Fix orphan chat tool results

Author: Codex

src/adapters/openai-chat.ts

@@ -7,6 +7,7 @@ import { contentPartsToText } from "./image";
 function messagesToChatFormat(parsed: OcxParsedRequest): unknown[] {
   const out: unknown[] = [];
   const { context, options } = parsed;
+  let pendingToolCallIds = new Set<string>();
 
   if (context.systemPrompt && context.systemPrompt.length > 0) {
     // Codex sends its GPT-5 identity prompt for EVERY model (the per-model catalog
@@ -39,6 +40,7 @@ function messagesToChatFormat(parsed: OcxParsedRequest): unknown[] {
             out.push({ role: "user", content: chatParts });
           }
         }
+        pendingToolCallIds = new Set();
         break;
       }
       case "assistant": {
@@ -61,14 +63,33 @@ function messagesToChatFormat(parsed: OcxParsedRequest): unknown[] {
         // like DeepSeek reject an assistant message with neither content nor tool_calls.
         if (chatMsg.content === undefined && chatMsg.tool_calls === undefined) break;
         out.push(chatMsg);
+        pendingToolCallIds = new Set(toolCalls.map(tc => tc.id).filter(Boolean));
         break;
       }
       case "toolResult": {
+        let toolCallId = msg.toolCallId;
+        if (!toolCallId) toolCallId = `call_orphan_${out.length}`;
+        if (!pendingToolCallIds.has(toolCallId)) {
+          // WS turns can arrive with only tool outputs; chat-completions providers reject a bare
+          // role:"tool" message unless an assistant tool_call with the same id immediately precedes it.
+          const name = safeToolName(msg.toolName);
+          out.push({
+            role: "assistant",
+            content: null,
+            tool_calls: [{
+              id: toolCallId,
+              type: "function",
+              function: { name, arguments: "{}" },
+            }],
+          });
+          pendingToolCallIds = new Set([toolCallId]);
+        }
         out.push({
           role: "tool",
-          tool_call_id: msg.toolCallId,
+          tool_call_id: toolCallId,
           content: contentPartsToText(msg.content),
         });
+        pendingToolCallIds.delete(toolCallId);
         break;
       }
     }
@@ -77,6 +98,12 @@ function messagesToChatFormat(parsed: OcxParsedRequest): unknown[] {
   return out;
 }
 
+function safeToolName(name: string | undefined): string {
+  const raw = name && name.trim().length > 0 ? name : "tool_result";
+  const sanitized = raw.replace(/[^A-Za-z0-9_-]/g, "_");
+  return sanitized.length > 0 ? sanitized : "tool_result";
+}
+
 function toolsToChatFormat(parsed: OcxParsedRequest): unknown[] | undefined {
   if (!parsed.context.tools || parsed.context.tools.length === 0) return undefined;
   return parsed.context.tools.map(t => ({

tests/adapter-usage.test.ts

@@ -130,3 +130,84 @@ describe("usage and content retention (F2)", () => {
     expect(dones[0]).toEqual({ type: "done", usage: { inputTokens: 4, outputTokens: 2 } });
   });
 });
+
+describe("openai-chat tool history repair", () => {
+  test("inserts a synthetic assistant tool_call before orphan tool results", () => {
+    const adapter = createOpenAIChatAdapter(provider);
+    const request = adapter.buildRequest({
+      modelId: "deepseek-v4",
+      context: {
+        messages: [{
+          role: "toolResult",
+          toolCallId: "call_1",
+          toolName: "codex.list_mcp_resources",
+          content: '{"resources":[]}',
+          isError: false,
+          timestamp: 0,
+        }],
+      },
+      stream: true,
+      options: {},
+    });
+    const body = JSON.parse(request.body) as { messages: Record<string, unknown>[] };
+
+    expect(body.messages).toHaveLength(2);
+    expect(body.messages[0]).toMatchObject({
+      role: "assistant",
+      content: null,
+      tool_calls: [{
+        id: "call_1",
+        type: "function",
+        function: { name: "codex_list_mcp_resources", arguments: "{}" },
+      }],
+    });
+    expect(body.messages[1]).toMatchObject({
+      role: "tool",
+      tool_call_id: "call_1",
+      content: '{"resources":[]}',
+    });
+  });
+
+  test("keeps paired tool results attached to the prior assistant tool_call", () => {
+    const adapter = createOpenAIChatAdapter(provider);
+    const request = adapter.buildRequest({
+      modelId: "deepseek-v4",
+      context: {
+        messages: [
+          {
+            role: "assistant",
+            content: [{
+              type: "toolCall",
+              id: "call_1",
+              name: "read_file",
+              arguments: { path: "README.md" },
+            }],
+            model: "deepseek-v4",
+            timestamp: 0,
+          },
+          {
+            role: "toolResult",
+            toolCallId: "call_1",
+            toolName: "read_file",
+            content: "contents",
+            isError: false,
+            timestamp: 0,
+          },
+        ],
+      },
+      stream: true,
+      options: {},
+    });
+    const body = JSON.parse(request.body) as { messages: Record<string, unknown>[] };
+
+    expect(body.messages).toHaveLength(2);
+    expect(body.messages[0]).toMatchObject({
+      role: "assistant",
+      tool_calls: [{
+        id: "call_1",
+        function: { name: "read_file", arguments: '{"path":"README.md"}' },
+      }],
+    });
+    expect(body.messages[1]).toMatchObject({ role: "tool", tool_call_id: "call_1" });
+  });
+});