diff --git a/codeagent-wrapper/internal/executor/env_stderr_test.go b/codeagent-wrapper/internal/executor/env_stderr_test.go
index 2af7439..cfd2504 100644
--- a/codeagent-wrapper/internal/executor/env_stderr_test.go
+++ b/codeagent-wrapper/internal/executor/env_stderr_test.go
@@ -125,6 +125,9 @@ func TestEnvInjection_LogsToStderrAndMasksKey(t *testing.T) {
 	if cmd.env["ANTHROPIC_API_KEY"] != apiKey {
 		t.Fatalf("ANTHROPIC_API_KEY=%q, want %q", cmd.env["ANTHROPIC_API_KEY"], apiKey)
 	}
+	if cmd.env["CLAUDE_CODE_TMPDIR"] == "" {
+		t.Fatalf("expected CLAUDE_CODE_TMPDIR to be set for nested claude, got empty")
+	}
 
 	if !strings.Contains(got, "Env: ANTHROPIC_BASE_URL="+baseURL) {
 		t.Fatalf("stderr missing base URL env log; stderr=%q", got)
@@ -132,4 +135,7 @@ func TestEnvInjection_LogsToStderrAndMasksKey(t *testing.T) {
 	if !strings.Contains(got, "Env: ANTHROPIC_API_KEY=eyJh****test") {
 		t.Fatalf("stderr missing masked API key log; stderr=%q", got)
 	}
+	if !strings.Contains(got, "CLAUDE_CODE_TMPDIR: ") {
+		t.Fatalf("stderr missing CLAUDE_CODE_TMPDIR log; stderr=%q", got)
+	}
 }
diff --git a/codeagent-wrapper/internal/executor/executor.go b/codeagent-wrapper/internal/executor/executor.go
index 1f95301..d1e79aa 100644
--- a/codeagent-wrapper/internal/executor/executor.go
+++ b/codeagent-wrapper/internal/executor/executor.go
@@ -1154,10 +1154,23 @@ func RunCodexTaskWithContext(parentCtx context.Context, taskSpec TaskSpec, backe
 
 	injectTempEnv(cmd)
 
-	// Claude Code sets CLAUDECODE=1 in its child processes. If we don't
-	// remove it, the spawned `claude -p` detects the variable and refuses
-	// to start ("cannot be launched inside another Claude Code session").
 	if commandName == "claude" {
+		// Claude 2.1.45+ calls Nz7() on startup to clean its tasks directory,
+		// which deletes the parent session's *.output files and causes "(no output)".
+		// Assign each nested claude its own isolated tmpdir so it only cleans its own files.
+		nestedTmpDir, err := os.MkdirTemp("", fmt.Sprintf("cc-nested-%d-", os.Getpid()))
+		if err != nil {
+			logWarnFn("Failed to create isolated CLAUDE_CODE_TMPDIR: " + err.Error())
+		} else {
+			cmd.SetEnv(map[string]string{"CLAUDE_CODE_TMPDIR": nestedTmpDir})
+			defer os.RemoveAll(nestedTmpDir) //nolint:errcheck
+			logInfoFn("CLAUDE_CODE_TMPDIR: " + nestedTmpDir)
+			fmt.Fprintln(os.Stderr, "  CLAUDE_CODE_TMPDIR: "+nestedTmpDir)
+		}
+
+		// Claude Code sets CLAUDECODE=1 in its child processes. If we don't
+		// remove it, the spawned `claude -p` detects the variable and refuses
+		// to start ("cannot be launched inside another Claude Code session").
 		cmd.UnsetEnv("CLAUDECODE")
 	}