feat: add conversation transcript lookup after summarization (#4475)

* feat: add conversation transcript lookup after summarization After conversation history is compacted, inform the model it can look up the full pre-compaction transcript via read_file. The transcript is a JSONL file produced by ISessionTranscriptService. Key changes: - Add isTranscriptUri() to ISessionTranscriptService for read_file allowlisting - Allowlist transcript URIs in assertFileOkForTool and isFileExternalAndNeedsConfirmation - Lazily start transcript session in SummarizedConversationHistory before summarization runs (idempotent if hooks already started it) - After summarization, flush transcript and pass path to SummaryMessageElement which tells the model about the file - Gate behind ConfigKey.ConversationTranscriptLookup (ExperimentBased, default off) - Add setting in package.json preview section with onExp tag * fix: update transcript lookup instruction to use ToolName.ReadFile
2026-05-30 12:15:32 +01:00 · 2026-03-17 23:06:21 -07:00
parent 8ab4b1ac24
commit 35e83ba656
7 changed files with 102 additions and 2 deletions
@@ -3235,6 +3235,15 @@
 							"preview",
 							"onExp"
 						]
+					},
+					"github.copilot.chat.conversationTranscriptLookup.enabled": {
+						"type": "boolean",
+						"default": false,
+						"description": "%github.copilot.config.conversationTranscriptLookup.enabled%",
+						"tags": [
+							"preview",
+							"onExp"
+						]
 					}
 				}
 			},
@@ -265,6 +265,7 @@
 	"github.copilot.config.editsNewNotebook.enabled": "Whether to enable the new notebook tool in Copilot Edits.",
 	"github.copilot.config.notebook.inlineEditAgent.enabled": "Enable agent-like behavior from the notebook inline chat widget.",
 	"github.copilot.config.summarizeAgentConversationHistory.enabled": "Whether to auto-compact agent conversation history once the context window is filled.",
+	"github.copilot.config.conversationTranscriptLookup.enabled": "When enabled, after conversation history is summarized the model is informed it can look up the full conversation transcript via read_file.",
 	"github.copilot.tools.createNewWorkspace.name": "Create New Workspace",
 	"github.copilot.tools.openEmptyFolder.name": "Open an empty folder as VS Code workspace",
 	"github.copilot.tools.getProjectSetupInfo.name": "Get Project Setup Info",
@@ -14,6 +14,7 @@ import { IEnvService } from '../../../platform/env/common/envService';
 import { IVSCodeExtensionContext } from '../../../platform/extContext/common/extensionContext';
 import { IFileSystemService, createDirectoryIfNotExists } from '../../../platform/filesystem/common/fileSystemService';
 import { ILogService } from '../../../platform/log/common/logService';
+import { extUriBiasedIgnorePathCase } from '../../../util/vs/base/common/resources';
 import { URI } from '../../../util/vs/base/common/uri';
 import { generateUuid } from '../../../util/vs/base/common/uuid';

@@ -215,6 +216,14 @@ export class SessionTranscriptService implements ISessionTranscriptService {
 		return this._activeSessions.get(sessionId)?.uri;
 	}

+	isTranscriptUri(uri: URI): boolean {
+		const dir = this._getTranscriptsDir();
+		if (!dir) {
+			return false;
+		}
+		return extUriBiasedIgnorePathCase.isEqualOrParent(uri, dir);
+	}
+
 	async cleanupOldTranscripts(maxRetained: number = DEFAULT_MAX_RETAINED): Promise<void> {
 		const dir = this._getTranscriptsDir();
 		if (!dir) {
@@ -10,6 +10,7 @@ import { ChatMessage } from '@vscode/prompt-tsx/dist/base/output/rawTypes';
 import type { ChatResponsePart, ChatResultPromptTokenDetail, LanguageModelToolInformation, NotebookDocument, Progress } from 'vscode';
 import { IChatHookService, PreCompactHookInput } from '../../../../platform/chat/common/chatHookService';
 import { ChatFetchResponseType, ChatLocation, ChatResponse, FetchSuccess } from '../../../../platform/chat/common/commonTypes';
+import { IHistoricalTurn, ISessionTranscriptService } from '../../../../platform/chat/common/sessionTranscriptService';
 import { ConfigKey, IConfigurationService } from '../../../../platform/configuration/common/configurationService';
 import { isAnthropicFamily } from '../../../../platform/endpoint/common/chatModelCapabilities';
 import { IEndpointProvider } from '../../../../platform/endpoint/common/endpointProvider';
@@ -248,7 +249,7 @@ class ConversationHistory extends PromptElement<SummarizedAgentHistoryProps> {
 		}

