fix(research): expand skill-hub mode list and parse block-scalar descriptions

Frontmatter validation in the research skill-hub starter now mirrors the
shapes already used by `skills/*/SKILL.md`:

- `ALLOWED_OD_MODES` adds `image`, `video`, `audio`, and `utility` so
  media and utility skills (e.g. `image-poster`, `video-shortform`,
  `audio-jingle`, `pptx-html-fidelity-audit`) are no longer rejected by a
  hub mirroring the catalog.
- The minimal YAML parser now reads `description: |`, `description: |-`,
  `description: >`, and `description: >-` block scalars instead of
  storing the literal `|` / `>`. Continuation lines are joined with `\n`
  and right-trimmed, matching `apps/daemon/src/frontmatter.ts`.
- Adds `apps/daemon/tests/research-skill-hub-frontmatter.test.ts` with
  fixture coverage against representative live skills for every
  currently-used `od.mode` value plus inline cases for `>` / `|-`.

Generated-By: looper 0.4.0 (runner=fixer, agent=claude-code)

apps/daemon/src/research/skill-hub.ts

@@ -246,13 +246,34 @@ async function fetchRawCapped(url: string, token?: string): Promise<string | nul
 const FRONTMATTER_PATTERN = /^---\r?\n([\s\S]*?)\r?\n---\r?\n?([\s\S]*)$/;
 const NAME_PATTERN = /^[a-z0-9][a-z0-9._-]{0,127}$/i;
 const SLUG_PATTERN = /^[a-z0-9][a-z0-9-]{0,127}$/;
-const ALLOWED_OD_MODES = new Set(['prototype', 'deck', 'template', 'design-system']);
+// Values observed across the 65+ skills currently shipped in `skills/*/SKILL.md`
+// plus the four documented in `docs/skills-protocol.md`. Keep this list aligned
+// with reality so a hub mirroring the catalog does not reject media or utility
+// skills (PR #617 review). The integration PR should replace this with a
+// shared schema export from `apps/daemon/src/skills.ts`.
+const ALLOWED_OD_MODES = new Set([
+  'prototype',
+  'deck',
+  'template',
+  'design-system',
+  'image',
+  'video',
+  'audio',
+  'utility',
+]);
 
