fix(ci): derive traceability denominators from requirements.md (DR-093)

The coverage gate divided traced counts by hardcoded literals (UR/39,
IR/24, DR/48, JA/3, TOTAL_REQS=114) that had fallen out of date as
requirements grew to 211. It reported 158% coverage — JA alone printed
800% — so the 50% threshold was mathematically unreachable and the job
could not fail. Coverage could have collapsed to 30% and CI would still
have printed a green tick.

Real coverage is 86%. The number was fine; the gate was dead.

extract-traces.ts now owns both sides of the fraction:

- countDefinedRequirements() counts an ID only where it leads a markdown
  table row, ignoring the "Traces To" column and prose. IDs are
  deduplicated because requirements.md lists every UR twice (§1
  definition + §3 matrix), which would otherwise report UR as 121/61.
- computeCoverage() uses the intersection of traced and defined IDs, so
  a TRACES comment naming a deleted or typo'd requirement is reported as
  `orphaned` rather than inflating the ratio past 100%. UT/IT test
  identifiers are excluded as a separate taxonomy.
- CI reads .coverage.percent and fails on <50% or >100%; a >100% reading
  is now a hard error rather than the condition that hid this bug.
- New `bun run traces:coverage` runs the same computation locally.
- scripts/ added to the scan roots — the coverage tool was invisible to
  the matrix it generates.

Tests written first (15, over fixtures so they don't drift as
requirements are added). vitest include widened to scripts/** so build
tooling is covered by the normal suite.

Verified empirically rather than by inspection: forcing the threshold to
99% fails; adding a requirement lowers coverage 86%→85%; a TRACES: DR-999
lands in `orphaned` without changing `covered`.

traceability-ci.md documented the same stale numbers and would have let
the broken arithmetic be reconstructed — replaced with a pointer to the
live command.

.gitea/workflows/traceability-check.yml

@@ -42,30 +42,45 @@ jobs:
           echo "📊 Validating requirement traceability..."
           echo ""
 
-          # Parse JSON
+          # Denominators come from docs/requirements.md at run time — NEVER
+          # hardcode them here. This step previously divided by frozen literals
+          # (UR/39, IR/24, DR/48, JA/3, total 114) while the file had grown to
+          # 211 requirements, so it reported 158% coverage and the threshold
+          # below could never trip. See docs/specs/traceability-gate-repair.md.
           TOTAL_TRACES=$(jq '.totalTraces' traces-report.json)
-          UR=$(jq '.byType.UR | length' traces-report.json)
-          IR=$(jq '.byType.IR | length' traces-report.json)
-          DR=$(jq '.byType.DR | length' traces-report.json)
-          JA=$(jq '.byType.JA | length' traces-report.json)
+          COVERED=$(jq '.coverage.covered' traces-report.json)
+          TOTAL_REQS=$(jq '.coverage.total' traces-report.json)
+          COVERAGE=$(jq '.coverage.percent' traces-report.json)
 
-          # Print coverage report
           echo "✅ TRACES Found: $TOTAL_TRACES"
           echo ""
-          echo "📋 Coverage Summary:"
-          echo "   User Requirements (UR):         $UR / 39 ($(( UR * 100 / 39 ))%)"
-          echo "   Integration Requirements (IR): $IR / 24 ($(( IR * 100 / 24 ))%)"
-          echo "   Development Requirements (DR): $DR / 48 ($(( DR * 100 / 48 ))%)"
-          echo "   Jellyfin API Requirements (JA): $JA / 3 ($(( JA * 100 / 3 ))%)"
+          echo "📋 Coverage Summary (traced / defined):"
+          for T in UR IR DR JA; do
+            TRACED=$(jq --arg t "$T" '[.byType[$t][] | select(. != null)] | length' traces-report.json)
+            DEFINED=$(jq --arg t "$T" '.defined[$t]' traces-report.json)
+            echo "   $T: $TRACED / $DEFINED"
+          done
           echo ""
 
-          COVERED=$((UR + IR + DR + JA))
-          TOTAL_REQS=114
-          COVERAGE=$((COVERED * 100 / TOTAL_REQS))
-
           echo "📈 Overall Coverage: $COVERED / $TOTAL_REQS ($COVERAGE%)"
           echo ""
 