 		if (summaryForCurrentTurn) {
-			history.push(<SummaryMessageElement endpoint={this.props.endpoint} summaryText={summaryForCurrentTurn} />);
+			history.push(<SummaryMessageElement endpoint={this.props.endpoint} summaryText={summaryForCurrentTurn} transcriptPath={this.props.transcriptPath} />);

 			return (<PrioritizedList priority={this.props.priority} descending={false} passPriority={true}>
 				{history.reverse()}
@@ -308,7 +309,7 @@ class ConversationHistory extends PromptElement<SummarizedAgentHistoryProps> {

 			if (summaryForTurn) {
 				// We have a summary for a tool call round that was part of this turn
-				turnComponents.push(<SummaryMessageElement endpoint={this.props.endpoint} summaryText={summaryForTurn.text} />);
+				turnComponents.push(<SummaryMessageElement endpoint={this.props.endpoint} summaryText={summaryForTurn.text} transcriptPath={this.props.transcriptPath} />);
 			} else if (!turn.isContinuation) {
 				turnComponents.push(<AgentUserMessage flexGrow={1} {...getUserMessagePropsFromTurn(turn, this.props.endpoint, {
 					userQueryTagName: this.props.userQueryTagName,
@@ -408,6 +409,8 @@ export interface SummarizedAgentHistoryProps extends BasePromptElementProps, Age
 	readonly summarizationInstructions?: string;
 	/** Whether this summarization was triggered as a background or foreground operation. Defaults to 'foreground'. */
 	readonly summarizationSource?: 'background' | 'foreground';
+	/** Path to the conversation transcript JSONL file, used to inform the model after summarization */
+	readonly transcriptPath?: string;
 }

 /**
@@ -417,6 +420,9 @@ export class SummarizedConversationHistory extends PromptElement<SummarizedAgent
 	constructor(
 		props: SummarizedAgentHistoryProps,
 		@IInstantiationService private readonly instantiationService: IInstantiationService,
+		@ISessionTranscriptService private readonly sessionTranscriptService: ISessionTranscriptService,
+		@IConfigurationService private readonly configurationService: IConfigurationService,
+		@IExperimentationService private readonly experimentationService: IExperimentationService,
 	) {
 		super(props);
 	}
@@ -424,7 +430,16 @@ export class SummarizedConversationHistory extends PromptElement<SummarizedAgent
 	override async render(state: void, sizing: PromptSizing, progress: Progress<ChatResponsePart> | undefined, token: CancellationToken | undefined) {
 		const promptContext = { ...this.props.promptContext };
 		let historyMetadata: SummarizedConversationHistoryMetadata | undefined;
+		const transcriptLookupEnabled = this.configurationService.getExperimentBasedConfig(ConfigKey.ConversationTranscriptLookup, this.experimentationService);
+
 		if (this.props.triggerSummarize) {
+			// If transcript lookup is enabled, lazily start the transcript session now
+			// (before summarization) so it captures the full pre-compaction conversation.
+			// startSession is idempotent — if hooks already started it, this is a no-op.
+			if (transcriptLookupEnabled) {
+				await this.ensureTranscriptSession();
+			}
+
 			const summarizer = this.instantiationService.createInstance(ConversationHistorySummarizer, this.props, sizing, progress, token);
 			const summResult = await summarizer.summarizeHistory();
 			if (summResult) {
@@ -442,15 +457,62 @@ export class SummarizedConversationHistory extends PromptElement<SummarizedAgent
 			}
 		}

