Fix tool call name merging

gui/src/util/toolCallState.test.ts

@@ -57,6 +57,129 @@ describe("addToolCallDeltaToState", () => {
     expect(result.toolCall.function.name).toBe("searchFiles");
   });
 
+  it("should handle name streaming in full progressive chunks", () => {
+    // Test case where model streams the name progressively but includes full prefix each time
+    // e.g. "readFi" -> "readFil" -> "readFile"
+    const currentState: ToolCallState = {
+      status: "generating",
+      toolCall: {
+        id: "call123",
+        type: "function",
+        function: {
+          name: "readFi",
+          arguments: "{}",
+        },
+      },
+      toolCallId: "call123",
+      parsedArgs: {},
+    };
+
+    const delta: ToolCallDelta = {
+      function: {
+        name: "readFil",
+      },
+    };
+
+    const result = addToolCallDeltaToState(delta, currentState);
+    expect(result.toolCall.function.name).toBe("readFil");
+
+    // Continue the streaming
+    const nextDelta: ToolCallDelta = {
+      function: {
+        name: "readFile",
+      },
+    };
+
+    const finalResult = addToolCallDeltaToState(nextDelta, result);
+    expect(finalResult.toolCall.function.name).toBe("readFile");
+  });
+
+  it("should keep original name when receiving duplicate name chunks", () => {
+    // Test case where model streams the complete name multiple times
+    // e.g. "readFile" -> "readFile" -> "readFile"
+    const currentState: ToolCallState = {
+      status: "generating",
+      toolCall: {
+        id: "call123",
+        type: "function",
+        function: {
+          name: "readFile",
+          arguments: "{}",
+        },
+      },
+      toolCallId: "call123",
+      parsedArgs: {},
+    };
+
+    const delta: ToolCallDelta = {
+      function: {
+        name: "readFile",
+      },
+    };
+
+    const result = addToolCallDeltaToState(delta, currentState);
+    expect(result.toolCall.function.name).toBe("readFile");
+  });
+
+  it("should handle partial name streaming", () => {
+    // Test case where model streams the name in parts
+    // e.g. "read" -> "File"
+    const currentState: ToolCallState = {
+      status: "generating",
+      toolCall: {
+        id: "call123",
+        type: "function",
+        function: {
+          name: "read",
+          arguments: "{}",
+        },
+      },
+      toolCallId: "call123",
+      parsedArgs: {},
+    };
+
+    const delta: ToolCallDelta = {
+      function: {
+        name: "File",
+      },
+    };
+
+    const result = addToolCallDeltaToState(delta, currentState);
+    expect(result.toolCall.function.name).toBe("readFile");
+  });
+
+  it("should ignore new tool calls with different IDs", () => {
+    const currentState: ToolCallState = {
+      status: "generating",
+      toolCall: {
+        id: "call123",
+        type: "function",
+        function: {
+          name: "searchFiles",
+          arguments: '{"query":"test"}',
+        },
+      },
+      toolCallId: "call123",
+      parsedArgs: { query: "test" },
+    };
+
+    const delta: ToolCallDelta = {
+      id: "call456", // Different ID
+      type: "function",
+      function: {
+        name: "readFile",
+        arguments: '{"path":"file.txt"}',
+      },
+    };
+
+    const result = addToolCallDeltaToState(delta, currentState);
+
+    // Should keep the original state and ignore the new call
+    expect(result).toBe(currentState);
+    expect(result.toolCall.id).toBe("call123");
+    expect(result.toolCall.function.name).toBe("searchFiles");
+  });
+
   it("should merge function argument deltas correctly", () => {
     const currentState: ToolCallState = {
       status: "generating",

gui/src/util/toolCallState.ts

@@ -8,6 +8,15 @@ export function addToolCallDeltaToState(
   toolCallDelta: ToolCallDelta,
   currentState: ToolCallState | undefined,
 ): ToolCallState {
+  // This prevents multiple tool calls for now, by ignoring new tool call ids
+  if (
+    toolCallDelta.id &&
+    currentState?.toolCallId &&
+    toolCallDelta.id !== currentState?.toolCallId
+  ) {
+    return currentState;
+  }
+
   const currentCall = currentState?.toolCall;
 
   // These will/should not be partially streamed
@@ -21,8 +30,18 @@ export function addToolCallDeltaToState(
   const nameDelta = toolCallDelta.function?.name ?? "";
   const argsDelta = toolCallDelta.function?.arguments ?? "";
 
-  const mergedName =
-    currentName === nameDelta ? currentName : currentName + nameDelta; // Some models may include the name repeatedly. This doesn't account for an edge case where the name is like "dothisdothis" and it happens to stream name in chunks "dothis" and "dothis" but that's a super edge case
+  let mergedName = currentName;
+  if (nameDelta.startsWith(currentName)) {
+    // Case where model progresssively streams name but full name each time e.g. "readFi" -> "readFil" -> "readFile"
+    mergedName = nameDelta;
+  } else if (currentName.startsWith(nameDelta)) {
+    // Case where model streams in full name each time e.g. readFile -> readFile -> readFile
+    // do nothing
+  } else {
+    // Case where model streams in name in parts e.g. "read" -> "File"
+    mergedName = currentName + nameDelta;
+  }
+
   const mergedArgs = currentArgs + argsDelta;
 
   const [_, parsedArgs] = incrementalParseJson(mergedArgs || "{}");