diff --git a/src/gateway/openresponses-http.test.ts b/src/gateway/openresponses-http.test.ts
index 4f2c184a162..8d21e515e45 100644
--- a/src/gateway/openresponses-http.test.ts
+++ b/src/gateway/openresponses-http.test.ts
@@ -466,8 +466,42 @@ describe("OpenResponses HTTP API (e2e)", () => {
         (optsInputFile as { extraSystemPrompt?: string } | undefined)?.extraSystemPrompt ?? "";
       expect(inputFileMessage).toBe("read this");
       expect(inputFilePrompt).toContain('<file name="hello.txt">');
+      expect(inputFilePrompt).toContain('<<<EXTERNAL_UNTRUSTED_CONTENT id="');
+      expect(inputFilePrompt).toContain("Source: External");
       await ensureResponseConsumed(resInputFile);
 
+      mockAgentOnce([{ text: "ok" }]);
+      const resInputFileWhitespace = await postResponses(port, {
+        model: "openclaw",
+        input: [
+          {
+            type: "message",
+            role: "user",
+            content: [
+              { type: "input_text", text: "read this" },
+              {
+                type: "input_file",
+                source: {
+                  type: "base64",
+                  media_type: "text/plain",
+                  data: Buffer.from("  hello  ").toString("base64"),
+                  filename: "spaces.txt",
+                },
+              },
+            ],
+          },
+        ],
+      });
+      expect(resInputFileWhitespace.status).toBe(200);
+      const optsInputFileWhitespace = (agentCommand.mock.calls[0] as unknown[] | undefined)?.[0];
+      const inputFileWhitespacePrompt =
+        (optsInputFileWhitespace as { extraSystemPrompt?: string } | undefined)
+          ?.extraSystemPrompt ?? "";
+      expect(inputFileWhitespacePrompt).toContain('<file name="spaces.txt">');
+      expect(inputFileWhitespacePrompt).toContain("\n  hello  \n");
+      expect(inputFileWhitespacePrompt).toContain('<<<EXTERNAL_UNTRUSTED_CONTENT id="');
+      await ensureResponseConsumed(resInputFileWhitespace);
+
       mockAgentOnce([{ text: "ok" }]);
       const resInputFileInjection = await postResponses(port, {
         model: "openclaw",
diff --git a/src/gateway/openresponses-http.ts b/src/gateway/openresponses-http.ts
index fd58b92c481..b1a4d69e6e2 100644
--- a/src/gateway/openresponses-http.ts
+++ b/src/gateway/openresponses-http.ts
@@ -602,12 +602,12 @@ export async function handleOpenResponsesHttpRequest(
                       },
                 limits: limits.files,
               });
-              const text = file.text?.trim();
-              if (text) {
+              const rawText = file.text;
+              if (rawText?.trim()) {
                 fileContexts.push(
                   renderFileContextBlock({
                     filename: file.filename,
-                    content: wrapUntrustedFileContent(text),
+                    content: wrapUntrustedFileContent(rawText),
                   }),
                 );
               } else if (file.images && file.images.length > 0) {