+		// Resolve transcript path and flush to disk so the model can read the up-to-date file
+		let transcriptPath: string | undefined;
+		if (transcriptLookupEnabled) {
+			const sessionId = this.props.promptContext.conversation?.sessionId;
+			if (sessionId) {
+				const transcriptUri = this.sessionTranscriptService.getTranscriptPath(sessionId);
+				if (transcriptUri) {
+					await this.sessionTranscriptService.flush(sessionId);
+					transcriptPath = transcriptUri.fsPath;
+				}
+			}
+		}
+
 		return <>
 			{historyMetadata && <meta value={historyMetadata} />}
 			<ConversationHistory
 				{...this.props}
 				promptContext={promptContext}
+				transcriptPath={transcriptPath}
 				enableCacheBreakpoints={this.props.enableCacheBreakpoints} />
 		</>;
 	}

+	/**
+	 * Lazily starts a transcript session with the full conversation history.
+	 * This is called just before summarization so that the transcript file
+	 * contains the complete pre-compaction conversation. If a session was
+	 * already started (e.g. by hooks), this is a no-op.
+	 */
+	private async ensureTranscriptSession(): Promise<void> {
+		const sessionId = this.props.promptContext.conversation?.sessionId;
+		if (!sessionId) {
+			return;
+		}
+
+		// Build IHistoricalTurn[] from the prompt context's Turn[] history
+		const history: IHistoricalTurn[] = this.props.promptContext.history.map(turn => ({
+			userMessage: turn.request.message,
+			timestamp: turn.startTime,
+			rounds: turn.rounds.map(round => ({
+				response: round.response,
+				toolCalls: round.toolCalls.map(tc => ({
+					name: tc.name,
+					arguments: tc.arguments,
+					id: tc.id,
+				})),
+				reasoningText: round.thinking
+					? (Array.isArray(round.thinking.text) ? round.thinking.text.join('') : round.thinking.text)
+					: undefined,
+				timestamp: round.timestamp,
+			})),
+		}));
+
+		await this.sessionTranscriptService.startSession(sessionId, undefined, history.length > 0 ? history : undefined);
+	}
+
 	private addSummaryToHistory(summary: string, toolCallRoundId: string, thinking?: ThinkingData): void {
 		const round = this.props.promptContext.toolCallRounds?.find(round => round.id === toolCallRoundId);
 		if (round) {
@@ -918,6 +980,7 @@ export class SummarizedConversationHistoryPropsBuilder {
 interface SummaryMessageProps extends BasePromptElementProps {
 	readonly summaryText: string;
 	readonly endpoint: IChatEndpoint;
+	readonly transcriptPath?: string;
 }

 class SummaryMessageElement extends PromptElement<SummaryMessageProps> {
@@ -926,6 +989,7 @@ class SummaryMessageElement extends PromptElement<SummaryMessageProps> {
 			<Tag name='conversation-summary'>
 				{this.props.summaryText}
 			</Tag>
+			{this.props.transcriptPath && <><br />If you need specific details from before compaction (such as exact code snippets, error messages, tool results, or content you previously generated), use the {ToolName.ReadFile} tool to look up the full uncompacted conversation transcript at: {this.props.transcriptPath}</>}
 			{this.props.endpoint.family === 'gpt-4.1' && <Tag name='reminderInstructions'>
 				<DefaultOpenAIKeepGoingReminder />
 			</Tag>}
@@ -6,6 +6,7 @@
 import { PromptElement, PromptPiece } from '@vscode/prompt-tsx';
 import type * as vscode from 'vscode';
 import { IChatDebugFileLoggerService } from '../../../platform/chat/common/chatDebugFileLoggerService';
+import { ISessionTranscriptService } from '../../../platform/chat/common/sessionTranscriptService';
 import { ConfigKey, IConfigurationService } from '../../../platform/configuration/common/configurationService';
 import { ICustomInstructionsService, IInstructionIndexFile } from '../../../platform/customInstructions/common/customInstructionsService';
 import { IFileSystemService } from '../../../platform/filesystem/common/fileSystemService';
@@ -171,6 +172,7 @@ export async function assertFileOkForTool(accessor: ServicesAccessor, uri: URI,
 	const diskSessionResources = accessor.get(IChatDiskSessionResources);
 	const configurationService = accessor.get(IConfigurationService);
 	const chatDebugFileLogger = accessor.get(IChatDebugFileLoggerService);
+	const sessionTranscriptService = accessor.get(ISessionTranscriptService);

 	await assertFileNotContentExcluded(accessor, uri);

