fix(agent): stop tool preflight after extension abort

closes #4276

packages/coding-agent/src/core/agent-session.ts

@@ -185,6 +185,7 @@ export interface AgentSessionConfig {
 export interface ExtensionBindings {
 	uiContext?: ExtensionUIContext;
 	commandContextActions?: ExtensionCommandContextActions;
+	abortHandler?: () => void;
 	shutdownHandler?: ShutdownHandler;
 	onError?: ExtensionErrorListener;
 }
@@ -296,6 +297,7 @@ export class AgentSession {
 	private _sessionStartEvent: SessionStartEvent;
 	private _extensionUIContext?: ExtensionUIContext;
 	private _extensionCommandContextActions?: ExtensionCommandContextActions;
+	private _extensionAbortHandler?: () => void;
 	private _extensionShutdownHandler?: ShutdownHandler;
 	private _extensionErrorListener?: ExtensionErrorListener;
 	private _extensionErrorUnsubscriber?: () => void;
@@ -2042,6 +2044,9 @@ export class AgentSession {
 		if (bindings.commandContextActions !== undefined) {
 			this._extensionCommandContextActions = bindings.commandContextActions;
 		}
+		if (bindings.abortHandler !== undefined) {
+			this._extensionAbortHandler = bindings.abortHandler;
+		}
 		if (bindings.shutdownHandler !== undefined) {
 			this._extensionShutdownHandler = bindings.shutdownHandler;
 		}
@@ -2206,7 +2211,13 @@ export class AgentSession {
 				getModel: () => this.model,
 				isIdle: () => !this.isStreaming,
 				getSignal: () => this.agent.signal,
-				abort: () => this.abort(),
+				abort: () => {
+					if (this._extensionAbortHandler) {
+						this._extensionAbortHandler();
+						return;
+					}
+					void this.abort();
+				},
 				hasPendingMessages: () => this.pendingMessageCount > 0,
 				shutdown: () => {
 					this._extensionShutdownHandler?.();

packages/coding-agent/src/modes/interactive/interactive-mode.ts

@@ -1478,6 +1478,9 @@ export class InteractiveMode {
 		const uiContext = this.createExtensionUIContext();
 		await this.session.bindExtensions({
 			uiContext,
+			abortHandler: () => {
+				this.restoreQueuedMessagesToEditor({ abort: true });
+			},
 			commandContextActions: {
 				waitForIdle: () => this.session.agent.waitForIdle(),
 				newSession: async (options) => {
@@ -1627,7 +1630,9 @@ export class InteractiveMode {
 			model: this.session.model,
 			isIdle: () => !this.session.isStreaming,
 			signal: this.session.agent.signal,
-			abort: () => this.session.abort(),
+			abort: () => {
+				this.restoreQueuedMessagesToEditor({ abort: true });
+			},
 			hasPendingMessages: () => this.session.pendingMessageCount > 0,
 			shutdown: () => {
 				this.shutdownRequested = true;