fix: make OpenAI payload guard content-aware

src/agents/openai-compatible-conversation-turn.test.ts

@@ -0,0 +1,53 @@
+import { describe, expect, it } from "vitest";
+import { hasOpenAICompatibleConversationTurn } from "./openai-compatible-conversation-turn.js";
+
+describe("hasOpenAICompatibleConversationTurn", () => {
+  it("rejects missing, system-only, and tool-only payloads", () => {
+    expect(hasOpenAICompatibleConversationTurn(undefined)).toBe(false);
+    expect(hasOpenAICompatibleConversationTurn([{ role: "system", content: "policy" }])).toBe(
+      false,
+    );
+    expect(
+      hasOpenAICompatibleConversationTurn([
+        { role: "system", content: "policy" },
+        { role: "tool", content: "tool output", tool_call_id: "call_1" },
+      ]),
+    ).toBe(false);
+  });
+
+  it("rejects empty user and assistant placeholders", () => {
+    expect(hasOpenAICompatibleConversationTurn([{ role: "user", content: "" }])).toBe(false);
+    expect(hasOpenAICompatibleConversationTurn([{ role: "user", content: "   " }])).toBe(false);
+    expect(hasOpenAICompatibleConversationTurn([{ role: "assistant", content: null }])).toBe(false);
+    expect(hasOpenAICompatibleConversationTurn([{ role: "assistant", content: [] }])).toBe(false);
+  });
+
+  it("accepts non-empty user and assistant content", () => {
+    expect(hasOpenAICompatibleConversationTurn([{ role: "user", content: "hello" }])).toBe(true);
+    expect(
+      hasOpenAICompatibleConversationTurn([
+        { role: "user", content: [{ type: "text", text: "hello" }] },
+      ]),
+    ).toBe(true);
+    expect(
+      hasOpenAICompatibleConversationTurn([
+        { role: "user", content: [{ type: "image_url", image_url: { url: "data:image/png" } }] },
+      ]),
+    ).toBe(true);
+    expect(hasOpenAICompatibleConversationTurn([{ role: "assistant", content: "answer" }])).toBe(
+      true,
+    );
+  });
+
+  it("accepts assistant tool calls even when assistant content is empty", () => {
+    expect(
+      hasOpenAICompatibleConversationTurn([
+        {
+          role: "assistant",
+          content: null,
+          tool_calls: [{ id: "call_1", type: "function", function: { name: "status" } }],
+        },
+      ]),
+    ).toBe(true);
+  });
+});

src/agents/openai-compatible-conversation-turn.ts

@@ -0,0 +1,53 @@
+function hasNonEmptyString(value: unknown): boolean {
+  return typeof value === "string" && value.trim().length > 0;
+}
+
+function hasNonEmptyContentPart(part: unknown): boolean {
+  if (!part || typeof part !== "object") {
+    return false;
+  }
+  const record = part as Record<string, unknown>;
+  if (record.type === "text") {
+    return hasNonEmptyString(record.text);
+  }
+  return true;
+}
+
+function hasNonEmptyMessageContent(content: unknown): boolean {
+  if (hasNonEmptyString(content)) {
+    return true;
+  }
+  if (!Array.isArray(content)) {
+    return false;
+  }
+  return content.some(hasNonEmptyContentPart);
+}
+
+function hasAssistantToolCall(message: Record<string, unknown>): boolean {
+  const toolCalls = message.tool_calls;
+  return (
+    Array.isArray(toolCalls) &&
+    toolCalls.some((toolCall) => {
+      return Boolean(toolCall && typeof toolCall === "object");
+    })
+  );
+}
+
+export function hasOpenAICompatibleConversationTurn(messages: unknown): boolean {
+  if (!Array.isArray(messages)) {
+    return false;
+  }
+  return messages.some((message) => {
+    if (!message || typeof message !== "object") {
+      return false;
+    }
+    const record = message as Record<string, unknown>;
+    if (record.role === "user") {
+      return hasNonEmptyMessageContent(record.content);
+    }
+    if (record.role === "assistant") {
+      return hasNonEmptyMessageContent(record.content) || hasAssistantToolCall(record);
+    }
+    return false;
+  });
+}