 /**
  * Minimal frontmatter parser, intentionally a subset of
- * `apps/daemon/src/frontmatter.ts`. Supports the fields we actually validate
- * here (top-level scalars and the `od.mode` scalar). Anything more complex is
- * left as raw text for the integration PR to swap in the daemon parser.
+ * `apps/daemon/src/frontmatter.ts`. Supports top-level scalars, the `od:`
+ * nested-scalar block, and YAML block scalars (`|`, `|-`, `>`, `>-`) for
+ * `description` — which most existing `SKILL.md` files use. Anything more
+ * complex is left as raw text for the integration PR to swap in the daemon
+ * parser.
+ *
+ * Block scalars are joined with `\n` and right-trimmed, matching what
+ * `apps/daemon/src/frontmatter.ts` does today. This sacrifices strict YAML
+ * folding behavior for `>` in exchange for matching how the daemon already
+ * reads the same files; consistency with the live catalog is the point.
  */
 export function parseFrontmatter(raw: string): Record<string, unknown> {
   const text = raw.replace(/^/, '');
@@ -261,42 +282,112 @@ export function parseFrontmatter(raw: string): Record<string, unknown> {
   const yaml = match[1];
   if (!yaml) return {};
   const out: Record<string, unknown> = {};
-  let inOdBlock = false;
   const od: Record<string, unknown> = {};
-  for (const rawLine of yaml.split(/\r?\n/)) {
-    if (!rawLine.trim() || rawLine.trim().startsWith('#')) continue;
+  const lines = yaml.split(/\r?\n/);
+  let i = 0;
+  let inOdBlock = false;
+
+  while (i < lines.length) {
+    const rawLine = lines[i] ?? '';
+    if (!rawLine.trim() || rawLine.trim().startsWith('#')) {
+      i++;
+      continue;
+    }
     const indent = rawLine.match(/^\s*/)?.[0].length ?? 0;
     const line = rawLine.slice(indent);
+
     if (indent === 0) {
       if (line === 'od:' || line.startsWith('od:')) {
-        inOdBlock = true;
-        const inline = line.slice(3).trim();
-        if (inline) {
-          inOdBlock = false;
-          // od: <scalar> is not a documented shape; ignore.
-        }
+        inOdBlock = line === 'od:';
+        i++;
         continue;
       }
       inOdBlock = false;
       const kv = /^([A-Za-z_][A-Za-z0-9_-]*)\s*:\s*(.*)$/.exec(line);
-      if (!kv) continue;
+      if (!kv) {
+        i++;
+        continue;
+      }
       const key = kv[1];
       const val = (kv[2] ?? '').trim();
-      if (!key) continue;
+      if (!key) {
+        i++;
+        continue;
+      }
+      if (isBlockScalar(val)) {
+        const block = readBlockScalar(lines, i + 1, indent);
+        out[key] = block.value;
+        i = block.next;
+        continue;
+      }
       out[key] = stripQuotes(val);
-    } else if (inOdBlock && indent === 2) {
+      i++;
+      continue;
+    }
+
+    if (inOdBlock && indent === 2) {
       const kv = /^([A-Za-z_][A-Za-z0-9_-]*)\s*:\s*(.*)$/.exec(line);
-      if (!kv) continue;
+      if (!kv) {
+        i++;
+        continue;
+      }
       const key = kv[1];
       const val = (kv[2] ?? '').trim();
-      if (!key) continue;
+      if (!key) {
+        i++;
+        continue;
+      }
+      if (isBlockScalar(val)) {
+        const block = readBlockScalar(lines, i + 1, indent);
+        od[key] = block.value;
+        i = block.next;
+        continue;
+      }
       od[key] = stripQuotes(val);
+      i++;
+      continue;
     }
+
+    i++;
   }
   if (Object.keys(od).length > 0) out['od'] = od;
   return out;
 }
 
+function isBlockScalar(val: string): boolean {
+  return (
+    val === '|'
+    || val === '|-'
+    || val === '|+'
+    || val === '>'
+    || val === '>-'
+    || val === '>+'
+  );
+}
+
+function readBlockScalar(
+  lines: string[],
+  start: number,
+  parentIndent: number,
+): { value: string; next: number } {
+  const collected: string[] = [];
+  const childIndent = parentIndent + 2;
+  let i = start;
+  while (i < lines.length) {
+    const next = lines[i] ?? '';
+    if (next.trim() === '') {
+      collected.push('');
+      i++;
+      continue;
+    }
+    const nIndent = next.match(/^\s*/)?.[0].length ?? 0;
+    if (nIndent < childIndent) break;
+    collected.push(next.slice(childIndent));
+    i++;
+  }
+  return { value: collected.join('\n').trimEnd(), next: i };
+}
+
 function stripQuotes(s: string): string {
   if ((s.startsWith('"') && s.endsWith('"')) || (s.startsWith("'") && s.endsWith("'"))) {
     return s.slice(1, -1);

