Merge contributor foundation for pending-question authority

components/chat.tsx

@@ -72,6 +72,7 @@ import { CoverageRing } from "@/components/extraction-coverage";
 import { Button } from "@/components/ui/button";
 import {
 	activeProblemOf,
+	danglingQuestionOf,
 	dismissedAnswer,
 	endsInFailedTurn,
 	findPendingToolCall,
@@ -446,7 +447,7 @@ export function Chat({
 		// mount-only by design (turnInFlight read at initial value)
 	}, []);
 
-	const pending = findPendingToolCall(messages);
+	const pending = findPendingToolCall(messages, danglingQuestionOf(nativeMessages)?.toolCallId ?? null);
 	// The abort handler reads the pending question from a ref (the window
 	// listener is mount-scoped; the value it needs is render-scoped).
 	const pendingRef = useRef(pending);

src/core/pending.ts

@@ -105,14 +105,14 @@ export function filterEnabledTools<T>(tools: Record<string, T>, enabled?: Enable
 	return out;
 }
 
-function findPending(messages: UIMessage[], names: readonly string[]): PendingToolCall | null {
+function findPending(messages: UIMessage[], names: readonly string[], toolCallId?: string): PendingToolCall | null {
 	for (let m = messages.length - 1; m >= 0; m--) {
 		const msg = messages[m]!;
 		for (let p = 0; p < msg.parts.length; p++) {
 			const part = msg.parts[p]!;
 			if (isToolUIPart(part) && part.state === "input-available") {
 				const tool = part.type.slice("tool-".length);
-				if (names.includes(tool)) {
+				if (names.includes(tool) && (toolCallId === undefined || part.toolCallId === toolCallId)) {
 					return { toolCallId: part.toolCallId as string, tool, input: part.input };
 				}
 			}
@@ -121,8 +121,12 @@ function findPending(messages: UIMessage[], names: readonly string[]): PendingTo
 	return null;
 }
 
-export function findPendingToolCall(messages: UIMessage[]): PendingToolCall | null {
-	return findPending(messages, QUESTION_TOOLS);
+/** Grouped view messages lose native assistant boundaries. When the native
+ * record supplies an authority, expose only that call after view validation.
+ * null means no native question is pending; undefined keeps view-only callers. */
+export function findPendingToolCall(messages: UIMessage[], toolCallId?: string | null): PendingToolCall | null {
+	if (toolCallId === null) return null;
+	return findPending(messages, QUESTION_TOOLS, toolCallId);
 }
 
 // ─── Turn activity label (2026-09-19, the “Writing a question…” fix) ──────

tests/pending-authority.test.ts

@@ -0,0 +1,40 @@
+import assert from "node:assert/strict";
+import { test } from "node:test";
+import { findPendingToolCall } from "../src/core/pending.ts";
+import { danglingQuestionOf, newAnswerResult, type LhMessage } from "../src/core/native-messages.ts";
+import { inputAppends } from "../src/core/input-events.ts";
+import { projectView } from "../src/core/view.ts";
+
+function assistant(id: string, ...calls: string[]): LhMessage {
+	return { id, role: "assistant", content: calls.map(id => ({ type: "toolCall", id, name: "quiz", arguments: { question: id } })), stopReason: "toolUse", timestamp: 1 } as LhMessage;
+}
+
+function pending(messages: LhMessage[], view = projectView(messages)) {
+	return findPendingToolCall(view, danglingQuestionOf(messages)?.toolCallId ?? null);
+}
+
+test("a later assistant question supersedes an unanswered question in the same projected group", () => {
+	const messages = [assistant("old", "old-question"), assistant("new", "new-question")];
+	assert.equal(projectView(messages).length, 1, "the view merges both assistant boundaries");
+	const question = pending(messages)!;
+	assert.equal(question.toolCallId, "new-question");
+	assert.doesNotThrow(() => inputAppends({ messages }, { type: "answer", toolCallId: question.toolCallId, answer: { kind: "quiz", answers: [], dontKnow: true } as never }));
+});
+
+test("the newest assistant's parallel questions retain call order and never revive older questions", () => {
+	const messages = [assistant("old", "old-question"), assistant("new", "first", "second")];
+	assert.equal(pending(messages)?.toolCallId, "first");
+	messages.push({ ...newAnswerResult("first", "quiz", { kind: "quiz", answers: [], dontKnow: true } as never), id: "answer-first" });
+	assert.equal(pending(messages)?.toolCallId, "second");
+	messages.push({ ...newAnswerResult("second", "quiz", { kind: "quiz", answers: [], dontKnow: true } as never), id: "answer-second" });
+	assert.equal(pending(messages), null);
+});
+
+test("the authoritative question still waits for projected input validation", () => {
+	const messages = [assistant("old", "old-question"), assistant("new", "new-question")];
+	const view = projectView(messages);
+	for (const message of view) for (const part of message.parts) {
+		if (part.type === "tool-quiz" && part.toolCallId === "new-question") part.state = "input-streaming";
+	}
+	assert.equal(pending(messages, view), null);
+});