diff --git a/src/delegation/headless-executor.ts b/src/delegation/headless-executor.ts
index 3cf1b45f..9e2ad2c3 100644
--- a/src/delegation/headless-executor.ts
+++ b/src/delegation/headless-executor.ts
@@ -207,10 +207,15 @@ export class HeadlessExecutor {
         console.error(ui.info(`Delegating to ${modelName}...`));
       }
 
+      // Strip Claude Code nested session guard env var to allow CCS delegation
+      // (Claude Code v2.1.39+ sets CLAUDECODE to detect nested sessions)
+      const { CLAUDECODE: _nested, ...cleanEnv } = process.env;
+
       const proc = spawn(claudeCli, args, {
         cwd,
         stdio: ['ignore', 'pipe', 'pipe'],
         timeout,
+        env: cleanEnv,
       });
 
       let stdout = '';
diff --git a/src/utils/shell-executor.ts b/src/utils/shell-executor.ts
index 017cd709..e8a8b93f 100644
--- a/src/utils/shell-executor.ts
+++ b/src/utils/shell-executor.ts
@@ -84,6 +84,10 @@ export function execClaude(
     ? { ...baseEnv, ...envVars, ...webSearchEnv }
     : { ...baseEnv, ...webSearchEnv };
 
+  // Strip Claude Code nested session guard env var to allow CCS delegation
+  // (Claude Code v2.1.39+ sets CLAUDECODE to detect nested sessions)
+  delete env.CLAUDECODE;
+
   // propagate key env vars to tmux session so agent team teammates
   // (spawned via tmux split-window) inherit the correct config dir
   if (process.env.TMUX && envVars) {