feat(core): add 100k tokens limit for the docs context (#10211)

Support issue [BS-2352](https://linear.app/affine-design/issue/BS-2352).

![截屏2025-02-16 21.32.16.png](https://graphite-user-uploaded-assets-prod.s3.amazonaws.com/sJGviKxfE3Ap685cl5bj/813b2f67-918b-4c61-ba2e-b5066792a4fd.png)

packages/frontend/core/src/blocksuite/presets/ai/chat-panel/chat-context.ts

@@ -78,6 +78,7 @@ export interface BaseChip {
 export interface DocChip extends BaseChip {
   docId: string;
   markdown?: Signal<string>;
+  tokenCount?: number;
 }
 
 export interface FileChip extends BaseChip {

packages/frontend/core/src/blocksuite/presets/ai/chat-panel/chat-panel-chips.ts

@@ -12,8 +12,21 @@ import { repeat } from 'lit/directives/repeat.js';
 
 import { AIProvider } from '../provider';
 import type { DocDisplayConfig, DocSearchMenuConfig } from './chat-config';
-import type { BaseChip, ChatChip, ChatContextValue } from './chat-context';
-import { getChipKey, isDocChip, isFileChip } from './components/utils';
+import type {
+  ChatChip,
+  ChatContextValue,
+  DocChip,
+  FileChip,
+} from './chat-context';
+import {
+  estimateTokenCount,
+  getChipKey,
+  isDocChip,
+  isFileChip,
+} from './components/utils';
+
+// 100k tokens limit for the docs context
+const MAX_TOKEN_COUNT = 100000;
 
 export class ChatPanelChips extends WithDisposable(ShadowlessElement) {
   static override styles = css`
@@ -91,6 +104,7 @@ export class ChatPanelChips extends WithDisposable(ShadowlessElement) {
               .addChip=${this._addChip}
               .updateChip=${this._updateChip}
               .removeChip=${this._removeChip}
+              .checkTokenLimit=${this._checkTokenLimit}
               .docDisplayConfig=${this.docDisplayConfig}
               .host=${this.host}
             ></chat-panel-doc-chip>`;
@@ -189,7 +203,7 @@ export class ChatPanelChips extends WithDisposable(ShadowlessElement) {
 
   private readonly _updateChip = (
     chip: ChatChip,
-    options: Partial<BaseChip>
+    options: Partial<DocChip | FileChip>
   ) => {
     const index = this.chatContextValue.chips.findIndex(item => {
       if (isDocChip(chip)) {
@@ -264,4 +278,25 @@ export class ChatPanelChips extends WithDisposable(ShadowlessElement) {
       });
     }
   };
+
+  private readonly _checkTokenLimit = (
+    newChip: DocChip,
+    newTokenCount: number
+  ) => {
+    const estimatedTokens = this.chatContextValue.chips.reduce((acc, chip) => {
+      if (isFileChip(chip)) {
+        return acc;
+      }
+      if (chip.docId === newChip.docId) {
+        return acc + newTokenCount;
+      }
+      if (chip.markdown?.value && chip.state === 'success') {
+        const tokenCount =
+          chip.tokenCount ?? estimateTokenCount(chip.markdown.value);
+        return acc + tokenCount;
+      }
+      return acc;
+    }, 0);
+    return estimatedTokens <= MAX_TOKEN_COUNT;
+  };
 }

packages/frontend/core/src/blocksuite/presets/ai/chat-panel/components/doc-chip.ts

@@ -13,8 +13,8 @@ import { property } from 'lit/decorators.js';
 
 import { extractMarkdownFromDoc } from '../../utils/extract';
 import type { DocDisplayConfig } from '../chat-config';
-import type { BaseChip, ChatChip, DocChip } from '../chat-context';
-import { getChipIcon, getChipTooltip } from './utils';
+import type { ChatChip, DocChip } from '../chat-context';
+import { estimateTokenCount, getChipIcon, getChipTooltip } from './utils';
 
 const EXTRACT_DOC_THROTTLE = 1000;
 
@@ -28,11 +28,17 @@ export class ChatPanelDocChip extends SignalWatcher(
   accessor addChip!: (chip: ChatChip) => void;
 
   @property({ attribute: false })
-  accessor updateChip!: (chip: ChatChip, options: Partial<BaseChip>) => void;
+  accessor updateChip!: (chip: ChatChip, options: Partial<DocChip>) => void;
 
   @property({ attribute: false })
   accessor removeChip!: (chip: ChatChip) => void;
 
+  @property({ attribute: false })
+  accessor checkTokenLimit!: (
+    newChip: DocChip,
+    newTokenCount: number
+  ) => boolean;
+
   @property({ attribute: false })
   accessor docDisplayConfig!: DocDisplayConfig;
 
@@ -103,15 +109,22 @@ export class ChatPanelDocChip extends SignalWatcher(
       if (!doc.ready) {
         doc.load();
       }
-      const result = await extractMarkdownFromDoc(doc, this.host.std.provider);
-      if (this.chip.markdown) {
-        this.chip.markdown.value = result.markdown;
+      const value = await extractMarkdownFromDoc(doc, this.host.std.provider);
+      const tokenCount = estimateTokenCount(value);
+      if (this.checkTokenLimit(this.chip, tokenCount)) {
+        const markdown = this.chip.markdown ?? new Signal<string>('');
+        markdown.value = value;
+        this.updateChip(this.chip, {
+          state: 'success',
+          markdown,
+          tokenCount,
+        });
       } else {
-        this.chip.markdown = new Signal<string>(result.markdown);
+        this.updateChip(this.chip, {
+          state: 'failed',
+          tooltip: 'Content exceeds token limit',
+        });
       }
-      this.updateChip(this.chip, {
-        state: 'success',
-      });
     } catch (e) {
       this.updateChip(this.chip, {
         state: 'failed',

packages/frontend/core/src/blocksuite/presets/ai/chat-panel/components/utils.ts

@@ -69,3 +69,14 @@ export function getChipKey(chip: ChatChip) {
   }
   return null;
 }
+
+export function estimateTokenCount(text: string): number {
+  const chinese = text.match(/[\u4e00-\u9fa5]/g)?.length || 0;
+  const english = text.replace(/[\u4e00-\u9fa5]/g, '');
+  // Split English text into words by whitespace
+  const englishWords = english.trim().split(/\s+/).length;
+
+  // Chinese characters: 1 character ≈ 2.5 tokens
+  // English words: 1 word ≈ 1.3 tokens
+  return Math.ceil(chinese * 2.5 + englishWords * 1.3);
+}

packages/frontend/core/src/blocksuite/presets/ai/utils/extract.ts

@@ -158,7 +158,7 @@ export async function extractPageAll(
 export async function extractMarkdownFromDoc(
   doc: Store,
   provider: ServiceProvider
-): Promise<{ docId: string; markdown: string }> {
+): Promise<string> {
   const transformer = await getTransformer(doc);
   const adapter = new MarkdownAdapter(transformer, provider);
   const blockModels = getNoteBlockModels(doc);
@@ -177,10 +177,7 @@ export async function extractMarkdownFromDoc(
     snapshot,
     assets: transformer.assetsManager,
   });
-  return {
-    docId: doc.id,
-    markdown: content.file,
-  };
+  return content.file;
 }
 
 function getNoteBlockModels(doc: Store) {