fix: install Cursor rules as mdc files

scripts/lib/install-targets/cursor-project.js

@@ -40,6 +40,11 @@ module.exports = createInstallTargetAdapter({
               repoRoot,
               sourceRelativePath,
               destinationDir: path.join(targetRoot, 'rules'),
+              destinationNameTransform(fileName) {
+                return fileName.endsWith('.md')
+                  ? `${fileName.slice(0, -3)}.mdc`
+                  : fileName;
+              },
             });
           }
 

scripts/lib/install-targets/helpers.js

@@ -181,7 +181,13 @@ function createNamespacedFlatRuleOperations(adapter, moduleId, sourceRelativePat
   return operations;
 }
 
-function createFlatRuleOperations({ moduleId, repoRoot, sourceRelativePath, destinationDir }) {
+function createFlatRuleOperations({
+  moduleId,
+  repoRoot,
+  sourceRelativePath,
+  destinationDir,
+  destinationNameTransform,
+}) {
   const normalizedSourcePath = normalizeRelativePath(sourceRelativePath);
   const sourceRoot = path.join(repoRoot || '', normalizedSourcePath);
 
@@ -201,7 +207,10 @@ function createFlatRuleOperations({ moduleId, repoRoot, sourceRelativePath, dest
     if (entry.isDirectory()) {
       const relativeFiles = listRelativeFiles(entryPath);
       for (const relativeFile of relativeFiles) {
-        const flattenedFileName = `${namespace}-${normalizeRelativePath(relativeFile).replace(/\//g, '-')}`;
+        const defaultFileName = `${namespace}-${normalizeRelativePath(relativeFile).replace(/\//g, '-')}`;
+        const flattenedFileName = typeof destinationNameTransform === 'function'
+          ? destinationNameTransform(defaultFileName)
+          : defaultFileName;
         operations.push(createManagedOperation({
           moduleId,
           sourceRelativePath: path.join(normalizedSourcePath, namespace, relativeFile),
@@ -210,10 +219,13 @@ function createFlatRuleOperations({ moduleId, repoRoot, sourceRelativePath, dest
         }));
       }
     } else if (entry.isFile()) {
+      const destinationFileName = typeof destinationNameTransform === 'function'
+        ? destinationNameTransform(entry.name)
+        : entry.name;
       operations.push(createManagedOperation({
         moduleId,
         sourceRelativePath: path.join(normalizedSourcePath, entry.name),
-        destinationPath: path.join(destinationDir, entry.name),
+        destinationPath: path.join(destinationDir, destinationFileName),
         strategy: 'flatten-copy',
       }));
     }

tests/lib/install-targets.test.js

@@ -103,7 +103,7 @@ function runTests() {
     assert.strictEqual(preserved.strategy, 'flatten-copy');
     assert.strictEqual(
       preserved.destinationPath,
-      path.join(projectRoot, '.cursor', 'rules', 'common-coding-style.md')
+      path.join(projectRoot, '.cursor', 'rules', 'common-coding-style.mdc')
     );
   })) passed++; else failed++;
 
@@ -126,16 +126,16 @@ function runTests() {
     assert.ok(
       plan.operations.some(operation => (
         normalizedRelativePath(operation.sourceRelativePath) === 'rules/common/coding-style.md'
-        && operation.destinationPath === path.join(projectRoot, '.cursor', 'rules', 'common-coding-style.md')
+        && operation.destinationPath === path.join(projectRoot, '.cursor', 'rules', 'common-coding-style.mdc')
       )),
-      'Should flatten common rules into namespaced files'
+      'Should flatten common rules into namespaced .mdc files'
     );
     assert.ok(
       plan.operations.some(operation => (
         normalizedRelativePath(operation.sourceRelativePath) === 'rules/typescript/testing.md'
-        && operation.destinationPath === path.join(projectRoot, '.cursor', 'rules', 'typescript-testing.md')
+        && operation.destinationPath === path.join(projectRoot, '.cursor', 'rules', 'typescript-testing.mdc')
       )),
-      'Should flatten language rules into namespaced files'
+      'Should flatten language rules into namespaced .mdc files'
     );
     assert.ok(
       !plan.operations.some(operation => (
@@ -143,6 +143,12 @@ function runTests() {
       )),
       'Should not preserve nested rule directories for cursor installs'
     );
+    assert.ok(
+      !plan.operations.some(operation => (
+        operation.destinationPath === path.join(projectRoot, '.cursor', 'rules', 'common-coding-style.md')
+      )),
+      'Should not emit .md Cursor rule files'
+    );
   })) passed++; else failed++;
 
   if (test('plans antigravity remaps for workflows, skills, and flat rules', () => {

tests/scripts/install-apply.test.js

@@ -130,8 +130,8 @@ function runTests() {
       const result = run(['--target', 'cursor', 'typescript'], { cwd: projectDir, homeDir });
       assert.strictEqual(result.code, 0, result.stderr);
 
-      assert.ok(fs.existsSync(path.join(projectDir, '.cursor', 'rules', 'common-coding-style.md')));
+      assert.ok(fs.existsSync(path.join(projectDir, '.cursor', 'rules', 'common-coding-style.mdc')));
-      assert.ok(fs.existsSync(path.join(projectDir, '.cursor', 'rules', 'typescript-testing.md')));
+      assert.ok(fs.existsSync(path.join(projectDir, '.cursor', 'rules', 'typescript-testing.mdc')));
       assert.ok(fs.existsSync(path.join(projectDir, '.cursor', 'agents', 'architect.md')));
       assert.ok(fs.existsSync(path.join(projectDir, '.cursor', 'commands', 'plan.md')));
       assert.ok(fs.existsSync(path.join(projectDir, '.cursor', 'hooks.json')));