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7a1ad33 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 | /**
* @license
* Copyright 2025 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
import type { MessageRecord } from './chatRecordingService.js';
import type { BaseLlmClient } from '../core/baseLlmClient.js';
import { partListUnionToString } from '../core/geminiRequest.js';
import { debugLogger } from '../utils/debugLogger.js';
import type { Content } from '@google/genai';
import { getResponseText } from '../utils/partUtils.js';
import { LlmRole } from '../telemetry/types.js';
const DEFAULT_MAX_MESSAGES = 20;
const DEFAULT_TIMEOUT_MS = 5000;
const MAX_MESSAGE_LENGTH = 500;
const SUMMARY_PROMPT = `Summarize the user's primary intent or goal in this conversation in ONE sentence (max 80 characters).
Focus on what the user was trying to accomplish.
Examples:
- "Add dark mode to the app"
- "Fix authentication bug in login flow"
- "Understand how the API routing works"
- "Refactor database connection logic"
- "Debug memory leak in production"
Conversation:
{conversation}
Summary (max 80 chars):`;
/**
* Options for generating a session summary.
*/
export interface GenerateSummaryOptions {
messages: MessageRecord[];
maxMessages?: number;
timeout?: number;
}
/**
* Service for generating AI summaries of chat sessions.
* Uses Gemini Flash Lite to create concise, user-intent-focused summaries.
*/
export class SessionSummaryService {
constructor(private readonly baseLlmClient: BaseLlmClient) {}
/**
* Generate a 1-line summary of a chat session focusing on user intent.
* Returns null if generation fails for any reason.
*/
async generateSummary(
options: GenerateSummaryOptions,
): Promise<string | null> {
const {
messages,
maxMessages = DEFAULT_MAX_MESSAGES,
timeout = DEFAULT_TIMEOUT_MS,
} = options;
try {
// Filter to user/gemini messages only (exclude system messages)
const filteredMessages = messages.filter((msg) => {
// Skip system messages (info, error, warning)
if (msg.type !== 'user' && msg.type !== 'gemini') {
return false;
}
const content = partListUnionToString(msg.content);
return content.trim().length > 0;
});
// Apply sliding window selection: first N + last N messages
let relevantMessages: MessageRecord[];
if (filteredMessages.length <= maxMessages) {
// If fewer messages than max, include all
relevantMessages = filteredMessages;
} else {
// Sliding window: take the first and last messages.
const firstWindowSize = Math.ceil(maxMessages / 2);
const lastWindowSize = Math.floor(maxMessages / 2);
const firstMessages = filteredMessages.slice(0, firstWindowSize);
const lastMessages = filteredMessages.slice(-lastWindowSize);
relevantMessages = firstMessages.concat(lastMessages);
}
if (relevantMessages.length === 0) {
debugLogger.debug('[SessionSummary] No messages to summarize');
return null;
}
// Format conversation for the prompt
const conversationText = relevantMessages
.map((msg) => {
const role = msg.type === 'user' ? 'User' : 'Assistant';
const content = partListUnionToString(msg.content);
// Truncate very long messages to avoid token limit
const truncated =
content.length > MAX_MESSAGE_LENGTH
? content.slice(0, MAX_MESSAGE_LENGTH) + '...'
: content;
return `${role}: ${truncated}`;
})
.join('\n\n');
const prompt = SUMMARY_PROMPT.replace('{conversation}', conversationText);
// Create abort controller with timeout
const abortController = new AbortController();
const timeoutId = setTimeout(() => {
abortController.abort();
}, timeout);
try {
const contents: Content[] = [
{
role: 'user',
parts: [{ text: prompt }],
},
];
const response = await this.baseLlmClient.generateContent({
modelConfigKey: { model: 'summarizer-default' },
contents,
abortSignal: abortController.signal,
promptId: 'session-summary-generation',
role: LlmRole.UTILITY_SUMMARIZER,
});
const summary = getResponseText(response);
if (!summary || summary.trim().length === 0) {
debugLogger.debug('[SessionSummary] Empty summary returned');
return null;
}
// Clean the summary
let cleanedSummary = summary
.replace(/\n+/g, ' ') // Collapse newlines to spaces
.replace(/\s+/g, ' ') // Normalize whitespace
.trim(); // Trim after all processing
// Remove quotes if the model added them
cleanedSummary = cleanedSummary.replace(/^["']|["']$/g, '');
debugLogger.debug(`[SessionSummary] Generated: "${cleanedSummary}"`);
return cleanedSummary;
} finally {
clearTimeout(timeoutId);
}
} catch (error) {
// Log the error but don't throw - we want graceful degradation
if (error instanceof Error && error.name === 'AbortError') {
debugLogger.debug('[SessionSummary] Timeout generating summary');
} else {
debugLogger.debug(
`[SessionSummary] Error generating summary: ${error instanceof Error ? error.message : String(error)}`,
);
}
return null;
}
}
}
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