Merge PR #6973: fix(coding-agent): share parent local:// root with /tan clone (@roboomp)

packages/coding-agent/src/internal-urls/local-protocol.ts

@@ -390,8 +390,9 @@ export class LocalProtocolHandler implements ProtocolHandler {
 
 	/**
 	 * Install a process-global override that wins over the AgentRegistry-based
-	 * derivation. Used by SDK consumers that wire `localProtocolOptions` on
-	 * `createAgentSession` and by subagents that share their parent's root.
+	 * derivation. Used by top-level SDK consumers that wire
+	 * `localProtocolOptions` on `createAgentSession`; subagents keep their
+	 * inherited mapping session-bound.
 	 */
 	static setOverride(value: LocalProtocolOptions | undefined): void {
 		LocalProtocolHandler.#override = value;

packages/coding-agent/src/modes/controllers/tan-command-controller.ts

@@ -80,6 +80,19 @@ export class TanCommandController {
 		const ownerId = session.getAgentId() ?? MAIN_AGENT_ID;
 		const mcpManager = this.ctx.mcpManager;
 		const cwd = this.ctx.sessionManager.getCwd();
+		const parentArtifactsDir = this.ctx.sessionManager.getArtifactsDir();
+		// Snapshot the parent session's local:// mapping when dispatching. The
+		// interactive SessionManager is mutable and may switch transcripts while
+		// this background tan is still running. Use the session-manager id (not
+		// `session.sessionId`, which can diverge after `/fresh` or a provider
+		// session override) so the tan resolves the same local root the parent's
+		// large-paste writes and `local://` reads use — notably the Windows
+		// short-root fallback keys `%TEMP%/omp-local/<id>` off this id.
+		const parentLocalSessionId = this.ctx.sessionManager.getSessionId();
+		const localProtocolOptions = {
+			getArtifactsDir: () => parentArtifactsDir,
+			getSessionId: () => parentLocalSessionId,
+		};
 		// Nest the clone inside the parent's artifact directory (like a subagent
 		// session) rather than as a top-level sibling, so it shares the parent's
 		// artifacts in place — no copy needed.
@@ -132,6 +145,7 @@ export class TanCommandController {
 							parentAgentId: ownerId,
 							agentRegistry,
 							disableExtensionDiscovery: true,
+							localProtocolOptions,
 						});
 						clone = created.session;
 						clone.sessionManager?.appendSessionInit?.({

packages/coding-agent/src/sdk.ts

@@ -1773,7 +1773,7 @@ export async function createAgentSession(options: CreateAgentSessionOptions = {}
 			getArtifactsDir,
 			getSessionId: () => sessionManager.getSessionId?.() ?? null,
 		};
-		if (options.localProtocolOptions) {
+		if (options.localProtocolOptions && !options.parentTaskPrefix) {
 			LocalProtocolHandler.setOverride(options.localProtocolOptions);
 		}
 		toolSession.getArtifactsDir = getArtifactsDir;