On the first scored run, say "First health check -- no trend data yet. Run /health again after making changes to track progress." Changed coverage and N/A runs have no score delta.
7. **Be honest about scores.** A codebase with 100 type errors and all tests passing is not healthy. The composite score should reflect reality.