fix(consult): drop traces, budget checkpoints, silent summary inherit

BUG-729: dropped history rounds leave an omission marker in the model-visible summary slot.
BUG-730: checkpoint threshold is 0.4 of historyBudgetChars (128k still 16,000).
BUG-731: session_full new chat copies owned context_summary on the server; clients send only continued_from_session_id.

frontend/src/app/api/consult/route.ts

@@ -330,6 +330,7 @@ export async function POST(request: Request) {
       { status: 503 },
     );
   }
+  const sessionContextWindow = sessionModel.contextWindow;
 
   if (parsed.data.entrypoint === "birth_time_rectification") {
     return NextResponse.json(
@@ -353,7 +354,7 @@ export async function POST(request: Request) {
   // Client `history` stays in the request schema for old bundles and is not read.
   const contextSummary = parseSessionContextSummary(chatSession.context_summary);
   const historyWindow = consultationHistoryWindow(chatSession.messages, contextSummary, {
-    contextWindow: sessionModel.contextWindow,
+    contextWindow: sessionContextWindow,
   });
   const storedHistory = historyWindow.tail;
   const userControlledPrompt = [
@@ -596,6 +597,7 @@ export async function POST(request: Request) {
       await checkpointSessionContextSummary({
         messages: sessionRow.messages,
         summary: sessionRow.context_summary,
+        contextWindow: sessionContextWindow,
         generateText: (prompt, signal) => generateSessionContextSummaryText(summaryModel, prompt, signal),
         update: async (summary, seenUpdatedAt) => {
           let query = supabase.from("chat_sessions")
@@ -875,6 +877,7 @@ export async function POST(request: Request) {
             instruction: modeInstruction,
             extra: generalDailyContextPrompt(generalDailyContext),
             summaryText: historyWindow.summaryText,
+            droppedCount: historyWindow.droppedCount,
             question: resolvedQuestion.modelQuestion,
           }),
         },
@@ -1271,6 +1274,7 @@ export async function POST(request: Request) {
           instruction: generalNoMinuteInstruction(Boolean(generalDailyContext)),
           extra: generalDailyContextPrompt(generalDailyContext),
           summaryText: historyWindow.summaryText,
+          droppedCount: historyWindow.droppedCount,
           question: resolvedQuestion.modelQuestion,
         }),
       },
@@ -1355,6 +1359,7 @@ export async function POST(request: Request) {
           name,
           instruction: "先用 3–6 句口语直接回答下面的问题，不要加标题；形状为一句结论、2–3 条短要点（每条完整句子、不超过 30 字）、一句下一步，总量不超过 400 字；然后再按 skill Level 2 骨架写：原始结构、六步宫位、Yoga 表、时机、综合、文末技法审计表，最后才是现代生活。骨架不可省略。星盘事实只使用系统里已经注入的计算结果，不要复述内部字段、JSON 或再跑一遍咨询流程。",
           summaryText: historyWindow.summaryText,
+          droppedCount: historyWindow.droppedCount,
           question: resolvedQuestion.modelQuestion,
         }),
       },
@@ -1379,6 +1384,7 @@ export async function POST(request: Request) {
             name,
             instruction: "先用 3–6 句口语直接回答下面的问题，不要加标题；形状为一句结论、2–3 条短要点（每条完整句子、不超过 30 字）、一句下一步，总量不超过 400 字；然后再按 skill Level 2 骨架写：原始结构、六步宫位、Yoga 表、时机、综合、文末技法审计表，最后才是现代生活。骨架不可省略。星盘事实只使用系统里已经注入的计算结果，不要复述内部字段、JSON 或再跑一遍咨询流程。",
             summaryText: historyWindow.summaryText,
+            droppedCount: historyWindow.droppedCount,
             question: resolvedQuestion.modelQuestion,
           }),
         },

