sessions: support chat-scoped multi-repository workspaces

src/vs/platform/agentHost/browser/agentHostProtocolClient.ts

@@ -1650,6 +1650,9 @@ export class AgentHostProtocolClient extends Disposable implements IAgentConnect
 					...(options.sideChat.selection ? { selection: options.sideChat.selection } : {}),
 				}
 			} : {}),
+			...(options?.workingDirectories !== undefined && !options.fork
+				? { workingDirectories: options.workingDirectories.map(directory => fromAgentHostUri(directory).toString()) }
+				: {}),
 		});
 	}
 

src/vs/platform/agentHost/common/agentHostChangesetOperationService.ts

@@ -87,6 +87,14 @@ export interface IChangesetOperationContext {
 	readonly gitHubState?: ISessionGitHubState;
 }
 
+/** Host-owned repository context for one concrete changeset channel. */
+export interface IChangesetOperationTargetContext {
+	readonly ownerUri: URI;
+	readonly workingDirectories: readonly URI[];
+	readonly gitState?: ISessionGitState;
+	readonly gitHubState?: ISessionGitHubState;
+}
+
 /**
  * Registration surface handed to changeset operation contributions.
  *
@@ -142,6 +150,8 @@ export interface IAgentHostChangesetOperationService extends IDisposable {
 	 * unregisters the handlers and disposes the contribution.
 	 */
 	registerContribution(contribution: IChangesetOperationContribution): IDisposable;
+	/** Associates a concrete changeset channel with its trusted repository context. */
+	setChangesetTarget(sessionKey: string, changeset: string, target: IChangesetOperationTargetContext | undefined): void;
 	/**
 	 * Recomputes operations using the provided or current Git state.
 	 * Without Git state, clears cached operations but defers initial publication.

src/vs/platform/agentHost/common/agentHostGitStateService.ts

@@ -38,6 +38,9 @@ export interface IAgentHostGitStateService {
 	 */
 	refreshSessionGitState(sessionKey: string, workingDirectory?: URI): Promise<void>;
 
+	/** Finds the pull request for a working directory without changing session-level Git metadata. */
+	findPullRequestForWorkingDirectory(sessionKey: string, workingDirectory: URI): Promise<string | undefined>;
+
 	/** Merges the branch identity known when an isolated worktree materializes into session metadata. */
 	getMaterializedWorktreeMeta(sessionKey: string, branchName: string): SessionSummaryMeta | undefined;
 

src/vs/platform/agentHost/common/agentHostSchema.ts

@@ -551,6 +551,9 @@ export const agentHostProxyConfigSchema = createSchema(agentHostProxyConfigDefin
 /** Root config key forwarded from the renderer for active-agent title generation. */
 export const AgentHostActiveAgentTitleGenerationConfigKey = 'activeAgentTitleGeneration';
 
+/** Root config key controlling whether create_session exposes its relationship choice. */
+export const AgentHostCreateSessionRelationshipConfigKey = 'createSessionRelationship';
+
 /** Root config key controlling rich-link guidance for Markdown plan documents. */
 export const AgentHostMarkdownPlanRichLinksEnabledConfigKey = 'markdownPlanRichLinksEnabled';
 
@@ -881,6 +884,12 @@ export const platformRootSchema = createSchema({
 		description: localize('agentHost.config.activeAgentTitleGeneration.description', "Whether the active agent names sessions and chats with rename tools instead of utility-model title generation."),
 		default: false,
 	}),
+	[AgentHostCreateSessionRelationshipConfigKey]: schemaProperty<boolean>({
+		type: 'boolean',
+		title: localize('agentHost.config.createSessionRelationship.title', "Create Session Relationship"),
+		description: localize('agentHost.config.createSessionRelationship.description', "Whether agents can choose between creating a chat in the current session and creating an independent session. When disabled, delegated work is always created as a chat in the current session."),
+		default: true,
+	}),
 	[AgentHostMarkdownPlanRichLinksEnabledConfigKey]: schemaProperty<boolean>({
 		type: 'boolean',
 		title: localize('agentHost.config.markdownPlanRichLinks.title', "Markdown Plan Rich Links"),

