#780 Exclude top-level skills/_partials/ from skill installation

packages/agents/src/commands/__tests__/install-includes.test.ts

@@ -371,6 +371,44 @@ describe('install with include directives', () => {
       expect(existsSync(path.join(claudeHome, 'skills', 'demo-skill', 'modules', '_partials'))).toBe(false);
     });
 
+    it('does not install the top-level shared skills/_partials/ directory', async () => {
+      const contentDir = path.join(tempDir, 'fake-content');
+      // A `_partials` key under `skills` synthesizes the shared `content/skills/_partials/` directory as a sibling of
+      // real skills, covering the top-level enumeration case. The per-skill walk exclusions only match `_partials` as a
+      // child mid-walk, so a separate top-level exclusion is required when it is the walk root.
+      await buildContentTree(contentDir, {
+        skills: {
+          _partials: {
+            'plan-template.md': 'shared partial body\n',
+          },
+        },
+      });
+
+      const claudeHome = await setupClaudeHome();
+      await installCommand(makeOptions(), tempDir, contentDir);
+
+      expect(existsSync(path.join(claudeHome, 'skills', '_partials'))).toBe(false);
+      expect(existsSync(path.join(claudeHome, 'skills', '_partials', 'plan-template.md'))).toBe(false);
+    });
+
+    it('still installs other reserved top-level directories that skills reference at runtime (e.g. _data)', async () => {
+      // Guards the `_partials` exclusion from being over-generalized to an `_`-prefix skip: `_data/` is referenced by
+      // skills at runtime via absolute paths, so it must keep installing.
+      const contentDir = path.join(tempDir, 'fake-content');
+      await buildContentTree(contentDir, {
+        skills: {
+          _data: {
+            'design-priorities.md': 'shared data body\n',
+          },
+        },
+      });
+
+      const claudeHome = await setupClaudeHome();
+      await installCommand(makeOptions(), tempDir, contentDir);
+
+      expect(existsSync(path.join(claudeHome, 'skills', '_data', 'design-priorities.md'))).toBe(true);
+    });
+
     it('rewrites markdown links inside expanded skill content (expand-then-rewrite ordering)', async () => {
       const contentDir = path.join(tempDir, 'fake-content');
       await buildContentTree(contentDir, {

packages/agents/src/commands/__tests__/install.test.ts

@@ -72,7 +72,10 @@ describe(installCommand, () => {
     // Check that skills were installed — count should match shared + platform-specific
     const contentDir = resolveContentDir();
     const allSkillEntries = await readdir(path.join(contentDir, 'skills'));
-    const sharedSkillCount = allSkillEntries.filter((e) => e !== '_platforms' && !e.startsWith('.')).length;
+    // Mirror the install enumeration's skip set: `_platforms` and `_partials` are excluded, dotfiles too.
+    const sharedSkillCount = allSkillEntries.filter(
+      (e) => e !== '_platforms' && e !== '_partials' && !e.startsWith('.'),
+    ).length;
     const platformSkillsDir = path.join(contentDir, 'skills', '_platforms', 'claude');
     const platformSkillEntries = existsSync(platformSkillsDir) ? await readdir(platformSkillsDir) : [];
     const platformSkillCount = platformSkillEntries.filter((e) => !e.startsWith('.')).length;

packages/agents/src/commands/install.ts

@@ -190,9 +190,14 @@ async function installSkills(
   const dirEntries = await readdir(skillsSrcDir);
   const entries: Array<ManifestEntry> = [];
 
-  // Install shared skills and support directories (skip _platforms and dotfiles)
+  // Install shared skills and support directories. Skip `_platforms` (installed by the platform-specific pass below)
+  // and `_partials` (an install-time include target whose content is inlined into including skills, never installed as
+  // a standalone directory), plus dotfiles. This mirrors the per-skill `_partials` walk exclusion, which only matches
+  // `_partials` as a child and so never fires when it is the enumeration root. Other reserved directories such as
+  // `_data/` install normally — skills reference them at runtime by absolute path, so the skip is by name, not by the
+  // leading-underscore convention.
   for (const entry of dirEntries) {
-    if (entry === '_platforms' || entry.startsWith('.')) {
+    if (entry === '_platforms' || entry === '_partials' || entry.startsWith('.')) {
       continue;
     }
     const result = await installSkillEntry(