fix(discovery): isolated plugin root caches by home

Included the resolved OMP plugin registry path in cache identity and covered shared Claude config directories across isolated SDK homes.

packages/coding-agent/src/discovery/helpers.ts

@@ -906,17 +906,18 @@ export function registerPluginCacheInvalidator(invalidator: () => void): void {
  * List all installed Claude Code plugin roots from its active plugin cache and
  * ~/.omp/plugins/installed_plugins.json, plus the nearest project registry when present.
  *
- * Results are cached per Claude config directory, project registry, and canonical active project.
+ * Results are cached per Claude and OMP config directories, project registry, and canonical active project.
  */
 export async function listClaudePluginRoots(
 	home: string,
 	cwd?: string,
 ): Promise<{ roots: ClaudePluginRoot[]; warnings: string[] }> {
 	const claudeConfigDir = resolveClaudePaths(home).configDir;
+	const ompRegistryPath = path.join(getPluginsDir(home), "installed_plugins.json");
 	const resolvedProjectPath = cwd ? await resolveActiveProjectRegistryPath(cwd) : null;
 	const projectRoot = resolvedProjectPath ? path.dirname(path.dirname(path.dirname(resolvedProjectPath))) : cwd;
 	const activeClaudeProjectPath = projectRoot ? await canonicalClaudeProjectPath(projectRoot) : null;
-	const cacheKey = `${claudeConfigDir}:${resolvedProjectPath ?? ""}:${activeClaudeProjectPath ?? ""}`;
+	const cacheKey = `${claudeConfigDir}:${ompRegistryPath}:${resolvedProjectPath ?? ""}:${activeClaudeProjectPath ?? ""}`;
 	const cached = pluginRootsCache.get(cacheKey);
 	if (cached) return cached;
 
@@ -983,7 +984,7 @@ export async function listClaudePluginRoots(
 	// In production `home` is `os.homedir()`, so `getPluginsDir(home)` resolves to the
 	// same XDG-aware path the marketplace writer uses (reads and writes always agree).
 	// Tests pass a temp dir, which short-circuits the resolver for deterministic isolation.
-	const ompRegistryPath = path.join(getPluginsDir(home), "installed_plugins.json");
+	// Computed before the cache lookup because isolated SDK homes select distinct OMP registries.
 	const ompContent = await readFile(ompRegistryPath);
 	if (ompContent) {
 		const ompRegistry = parseClaudePluginsRegistry(ompContent);

packages/coding-agent/test/discovery/claude-plugins.test.ts

@@ -393,6 +393,41 @@ describe("listClaudePluginRoots", () => {
 		expect(result3.roots).toHaveLength(2);
 	});
 
+	test("isolates cached OMP plugin roots by home when Claude config is shared", async () => {
+		const sharedClaudeConfig = path.join(tempDir, "shared-claude");
+		const firstHome = path.join(tempDir, "first-home");
+		const secondHome = path.join(tempDir, "second-home");
+		process.env.CLAUDE_CONFIG_DIR = sharedClaudeConfig;
+		for (const [home, pluginId] of [
+			[firstHome, "first@market"],
+			[secondHome, "second@market"],
+		] as const) {
+			const pluginsDir = path.join(home, ".omp", "plugins");
+			await fs.mkdir(pluginsDir, { recursive: true });
+			await fs.writeFile(
+				path.join(pluginsDir, "installed_plugins.json"),
+				JSON.stringify({
+					version: 2,
+					plugins: {
+						[pluginId]: [
+							{
+								scope: "user",
+								installPath: `/path/to/${pluginId.split("@")[0]}`,
+								version: "1.0.0",
+							},
+						],
+					},
+				}),
+			);
+		}
+
+		const first = await listClaudePluginRoots(firstHome);
+		const second = await listClaudePluginRoots(secondHome);
+
+		expect(first.roots.map(root => root.id)).toEqual(["first@market"]);
+		expect(second.roots.map(root => root.id)).toEqual(["second@market"]);
+	});
+
 	test("defaults scope to user when not specified", async () => {
 		const pluginsDir = path.join(tempDir, ".claude", "plugins");
 		await fs.mkdir(pluginsDir, { recursive: true });