src/vs/platform/agentHost/common/agentHostStarter.config.contribution.ts

@@ -15,6 +15,7 @@ import {
 	AgentHostByokModelsEnabledSettingId,
 	AgentHostGitHubMcpServerEnabledSettingId,
 	AgentHostActiveAgentTitleGenerationSettingId,
+	AgentHostCreateSessionRelationshipSettingId,
 	AgentHostClaudeAgentEnabledSettingId,
 	AgentHostClaudeMultiRootEnabledSettingId,
 	AgentHostCodexAgentBinaryArgsSettingId,
@@ -40,6 +41,7 @@ import {
 	AgentHostActiveAgentTitleGenerationConfigKey,
 	AgentHostAutoAttachPullRequestsConfigKey,
 	AgentHostByokModelsEnabledConfigKey,
+	AgentHostCreateSessionRelationshipConfigKey,
 	AgentHostGitHubMcpServerEnabledConfigKey,
 	AgentHostCodexEnabledConfigKey,
 	AgentHostCodexMultiRootEnabledConfigKey,
@@ -191,6 +193,15 @@ configurationRegistry.registerConfiguration({
 			experiment: { mode: 'auto' },
 			agentHost: { key: AgentHostActiveAgentTitleGenerationConfigKey },
 		},
+		[AgentHostCreateSessionRelationshipSettingId]: {
+			type: 'boolean',
+			description: nls.localize('chat.agentHost.experimental.createSessionRelationship', "Controls whether agents can choose to create delegated work in the current session or as an independent session. When disabled, delegated work is always created as a chat in the current session."),
+			default: true,
+			scope: ConfigurationScope.APPLICATION,
+			tags: ['experimental', 'advanced'],
+			experiment: { mode: 'auto' },
+			agentHost: { key: AgentHostCreateSessionRelationshipConfigKey },
+		},
 		...artifactToolsConfigurationProperties,
 		[AgentHostAutoAttachPullRequestsSettingId]: {
 			type: 'boolean',

src/vs/platform/agentHost/common/agentMerge.ts

@@ -80,6 +80,12 @@ export interface AgentMergeSessionOverrides {
 export interface AgentMergeTarget {
 	readonly branchName: string;
 	readonly pullRequestUrl?: string;
+	/** Chat whose repository and turns Agent Merge owns. Absent on legacy targets. */
+	readonly chatUri?: string;
+	/** Working directory Agent Merge must inspect and mutate. Absent on legacy targets. */
+	readonly workingDirectory?: string;
+	/** Whether the controller still needs to announce this newly enabled target. */
+	readonly announcementPending?: boolean;
 	readonly enabledAt: string;
 	readonly commentWatermark: string;
 }
@@ -283,6 +289,10 @@ export const agentMergeDisableReasons = {
 		log: 'the associated pull request URL is invalid',
 		notice: localize('agentMerge.disabled.invalidPullRequestUrl', "Agent Merge was disabled because the associated pull request URL is invalid."),
 	}),
+	targetUnavailable: (): AgentMergeDisableReason => ({
+		log: 'the owning chat or working directory is no longer available',
+		notice: localize('agentMerge.disabled.targetUnavailable', "Agent Merge was disabled because its chat or working directory is no longer available in this session."),
+	}),
 	differentGitHubHost: (): AgentMergeDisableReason => ({
 		log: 'the bound pull request belongs to a different GitHub host than the signed-in account',
 		notice: localize('agentMerge.disabled.differentGitHubHost', "Agent Merge was disabled because its pull request belongs to a different GitHub host than the signed-in account."),
@@ -597,6 +607,9 @@ function readTarget(value: unknown): AgentMergeTarget | undefined {
 		enabledAt: value.enabledAt,
 		commentWatermark: value.commentWatermark,
 		...(typeof value.pullRequestUrl === 'string' ? { pullRequestUrl: value.pullRequestUrl } : {}),
+		...(typeof value.chatUri === 'string' ? { chatUri: value.chatUri } : {}),
+		...(typeof value.workingDirectory === 'string' ? { workingDirectory: value.workingDirectory } : {}),
+		...(value.announcementPending === true ? { announcementPending: true } : {}),
 	};
 }
 

src/vs/platform/agentHost/common/agentService.ts

@@ -115,6 +115,9 @@ export const AgentHostGitHubMcpServerEnabledSettingId = 'chat.agentHost.githubMc
 /** Configuration key gating active-agent session and chat title generation. */
 export const AgentHostActiveAgentTitleGenerationSettingId = 'chat.agentHost.experimental.activeAgentTitleGeneration';
 