+          # Traced IDs that requirements.md does not define (typo, or a deleted
+          # requirement). These do not count toward coverage.
+          ORPHANED=$(jq -c '.coverage.orphaned' traces-report.json)
+          if [ "$ORPHANED" != "[]" ]; then
+            echo "⚠️  Traced but not defined in requirements.md: $ORPHANED"
+            echo ""
+          fi
+
+          # A ratio above 100% means the computation is broken — the exact
+          # condition that hid the stale-denominator bug. Fail loudly.
+          if [ "$COVERAGE" -gt 100 ]; then
+            echo "❌ ERROR: Coverage ($COVERAGE%) exceeds 100% — the gate is miscomputing."
+            echo "   Orphaned IDs: $ORPHANED"
+            exit 1
+          fi
+
           # Check minimum threshold
           MIN_THRESHOLD=50
           if [ "$COVERAGE" -lt "$MIN_THRESHOLD" ]; then

docs/traceability-ci.md

@@ -43,14 +43,26 @@ Extracts all TRACES comments from:
 
 ### 2. Coverage Thresholds
 The workflow checks:
-- **Minimum overall coverage:** 50% (57+ requirements traced)
-- **Requirements by type:**
-  - UR (User): 23+ of 39
-  - IR (Integration): 5+ of 24
-  - DR (Development): 28+ of 48
-  - JA (Jellyfin API): 0+ of 3
+- **Minimum overall coverage:** 50%
 
-If coverage drops below threshold, the workflow **fails** and blocks merge.
+Denominators are **derived from `docs/requirements.md` at run time** — they are
+never hardcoded here or in the workflow. Run `bun run traces:coverage` for the
+current per-type breakdown; any number written into this document is a snapshot
+that will drift.
+
+> **Why this matters.** The workflow used to divide by frozen literals
+> (UR/39, IR/24, DR/48, JA/3, total 114) while `requirements.md` had grown past
+> 200. It reported **158%** coverage, so the 50% threshold was unreachable and
+> the job could not fail regardless of how far coverage dropped. See
+> [specs/traceability-gate-repair.md](specs/traceability-gate-repair.md).
+
+Coverage is the *intersection* of traced and defined IDs: an ID that appears in
+a `TRACES:` comment but is not defined in `requirements.md` is reported as
+**orphaned** and does not count toward coverage. UT/IT test identifiers are a
+separate taxonomy and are excluded entirely.
+
+The workflow **fails** and blocks merge if coverage drops below 50% — or if it
+computes above 100%, which can only mean the gate is miscounting.
 
 ### 3. Modified File Checking
 On pull requests, the workflow:
@@ -153,11 +165,13 @@ cat docs/traceability.md
 ## Coverage Goals
 
 ### Current Status
-- Overall: 51% (56/114)
-- UR: 59% (23/39)
-- IR: 21% (5/24)
-- DR: 58% (28/48)
-- JA: 0% (0/3)
+
+Run `bun run traces:coverage` — it prints the live figure and exits non-zero
+below threshold. Numbers are deliberately not pinned here; the previous snapshot
+in this section (51%, 56/114) was stale by roughly 100 requirements and was what
+made the broken CI arithmetic look plausible for so long.
+
+As of July 2026 overall coverage is ~86% (182/212).
 
 ### Targets
 - **Short term** (Sprint): Maintain ≥50% overall

package.json

@@ -36,6 +36,7 @@
     "traces": "bun run scripts/extract-traces.ts",
     "traces:json": "bun run scripts/extract-traces.ts --format json",
     "traces:markdown": "bun run scripts/extract-traces.ts --format markdown > docs/traceability.md",
+    "traces:coverage": "bun run scripts/extract-traces.ts --format coverage",
     "release:notes": "bun run scripts/release-notes.ts"
   },
   "license": "MIT",

