# Task ID: 56

**Title:** Implement prompt link resolution service

**Status:** done

**Dependencies:** 40 ✓

**Priority:** medium

**Description:** Create a service that fetches linked prompt content from source MCP servers using the project's service account, with dead link detection.

**Details:**

1. Create `/src/mcplocal/src/services/link-resolver.service.ts`:
   ```typescript
   export class LinkResolverService {
     constructor(private mcpdClient: McpdClient) {}
     
     async resolveLink(linkTarget: string): Promise<{
       content: string | null;
       status: 'alive' | 'dead' | 'unknown';
       error?: string;
     }> {
       // Parse linkTarget: project/server:resource-uri
       const { project, server, uri } = this.parseLink(linkTarget);
       
       try {
         // Use service account for source project
         const content = await this.fetchResource(project, server, uri);
         return { content, status: 'alive' };
       } catch (error) {
         this.logDeadLink(linkTarget, error);
         return { 
           content: null, 
           status: 'dead',
           error: error.message 
         };
       }
     }
     
     private parseLink(linkTarget: string): { project: string; server: string; uri: string } {
       const match = linkTarget.match(/^([^/]+)\/([^:]+):(.+)$/);
       if (!match) throw new Error('Invalid link format');
       return { project: match[1], server: match[2], uri: match[3] };
     }
     
     private async fetchResource(project: string, server: string, uri: string): Promise<string> {
       // Call mcpd to fetch resource via service account
       // mcpd routes to the source project's MCP server
     }
   }
   ```

2. Log dead links as errors

3. Cache resolution results

**Test Strategy:**

- Unit test: Valid link parsed correctly
- Unit test: Invalid link format throws error
- Unit test: Successful resolution returns content and status='alive'
- Unit test: Failed resolution returns status='dead' with error
- Unit test: Dead link logged as error
- Unit test: Service account header included in request
- Integration test: End-to-end link resolution