From 228cd488523bbabb29115a1232e723dfe4674ddf Mon Sep 17 00:00:00 2001
From: Alexander Davydov <nyddle@gmail.com>
Date: Mon, 16 Mar 2026 15:08:10 +0300
Subject: [PATCH] GigaChat: preserve parallel tool history

---
 src/agents/gigachat-stream.tool-calls.test.ts | 83 +++++++++++++++++++
 src/agents/gigachat-stream.ts                 | 47 +++++++----
 2 files changed, 113 insertions(+), 17 deletions(-)

diff --git a/src/agents/gigachat-stream.tool-calls.test.ts b/src/agents/gigachat-stream.tool-calls.test.ts
index e27c2fa3095..9a78e1d1d31 100644
--- a/src/agents/gigachat-stream.tool-calls.test.ts
+++ b/src/agents/gigachat-stream.tool-calls.test.ts
@@ -150,4 +150,87 @@ describe("createGigachatStreamFn tool calling", () => {
     );
     expect(event.content).toEqual([{ type: "text", text: "done" }]);
   });
+
+  it("preserves all historical tool calls from a single assistant turn", async () => {
+    request.mockResolvedValueOnce({
+      status: 200,
+      data: createSseStream(['data: {"choices":[{"delta":{"content":"done"}}]}', "data: [DONE]"]),
+    });
+
+    const streamFn = createGigachatStreamFn({
+      baseUrl: "https://gigachat.devices.sberbank.ru/api/v1",
+      authMode: "oauth",
+    });
+
+    const stream = streamFn(
+      { api: "gigachat", provider: "gigachat", id: "GigaChat-2-Max" } as never,
+      {
+        messages: [
+          {
+            role: "assistant",
+            content: [
+              { type: "text", text: "Working on it" },
+              {
+                type: "toolCall",
+                id: "call_1",
+                name: "llm-task",
+                arguments: { prompt: "first" },
+              },
+              {
+                type: "toolCall",
+                id: "call_2",
+                name: "web_search",
+                arguments: { query: "second" },
+              },
+            ],
+          },
+        ],
+        tools: [
+          {
+            name: "llm-task",
+            description: "Run a task",
+            parameters: {
+              type: "object",
+              properties: {
+                prompt: { type: "string" },
+              },
+            },
+          },
+          {
+            name: "web_search",
+            description: "Search the web",
+            parameters: {
+              type: "object",
+              properties: {
+                query: { type: "string" },
+              },
+            },
+          },
+        ],
+      } as never,
+      { apiKey: "token" } as never,
+    );
+
+    const event = await stream.result();
+
+    expect(request).toHaveBeenCalledWith(
+      expect.objectContaining({
+        data: expect.objectContaining({
+          messages: [
+            expect.objectContaining({
+              role: "assistant",
+              content: "Working on it",
+              function_call: expect.objectContaining({ name: "llm_task" }),
+            }),
+            expect.objectContaining({
+              role: "assistant",
+              content: "",
+              function_call: expect.objectContaining({ name: "gpt2giga_user_search_web" }),
+            }),
+          ],
+        }),
+      }),
+    );
+    expect(event.content).toEqual([{ type: "text", text: "done" }]);
+  });
 });
diff --git a/src/agents/gigachat-stream.ts b/src/agents/gigachat-stream.ts
index ceb6117cb11..caf67c8ddeb 100644
--- a/src/agents/gigachat-stream.ts
+++ b/src/agents/gigachat-stream.ts
@@ -39,6 +39,10 @@ export type GigachatStreamOptions = {
   scope?: string;
 };
 
+function stripLeakedFunctionCallPrelude(text: string): string {
+  return text.replace(/^\s*assistant\s+function\s+call(?:recipient)?\{\s*/i, "");
+}
+
 // ── Function name sanitization ──────────────────────────────────────────────
 // GigaChat requires function names to be alphanumeric + underscore only.
 
@@ -485,26 +489,34 @@ export function createGigachatStreamFn(opts: GigachatStreamOptions): StreamFn {
               .filter((c): c is TextContent => c.type === "text")
               .map((c) => c.text)
               .join("");
-            const toolCall = contentParts.find((c): c is ToolCall => c.type === "toolCall");
+            const toolCalls = contentParts.filter((c): c is ToolCall => c.type === "toolCall");
 
-            if (toolCall && toolCall.name && functionsEnabled) {
-              const gigaToolName = rememberToolNameMapping(
-                toolNameToGiga,
-                gigaToToolName,
-                toolCall.name,
-              );
-              messages.push({
-                role: "assistant",
-                content: text ? sanitizeContent(text) : "",
-                function_call: {
-                  name: gigaToolName,
-                  arguments: toolCall.arguments ?? {},
-                },
-              });
+            if (toolCalls.length > 0 && functionsEnabled) {
+              for (const [index, toolCall] of toolCalls.entries()) {
+                if (!toolCall.name) {
+                  continue;
+                }
+                const gigaToolName = rememberToolNameMapping(
+                  toolNameToGiga,
+                  gigaToToolName,
+                  toolCall.name,
+                );
+                messages.push({
+                  role: "assistant",
+                  content: index === 0 && text ? sanitizeContent(text) : "",
+                  function_call: {
+                    name: gigaToolName,
+                    arguments: toolCall.arguments ?? {},
+                  },
+                });
+              }
             } else if (text) {
               messages.push({ role: "assistant", content: sanitizeContent(text) });
-            } else if (toolCall && !functionsEnabled) {
-              messages.push({ role: "assistant", content: `[Called ${toolCall.name}]` });
+            } else if (toolCalls.length > 0 && !functionsEnabled) {
+              messages.push({
+                role: "assistant",
+                content: toolCalls.map((toolCall) => `[Called ${toolCall.name}]`).join(" "),
+              });
             }
           } else if (msg.role === "toolResult" && functionsEnabled) {
             const toolName = msg.toolName ?? "unknown";
@@ -729,6 +741,7 @@ export function createGigachatStreamFn(opts: GigachatStreamOptions): StreamFn {
         }
 
         if (functionCallBuffer && functionCallBuffer.name) {
+          accumulatedContent = stripLeakedFunctionCallPrelude(accumulatedContent);
           let parsedArgs: Record<string, unknown> = {};
           try {
             if (functionCallBuffer.arguments) {