scripts/extract-traces.test.ts

@@ -0,0 +1,182 @@
+/**
+ * Tests for the traceability coverage computation.
+ *
+ * These run over fixture strings rather than the live docs/requirements.md, so
+ * their meaning does not drift as requirements are added.
+ *
+ * Background: the CI gate divided traced-requirement counts by hardcoded
+ * denominators (UR/39, IR/24, DR/48, JA/3, total 114) that had fallen out of
+ * date, reporting 158% coverage and making the 50% threshold unreachable. These
+ * tests pin the parsing and arithmetic that replace those literals.
+ *
+ * @req-test: UT-089 - Requirement definitions parsed from requirements.md
+ * @req-test: UT-090 - Coverage is the intersection of traced and defined IDs
+ */
+
+import { describe, it, expect } from "vitest";
+import { countDefinedRequirements, computeCoverage } from "./extract-traces";
+
+describe("countDefinedRequirements", () => {
+  it("counts a well-formed table row as a defined requirement", () => {
+    const md = `
+| ID | Requirement | Priority | Status |
+|----|-------------|----------|--------|
+| UR-001 | Run the app on multiple platforms | High | In Progress |
+| UR-002 | Access media when online or offline | High | Done |
+`;
+    const defined = countDefinedRequirements(md);
+    expect(defined.UR).toBe(2);
+    expect(defined.DR).toBe(0);
+  });
+
+  it("does not count IDs that appear only in the Traces To column", () => {
+    // The bug this rule avoids: a naive grep for /DR-\d{3}/ over the whole file
+    // counts DR-001 here as "defined", inflating the denominator with IDs that
+    // are merely referenced.
+    const md = `
+| DR-001 | Player state machine | Player | UR-005 | Done |
+| DR-002 | MediaItem struct | Player | UR-003, UR-004 | Done |
+`;
+    const defined = countDefinedRequirements(md);
+    expect(defined.DR).toBe(2);
+    // UR-005/UR-003/UR-004 are referenced, never defined here.
+    expect(defined.UR).toBe(0);
+  });
+
+  it("does not count IDs mentioned in prose", () => {
+    const md = `
+Some prose explaining that UR-005 relates to DR-001 and JA-002.
+
+| UR-005 | Control media playback | High | Done |
+`;
+    const defined = countDefinedRequirements(md);
+    expect(defined.UR).toBe(1);
+    expect(defined.DR).toBe(0);
+    expect(defined.JA).toBe(0);
+  });
+
+  it("deduplicates an ID listed in both the spec table and the traceability matrix", () => {
+    // requirements.md lists every UR twice: once in §1 (definition) and again in
+    // §3 (traceability matrix), both as a leading table cell. Counting rows
+    // instead of unique IDs double-counts the UR denominator (121 vs 61).
+    const md = `
+| UR-005 | Control media playback | High | Done |
+| UR-006 | Browse the library | High | Done |
+
+### Traceability Matrix
+
+| UR-005 | - | DR-001, DR-005, DR-009 |
+| UR-006 | - | DR-012 |
+`;
+    const defined = countDefinedRequirements(md);
+    expect(defined.UR).toBe(2);
+  });
+
+  it("collects the defined ID set, not just counts", () => {
+    const md = `
+| UR-001 | A | High | Done |
+| DR-050 | B | Player | UR-001 | Done |
+`;
+    const defined = countDefinedRequirements(md);
+    expect(defined.ids.has("UR-001")).toBe(true);
+    expect(defined.ids.has("DR-050")).toBe(true);
+    expect(defined.ids.has("UR-999")).toBe(false);
+  });
+});
+
+describe("computeCoverage", () => {
+  const defined = {
+    UR: 2,
+    IR: 0,
+    DR: 2,
+    JA: 0,
+    total: 4,
+    ids: new Set(["UR-001", "UR-002", "DR-001", "DR-002"]),