+/** Configuration key controlling whether agents choose how delegated work relates to the current session. */
+export const AgentHostCreateSessionRelationshipSettingId = 'chat.agentHost.experimental.createSessionRelationship';
+
 /** Configuration key enabling rich-link guidance for Markdown plan documents. */
 export const AgentHostMarkdownPlanRichLinksEnabledSettingId = 'chat.agentHost.experimental.markdownPlanRichLinks';
 

src/vs/platform/agentHost/common/changesetUri.ts

@@ -7,7 +7,7 @@ import { localize } from '../../../nls.js';
 import { readAgentMergeSessionState } from './agentMerge.js';
 import { isAgentMergeMessage } from './meta/agentMergeMessageMeta.js';
 import { AgentSystemNotificationKind, readAgentSystemNotificationMeta } from './meta/agentSystemNotificationMeta.js';
-import { MessageKind, readSessionGitState, readSessionWorkspaceless, ResponsePartKind, SessionLifecycle, type Changeset, type ISessionGitState, type ISessionWithDefaultChat, type URI } from './state/sessionState.js';
+import { isAhpChatChannel, MessageKind, parseDefaultChatUri, readSessionGitState, readSessionWorkspaceless, ResponsePartKind, SessionLifecycle, type Changeset, type ISessionGitState, type ISessionWithDefaultChat, type URI } from './state/sessionState.js';
 
 /**
  * Helpers for building / parsing the URI clients subscribe to in order to
@@ -282,6 +282,15 @@ export function parseChangesetUri(uri: URI): { sessionUri: URI; changesetId: str
 	return { sessionUri, changesetId, kind: ChangesetKind.Unknown };
 }
 
+/** Resolves the parent session of either a session- or chat-owned changeset URI. */
+export function getChangesetSessionUri(uri: URI): URI | undefined {
+	const owner = parseChangesetUri(uri)?.sessionUri;
+	if (!owner) {
+		return undefined;
+	}
+	return isAhpChatChannel(owner) ? parseDefaultChatUri(owner) : owner;
+}
+
 /** Returns `true` iff `uri` looks like a changeset URI we recognise. */
 export function isChangesetUri(uri: URI): boolean {
 	return parseChangesetUri(uri) !== undefined;

src/vs/platform/agentHost/common/sessionArtifactCollection.ts

@@ -12,6 +12,8 @@ export interface ISessionArtifactInput {
 	readonly label: string;
 	/** `true` for an artifact the session produced, `false` for a reference. */
 	readonly isArtifact: boolean;
+	/** Host-owned chat attribution. Model-provided inputs never populate this field. */
+	readonly chat?: string;
 	readonly link?: string;
 	readonly uri?: string;
 	readonly commitHash?: string;
@@ -153,7 +155,8 @@ export class SessionArtifactCollection {
 	add(input: ISessionArtifactInput, createId: () => string): IAddSessionArtifactResult {
 		const artifact = this._create(input, createId);
 		const value = getSessionArtifactValue(artifact);
-		const existing = this._artifacts.find(candidate => getSessionArtifactValue(candidate) === value);
+		const existing = this._artifacts.find(candidate =>
+			candidate.chat === artifact.chat && getSessionArtifactValue(candidate) === value);
 		if (existing) {
 			return { artifacts: this._artifacts, artifact: existing, added: false };
 		}
@@ -187,13 +190,15 @@ export class SessionArtifactCollection {
 			id: string;
 			type: SessionArtifactType;
 			label: string;
+			chat?: string;
 			isArtifact: boolean;
 			link?: string;
 			uri?: string;
 			commitHash?: string;
 			isGitHub?: boolean;
 		} = { id: createId(), type: input.type, label: input.label, isArtifact: input.isArtifact };
 
