fix: reduce brew noise in onboarding

src/agents/skills-status.test.ts

@@ -0,0 +1,42 @@
+import { describe, expect, it } from "vitest";
+import type { SkillEntry } from "./skills/types.js";
+import { buildWorkspaceSkillStatus } from "./skills-status.js";
+
+describe("buildWorkspaceSkillStatus", () => {
+  it("does not surface install options for OS-scoped skills on unsupported platforms", () => {
+    if (process.platform === "win32") {
+      // Keep this simple; win32 platform naming is already explicitly handled elsewhere.
+      return;
+    }
+
+    const mismatchedOs = process.platform === "darwin" ? "linux" : "darwin";
+
+    const entry: SkillEntry = {
+      skill: {
+        name: "os-scoped",
+        description: "test",
+        source: "test",
+        filePath: "/tmp/os-scoped",
+        baseDir: "/tmp",
+      },
+      frontmatter: {},
+      metadata: {
+        os: [mismatchedOs],
+        requires: { bins: ["fakebin"] },
+        install: [
+          {
+            id: "brew",
+            kind: "brew",
+            formula: "fake",
+            bins: ["fakebin"],
+            label: "Install fake (brew)",
+          },
+        ],
+      },
+    };
+
+    const report = buildWorkspaceSkillStatus("/tmp/ws", { entries: [entry] });
+    expect(report.skills).toHaveLength(1);
+    expect(report.skills[0]?.install).toEqual([]);
+  });
+});

src/agents/skills-status.ts

@@ -111,6 +111,13 @@ function normalizeInstallOptions(
   entry: SkillEntry,
   prefs: SkillsInstallPreferences,
 ): SkillInstallOption[] {
+  // If the skill is explicitly OS-scoped, don't surface install actions on unsupported platforms.
+  // (Installers run locally; remote OS eligibility is handled separately.)
+  const requiredOs = entry.metadata?.os ?? [];
+  if (requiredOs.length > 0 && !requiredOs.includes(process.platform)) {
+    return [];
+  }
+
   const install = entry.metadata?.install ?? [];
   if (install.length === 0) {
     return [];