From acfa9877b32a6de63cab204890c98df0c2f63c5d Mon Sep 17 00:00:00 2001
From: Peter Steinberger <steipete@gmail.com>
Date: Mon, 27 Apr 2026 02:02:16 +0100
Subject: [PATCH] fix: parse Ollama tool call arguments

---
 extensions/ollama/src/stream-runtime.test.ts | 69 +++++++++++++++++++-
 extensions/ollama/src/stream.ts              |  8 ++-
 2 files changed, 74 insertions(+), 3 deletions(-)

diff --git a/extensions/ollama/src/stream-runtime.test.ts b/extensions/ollama/src/stream-runtime.test.ts
index d6598dd04eb..dcd664b1f2d 100644
--- a/extensions/ollama/src/stream-runtime.test.ts
+++ b/extensions/ollama/src/stream-runtime.test.ts
@@ -606,6 +606,73 @@ describe("buildAssistantMessage", () => {
     expect(toolCall.id).toMatch(/^ollama_call_[0-9a-f-]{36}$/);
   });
 
+  it("parses stringified tool call arguments from Ollama responses", () => {
+    const response = {
+      model: "qwen3:32b",
+      created_at: "2026-01-01T00:00:00Z",
+      message: {
+        role: "assistant" as const,
+        content: "",
+        tool_calls: [{ function: { name: "bash", arguments: '{"command":"ls","path":"/tmp"}' } }],
+      },
+      done: true,
+    };
+    const result = buildAssistantMessage(response, modelInfo);
+    expect(result.content[0]).toMatchObject({
+      type: "toolCall",
+      name: "bash",
+      arguments: { command: "ls", path: "/tmp" },
+    });
+  });
+
+  it("preserves unsafe integers in stringified tool call arguments", () => {
+    const response = {
+      model: "qwen3:32b",
+      created_at: "2026-01-01T00:00:00Z",
+      message: {
+        role: "assistant" as const,
+        content: "",
+        tool_calls: [
+          {
+            function: {
+              name: "send",
+              arguments: '{"target":9223372036854775807,"nested":{"thread":1234567890123456789}}',
+            },
+          },
+        ],
+      },
+      done: true,
+    };
+    const result = buildAssistantMessage(response, modelInfo);
+    expect(result.content[0]).toMatchObject({
+      type: "toolCall",
+      name: "send",
+      arguments: {
+        target: "9223372036854775807",
+        nested: { thread: "1234567890123456789" },
+      },
+    });
+  });
+
+  it("falls back to empty arguments for malformed stringified tool call arguments", () => {
+    const response = {
+      model: "qwen3:32b",
+      created_at: "2026-01-01T00:00:00Z",
+      message: {
+        role: "assistant" as const,
+        content: "",
+        tool_calls: [{ function: { name: "bash", arguments: '{"command":"ls"' } }],
+      },
+      done: true,
+    };
+    const result = buildAssistantMessage(response, modelInfo);
+    expect(result.content[0]).toMatchObject({
+      type: "toolCall",
+      name: "bash",
+      arguments: {},
+    });
+  });
+
   it("sets all costs to zero for local models", () => {
     const response = {
       model: "qwen3:32b",
@@ -701,7 +768,7 @@ describe("parseNdjsonStream", () => {
 
     // Simulate the accumulation logic from createOllamaStreamFn
     const accumulatedToolCalls: Array<{
-      function: { name: string; arguments: Record<string, unknown> };
+      function: { name: string; arguments: unknown };
     }> = [];
     const chunks = [];
     for await (const chunk of parseNdjsonStream(reader)) {
diff --git a/extensions/ollama/src/stream.ts b/extensions/ollama/src/stream.ts
index c1f45a2070e..4dfd694fcdd 100644
--- a/extensions/ollama/src/stream.ts
+++ b/extensions/ollama/src/stream.ts
@@ -350,7 +350,7 @@ interface OllamaTool {
 interface OllamaToolCall {
   function: {
     name: string;
-    arguments: Record<string, unknown>;
+    arguments: Record<string, unknown> | string;
   };
 }
 
@@ -406,6 +406,10 @@ function ensureArgsObject(value: unknown): Record<string, unknown> {
   return parseJsonObjectPreservingUnsafeIntegers(value) ?? {};
 }
 
+function normalizeOllamaToolCallArguments(value: unknown): Record<string, unknown> {
+  return ensureArgsObject(value);
+}
+
 function normalizeOllamaCompatMessageToolArgs(payloadRecord: Record<string, unknown>): void {
   const messages = payloadRecord.messages;
   if (!Array.isArray(messages)) {
@@ -653,7 +657,7 @@ export function buildAssistantMessage(
         type: "toolCall",
         id: `ollama_call_${randomUUID()}`,
         name: toolCall.function.name,
-        arguments: toolCall.function.arguments,
+        arguments: normalizeOllamaToolCallArguments(toolCall.function.arguments),
       });
     }
   }