fix: guard blank prompt submissions (#74168)

Fixes #74137.\n\nThanks @yelog.

CHANGELOG.md

@@ -13,6 +13,7 @@ Docs: https://docs.openclaw.ai
 
 - Agents/tool-result guard: use the resolved runtime context token budget for non-context-engine tool-result overflow checks, so long tool-heavy sessions no longer compact early when `contextTokens` is larger than native `contextWindow`. Fixes #74917. Thanks @kAIborg24.
 - Gateway/systemd: exit with sysexits 78 for supervised lock and `EADDRINUSE` conflicts so `RestartPreventExitStatus=78` stops `Restart=always` restart loops instead of repeatedly reloading plugins against an occupied port. Fixes #75115. Thanks @yhyatt.
+- Agents/runtime: skip blank visible user prompts at the embedded-runner boundary before provider submission while still allowing internal runtime-only turns and media-only prompts, so Telegram/group sessions no longer leak raw empty-input provider errors when replay history exists. Fixes #74137. Thanks @yelog, @Gracker, and @nhaener.
 - Plugins/runtime-deps: replace stale symlinked mirror target roots before writing runtime-mirror temp files and skip rewriting already materialized hardlinks, so cross-version container upgrades no longer crash-loop on read-only image-layer paths while warm mirrors do less churn. Fixes #75108; refs #75069. Thanks @coletebou and @xiaohuaxi.
 - Auto-reply/group chats: fall back to automatic source delivery when a channel precomputes message-tool-only replies but the `message` tool is unavailable, so Discord/Slack-style group turns do not silently complete without a visible reply. Fixes #74868. Thanks @kagura-agent.
 - Browser/gateway: share one browser control runtime across the HTTP control server and `browser.request`, and refresh browser profile config from the source snapshot, so CLI status/start honors configured `browser.executablePath`, `headless`, and `noSandbox` instead of falling back to stale auto-detection. Fixes #75087; repairs #73617. Thanks @civiltox and @martingarramon.

src/agents/pi-embedded-runner/run/attempt.prompt-helpers.test.ts

@@ -18,7 +18,7 @@ vi.mock("../../../plugins/host-hook-state.js", () => hostHookStateMocks);
 
 import {
   forgetPromptBuildDrainCacheForRun,
-  hasPromptSubmissionContent,
+  resolvePromptSubmissionSkipReason,
   resolveAttemptPrependSystemContext,
   resolvePromptBuildHookResult,
 } from "./attempt.prompt-helpers.js";
@@ -73,42 +73,64 @@ describe("resolveAttemptPrependSystemContext", () => {
   });
 });
 
-describe("hasPromptSubmissionContent", () => {
-  it("rejects empty prompt submissions without history or images", () => {
+describe("resolvePromptSubmissionSkipReason", () => {
+  it("skips empty prompt submissions without history or images", () => {
     expect(
-      hasPromptSubmissionContent({
+      resolvePromptSubmissionSkipReason({
         prompt: "   ",
         messages: [],
         imageCount: 0,
       }),
-    ).toBe(false);
+    ).toBe("empty_prompt_history_images");
   });
 
-  it("allows blank prompt submissions when replay history has content", () => {
+  it("skips blank visible user prompt submissions even when replay history exists", () => {
     expect(
-      hasPromptSubmissionContent({
+      resolvePromptSubmissionSkipReason({
         prompt: "   ",
         messages: [{ role: "user", content: "previous turn", timestamp: 1 }],
         imageCount: 0,
       }),
-    ).toBe(true);
+    ).toBe("blank_user_prompt");
   });
 
   it("allows text or image prompt submissions", () => {
     expect(
-      hasPromptSubmissionContent({
+      resolvePromptSubmissionSkipReason({
         prompt: "hello",
         messages: [],
         imageCount: 0,
       }),
-    ).toBe(true);
+    ).toBeNull();
     expect(
-      hasPromptSubmissionContent({
+      resolvePromptSubmissionSkipReason({
         prompt: "   ",
         messages: [],
         imageCount: 1,
       }),
-    ).toBe(true);
+    ).toBeNull();
+  });
+
+  it("allows blank prompt on runtimeOnly turns", () => {
+    expect(
+      resolvePromptSubmissionSkipReason({
+        prompt: "",
+        messages: [],
+        runtimeOnly: true,
+        imageCount: 0,
+      }),
+    ).toBeNull();
+  });
+
+  it("treats undefined runtimeOnly as a visible user submission", () => {
+    expect(
+      resolvePromptSubmissionSkipReason({
+        prompt: "",
+        messages: [],
+        runtimeOnly: undefined,
+        imageCount: 0,
+      }),
+    ).toBe("empty_prompt_history_images");
   });
 });
 

src/agents/pi-embedded-runner/run/attempt.prompt-helpers.ts

@@ -236,12 +236,21 @@ export function shouldWarnOnOrphanedUserRepair(
   return trigger === "user" || trigger === "manual";
 }
 
