feat: MCP server error handling for missing binary

Added comprehensive error handling for when renamify CLI binary is missing:
- Detects ENOENT errors and provides helpful installation instructions
- Includes curl install command and documentation link
- Added tests for both executeCommand and preview error scenarios
- Distinguishes between missing binary vs missing plan file errors

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: ndbroadbent

renamify-mcp/src/renamify-service.error.test.ts

@@ -32,8 +32,8 @@ describe('RenamifyService Error Handling', () => {
         service.plan({ search: 'old', replace: 'new' })
       ).rejects.toThrow(
         'Renamify CLI not found. Please install it using:\n\n' +
-        'curl -fsSL https://docspring.github.io/renamify/install.sh | bash\n\n' +
-        'For more installation options, visit: https://docspring.github.io/renamify/installation/'
+          'curl -fsSL https://docspring.github.io/renamify/install.sh | bash\n\n' +
+          'For more installation options, visit: https://docspring.github.io/renamify/installation/'
       );
     });
 
@@ -96,8 +96,8 @@ describe('RenamifyService Error Handling', () => {
 
       await expect(service.preview({})).rejects.toThrow(
         'Renamify CLI not found. Please install it using:\n\n' +
-        'curl -fsSL https://docspring.github.io/renamify/install.sh | bash\n\n' +
-        'For more installation options, visit: https://docspring.github.io/renamify/installation/'
+          'curl -fsSL https://docspring.github.io/renamify/install.sh | bash\n\n' +
+          'For more installation options, visit: https://docspring.github.io/renamify/installation/'
       );
     });
 

renamify-mcp/src/renamify-service.ts

@@ -169,11 +169,15 @@ export class RenamifyService {
       return result.stdout;
     } catch (error) {
       // Check if the binary is missing (ENOENT error)
-      if (error instanceof Error && 'code' in error && error.code === 'ENOENT') {
+      if (
+        error instanceof Error &&
+        'code' in error &&
+        error.code === 'ENOENT'
+      ) {
         throw new Error(
           'Renamify CLI not found. Please install it using:\n\n' +
-          'curl -fsSL https://docspring.github.io/renamify/install.sh | bash\n\n' +
-          'For more installation options, visit: https://docspring.github.io/renamify/installation/'
+            'curl -fsSL https://docspring.github.io/renamify/install.sh | bash\n\n' +
+            'For more installation options, visit: https://docspring.github.io/renamify/installation/'
         );
       }
 
@@ -308,13 +312,12 @@ export class RenamifyService {
           // This is an execa error - binary not found
           throw new Error(
             'Renamify CLI not found. Please install it using:\n\n' +
-            'curl -fsSL https://docspring.github.io/renamify/install.sh | bash\n\n' +
-            'For more installation options, visit: https://docspring.github.io/renamify/installation/'
+              'curl -fsSL https://docspring.github.io/renamify/install.sh | bash\n\n' +
+              'For more installation options, visit: https://docspring.github.io/renamify/installation/'
           );
-        } else {
-          // This is a file access error - plan file not found
-          throw new Error(`Plan file not found: ${planPath}`);
         }
+        // This is a file access error - plan file not found
+        throw new Error(`Plan file not found: ${planPath}`);
       }
       if ('stderr' in error) {
         const execaError = error as ExecaError;