diff --git a/src/run-claude-sdk.ts b/src/run-claude-sdk.ts
index d032f93..d388610 100644
--- a/src/run-claude-sdk.ts
+++ b/src/run-claude-sdk.ts
@@ -16,7 +16,7 @@ export type ClaudeRunResult = {
   structuredOutput?: string;
 };
 
-const EXECUTION_FILE = `${process.env.RUNNER_TEMP}/claude-execution-output.json`;
+const EXECUTION_FILE = `${process.env.RUNNER_TEMP || "/tmp"}/claude-execution-output.json`;
 
 /** Filename for the user request file, written by prompt generation */
 const USER_REQUEST_FILENAME = "claude-user-request.txt";