src/agents/openai-transport-stream.test.ts

@@ -1062,7 +1062,9 @@ describe("openai transport stream", () => {
     }
 
     expect(errorPayload).toMatchObject({ stopReason: "error" });
-    expect(String(errorPayload?.errorMessage)).toContain("contains no user or assistant messages");
+    expect(String(errorPayload?.errorMessage)).toContain(
+      "contains no non-empty user or assistant messages",
+    );
     expect(String(errorPayload?.errorMessage)).toContain("system/tool-only request");
   });
 

src/agents/openai-transport-stream.ts

@@ -40,6 +40,7 @@ import {
   resolveModelSseDebugMode,
 } from "./model-transport-debug.js";
 import { formatModelTransportDebugBaseUrl } from "./model-transport-url.js";
+import { hasOpenAICompatibleConversationTurn } from "./openai-compatible-conversation-turn.js";
 import { detectOpenAICompletionsCompat } from "./openai-completions-compat.js";
 import {
   flattenCompletionMessagesToStringContent,
@@ -2295,21 +2296,11 @@ function assertOpenAICompletionsPayloadHasConversationTurn(
   model: Model<Api>,
 ): void {
   const messages = params.messages;
-  if (!Array.isArray(messages)) {
-    return;
-  }
-  const hasConversationTurn = messages.some((message) => {
-    if (!message || typeof message !== "object") {
-      return false;
-    }
-    const role = (message as { role?: unknown }).role;
-    return role === "user" || role === "assistant";
-  });
-  if (hasConversationTurn) {
+  if (!Array.isArray(messages) || hasOpenAICompatibleConversationTurn(messages)) {
     return;
   }
   throw new Error(
-    `OpenAI-compatible chat payload for ${model.provider}/${model.id} contains no user or assistant messages after compaction and transport transforms; refusing to send a system/tool-only request. Start a new user turn or repair the compacted session history.`,
+    `OpenAI-compatible chat payload for ${model.provider}/${model.id} contains no non-empty user or assistant messages after compaction and transport transforms; refusing to send a system/tool-only request. Start a new user turn or repair the compacted session history.`,
   );
 }
 

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

@@ -143,6 +143,19 @@ describe("resolvePromptSubmissionSkipReason", () => {
     ).toBe("empty_prompt_history_images");
   });
 
+  it("treats empty user and assistant placeholders as empty history", () => {
+    expect(
+      resolvePromptSubmissionSkipReason({
+        prompt: "   ",
+        messages: [
+          { role: "user", content: "   " },
+          { role: "assistant", content: [] },
+        ],
+        imageCount: 0,
+      }),
+    ).toBe("empty_prompt_history_images");
+  });
+
   it("allows text or image prompt submissions", () => {
     expect(
       resolvePromptSubmissionSkipReason({

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

@@ -18,6 +18,7 @@ import { listActiveProcessSessionReferences } from "../../bash-process-reference
 import { resolveHeartbeatPromptForSystemPrompt } from "../../heartbeat-system-prompt.js";
 import { buildActiveImageGenerationTaskPromptContextForSession } from "../../image-generation-task-status.js";
 import { buildActiveMusicGenerationTaskPromptContextForSession } from "../../music-generation-task-status.js";
+import { hasOpenAICompatibleConversationTurn } from "../../openai-compatible-conversation-turn.js";
 import { resolveProcessToolScopeKey } from "../../pi-tools.js";
 import { prependSystemPromptAdditionAfterCacheBoundary } from "../../system-prompt-cache-boundary.js";
 import { resolveEffectiveToolFsWorkspaceOnly } from "../../tool-fs-policy.js";
@@ -242,16 +243,6 @@ export function shouldWarnOnOrphanedUserRepair(
 
 export type PromptSubmissionSkipReason = "blank_user_prompt" | "empty_prompt_history_images";
 
-function hasProviderVisibleConversationTurn(messages: readonly unknown[]): boolean {
-  return messages.some((message) => {
-    if (!message || typeof message !== "object") {
-      return false;
-    }
-    const role = (message as { role?: unknown }).role;
-    return role === "user" || role === "assistant";
-  });
-}
-
 export function resolvePromptSubmissionSkipReason(params: {
   prompt: string;
   messages: readonly unknown[];
@@ -261,7 +252,7 @@ export function resolvePromptSubmissionSkipReason(params: {
   if (params.prompt.trim().length > 0 || params.imageCount > 0) {
     return null;
   }
-  return hasProviderVisibleConversationTurn(params.messages)
+  return hasOpenAICompatibleConversationTurn(params.messages)
     ? "blank_user_prompt"
     : "empty_prompt_history_images";
 }