frontend/src/app/api/sessions/route.ts

@@ -1,6 +1,12 @@
 import { NextResponse } from "next/server";
-import { chatSessionCreateSchema, ChatSessionBodyTooLargeError, readChatSessionJson } from "@/lib/chat-session-write-contract";
+import {
+  chatSessionCreateInsertRow,
+  chatSessionCreateSchema,
+  ChatSessionBodyTooLargeError,
+  readChatSessionJson,
+} from "@/lib/chat-session-write-contract";
 import { consumeUserRequestRateLimit } from "@/lib/request-rate-limit";
+import { resolveInheritedContextSummary } from "@/lib/session-context-summary";
 import { isSupabaseConfigurationError } from "@/lib/supabase/config";
 import { createServerSupabaseClient } from "@/lib/supabase/server";
 import {
@@ -94,13 +100,28 @@ export async function POST(request: Request) {
     }
     const parsed = chatSessionCreateSchema.safeParse(await readChatSessionJson(request));
     if (!parsed.success) return NextResponse.json({ error: "聊天记录格式不正确" }, { status: 400 });
-    const { id, updated_at: _ignoredClientClock, ...values } = parsed.data;
-    const { error } = await supabase.from("chat_sessions").insert({
-      id,
-      user_id: user.id,
-      ...values,
-      updated_at: new Date().toISOString(),
+    const { id, updated_at: _ignoredClientClock, continued_from_session_id: continuedFromSessionId, ...values } = parsed.data;
+    const inheritedSummary = await resolveInheritedContextSummary({
+      continuedFromSessionId,
+      loadOwnedSummary: async (sourceId) => {
+        const { data } = await supabase
+          .from("chat_sessions")
+          .select("context_summary")
+          .eq("id", sourceId)
+          .eq("user_id", user.id)
+          .maybeSingle();
+        return data?.context_summary ?? null;
+      },
     });
+    const { error } = await supabase.from("chat_sessions").insert(
+      chatSessionCreateInsertRow({
+        id,
+        userId: user.id,
+        values,
+        inheritedSummary,
+        updatedAt: new Date().toISOString(),
+      }),
+    );
     if (error) return NextResponse.json({ error: "聊天记录暂时无法同步" }, { status: 500 });
     return NextResponse.json({ ok: true }, { status: 201 });
   } catch (error) {

frontend/src/hooks/use-consultation-run.ts

@@ -135,7 +135,7 @@ export type ConsultationRunParams = {
   uiPreviewMode: MutableRefObject<string | null>;
   persistSession: (session: ChatSession, mode?: "create" | "update") => Promise<void>;
   updateSession: (sessionId: string, change: (session: ChatSession) => ChatSession) => void;
-  startNewChat: () => Promise<ChatSession | null>;
+  startNewChat: (options?: { continuedFromSessionId?: string }) => Promise<ChatSession | null>;
   continueInNewChat: (prompt: { question: string; theme: Theme }) => Promise<void>;
   refreshAccount: () => Promise<void>;
   openAccountDialog: (dialog: AccountDialog, options?: HTMLButtonElement | null | OpenAccountDialogOptions) => void;

frontend/src/hooks/use-session-management.ts

@@ -139,7 +139,11 @@ export function useSessionManagement(params: SessionManagementParams) {
     setSessions((current) => current.map((session) => (session.id === sessionId ? change(session) : session)));
   }
 
-  async function persistSession(session: ChatSession, mode: "create" | "update" = "update") {
+  async function persistSession(
+    session: ChatSession,
+    mode: "create" | "update" = "update",
+    options?: { continuedFromSessionId?: string },
+  ) {
     if (!account) throw new Error("账户尚未加载完成");
     if (process.env.NODE_ENV === "development" && uiPreview.current) return;
     const values = mode === "create"
@@ -153,6 +157,9 @@ export function useSessionManagement(params: SessionManagementParams) {
         chart_profile_id: session.chartProfileId,
         chart_profile_name: session.chartProfileName,
         chart_profile_role: session.chartProfileRole,
+        ...(options?.continuedFromSessionId
+          ? { continued_from_session_id: options.continuedFromSessionId }
+          : {}),
       }
       : {
         title: session.title,
@@ -192,7 +199,10 @@ export function useSessionManagement(params: SessionManagementParams) {
 
   async function continueInNewChat(prompt: { question: string; theme: Theme }) {
     setSessionFullPrompt(null);
-    const created = await startNewChat();
+    const sourceSessionId = activeSessionId;
+    const created = await startNewChat(
+      sourceSessionId ? { continuedFromSessionId: sourceSessionId } : undefined,
+    );
     if (!created) return;
     setDraft(prompt.question);
     setDraftTheme(prompt.theme);
@@ -294,7 +304,7 @@ export function useSessionManagement(params: SessionManagementParams) {
     }
   }
 
