fix(consult): treat pinched answers as failed and restore reply actions

Incomplete Flash generations were billed as completed consultations. Fail
those runs, keep the partial text, and reuse the rectification like/copy/rerun
bar on ordinary chat replies.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/lib/agent-observability.ts

@@ -180,6 +180,7 @@ export const logAgentObservability = createAgentObservabilityLogger();
 const knownErrorCodes = new Set([
   "runtime_contract_incomplete",
   "empty_answer",
+  "answer_truncated",
   "calculation_failed",
   "timeout",
   "cancelled",

frontend/src/lib/consultation-agent-events.ts

@@ -100,7 +100,7 @@ const runCompletedSchema = z.object({ type: z.literal("run.completed"), receipt:
 // and losing the whole failure event would be worse than losing its receipt.
 const runFailedSchema = z.object({
   type: z.literal("run.failed"),
-  code: z.enum(["runtime_contract_incomplete", "calculation_failed", "empty_answer", "cancelled"]),
+  code: z.enum(["runtime_contract_incomplete", "calculation_failed", "empty_answer", "answer_truncated", "cancelled"]),
   message: z.string().max(200),
   receipt: agentExecutionReceiptSchema.optional(),
 }).strict();

frontend/src/lib/stream-agent-response.ts

@@ -77,6 +77,27 @@ function safeToolError(error: unknown) {
   return "calculation_failed" as const;
 }
 
+function isTimeoutOrAbort(error: unknown) {
+  return error instanceof Error && (error.name === "TimeoutError" || error.name === "AbortError");
+}
+
+type RunFailedCode = "runtime_contract_incomplete" | "empty_answer" | "answer_truncated" | "calculation_failed";
+
+function runFailedCode(error: unknown, emitted: boolean): RunFailedCode {
+  if (error instanceof Error && error.message === "runtime_contract_incomplete") return "runtime_contract_incomplete";
+  if (error instanceof Error && error.message === "empty_answer") return "empty_answer";
+  if (error instanceof Error && error.message === "answer_truncated") return "answer_truncated";
+  if (emitted && isTimeoutOrAbort(error)) return "answer_truncated";
+  return "calculation_failed";
+}
+
+function runFailedMessage(code: RunFailedCode) {
+  if (code === "runtime_contract_incomplete") return "Agent 未完成必要的方法与计算步骤，本次不会扣点。";
+  if (code === "empty_answer") return "计算已完成，但这次没有生成回答，本次不会扣点。请再发送一次。";
+  if (code === "answer_truncated") return "回答未完成，已保留现有内容；本次不会扣点。";
+  return "咨询暂时无法完成，本次不会扣点。";
+}
+
 /**
  * Whether a tool result is really an input rejection Mastra resolved with.
  *
@@ -287,19 +308,26 @@ export function streamAgentResponse(options: StreamAgentResponseOptions) {
     // A retry runs a second model loop under the same step budget, so the run
     // total accumulates while the finish reason describes the latest attempt.
     const stepCountBeforeAttempt = options.state.modelStepCount;
-    for await (const chunk of readChunks(stream)) {
-      for (const event of mapChunk(chunk, options, startedAt, toolErrors)) send(controller, event);
-      if (chunk.type === "step-finish") options.state.modelStepCount += 1;
-      if (chunk.type === "finish") {
-        const finish = finishTelemetry(chunk);
-        options.state.modelFinishReason = finish.reason;
-        if (finish.stepCount !== null) options.state.modelStepCount = stepCountBeforeAttempt + finish.stepCount;
-      }
-      if (chunk.type === "text-delta" && typeof chunk.payload?.text === "string") {
-        await outputText(visible.push(chunk.payload.text));
+    try {
+      for await (const chunk of readChunks(stream)) {
+        for (const event of mapChunk(chunk, options, startedAt, toolErrors)) send(controller, event);
+        if (chunk.type === "step-finish") options.state.modelStepCount += 1;
+        if (chunk.type === "finish") {
+          const finish = finishTelemetry(chunk);
+          options.state.modelFinishReason = finish.reason;
+          if (finish.stepCount !== null) options.state.modelStepCount = stepCountBeforeAttempt + finish.stepCount;
+        }
+        if (chunk.type === "text-delta" && typeof chunk.payload?.text === "string") {
+          await outputText(visible.push(chunk.payload.text));
+        }
       }
+      await outputText(visible.finish(""));
+    } catch (error) {
+      try {
+        await outputText(visible.finish(""));
+      } catch {}
+      throw error;
     }
-    await outputText(visible.finish(""));
   }
 
   const body = new ReadableStream<Uint8Array>({
@@ -330,6 +358,10 @@ export function streamAgentResponse(options: StreamAgentResponseOptions) {
           // Still nothing to show. Failing is the honest outcome and it is the
           // one that does not charge for the run.
           if (!/\S/.test(fullOutput)) throw new Error("empty_answer");
+          // A spoken answer that stopped because the token budget ran out is
+          // not a completed consultation. The heading may already be on screen,
+          // so keep it and refuse to bill.
+          if (options.state.modelFinishReason === "length") throw new Error("answer_truncated");
           settling = true;
           const receipt = agentExecutionReceiptSchema.parse(options.receipt());
           await options.onComplete?.(fullOutput, receipt);
@@ -344,11 +376,7 @@ export function streamAgentResponse(options: StreamAgentResponseOptions) {
           try {
             await options.onError?.(error, emitted, fullOutput);
           } catch {}
-          const code = error instanceof Error && error.message === "runtime_contract_incomplete"
-            ? "runtime_contract_incomplete" as const
-            : error instanceof Error && error.message === "empty_answer"
-              ? "empty_answer" as const
-              : "calculation_failed" as const;
+          const code = runFailedCode(error, emitted);
           // Step durations, the step budget and the workflow route are the only
           // evidence the caller has for why a run failed. Building the receipt
           // must not be able to replace the failure event with a silent close.
@@ -359,11 +387,7 @@ export function streamAgentResponse(options: StreamAgentResponseOptions) {
           send(controller, {
             type: "run.failed",
             code,
-            message: code === "runtime_contract_incomplete"
-              ? "Agent 未完成必要的方法与计算步骤，本次不会扣点。"
-              : code === "empty_answer"
-                ? "计算已完成，但这次没有生成回答，本次不会扣点。请再发送一次。"
-                : "咨询暂时无法完成，本次不会扣点。",
+            message: runFailedMessage(code),
             ...(failureReceipt ? { receipt: failureReceipt } : {}),
           });
           if (!disconnected) controller.close();