[MCP] Add support for the /llms.txt component endpoint

.changeset/gold-snakes-smash.md

@@ -0,0 +1,5 @@
+---
+'@primer/mcp': minor
+---
+
+Adds support for fetching docs via the `/llms.txt` endpoint per-component

packages/mcp/src/primer.ts

@@ -21,10 +21,6 @@ function idToSlug(id: string): string {
     return 'dialog'
   }
 
-  if (id.startsWith('skeleton')) {
-    return 'skeleton-loaders'
-  }
-
   return id.replaceAll('_', '-')
 }
 

packages/mcp/src/server.ts

@@ -111,12 +111,27 @@ server.registerTool(
     })
     if (!match) {
       return {
-        content: [
-          {
-            type: 'text',
-            text: `There is no component named \`${name}\` in the @primer/react package. For a full list of components, use the \`list_components\` tool.`,
-          },
-        ],
+        isError: true,
+        errorMessage: `There is no component named \`${name}\` in the @primer/react package. For a full list of components, use the \`list_components\` tool.`,
+        content: [],
+      }
+    }
+
+    const llmsUrl = new URL(`/product/components/${match.slug}/llms.txt`, 'https://primer.style')
+    const llmsResponse = await fetch(llmsUrl)
+    if (llmsResponse.ok) {
+      try {
+        const llmsText = await llmsResponse.text()
+        return {
+          content: [
+            {
+              type: 'text',
+              text: llmsText,
+            },
+          ],
+        }
+      } catch (_: unknown) {
+        // If there's an error fetching or processing the llms.txt, we fall back to the regular documentation
       }
     }
 
@@ -691,13 +706,7 @@ server.registerTool(
     inputSchema: {
       surroundingText: z.string().describe('Text surrounding the image, relevant to the image.'),
       alt: z.string().describe('The alt text of the image being evaluated'),
-      image: z
-        .union([
-          z.instanceof(File).describe('The image src file being evaluated'),
-          z.url().describe('The URL of the image src being evaluated'),
-          z.string().describe('The file path of the image src being evaluated'),
-        ])
-        .describe('The image file, file path, or URL being evaluated'),
+      image: z.string().describe('The image URL or file path being evaluated'),
     },
   },
   async ({surroundingText, alt, image}) => {