Fix system-message tools parser when tool call is non-terminal

core/tools/systemMessageTools/buildToolsSystemMessage.ts

@@ -40,7 +40,7 @@ export const generateToolsSystemMessage = (
       `\nAlso, these additional tool definitions show other tools you can call with the same syntax:`,
     );
 
-    for (const tool of tools) {
+    for (const tool of withDynamicMessage) {
       try {
         const definition = framework.toolToSystemToolDefinition(tool);
         instructions.push(`\n${definition}`);

core/tools/systemMessageTools/interceptSystemToolCalls.ts

@@ -46,7 +46,7 @@ export async function* interceptSystemToolCalls(
       return result.value;
     } else {
       for await (const message of result.value) {
-        if (abortController.signal.aborted || parseState?.done) {
+        if (abortController.signal.aborted) {
           break;
         }
         // Skip non-assistant messages or messages with native tool calls
@@ -96,12 +96,13 @@ export async function* interceptSystemToolCalls(
                 },
               ];
             }
-          } else {
-            // Prevent content after tool calls for now
-            if (parseState) {
-              continue;
+            // Completed tool calls should not terminate parsing for subsequent
+            // chunks/messages; reset state so normal content (or another tool
+            // call) can be handled.
+            if (parseState.done) {
+              parseState = undefined;
             }
-
+          } else {
             // Yield normal assistant message
             yield [
               {

core/tools/systemMessageTools/toolCodeblocks/buildSystemMessage.vitest.ts

@@ -191,6 +191,11 @@ describe("generateToolsSystemMessage", () => {
 
     const hasDynamicToolsSection = /additional tool definitions/i.test(result);
     expect(hasDynamicToolsSection).toBe(true);
+
+    // Dynamic definitions should not duplicate tools that already have predefined messages.
+    expect(result.match(/TOOL_NAME: tool_with_description/g)?.length ?? 0).toBe(
+      1,
+    );
   });
 
   it("includes example tool definition and call", () => {

core/tools/systemMessageTools/toolCodeblocks/interceptSystemToolCalls.vitest.ts

@@ -242,15 +242,15 @@
     ).toBe("}");
   });
 
-  it("ignores content after a tool call", async () => {
+  it("preserves content after a tool call", async () => {
     const messages: ChatMessage[][] = [
       [{ role: "assistant", content: "```tool\n" }],
       [{ role: "assistant", content: "TOOL_NAME: test_tool\n" }],
       [{ role: "assistant", content: "BEGIN_ARG: arg1\n" }],
       [{ role: "assistant", content: "value1\n" }],
       [{ role: "assistant", content: "END_ARG\n" }],
       [{ role: "assistant", content: "```\n" }],
-      [{ role: "assistant", content: "This content should be ignored" }],
+      [{ role: "assistant", content: "This content should be preserved" }],
     ];
 
     const generator = interceptSystemToolCalls(
@@ -265,9 +265,79 @@
       result = await generator.next();
     }
 
-    // The content after the tool call should be ignored
+    // The content after the tool call should be preserved
     result = await generator.next();
-    expect(result.value).toBeUndefined();
+    expect(result.value).toEqual([
+      {
+        role: "assistant",
+        content: [{ type: "text", text: "This content should be preserved" }],
+      },
+    ]);
+  });
+
+  it("parses a tool call that appears mid-message and preserves trailing content", async () => {
+    const messages: ChatMessage[][] = [
+      [
+        {
+          role: "assistant",
+          content:
+            "Before tool\n```tool\nTOOL_NAME: test_tool\nBEGIN_ARG: arg1\nvalue1\nEND_ARG\n```\nAfter tool",
+        },
+      ],
+    ];
+
+    const generator = interceptSystemToolCalls(
+      createAsyncGenerator(messages),
+      abortController,
+      framework,
+    );
+
+    let result = await generator.next();
+    expect(result.value).toEqual([
+      {
+        role: "assistant",
+        content: [{ type: "text", text: "Before tool" }],
+      },
+    ]);
+
+    result = await generator.next();
+    expect(result.value).toEqual([
+      {
+        role: "assistant",
+        content: [{ type: "text", text: "\n" }],
+      },
+    ]);
+
+    result = await generator.next();
+    expect(
+      (result.value as AssistantChatMessage[])[0].toolCalls?.[0].function?.name,
+    ).toBe("test_tool");
+
+    result = await generator.next();
+    expect(
+      (result.value as AssistantChatMessage[])[0].toolCalls?.[0].function
+        ?.arguments,
+    ).toContain('{"arg1":');
+
+    result = await generator.next();
+    expect(
+      (result.value as AssistantChatMessage[])[0].toolCalls?.[0].function
+        ?.arguments,
+    ).toBe('"value1"');
+
+    result = await generator.next();
+    expect(
+      (result.value as AssistantChatMessage[])[0].toolCalls?.[0].function
+        ?.arguments,
+    ).toBe("}");
+
+    result = await generator.next();
+    expect(result.value).toEqual([
+      {
+        role: "assistant",
+        content: [{ type: "text", text: "After tool" }],
+      },
+    ]);
   });
 
   it("stops processing when aborted", async () => {