DBP-128: reduce AI cost

app/api/chat/route.ts

@@ -4,12 +4,10 @@ import { getAuthorizedUserInfo } from "@/lib/auth.rsc";
 import { createPostHogClient } from "@/lib/posthog.rsc";
 import { anthropic, type AnthropicProviderOptions } from "@ai-sdk/anthropic";
 import { withTracing } from "@posthog/ai";
-import { convertToModelMessages, stepCountIs, streamText, tool, type UIMessage } from "ai";
+import { convertToModelMessages, pruneMessages, stepCountIs, streamText, tool, type UIMessage } from "ai";
 import { NextResponse } from "next/server";
 import { z } from "zod";
 
-export const maxDuration = 30;
-
 const QUESTION_INFO = graphql(`
   query QuestionInfo($id: ID!) {
     question(id: $id) {
@@ -101,18 +99,25 @@ export async function POST(req: Request) {
     );
   }
 
-  const model = anthropic("claude-sonnet-4-5");
+  const model = anthropic("claude-haiku-4-5");
   const posthogClient = await createPostHogClient();
 
   const tracedModel = withTracing(model, posthogClient, {
     posthogDistinctId: userInfo.sub,
   });
 
+  const prunedMessages = pruneMessages({
+    messages: convertToModelMessages(messages),
+    reasoning: "none",
+    toolCalls: "before-last-message",
+    emptyMessages: "remove",
+  });
+
   const result = streamText({
     model: tracedModel,
     providerOptions: {
       anthropic: {
-        thinking: { type: "enabled", budgetTokens: 12000 },
+        thinking: { type: "enabled", budgetTokens: 2000 },
       } satisfies AnthropicProviderOptions,
     },
     messages: [
@@ -136,7 +141,7 @@ export async function POST(req: Request) {
           } satisfies AnthropicProviderOptions,
         },
       },
-      ...convertToModelMessages(messages),
+      ...prunedMessages,
     ],
     stopWhen: stepCountIs(10),
     tools: {

gql/graphql.ts

@@ -49,6 +49,17 @@ export type CreateGroupInput = {
   scopeSetIDs?: InputMaybe<Array<Scalars['ID']['input']>>;
 };
 
+/**
+ * CreatePointInput is used for create Point object.
+ * Input was generated by ent.
+ */
+export type CreatePointInput = {
+  description?: InputMaybe<Scalars['String']['input']>;
+  grantedAt?: InputMaybe<Scalars['Time']['input']>;
+  points?: InputMaybe<Scalars['Int']['input']>;
+  userID: Scalars['ID']['input'];
+};
+
 /**
  * CreateQuestionInput is used for create Question object.
  * Input was generated by ent.
@@ -388,6 +399,8 @@ export type Mutation = {
   createDatabase: Database;
   /** Create a new group. */
   createGroup?: Maybe<Group>;
+  /** Create a new point record for a user. */
+  createPoint?: Maybe<Point>;
   /** Create a question. */
   createQuestion: Question;
   /** Create a new scope set. */
@@ -440,6 +453,11 @@ export type MutationCreateGroupArgs = {
 };
 
 
+export type MutationCreatePointArgs = {
+  input: CreatePointInput;
+};
+
+
 export type MutationCreateQuestionArgs = {
   input: CreateQuestionInput;
 };
@@ -897,13 +915,13 @@ export enum QuestionOrderField {
 
 export type QuestionStatistics = {
   __typename?: 'QuestionStatistics';
-  /** 嘗試人數 */
+  /** Number of users who attempted */
   attemptedUsers: Scalars['Int']['output'];
-  /** 答案正確的提交數 */
+  /** Number of correct submissions */
   correctSubmissionCount: Scalars['Int']['output'];
-  /** 通過的學生數 */
+  /** Number of users who passed */
   passedUsers: Scalars['Int']['output'];
-  /** 所有提交數 */
+  /** Total number of submissions */
   submissionCount: Scalars['Int']['output'];
 };
 

schema.graphql

@@ -43,6 +43,17 @@ input CreateGroupInput {
   scopeSetIDs: [ID!]
 }
 
+"""
+CreatePointInput is used for create Point object.
+Input was generated by ent.
+"""
+input CreatePointInput {
+  description: String
+  grantedAt: Time
+  points: Int
+  userID: ID!
+}
+
 """
 CreateQuestionInput is used for create Question object.
 Input was generated by ent.
@@ -383,6 +394,8 @@ type Mutation {
   createDatabase(input: CreateDatabaseInput!): Database!
   """Create a new group."""
   createGroup(input: CreateGroupInput!): Group
+  """Create a new point record for a user."""
+  createPoint(input: CreatePointInput!): Point
   """Create a question."""
   createQuestion(input: CreateQuestionInput!): Question!
   """Create a new scope set."""
@@ -770,13 +783,13 @@ enum QuestionOrderField {
 }
 
 type QuestionStatistics {
-  """嘗試人數"""
+  """Number of users who attempted"""
   attemptedUsers: Int!
-  """答案正確的提交數"""
+  """Number of correct submissions"""
   correctSubmissionCount: Int!
-  """通過的學生數"""
+  """Number of users who passed"""
   passedUsers: Int!
-  """所有提交數"""
+  """Total number of submissions"""
   submissionCount: Int!
 }