fix: tolerate Bun's spurious EEXIST from recursive mkdir on Windows ReadOnly dirs

scripts/fs-utils.ts

@@ -0,0 +1,29 @@
+import * as fs from 'fs';
+
+/**
+ * Drop-in replacement for fs.mkdirSync(dir, { recursive: true }).
+ *
+ * Bun on Windows (still present in 1.3.11) throws EEXIST from recursive
+ * mkdirSync when the target directory already exists AND carries the
+ * FILE_ATTRIBUTE_READONLY attribute (harmless on directories - Explorer
+ * repurposes it as a "customized folder" marker). Node treats the same
+ * call as a no-op success. See oven-sh/bun#16466 (the plain-dir variant,
+ * fixed) - the ReadOnly variant still reproduces.
+ *
+ * Guard: swallow EEXIST only after confirming the path is an existing
+ * directory; a collision with a regular file still throws.
+ */
+export function mkdirpSync(dir: string): void {
+  try {
+    fs.mkdirSync(dir, { recursive: true });
+  } catch (error) {
+    if ((error as { code?: string }).code === 'EEXIST') {
+      try {
+        if (fs.statSync(dir).isDirectory()) return;
+      } catch {
+        // fall through and rethrow the original mkdir error
+      }
+    }
+    throw error;
+  }
+}

scripts/gen-llms-txt.ts

@@ -20,6 +20,7 @@
 import * as fs from 'fs';
 import * as path from 'path';
 import { discoverTemplates } from './discover-skills';
+import { mkdirpSync } from './fs-utils';
 import { COMMAND_DESCRIPTIONS as BROWSE_COMMANDS } from '../browse/src/commands';
 
 const ROOT = path.resolve(import.meta.dir, '..');
@@ -224,7 +225,7 @@ export async function generateLlmsTxt(opts: GenerateOptions = {}): Promise<Gener
 export async function writeLlmsTxt(opts: GenerateOptions & { outputPath?: string } = {}): Promise<GenerateResult> {
   const result = await generateLlmsTxt(opts);
   const outputPath = opts.outputPath ?? OUTPUT;
-  fs.mkdirSync(path.dirname(outputPath), { recursive: true });
+  mkdirpSync(path.dirname(outputPath));
   fs.writeFileSync(outputPath, result.content, { encoding: 'utf-8' });
   return result;
 }

scripts/gen-skill-docs.ts

@@ -13,6 +13,7 @@ import { COMMAND_DESCRIPTIONS } from '../browse/src/commands';
 import { SNAPSHOT_FLAGS } from '../browse/src/snapshot';
 import { discoverTemplates, discoverSectionTemplates } from './discover-skills';
 import { writeLlmsTxt } from './gen-llms-txt';
+import { mkdirpSync } from './fs-utils';
 import * as fs from 'fs';
 import * as path from 'path';
 import type { Host, TemplateContext } from './resolvers/types';
@@ -752,7 +753,7 @@ function processExternalHost(
 
   const name = externalSkillName(skillDir === '.' ? '' : skillDir, frontmatterName);
   const outputDir = path.join(ROOT, hostConfig.hostSubdir, 'skills', name);
-  fs.mkdirSync(outputDir, { recursive: true });
+  mkdirpSync(outputDir);
   const outputPath = path.join(outputDir, 'SKILL.md');
 
   // Guard against symlink loops
@@ -787,7 +788,7 @@ function processExternalHost(
   // Config-driven: generate metadata (e.g., openai.yaml for Codex)
   if (hostConfig.generation.generateMetadata && !symlinkLoop) {
     const agentsDir = path.join(outputDir, 'agents');
-    fs.mkdirSync(agentsDir, { recursive: true });
+    mkdirpSync(agentsDir);
     const shortDescription = condenseOpenAIShortDescription(extractedDescription);
     fs.writeFileSync(path.join(agentsDir, 'openai.yaml'), generateOpenAIYaml(name, shortDescription));
   }
@@ -921,7 +922,7 @@ function processSectionTemplate(
     const externalName = externalSkillName(skillDir, parentName);
     outputPath = path.join(ROOT, hostConfig.hostSubdir, 'skills', externalName, 'sections', fileName);
   }
-  if (!DRY_RUN) fs.mkdirSync(path.dirname(outputPath), { recursive: true });
+  if (!DRY_RUN) mkdirpSync(path.dirname(outputPath));
   return { outputPath, content };
 }
 
@@ -996,7 +997,7 @@ for (const currentHost of hostsToRun) {
       } else {
         // In-place writes land in existing dirs; --out-dir needs the mirrored
         // skill dir created first.
-        if (OUT_DIR) fs.mkdirSync(path.dirname(outputPath), { recursive: true });
+        if (OUT_DIR) mkdirpSync(path.dirname(outputPath));
         fs.writeFileSync(outputPath, content);
         console.log(`GENERATED: ${relOutput}`);
       }
@@ -1058,7 +1059,7 @@ for (const currentHost of hostsToRun) {
     // Generate gstack-lite and gstack-full for OpenClaw host
     if (currentHost === 'openclaw' && !DRY_RUN) {
       const openclawDir = path.join(ROOT, 'openclaw');
-      if (!fs.existsSync(openclawDir)) fs.mkdirSync(openclawDir, { recursive: true });
+      mkdirpSync(openclawDir);
 
       const gstackLite = `# gstack-lite Planning Discipline