@@ -194,6 +196,9 @@ export async function assertFileOkForTool(accessor: ServicesAccessor, uri: URI,
 	if (chatDebugFileLogger.isDebugLogUri(normalizedUri)) {
 		return;
 	}
+	if (sessionTranscriptService.isTranscriptUri(normalizedUri)) {
+		return;
+	}
 	if (await isExternalInstructionsFile(normalizedUri, customInstructionsService, buildPromptContext)) {
 		return;
 	}
@@ -269,6 +274,7 @@ export async function isFileExternalAndNeedsConfirmation(accessor: ServicesAcces
 	const configurationService = accessor.get(IConfigurationService);
 	const fileSystemService = accessor.get(IFileSystemService);
 	const chatDebugFileLogger = accessor.get(IChatDebugFileLoggerService);
+	const sessionTranscriptService = accessor.get(ISessionTranscriptService);

 	const normalizedUri = normalizePath(uri);

@@ -291,6 +297,9 @@ export async function isFileExternalAndNeedsConfirmation(accessor: ServicesAcces
 	if (chatDebugFileLogger.isDebugLogUri(normalizedUri)) {
 		return false;
 	}
+	if (sessionTranscriptService.isTranscriptUri(normalizedUri)) {
+		return false;
+	}
 	if (tabsAndEditorsService.tabs.some(tab => isEqual(tab.uri, uri))) {
 		return false;
 	}
@@ -242,6 +242,12 @@ export interface ISessionTranscriptService {
 	 * keeping at most `maxRetained` most-recent ended sessions.
 	 */
 	cleanupOldTranscripts(maxRetained?: number): Promise<void>;
+
+	/**
+	 * Check whether a URI is under the transcripts storage directory.
+	 * Used by {@link assertFileOkForTool} to allowlist tool reads.
+	 */
+	isTranscriptUri(uri: URI): boolean;
 }

 export class NullSessionTranscriptService implements ISessionTranscriptService {
@@ -258,4 +264,5 @@ export class NullSessionTranscriptService implements ISessionTranscriptService {
 	async endSession(): Promise<void> { }
 	getTranscriptPath(): URI | undefined { return undefined; }
 	async cleanupOldTranscripts(): Promise<void> { }
+	isTranscriptUri(): boolean { return false; }
 }
@@ -933,6 +933,7 @@ export namespace ConfigKey {
 	export const NewWorkspaceCreationAgentEnabled = defineSetting<boolean>('chat.newWorkspaceCreation.enabled', ConfigType.Simple, true);
 	export const NewWorkspaceUseContext7 = defineSetting<boolean>('chat.newWorkspace.useContext7', ConfigType.Simple, false);
 	export const SummarizeAgentConversationHistory = defineSetting<boolean>('chat.summarizeAgentConversationHistory.enabled', ConfigType.Simple, true);
+	export const ConversationTranscriptLookup = defineSetting<boolean>('chat.conversationTranscriptLookup.enabled', ConfigType.ExperimentBased, false);
 	export const BackgroundCompaction = defineSetting<boolean>('chat.backgroundCompaction', ConfigType.ExperimentBased, false);
 	export const VirtualToolThreshold = defineSetting<number>('chat.virtualTools.threshold', ConfigType.ExperimentBased, HARD_TOOL_LIMIT);
 	export const CurrentEditorAgentContext = defineSetting<boolean>('chat.agent.currentEditorContext.enabled', ConfigType.Simple, true);