fix(consult): 第 0 步改回 auto，供应商 error 块不再被吞掉

BUG-937 撤回 thinking 模式下的 required toolChoice，只留 activeTools。BUG-938 让咨询流识别 Mastra error 块，公开码 calculation_failed，内部码进日志且不触发合同 retry。

frontend/tests/agent-observability.test.ts

@@ -149,6 +149,14 @@ test("error normalization never records arbitrary exception messages", () => {
     toAgentObservabilityErrorCode(new Error("answer_truncated")),
     "answer_truncated",
   );
+  assert.equal(
+    toAgentObservabilityErrorCode(new Error("provider_error")),
+    "provider_error",
+  );
+  assert.equal(
+    toAgentObservabilityErrorCode(new Error("thinking_tool_choice_unsupported")),
+    "thinking_tool_choice_unsupported",
+  );
   assert.equal(
     toAgentObservabilityErrorCode(new Error("/opt/internal/users/alice.json")),
     "calculation_failed",

frontend/tests/consultation-agentic-runtime.test.ts

@@ -656,11 +656,11 @@ test("guided-topic entrypoint ignores a model domain rewrite instead of executin
 
 test("natal first step exposes only the chart calculation tool", () => {
   assert.equal(CONSULTATION_NATAL_CALC_TOOL_ID, "run-jyotish-consultation");
-  // 原值: toolChoice "auto" / 新值: 第 0 步 "required"、第 1 步仍 "auto"
-  // 原因: BUG-923 每轮必须先调排盘工具，提示词例外已删
+  // 原值: 第 0 步 toolChoice "required" / 新值: "auto"
+  // 原因: BUG-282 供应商拒收 thinking 模式下的 required，BUG-937 撤回
   assert.deepEqual(consultationNatalPrepareStep({ stepNumber: 0 }), {
     activeTools: ["run-jyotish-consultation"],
-    toolChoice: "required",
+    toolChoice: "auto",
   });
   assert.deepEqual(consultationNatalPrepareStep({ stepNumber: 1 }), {
     toolChoice: "auto",
@@ -669,9 +669,11 @@ test("natal first step exposes only the chart calculation tool", () => {
 
 test("window first step requires the window consultation tool", () => {
   assert.equal(CONSULTATION_WINDOW_CALC_TOOL_ID, "run-jyotish-window-consultation");
+  // 原值: 第 0 步 toolChoice "required" / 新值: "auto"
+  // 原因: BUG-282 供应商拒收 thinking 模式下的 required，BUG-937 撤回
   assert.deepEqual(consultationWindowPrepareStep({ stepNumber: 0 }), {
     activeTools: ["run-jyotish-window-consultation"],
-    toolChoice: "required",
+    toolChoice: "auto",
   });
   assert.deepEqual(consultationWindowPrepareStep({ stepNumber: 1 }), {
     toolChoice: "auto",
@@ -1266,6 +1268,79 @@ test("incomplete runtime contract fails without saving a successful answer", asy
   assert.equal(events.filter((event) => (event as { type?: string }).type === "run.failed").length, 1);
 });
 
