fix(core): detect XML-style malformed tool calls in raw text stream

Author: Grigory-Rylov

packages/core/src/session/runner/publish-llm-event.ts

@@ -115,9 +115,11 @@ export const createLLMEventPublisher = (events: EventV2.Interface, input: Input)
 
   const text = fragments("text", (textID, value) =>
     Effect.gen(function* () {
-      const toolCallMatch = value.match(
+      const bracketToolCallMatch = value.match(
         /\[Assistant tool call\]\s*:\s*(\w+)\s*\(/i,
       )
+      const xmlToolCallMatch = value.match(/<\w+>[\s\S]*?"name"\s*:\s*"([^"]+)"/u)
+      const toolCallMatch = bracketToolCallMatch ?? xmlToolCallMatch
       if (toolCallMatch) {
         textBasedToolCall = true
         yield* events.publish(SessionEvent.Text.Ended, {

packages/core/test/session-runner-tool-events.test.ts

@@ -112,6 +112,29 @@ test("binary failure emits no success event", async () => {
   expect(published.some((event) => event.type === "session.next.tool.failed.1")).toBe(true)
 })
 
+test("xml-style tool call in text emits error and sets hasTextBasedToolCall", async () => {
+  const { published, publisher } = capture()
+  const textID = "text-0"
+
+  await Effect.runPromise(publisher.publish(LLMEvent.textStart({ id: textID })))
+  await Effect.runPromise(
+    publisher.publish(
+      LLMEvent.textDelta({
+        id: textID,
+        text: '<tool_call>\ntool_use\n{"name": "read", "path": "foo.txt"}\n</tool_call>',
+      }),
+    ),
+  )
+  await Effect.runPromise(publisher.publish(LLMEvent.textEnd({ id: textID })))
+
+  const textEnded = published.find((event) => event.type === "session.next.text.ended.1")
+  expect(textEnded).toBeDefined()
+  expect((textEnded!.data as any).text).toContain("[ERROR]")
+  expect((textEnded!.data as any).text).toContain("read")
+  expect((textEnded!.data as any).text).not.toContain("tool_use")
+  expect(publisher.hasTextBasedToolCall()).toBe(true)
+})
+
 test("old success event data containing result still decodes", () => {
   const decoded = Schema.decodeUnknownSync(SessionEvent.Tool.Success.data)({
     sessionID,