apps/daemon/tests/research-skill-hub-frontmatter.test.ts

@@ -0,0 +1,115 @@
+import fs from 'node:fs';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+import { describe, expect, it } from 'vitest';
+
+import {
+  parseFrontmatter,
+  resolveManifest,
+  validateFrontmatter,
+} from '../src/research/skill-hub.js';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+const repoRoot = path.resolve(__dirname, '../../..');
+
+function readSkill(slug: string): string {
+  return fs.readFileSync(path.join(repoRoot, 'skills', slug, 'SKILL.md'), 'utf8');
+}
+
+describe('research/skill-hub frontmatter parser', () => {
+  it('reads `description: |` block scalars instead of storing the literal "|"', () => {
+    const fm = parseFrontmatter(readSkill('image-poster'));
+    expect(typeof fm['description']).toBe('string');
+    expect(fm['description']).not.toBe('|');
+    expect(fm['description']).not.toBe('');
+    expect(String(fm['description'])).toContain('Single-image generation');
+    expect(String(fm['description'])).toContain('PNG/JPEG');
+  });
+
+  it('reads `description: |` block scalars on the audio-jingle fixture', () => {
+    const fm = parseFrontmatter(readSkill('audio-jingle'));
+    expect(String(fm['description'])).toContain('Audio generation skill');
+    expect(String(fm['description'])).toContain('MP3/WAV');
+  });
+
+  it('reads `description: |` block scalars on the video-shortform fixture', () => {
+    const fm = parseFrontmatter(readSkill('video-shortform'));
+    expect(String(fm['description'])).toContain('Short-form video generation');
+  });
+
+  it('reads `description: >` folded scalars without storing the literal ">"', () => {
+    const raw = [
+      '---',
+      'name: demo',
+      'description: >',
+      '  First line.',
+      '  Second line.',
+      '---',
+      '',
+      '# body',
+    ].join('\n');
+    const fm = parseFrontmatter(raw);
+    expect(fm['description']).not.toBe('>');
+    expect(String(fm['description'])).toContain('First line.');
+    expect(String(fm['description'])).toContain('Second line.');
+  });
+
+  it('reads `description: |-` chomping marker as a non-literal value', () => {
+    const raw = [
+      '---',
+      'name: demo',
+      'description: |-',
+      '  First line.',
+      '  Second line.',
+      '---',
+      '',
+    ].join('\n');
+    const fm = parseFrontmatter(raw);
+    expect(fm['description']).not.toBe('|-');
+    expect(String(fm['description'])).toBe('First line.\nSecond line.');
+  });
+
+  it('parses `od.mode` from the nested `od:` block', () => {
+    const fm = parseFrontmatter(readSkill('image-poster'));
+    expect(fm['od']).toBeTypeOf('object');
+    expect((fm['od'] as Record<string, unknown>)['mode']).toBe('image');
+  });
+});
+
+describe('research/skill-hub validateFrontmatter mode coverage', () => {
+  // Canonical modes plus media/utility modes already in `skills/*/SKILL.md`.
+  const cases: Array<{ slug: string; mode: string }> = [
+    { slug: 'image-poster', mode: 'image' },
+    { slug: 'video-shortform', mode: 'video' },
+    { slug: 'audio-jingle', mode: 'audio' },
+    { slug: 'pptx-html-fidelity-audit', mode: 'utility' },
+    { slug: 'live-artifact', mode: 'prototype' },
+    { slug: 'simple-deck', mode: 'deck' },
+    { slug: 'design-brief', mode: 'design-system' },
+  ];
+
+  for (const { slug, mode } of cases) {
+    it(`accepts od.mode=${mode} from skills/${slug}`, () => {
+      const fm = parseFrontmatter(readSkill(slug));
+      expect((fm['od'] as Record<string, unknown> | undefined)?.['mode']).toBe(mode);
+      expect(validateFrontmatter('skills', fm, slug)).toBe(true);
+      expect(resolveManifest('skills', readSkill(slug), slug)).toBeTruthy();
+    });
+  }
+
+  it('still rejects an unknown od.mode value', () => {
+    const fm = parseFrontmatter(
+      [
+        '---',
+        'name: bogus-skill',
+        'description: A skill with a made-up mode.',
+        'od:',
+        '  mode: not-a-real-mode',
+        '---',
+      ].join('\n'),
+    );
+    expect(validateFrontmatter('skills', fm, 'bogus-skill')).toBe(false);
+  });
+});