+  };
+
+  it("computes coverage as traced ∩ defined over defined", () => {
+    const traced = ["UR-001", "DR-001"];
+    const cov = computeCoverage(traced, defined);
+    expect(cov.covered).toBe(2);
+    expect(cov.total).toBe(4);
+    expect(cov.percent).toBe(50);
+  });
+
+  it("does not let a traced-but-undefined ID inflate the numerator", () => {
+    // This is how a ratio exceeds 100%: a TRACES comment naming a typo'd or
+    // deleted requirement counted as covered.
+    const traced = ["UR-001", "DR-001", "DR-097"];
+    const cov = computeCoverage(traced, defined);
+    expect(cov.covered).toBe(2);
+    expect(cov.percent).toBe(50);
+  });
+
+  it("reports traced-but-undefined IDs as orphaned so they get fixed", () => {
+    const traced = ["UR-001", "DR-097", "JA-404"];
+    const cov = computeCoverage(traced, defined);
+    expect(cov.orphaned).toEqual(["DR-097", "JA-404"]);
+  });
+
+  it("has no orphans when every traced ID is defined", () => {
+    const cov = computeCoverage(["UR-001", "UR-002"], defined);
+    expect(cov.orphaned).toEqual([]);
+  });
+
+  it("ignores UT/IT test IDs entirely — they are a separate taxonomy", () => {
+    // UT/IT are defined in §4 of requirements.md, not among the four
+    // requirement types. Treating them as orphans buries real typos in ~60
+    // lines of noise, and counting them would corrupt the ratio.
+    const cov = computeCoverage(["UR-001", "UT-088", "IT-017"], defined);
+    expect(cov.orphaned).toEqual([]);
+    expect(cov.covered).toBe(1);
+  });
+
+  it("reports 0% rather than dividing by zero for an empty trace set", () => {
+    const cov = computeCoverage([], defined);
+    expect(cov.covered).toBe(0);
+    expect(cov.percent).toBe(0);
+  });
+
+  it("reports 0% rather than NaN when nothing is defined", () => {
+    const empty = { UR: 0, IR: 0, DR: 0, JA: 0, total: 0, ids: new Set<string>() };
+    const cov = computeCoverage([], empty);
+    expect(cov.percent).toBe(0);
+    expect(Number.isNaN(cov.percent)).toBe(false);
+  });
+
+  it("reports exactly 100% when all defined requirements are traced, never above", () => {
+    const traced = ["UR-001", "UR-002", "DR-001", "DR-002"];
+    const cov = computeCoverage(traced, defined);
+    expect(cov.percent).toBe(100);
+  });
+
+  it("ignores duplicate traced IDs", () => {
+    const traced = ["UR-001", "UR-001", "UR-001"];
+    const cov = computeCoverage(traced, defined);
+    expect(cov.covered).toBe(1);
+  });
+});
+
+describe("live requirements.md", () => {
+  it("parses the real file to the counts the CI gate must use", () => {
+    // Guards the specific regression: CI hardcoded UR/39, IR/24, DR/48, JA/3
+    // (total 114) while the real file had grown to 211. Update these numbers
+    // deliberately when requirements are added — that edit is the signal the
+    // denominator is live rather than frozen.
+    const fs = require("fs");
+    const path = require("path");
+    // import.meta.dir is Bun-only; derive from import.meta.url under vitest.
+    const here = path.dirname(new URL(import.meta.url).pathname);
+    const md = fs.readFileSync(
+      path.resolve(here, "../docs/requirements.md"),
+      "utf-8"
+    );
+    const defined = countDefinedRequirements(md);
+
+    expect(defined.UR).toBe(61);
+    expect(defined.IR).toBe(29);
+    expect(defined.DR).toBe(91);
+    expect(defined.JA).toBe(32);
+    expect(defined.total).toBe(213);
+  });
+});

