diff --git a/src/targets/droid.ts b/src/targets/droid.ts
index 85600766..bdf72f43 100644
--- a/src/targets/droid.ts
+++ b/src/targets/droid.ts
@@ -9,7 +9,16 @@ export async function writeDroidBundle(outputRoot: string, bundle: DroidBundle):
   if (bundle.commands.length > 0) {
     await ensureDir(paths.commandsDir)
     for (const command of bundle.commands) {
-      await writeText(path.join(paths.commandsDir, `${command.name}.md`), command.content + "\n")
+      // Split colon-separated names into nested directories (e.g. "ce:plan" -> "ce/plan.md")
+      // to avoid colons in filenames which are invalid on Windows/NTFS
+      const parts = command.name.split(":")
+      if (parts.length > 1) {
+        const nestedDir = path.join(paths.commandsDir, ...parts.slice(0, -1))
+        await ensureDir(nestedDir)
+        await writeText(path.join(nestedDir, `${parts[parts.length - 1]}.md`), command.content + "\n")
+      } else {
+        await writeText(path.join(paths.commandsDir, `${command.name}.md`), command.content + "\n")
+      }
     }
   }
 
diff --git a/src/targets/gemini.ts b/src/targets/gemini.ts
index 0bc8c666..e818d1e9 100644
--- a/src/targets/gemini.ts
+++ b/src/targets/gemini.ts
@@ -20,7 +20,16 @@ export async function writeGeminiBundle(outputRoot: string, bundle: GeminiBundle
 
   if (bundle.commands.length > 0) {
     for (const command of bundle.commands) {
-      await writeText(path.join(paths.commandsDir, `${command.name}.toml`), command.content + "\n")
+      // Split colon-separated names into nested directories (e.g. "ce:plan" -> "ce/plan.toml")
+      // to avoid colons in filenames which are invalid on Windows/NTFS
+      const parts = command.name.split(":")
+      if (parts.length > 1) {
+        const nestedDir = path.join(paths.commandsDir, ...parts.slice(0, -1))
+        await ensureDir(nestedDir)
+        await writeText(path.join(nestedDir, `${parts[parts.length - 1]}.toml`), command.content + "\n")
+      } else {
+        await writeText(path.join(paths.commandsDir, `${command.name}.toml`), command.content + "\n")
+      }
     }
   }
 
diff --git a/src/targets/opencode.ts b/src/targets/opencode.ts
index b4bf53e7..894cf2ce 100644
--- a/src/targets/opencode.ts
+++ b/src/targets/opencode.ts
@@ -75,7 +75,17 @@ export async function writeOpenCodeBundle(outputRoot: string, bundle: OpenCodeBu
   }
 
   for (const commandFile of bundle.commandFiles) {
-    const dest = path.join(openCodePaths.commandDir, `${commandFile.name}.md`)
+    // Split colon-separated names into nested directories (e.g. "ce:plan" -> "ce/plan.md")
+    // to avoid colons in filenames which are invalid on Windows/NTFS
+    const parts = commandFile.name.split(":")
+    let dest: string
+    if (parts.length > 1) {
+      const nestedDir = path.join(openCodePaths.commandDir, ...parts.slice(0, -1))
+      await ensureDir(nestedDir)
+      dest = path.join(nestedDir, `${parts[parts.length - 1]}.md`)
+    } else {
+      dest = path.join(openCodePaths.commandDir, `${commandFile.name}.md`)
+    }
     const cmdBackupPath = await backupFile(dest)
     if (cmdBackupPath) {
       console.log(`Backed up existing command file to ${cmdBackupPath}`)