Merge pull request #193 from storybookjs/fix-manifest-detection

Fix: Wrongly enabling docs toolset when only docs manifests where present

Author: JReinhold

.changeset/jolly-gifts-roll.md

@@ -0,0 +1,5 @@
+---
+'@storybook/addon-mcp': patch
+---
+
+Fix enabling docs toolset even when component manifests were not present

packages/addon-mcp/src/mcp-handler.test.ts

@@ -298,7 +298,7 @@ describe('mcpServerHandler', () => {
 				return { experimentalComponentsManifest: true };
 			}
 			if (key === 'experimental_manifests') {
-				return vi.fn();
+				return { components: { v: 1, components: {} } };
 			}
 			return defaultValue;
 		});
@@ -401,7 +401,7 @@ describe('mcpServerHandler', () => {
 				return { componentsManifest: true };
 			}
 			if (key === 'experimental_manifests') {
-				return vi.fn();
+				return { components: { v: 1, components: {} } };
 			}
 			return defaultValue;
 		});

packages/addon-mcp/src/preset.test.ts

@@ -77,7 +77,7 @@ describe('experimental_devServer', () => {
 						return Promise.resolve({ experimentalComponentsManifest: true });
 					}
 					if (key === 'experimental_manifests') {
-						return Promise.resolve({});
+						return Promise.resolve({ components: { v: 1, components: {} } });
 					}
 					return Promise.resolve(undefined);
 				}),

packages/addon-mcp/src/preset.ts

@@ -130,7 +130,7 @@ export const experimental_devServer: PresetPropertyFn<'experimental_devServer'>
 			</div>`;
 		} else if (!manifestStatus.hasFeatureFlag) {
 			docsNotice = `<div class="toolset-notice">
-				This toolset requires enabling the experimental component manifest feature.
+				This toolset requires enabling the component manifest feature.
 				<a target="_blank" href="https://github.com/storybookjs/mcp/tree/main/packages/addon-mcp#docs-tools-experimental">Learn how to enable it</a>
 			</div>`;
 		}

packages/addon-mcp/src/tools/is-manifest-available.test.ts

@@ -92,4 +92,27 @@ describe('getManifestStatus', () => {
 		const result = await getManifestStatus(mockOptions);
 		expect(result).toEqual(expected);
 	});
+
+	it('should correctly detect no manifests when components are not present in experimental_manifests', async () => {
+		// the `manifests` preset can be present but without manifests.components, because `addon-docs` sets manifests.docs
+		const result = await getManifestStatus({
+			presets: {
+				apply: vi.fn(async (key: string) => {
+					if (key === 'features') {
+						return { componentsManifest: true };
+					}
+					if (key === 'experimental_manifests') {
+						// addon-docs has set manifests.docs, but there are no actual component manifests
+						return { docs: { v: 1, docs: {} } };
+					}
+					return undefined;
+				}),
+			},
+		} as unknown as Options);
+		expect(result).toEqual({
+			available: false,
+			hasManifests: false,
+			hasFeatureFlag: true,
+		});
+	});
 });

packages/addon-mcp/src/tools/is-manifest-available.ts

@@ -21,7 +21,8 @@ export const getManifestStatus = async (options: Options): Promise<ManifestStatu
 		options.presets.apply('experimental_componentManifestGenerator'),
 	]);
 
-	const hasManifests = !!manifests || !!legacyComponentManifestGenerator;
+	const hasManifests =
+		(manifests && 'components' in manifests) || !!legacyComponentManifestGenerator;
 	const hasFeatureFlag = !!(
 		features?.componentsManifest ?? features?.experimentalComponentsManifest
 	);