scripts/extract-traces.ts

@@ -34,11 +34,20 @@ interface TracesData {
     DR: string[];
     JA: string[];
   };
+  /** Requirements *defined* in requirements.md — the coverage denominators. */
+  defined?: { UR: number; IR: number; DR: number; JA: number; total: number };
+  coverage?: CoverageResult;
 }
 
 // Repo root, derived from this script's location (scripts/ -> repo root).
 // Must NOT be hardcoded to a developer's machine, or CI checkouts see no files.
-const BASE_DIR = path.resolve(import.meta.dir, "..");
+//
+// `import.meta.dir` is a Bun extension and is undefined when this module is
+// imported by vitest (which runs it as an ordinary ESM module), so fall back to
+// import.meta.url — this file must stay importable for extract-traces.test.ts.
+const SCRIPT_DIR =
+  import.meta.dir ?? path.dirname(new URL(import.meta.url).pathname);
+const BASE_DIR = path.resolve(SCRIPT_DIR, "..");
 
 const TRACES_PATTERN = /TRACES:\s*([^\n]+)/gi;
 const REQ_ID_PATTERN = /([A-Z]{2})-(\d{3})/g;
@@ -50,7 +59,10 @@ function extractRequirementIds(tracesString: string): string[] {
 
 function getAllSourceFiles(): string[] {
   const baseDir = BASE_DIR;
-  const patterns = ["src", "src-tauri/src"];
+  // `scripts` is scanned too: build tooling implements requirements (e.g.
+  // DR-093, the coverage engine itself) and would otherwise be invisible to the
+  // very matrix it generates.
+  const patterns = ["src", "src-tauri/src", "scripts"];
   const files: string[] = [];
 
   function walkDir(dir: string) {
@@ -192,6 +204,109 @@ function extractTraces(): TracesData {
   };
 }
 
+// ---------------------------------------------------------------------------
+// Coverage: how many *defined* requirements are actually traced.
+//
+// The denominators MUST be derived from requirements.md, never hardcoded. The
+// CI gate previously divided by frozen literals (UR/39, IR/24, DR/48, JA/3,
+// total 114) while the real file had grown to 211 requirements, so it reported
+// 158% coverage and the 50% threshold became unreachable — the gate could not
+// fail. See docs/specs/traceability-gate-repair.md.
+//
+// TRACES: | DR-093
+// ---------------------------------------------------------------------------
+
+export interface DefinedRequirements {
+  UR: number;
+  IR: number;
+  DR: number;
+  JA: number;
+  total: number;
+  ids: Set<string>;
+}
+
+export interface CoverageResult {
+  covered: number;
+  total: number;
+  percent: number;
+  /** Traced in code but not defined in requirements.md (typo, or deleted req). */
+  orphaned: string[];
+}
+
+/**
+ * A requirement is *defined* only where its ID is the leading cell of a markdown
+ * table row: `| DR-001 | … |`.
+ *
+ * This deliberately ignores IDs in the "Traces To" column and in prose — a
+ * naive scan for /DR-\d{3}/ counts those as definitions and inflates the
+ * denominator. IDs are deduplicated because requirements.md lists each UR twice
+ * (once in §1 as a definition, again in §3's traceability matrix), which would
+ * otherwise double the UR count from 61 to 121.
+ *
+ * TRACES: | DR-093
+ */
+export function countDefinedRequirements(markdown: string): DefinedRequirements {
+  const ids = new Set<string>();
+  const ROW_ID = /^\|\s*(UR|IR|DR|JA)-(\d{3})\s*\|/;
+
+  for (const line of markdown.split("\n")) {
+    const match = line.match(ROW_ID);
+    if (match) ids.add(`${match[1]}-${match[2]}`);
+  }
+
+  const countOf = (type: string) =>
+    [...ids].filter((id) => id.startsWith(`${type}-`)).length;
+
+  return {
+    UR: countOf("UR"),
+    IR: countOf("IR"),
+    DR: countOf("DR"),
+    JA: countOf("JA"),
+    total: ids.size,
+    ids,
+  };
+}
+
+/**
+ * Coverage is the *intersection* of traced and defined IDs over defined IDs.
+ *
+ * Using the raw traced count as the numerator is what lets a ratio exceed 100%:
+ * a TRACES comment naming a requirement that no longer exists would count as
+ * covered. Those IDs are reported as `orphaned` so they get fixed rather than
+ * silently counted or silently dropped.
+ *
+ * TRACES: | DR-093
+ */
+export function computeCoverage(
+  tracedIds: string[],
+  defined: DefinedRequirements
+): CoverageResult {
+  // Only the four *requirement* types participate in coverage. UT/IT are test
+  // identifiers defined in §4 of requirements.md — a different taxonomy, and
+  // flagging them as orphans would bury real typos in ~60 lines of noise.
+  const isRequirement = (id: string) => /^(UR|IR|DR|JA)-\d{3}$/.test(id);
+
+  const traced = new Set(tracedIds.filter(isRequirement));
+  const covered = [...traced].filter((id) => defined.ids.has(id));
+  const orphaned = [...traced].filter((id) => !defined.ids.has(id)).sort();
+
+  return {
+    covered: covered.length,
+    total: defined.total,
+    percent:
+      defined.total === 0
+        ? 0
+        : Math.round((covered.length / defined.total) * 100),
+    orphaned,
+  };
+}
+
+/** Read requirements.md from the repo and count what it defines. */
+export function readDefinedRequirements(): DefinedRequirements {
+  const reqPath = path.join(BASE_DIR, "docs", "requirements.md");
+  return countDefinedRequirements(fs.readFileSync(reqPath, "utf-8"));
+}
+
 function generateMarkdown(data: TracesData): string {
   let md = `# Code Traceability Matrix
 