+test("a thinking-mode toolChoice rejection fails without a contract retry (BUG-938)", async () => {
+  const state = createConsultationRuntimeState();
+  let onErrorMessage = "";
+  async function* chunks() {
+    yield { type: "error", error: new Error("Thinking mode does not support this tool_choice") };
+  }
+  const response = streamAgentResponse({
+    runId: "run", requestId: "req", state, stream: chunks(), requireTool: true,
+    toolStatus: () => "blocked",
+    receipt: () => ({ ...receipt(state), steps: publicConsultationRuntimeSteps(state) }),
+    retry: async () => {
+      assert.fail("provider error must not trigger a contract retry");
+      return chunks();
+    },
+    onError: (error) => {
+      onErrorMessage = error instanceof Error ? error.message : String(error);
+    },
+  });
+  const events: unknown[] = [];
+  const parser = createNdjsonParser((event) => events.push(event));
+  parser.finish(await response.text());
+
+  assert.deepEqual(events.map((event) => (event as { type: string }).type), [
+    "run.started",
+    "skill.started",
+    "skill.completed",
+    "run.failed",
+  ]);
+  const failure = events.find((event) => (event as { type?: string }).type === "run.failed") as {
+    code: string;
+    receipt?: { steps: Array<{ kind: string; name: string; status: string }> };
+  };
+  assert.equal(failure.code, "calculation_failed");
+  assert.equal(onErrorMessage, "thinking_tool_choice_unsupported");
+  assert.equal(
+    events.some((event) => (event as { type?: string; phase?: string }).type === "activity"
+      && (event as { phase?: string }).phase === "loading-method"),
+    false,
+  );
+  assert.ok(failure.receipt?.steps.some((step) =>
+    step.kind === "validation" && step.name === "model-stream-error" && step.status === "failed"));
+  assert.doesNotMatch(JSON.stringify(events), /Thinking mode does not support this tool_choice/);
+});
+
+test("a generic provider stream error is calculation_failed and skips retry (BUG-938)", async () => {
+  const state = createConsultationRuntimeState();
+  let onErrorMessage = "";
+  async function* chunks() {
+    yield { type: "error", error: new Error("upstream 502") };
+  }
+  const response = streamAgentResponse({
+    runId: "run", requestId: "req", state, stream: chunks(), requireTool: true,
+    toolStatus: () => "blocked",
+    receipt: () => ({ ...receipt(state), steps: publicConsultationRuntimeSteps(state) }),
+    retry: async () => {
+      assert.fail("provider error must not trigger a contract retry");
+      return chunks();
+    },
+    onError: (error) => {
+      onErrorMessage = error instanceof Error ? error.message : String(error);
+    },
+  });
+  const events: unknown[] = [];
+  const parser = createNdjsonParser((event) => events.push(event));
+  parser.finish(await response.text());
+
+  const failure = events.find((event) => (event as { type?: string }).type === "run.failed") as { code: string };
+  assert.equal(failure.code, "calculation_failed");
+  assert.equal(onErrorMessage, "provider_error");
+  assert.equal(events.filter((event) => (event as { type?: string }).type === "run.failed").length, 1);
+  assert.doesNotMatch(JSON.stringify(events), /upstream 502/);
+});
+
 function toolOnlyRunState() {
   const state = createConsultationRuntimeState();
   state.jyotishSkillBound = true;

frontend/tests/consultation-workflow-contract.test.ts

@@ -26,22 +26,29 @@ test("natal and window instructions require a chart tool every turn (BUG-922)",
 });
 
 test("natal and window first steps require the chart tool (BUG-923)", () => {
+  // 原值: 第 0 步 toolChoice "required" / 新值: "auto"
+  // 原因: BUG-282 供应商拒收 thinking 模式下的 required，BUG-937 撤回
   assert.deepEqual(consultationNatalPrepareStep({ stepNumber: 0 }), {
     activeTools: ["run-jyotish-consultation"],
-    toolChoice: "required",
+    toolChoice: "auto",
   });
   assert.deepEqual(consultationNatalPrepareStep({ stepNumber: 1 }), {
     toolChoice: "auto",
   });
   assert.deepEqual(consultationWindowPrepareStep({ stepNumber: 0 }), {
     activeTools: ["run-jyotish-window-consultation"],
-    toolChoice: "required",
+    toolChoice: "auto",
   });
   assert.deepEqual(consultationWindowPrepareStep({ stepNumber: 1 }), {
     toolChoice: "auto",
   });
 });
 
+test("consultation prepareStep never sends required or named toolChoice (BUG-282 / BUG-937)", () => {
+  assert.doesNotMatch(tools, /toolChoice:\s*"required"/);
+  assert.doesNotMatch(tools, /type:\s*"tool",\s*toolName/);
+});
+
 test("consultation plans are server-owned and bounded", () => {
   assert.match(plan, /consultationPlanSchema/);
   assert.match(plan, /requestedDomains/);