+		if (input.chat !== undefined) { artifact.chat = input.chat; }
 		if (input.link !== undefined) { artifact.link = input.link; }
 		if (input.uri !== undefined) { artifact.uri = input.uri; }
 		if (input.commitHash !== undefined) { artifact.commitHash = input.commitHash; }

src/vs/platform/agentHost/common/sessionArtifacts.ts

@@ -34,6 +34,8 @@ export interface ISessionArtifact {
 	readonly id: string;
 	readonly type: SessionArtifactType;
 	readonly label: string;
+	/** Chat that recorded this entry. Absent for session-wide entries. */
+	readonly chat?: string;
 	/**
 	 * `true` for an artifact — something this session produced — and `false` for
 	 * a reference, something it only points the user at.
@@ -79,6 +81,7 @@ function parseSessionArtifact(value: unknown): ISessionArtifact | undefined {
 		id: string;
 		type: SessionArtifactType;
 		label: string;
+		chat?: string;
 		isArtifact: boolean;
 		link?: string;
 		uri?: string;
@@ -95,6 +98,7 @@ function parseSessionArtifact(value: unknown): ISessionArtifact | undefined {
 	if (typeof raw['uri'] === 'string') { artifact.uri = raw['uri']; }
 	if (typeof raw['commitHash'] === 'string') { artifact.commitHash = raw['commitHash']; }
 	if (typeof raw['isGitHub'] === 'boolean') { artifact.isGitHub = raw['isGitHub']; }
+	if (typeof raw['chat'] === 'string') { artifact.chat = raw['chat']; }
 	return artifact;
 }
 

src/vs/platform/agentHost/common/worktreePaths.ts

@@ -4,6 +4,7 @@
  *--------------------------------------------------------------------------------------------*/
 
 import { basename } from '../../../base/common/path.js';
+import { Schemas } from '../../../base/common/network.js';
 import { isEqual, isEqualOrParent, normalizePath } from '../../../base/common/resources.js';
 import { URI } from '../../../base/common/uri.js';
 
@@ -37,3 +38,18 @@ export function isWorktreeUnderRepository(candidate: URI, repositoryRoot: URI):
 	const normalizedCandidate = normalizePath(candidate);
 	return isEqualOrParent(normalizedCandidate, worktreesRoot) && !isEqual(normalizedCandidate, worktreesRoot);
 }
+
+/** Derives the source repository from a worktree directly under its conventional `<repo>.worktrees` sibling. */
+export function deriveRepositoryRootFromWorktree(worktree: URI): URI | undefined {
+	if (worktree.scheme !== Schemas.file) {
+		return undefined;
+	}
+	const worktreesRoot = URI.joinPath(worktree, '..');
+	const worktreesRootName = basename(worktreesRoot.fsPath);
+	const suffix = '.worktrees';
+	if (!worktreesRootName.endsWith(suffix)) {
+		return undefined;
+	}
+	const repositoryName = worktreesRootName.slice(0, -suffix.length);
+	return repositoryName ? URI.joinPath(worktreesRoot, '..', repositoryName) : undefined;
+}

src/vs/platform/agentHost/node/agentConfigurationService.ts

@@ -27,29 +27,48 @@ import type { ISessionSandboxPolicy } from './sessionSandbox.js';
 
 export const IAgentConfigurationService = createDecorator<IAgentConfigurationService>('agentConfigurationService');
 
+function getSessionWorkingDirectories(stateManager: AgentHostStateManager, session: ProtocolURI): string[] | undefined {
+	const summaryWorkingDirectories = stateManager.getSessionSummary(session)?.workingDirectories;
+	const stateWorkingDirectories = stateManager.getSessionState(session)?.workingDirectories;
+	if (!stateWorkingDirectories?.length) {
+		return summaryWorkingDirectories;
+	}
+	if (!summaryWorkingDirectories?.length) {
+		return stateWorkingDirectories;
+	}
+
+	const workingDirectories = [...stateWorkingDirectories];
+	for (const workingDirectory of summaryWorkingDirectories.slice(1)) {
+		if (!workingDirectories.includes(workingDirectory)) {
+			workingDirectories.push(workingDirectory);
+		}
+	}
+	return workingDirectories;
+}
+
 /**
  * @deprecated Use {@link getEffectiveWorkingDirectories} instead, which preserves every root instead of collapsing to the primary.
  */
 export function getEffectiveWorkingDirectory(stateManager: AgentHostStateManager, session: ProtocolURI): string | undefined {
-	const own = stateManager.getSessionState(session)?.workingDirectories?.[0];
+	const own = getSessionWorkingDirectories(stateManager, session)?.[0];
 	if (own !== undefined) {
 		return own;
 	}
 	const parentInfo = parseSubagentSessionUri(session);
 	if (parentInfo) {
-		return stateManager.getSessionState(parentInfo.parentSession.toString())?.workingDirectories?.[0];
+		return getSessionWorkingDirectories(stateManager, parentInfo.parentSession.toString())?.[0];
 	}
 	return undefined;
 }
 