@@ -265,21 +380,83 @@ function generateJson(data: TracesData): string {
   return JSON.stringify(data, null, 2);
 }
 
-// Main
-const args = Bun.argv.slice(2);
-const format = args.includes("--format")
+/**
+ * Human-readable coverage report; exits non-zero below the threshold so this is
+ * runnable as a local gate (`bun run traces:coverage`), not just in CI.
+ *
+ * TRACES: | DR-093
+ */
+function reportCoverage(data: TracesData, minThreshold: number): number {
+  const defined = data.defined!;
+  const cov = data.coverage!;
+
+  const definedIds = readDefinedRequirements().ids;
+
+  console.log("📋 Requirement coverage (traced / defined):");
+  for (const type of ["UR", "IR", "DR", "JA"] as const) {
+    const traced = data.byType[type].filter((id) => definedIds.has(id)).length;
+    console.log(`   ${type}: ${traced} / ${defined[type]}`);
+  }
+  console.log("");
+  console.log(`📈 Overall: ${cov.covered} / ${cov.total} (${cov.percent}%)`);
+
+  if (cov.orphaned.length > 0) {
+    console.log("");
+    console.log(
+      `⚠️  Traced but not defined in requirements.md: ${cov.orphaned.join(", ")}`
+    );
+    console.log("   Fix the TRACES comment or add the requirement.");
+  }
+
+  // A ratio above 100% means the computation is broken (the condition that hid
+  // the stale-denominator bug for so long). Fail loudly rather than report it.
+  if (cov.percent > 100) {
+    console.log("");
+    console.log(`❌ Coverage > 100% — the gate is miscomputing.`);
+    return 1;
+  }
+
+  if (cov.percent < minThreshold) {
+    console.log("");
+    console.log(`❌ Coverage (${cov.percent}%) is below minimum (${minThreshold}%)`);
+    return 1;
+  }
+
+  console.log("");
+  console.log(`✅ Coverage is acceptable (${cov.percent}% >= ${minThreshold}%)`);
+  return 0;
+}
+
+// Main — guarded so this module stays importable from extract-traces.test.ts.
+if (import.meta.main) {
+  const args = process.argv.slice(2);
+  const format = args.includes("--format")
     ? args[args.indexOf("--format") + 1]
     : "markdown";
 
-console.error("🔍 Extracting TRACES from codebase...");
-const data = extractTraces();
+  console.error("🔍 Extracting TRACES from codebase...");
+  const data = extractTraces();
 
-if (format === "json") {
+  const defined = readDefinedRequirements();
+  const allTraced = Object.keys(data.requirements);
+  data.defined = {
+    UR: defined.UR,
+    IR: defined.IR,
+    DR: defined.DR,
+    JA: defined.JA,
+    total: defined.total,
+  };
+  data.coverage = computeCoverage(allTraced, defined);
+
+  if (format === "json") {
     console.log(generateJson(data));
-} else {
+  } else if (format === "coverage") {
+    process.exit(reportCoverage(data, 50));
+  } else {
     console.log(generateMarkdown(data));
-}
+  }
 
-console.error(
+  console.error(
     `\n✅ Complete! Found ${data.totalTraces} TRACES across ${data.totalFiles} files`
-);
+  );
+}

vitest.config.ts

@@ -8,7 +8,9 @@ export default defineConfig({
     globals: true,
     environment: "jsdom",
     setupFiles: ["./src/test/setup-globals.ts", "./src/test/setup.ts"],
-    include: ["src/**/*.{test,spec}.{js,ts}"],
+    // `scripts/` is included so build tooling (the traceability coverage
+    // engine) is covered by the normal suite rather than only by CI.
+    include: ["src/**/*.{test,spec}.{js,ts}", "scripts/**/*.{test,spec}.{js,ts}"],
     coverage: {
       provider: "v8",
       reporter: ["text", "json", "html"],