-  async function startNewChat(): Promise<ChatSession | null> {
+  async function startNewChat(options?: { continuedFromSessionId?: string }): Promise<ChatSession | null> {
     if (!account || !modelCatalog || creatingSession) return null;
     const nextSession = {
       ...createSession(modelCatalog.defaultModelId),
@@ -312,7 +322,13 @@ export function useSessionManagement(params: SessionManagementParams) {
     setComposerNotice("");
     setRequestError(null);
     try {
-      await persistSession(nextSession, "create");
+      await persistSession(
+        nextSession,
+        "create",
+        options?.continuedFromSessionId
+          ? { continuedFromSessionId: options.continuedFromSessionId }
+          : undefined,
+      );
       return nextSession;
     } catch (caught) {
       setSessions((current) => current.filter((session) => session.id !== nextSession.id));

frontend/src/lib/chat-session-write-contract.ts

@@ -59,6 +59,7 @@ export const chatSessionCreateSchema = z.object({
   messages: z.array(chatMessageSchema).max(0),
   session_type: z.enum(["consultation", "birth_time_rectification"]),
   rectification_case_id: z.string().uuid().nullable(),
+  continued_from_session_id: z.string().uuid().optional(),
   ...chartBindingSchema,
   updated_at: z.string().datetime().optional(),
 }).strict();
@@ -148,11 +149,41 @@ export type ChatSessionCreate = Readonly<{
   messages: readonly [];
   session_type: "consultation" | "birth_time_rectification";
   rectification_case_id: string | null;
+  continued_from_session_id?: string;
   chart_profile_id?: string | null;
   chart_profile_name?: string | null;
   chart_profile_role?: "self" | "other" | null;
 }>;
 
+export type ChatSessionCreateInsertValues = Readonly<{
+  title: string;
+  theme: ConsultationDomain;
+  model_id: string;
+  messages: readonly unknown[];
+  session_type: "consultation" | "birth_time_rectification";
+  rectification_case_id: string | null;
+  chart_profile_id?: string | null;
+  chart_profile_name?: string | null;
+  chart_profile_role?: "self" | "other" | null;
+}>;
+
+export function chatSessionCreateInsertRow(input: {
+  id: string;
+  userId: string;
+  values: ChatSessionCreateInsertValues;
+  inheritedSummary?: unknown;
+  updatedAt: string;
+}): Record<string, unknown> {
+  const row: Record<string, unknown> = {
+    id: input.id,
+    user_id: input.userId,
+    ...input.values,
+    updated_at: input.updatedAt,
+  };
+  if (input.inheritedSummary) row.context_summary = input.inheritedSummary;
+  return row;
+}
+
 export type ChatSessionWrite = Readonly<{
   title: string;
   theme: ConsultationDomain;

frontend/src/lib/consultation-session-history.ts

@@ -1,11 +1,14 @@
 export const CONSULTATION_HISTORY_LIMIT = 12;
 export const CONSULTATION_HISTORY_MESSAGE_CHARS = 12_000;
-export const CONSULTATION_HISTORY_TAIL_MAX_CHARS = 16_000;
 export const CONSULTATION_HISTORY_SYSTEM_RESERVE_TOKENS = 60_000;
 export const CONSULTATION_HISTORY_CHAR_PER_TOKEN = 1.5;
 export const CONSULTATION_HISTORY_BUDGET_MIN_CHARS = 4_000;
 export const CONSULTATION_HISTORY_BUDGET_MAX_CHARS = 40_000;
 export const DEFAULT_MODEL_CONTEXT_WINDOW = 128_000;
+// 0.4 of the history budget. At the default 128k window the budget is 40,000,
+// so the checkpoint fires at 16,000 — the previous hard-coded threshold.
+// Smaller windows then checkpoint before the tail can exceed the budget.
+export const CONSULTATION_HISTORY_CHECKPOINT_BUDGET_RATIO = 0.4;
 
 export const SESSION_CONTEXT_SUMMARY_HEADING = "【会话摘要（服务端维护）】";
 
@@ -51,6 +54,15 @@ export function historyBudgetChars(contextWindow: number | null | undefined): nu
   );
 }
 
+export function consultationHistoryCheckpointChars(contextWindow: number | null | undefined): number {
+  const budget = historyBudgetChars(contextWindow);
+  const threshold = Math.floor(budget * CONSULTATION_HISTORY_CHECKPOINT_BUDGET_RATIO);
+  if (!(threshold < budget)) {
+    throw new Error("consultation history checkpoint threshold must stay below the history budget");
+  }
+  return threshold;
+}
+
 export function parseSessionContextSummary(value: unknown): SessionContextSummaryV1 | null {
   if (!value || typeof value !== "object" || Array.isArray(value)) return null;
   const row = value as Record<string, unknown>;
@@ -74,6 +86,13 @@ export function omissionMarker(omittedChars: number): string {
   return `……（以下省略 ${omittedChars} 字，结论已并入会话摘要）`;
 }
 