 export function getEffectiveWorkingDirectories(stateManager: AgentHostStateManager, session: ProtocolURI): string[] | undefined {
-	const own = stateManager.getSessionState(session)?.workingDirectories;
+	const own = getSessionWorkingDirectories(stateManager, session);
 	if (own !== undefined) {
 		return own;
 	}
 	const parentInfo = parseSubagentSessionUri(session);
 	if (parentInfo) {
-		return stateManager.getSessionState(parentInfo.parentSession.toString())?.workingDirectories;
+		return getSessionWorkingDirectories(stateManager, parentInfo.parentSession.toString());
 	}
 	return undefined;
 }

src/vs/platform/agentHost/node/agentHostCatalogProjection.ts

@@ -252,6 +252,7 @@ const artifactValidator = plainObject(vObj({
 	id: boundedString(),
 	type: vEnum('pullRequest', 'issue', 'commit', 'website', 'file', 'resource'),
 	label: boundedString(AGENT_HOST_CATALOG_TITLE_LENGTH_LIMIT),
+	chat: vOptionalProp(uriString()),
 	isArtifact: vOptionalProp(vBoolean()),
 	link: vOptionalProp(boundedString()),
 	uri: vOptionalProp(boundedString()),
@@ -299,6 +300,11 @@ const metadataValidator = plainObject(vObj({
 	[AH_META_DEV_CONTAINER_WORKTREE_DB_KEY]: vOptionalProp(devContainerWorktreeValidator),
 }));
 
+const workingDirectoriesValidator = new RefinedValidator(
+	boundedArray(uriString(), AGENT_HOST_CATALOG_CHILD_LIMIT),
+	value => hasUniqueValues(value, directory => directory) ? value : { message: 'Working directories must be unique.' },
+);
+
 const chatValidator = plainObject(vObj({
 	uri: uriString(),
 	order: safeInteger(),
@@ -307,6 +313,7 @@ const chatValidator = plainObject(vObj({
 	titleSource: vOptionalProp(vEnum('user', 'agent', 'auto')),
 	origin: vOptionalProp(jsonValue()),
 	inheritedTurnId: vOptionalProp(boundedString(AGENT_HOST_CATALOG_JSON_STRING_LENGTH_LIMIT)),
+	workingDirectories: vOptionalProp(workingDirectoriesValidator),
 }));
 
 const chatsValidator = new RefinedValidator(
@@ -323,11 +330,6 @@ const chatsValidator = new RefinedValidator(
 	},
 );
 
-const workingDirectoriesValidator = new RefinedValidator(
-	boundedArray(uriString(), AGENT_HOST_CATALOG_CHILD_LIMIT),
-	value => hasUniqueValues(value, directory => directory) ? value : { message: 'Working directories must be unique.' },
-);
-
 export const agentHostCatalogDataValidator = plainObject(vObj({
 	modifiedTime: safeInteger(),
 	summary: vOptionalProp(boundedString(AGENT_HOST_CATALOG_TITLE_LENGTH_LIMIT)),

src/vs/platform/agentHost/node/agentHostCatalogSourceResolver.ts

@@ -31,6 +31,7 @@ export interface ICatalogSourceState {
 		readonly title?: string;
 		readonly origin?: ChatOrigin;
 		readonly inheritedTurnId?: string;
+		readonly workingDirectories?: readonly string[];
 	}[];
 }
 
@@ -225,6 +226,7 @@ export class AgentHostCatalogSourceResolver {
 					titleSource: normalizeCatalogTitleSource(titleSource),
 					origin: toCatalogChatOrigin(chat.origin),
 					...(chat.inheritedTurnId !== undefined ? { inheritedTurnId: chat.inheritedTurnId } : {}),
+					...(chat.workingDirectories !== undefined ? { workingDirectories: chat.workingDirectories } : {}),
 				};
 			}),
 		};