-export function hasPromptSubmissionContent(params: {
+export type PromptSubmissionSkipReason = "blank_user_prompt" | "empty_prompt_history_images";
+
+export function resolvePromptSubmissionSkipReason(params: {
   prompt: string;
   messages: readonly unknown[];
   imageCount: number;
-}): boolean {
-  return params.prompt.trim().length > 0 || params.messages.length > 0 || params.imageCount > 0;
+  runtimeOnly?: boolean;
+}): PromptSubmissionSkipReason | null {
+  if (params.runtimeOnly) {
+    return null;
+  }
+  if (params.prompt.trim().length > 0 || params.imageCount > 0) {
+    return null;
+  }
+  return params.messages.length > 0 ? "blank_user_prompt" : "empty_prompt_history_images";
 }
 
 const QUEUED_USER_MESSAGE_MARKER =

src/agents/pi-embedded-runner/run/attempt.spawn-workspace.context-engine.test.ts

@@ -284,6 +284,44 @@ describe("runEmbeddedAttempt context engine sessionKey forwarding", () => {
     expect(contextCompiled?.data?.systemPrompt).toContain("internal heartbeat event");
   });
 
+  it("skips blank visible prompts with replay history before provider submission", async () => {
+    const sessionPrompt = vi.fn(async () => {
+      throw new Error("blank prompt should not be submitted");
+    });
+
+    const result = await createContextEngineAttemptRunner({
+      contextEngine: createContextEngineBootstrapAndAssemble(),
+      sessionKey,
+      tempPaths,
+      attemptOverrides: {
+        prompt: "  \n\t  ",
+      },
+      sessionPrompt,
+    });
+
+    expect(sessionPrompt).not.toHaveBeenCalled();
+    expect(result.finalPromptText).toBeUndefined();
+    expect(result.promptError).toBeFalsy();
+    expect(result.messagesSnapshot).toEqual([
+      expect.objectContaining({ role: "user", content: "seed" }),
+    ]);
+    const trajectoryEvents = (
+      await fs.readFile(path.join(tempPaths[0] ?? "", "session.trajectory.jsonl"), "utf8")
+    )
+      .trim()
+      .split("\n")
+      .map((line) => JSON.parse(line) as TrajectoryEvent);
+    expect(trajectoryEvents.some((event) => event.type === "prompt.submitted")).toBe(false);
+    expect(trajectoryEvents).toEqual(
+      expect.arrayContaining([
+        expect.objectContaining({
+          type: "prompt.skipped",
+          data: expect.objectContaining({ reason: "blank_user_prompt" }),
+        }),
+      ]),
+    );
+  });
+
   it("keeps gateway model runs independent from agent context and session history", async () => {
     const bootstrap = vi.fn(async () => ({ bootstrapped: true }));
     const assemble = vi.fn(async ({ messages }: { messages: AgentMessage[] }) => ({

src/agents/pi-embedded-runner/run/attempt.ts

@@ -268,7 +268,7 @@ import {
   resolveAttemptPrependSystemContext,
   resolvePromptBuildHookResult,
   resolvePromptModeForSession,
-  hasPromptSubmissionContent,
+  resolvePromptSubmissionSkipReason,
   shouldWarnOnOrphanedUserRepair,
   shouldInjectHeartbeatPrompt,
 } from "./attempt.prompt-helpers.js";
@@ -2677,23 +2677,26 @@ export async function runEmbeddedAttempt(
             transcriptLeafId,
           });
 
-          if (
-            !skipPromptSubmission &&
-            !promptSubmission.runtimeOnly &&
-            !hasPromptSubmissionContent({
-              prompt: promptSubmission.prompt,
-              messages: activeSession.messages,
-              imageCount: imageResult.images.length,
-            })
-          ) {
+          const promptSkipReason = skipPromptSubmission
+            ? null
+            : resolvePromptSubmissionSkipReason({
+                prompt: promptSubmission.prompt,
+                messages: activeSession.messages,
+                runtimeOnly: promptSubmission.runtimeOnly,
+                imageCount: imageResult.images.length,
+              });
+          if (promptSkipReason) {
             skipPromptSubmission = true;
-            log.info(
-              `embedded run prompt skipped: empty prompt/history/images ` +
-                `runId=${params.runId} sessionId=${params.sessionId} trigger=${params.trigger} ` +
-                `provider=${params.provider}/${params.modelId}`,
-            );
+            const skipContext =
+              `runId=${params.runId} sessionId=${params.sessionId} trigger=${params.trigger} ` +
+              `provider=${params.provider}/${params.modelId}`;
+            if (promptSkipReason === "blank_user_prompt") {
+              log.warn(`embedded run prompt skipped: blank user prompt ${skipContext}`);
+            } else {
+              log.info(`embedded run prompt skipped: empty prompt/history/images ${skipContext}`);
+            }
             trajectoryRecorder?.recordEvent("prompt.skipped", {
-              reason: "empty_prompt_history_images",
+              reason: promptSkipReason,
               prompt: promptSubmission.prompt,
               messages: activeSession.messages,
               imagesCount: imageResult.images.length,