+export function droppedRoundsMarker(droppedCount: number, hasSummary: boolean): string {
+  if (droppedCount <= 0) return "";
+  return hasSummary
+    ? `……（更早的 ${droppedCount} 轮问答已并入上面的会话摘要）`
+    : `……（更早的 ${droppedCount} 轮问答未能进入本轮上下文，结论尚未并入会话摘要）`;
+}
+
 export function clipConsultationHistoryText(text: string): string {
   if (text.length <= CONSULTATION_HISTORY_MESSAGE_CHARS) return text;
   const omitted = text.length - CONSULTATION_HISTORY_MESSAGE_CHARS;
@@ -165,16 +184,18 @@ export function consultationUserTurnContent(input: {
   instruction: string;
   extra?: string;
   summaryText?: string | null;
+  droppedCount?: number;
   question: string;
 }): string {
+  const summary = input.summaryText?.trim() ?? "";
+  const dropped = droppedRoundsMarker(input.droppedCount ?? 0, Boolean(summary));
   return [
     input.currentTime,
     input.name ? `用户称呼：${input.name}` : "",
     input.instruction,
     input.extra ?? "",
-    input.summaryText?.trim()
-      ? `${SESSION_CONTEXT_SUMMARY_HEADING}\n${input.summaryText.trim()}`
-      : "",
+    summary ? `${SESSION_CONTEXT_SUMMARY_HEADING}\n${summary}` : "",
+    dropped,
     input.question,
   ].filter(Boolean).join("\n");
 }

frontend/src/lib/session-context-summary.ts

@@ -1,7 +1,7 @@
 import { Agent } from "@mastra/core/agent";
 
 import {
-  CONSULTATION_HISTORY_TAIL_MAX_CHARS,
+  consultationHistoryCheckpointChars,
   lastConsultationPair,
   parseSessionContextSummary,
   storedConsultationTurns,
@@ -98,7 +98,7 @@ export function sanitizeSessionContextSummary(raw: string): string | null {
 export function tailCharCount(
   messages: unknown,
   summary: SessionContextSummaryV1 | null,
-  options: { excludeRequestId?: string } = {},
+  options: { excludeRequestId?: string; contextWindow?: number | null } = {},
 ): number {
   const turns = storedConsultationTurns(messages, { excludeRequestId: options.excludeRequestId });
   const tail = summary
@@ -110,9 +110,10 @@ export function tailCharCount(
 export function shouldCheckpoint(
   messages: unknown,
   summary: SessionContextSummaryV1 | null,
-  options: { excludeRequestId?: string } = {},
+  options: { excludeRequestId?: string; contextWindow?: number | null } = {},
 ): boolean {
-  return tailCharCount(messages, summary, options) > CONSULTATION_HISTORY_TAIL_MAX_CHARS;
+  return tailCharCount(messages, summary, options)
+    > consultationHistoryCheckpointChars(options.contextWindow);
 }
 
 export function messagesForSummaryInput(
@@ -215,6 +216,19 @@ export function nextSessionContextSummary(
   };
 }
 
+export async function resolveInheritedContextSummary(input: {
+  continuedFromSessionId?: string | null;
+  loadOwnedSummary: (sessionId: string) => Promise<unknown>;
+}): Promise<SessionContextSummaryV1 | null> {
+  const sourceId = input.continuedFromSessionId?.trim();
+  if (!sourceId) return null;
+  try {
+    return parseSessionContextSummary(await input.loadOwnedSummary(sourceId));
+  } catch {
+    return null;
+  }
+}
+
 export async function writeSessionContextSummary(input: {
   seenUpdatedAt: string | null;
   summary: SessionContextSummaryV1;
@@ -228,13 +242,17 @@ export async function checkpointSessionContextSummary(input: {
   messages: unknown;
   summary: unknown;
   excludeRequestId?: string;
+  contextWindow?: number | null;
   now?: () => Date;
   generateText: (prompt: string, signal?: AbortSignal) => Promise<string>;
   update: (summary: SessionContextSummaryV1, seenUpdatedAt: string | null) => Promise<boolean>;
   timeoutMs?: number;
 }): Promise<"written" | "skipped" | "abandoned" | "failed"> {
   const previous = parseSessionContextSummary(input.summary);
-  if (!shouldCheckpoint(input.messages, previous, { excludeRequestId: input.excludeRequestId })) {
+  if (!shouldCheckpoint(input.messages, previous, {
+    excludeRequestId: input.excludeRequestId,
+    contextWindow: input.contextWindow,
+  })) {
     return "skipped";
   }
   try {