Add extension mode context

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

@@ -56,6 +56,7 @@ import {
 	type ContextUsage,
 	type ExtensionCommandContextActions,
 	type ExtensionErrorListener,
+	type ExtensionMode,
 	ExtensionRunner,
 	type ExtensionUIContext,
 	type InputSource,
@@ -187,6 +188,7 @@ export interface AgentSessionConfig {
 
 export interface ExtensionBindings {
 	uiContext?: ExtensionUIContext;
+	mode?: ExtensionMode;
 	commandContextActions?: ExtensionCommandContextActions;
 	abortHandler?: () => void;
 	shutdownHandler?: ShutdownHandler;
@@ -300,6 +302,7 @@ export class AgentSession {
 	private _baseToolsOverride?: Record<string, AgentTool>;
 	private _sessionStartEvent: SessionStartEvent;
 	private _extensionUIContext?: ExtensionUIContext;
+	private _extensionMode: ExtensionMode = "print";
 	private _extensionCommandContextActions?: ExtensionCommandContextActions;
 	private _extensionAbortHandler?: () => void;
 	private _extensionShutdownHandler?: ShutdownHandler;
@@ -2064,6 +2067,9 @@ export class AgentSession {
 		if (bindings.uiContext !== undefined) {
 			this._extensionUIContext = bindings.uiContext;
 		}
+		if (bindings.mode !== undefined) {
+			this._extensionMode = bindings.mode;
+		}
 		if (bindings.commandContextActions !== undefined) {
 			this._extensionCommandContextActions = bindings.commandContextActions;
 		}
@@ -2136,7 +2142,7 @@ export class AgentSession {
 	}
 
 	private _applyExtensionBindings(runner: ExtensionRunner): void {
-		runner.setUIContext(this._extensionUIContext);
+		runner.setUIContext(this._extensionUIContext, this._extensionMode);
 		runner.bindCommandContext(this._extensionCommandContextActions);
 
 		this._extensionErrorUnsubscriber?.();

packages/coding-agent/src/core/extensions/index.ts

@@ -66,6 +66,7 @@ export type {
 	ExtensionFactory,
 	ExtensionFlag,
 	ExtensionHandler,
+	ExtensionMode,
 	// Runtime
 	ExtensionRuntime,
 	ExtensionShortcut,

packages/coding-agent/src/core/extensions/runner.ts

@@ -28,6 +28,7 @@ import type {
 	ExtensionError,
 	ExtensionEvent,
 	ExtensionFlag,
+	ExtensionMode,
 	ExtensionRuntime,
 	ExtensionShortcut,
 	ExtensionUIContext,
@@ -225,6 +226,7 @@ export class ExtensionRunner {
 	private extensions: Extension[];
 	private runtime: ExtensionRuntime;
 	private uiContext: ExtensionUIContext;
+	private mode: ExtensionMode = "print";
 	private cwd: string;
 	private sessionManager: SessionManager;
 	private modelRegistry: ModelRegistry;
@@ -354,8 +356,9 @@ export class ExtensionRunner {
 		this.reloadHandler = async () => {};
 	}
 
-	setUIContext(uiContext?: ExtensionUIContext): void {
+	setUIContext(uiContext?: ExtensionUIContext, mode: ExtensionMode = "print"): void {
 		this.uiContext = uiContext ?? noOpUIContext;
+		this.mode = mode;
 	}
 
 	getUIContext(): ExtensionUIContext {
@@ -578,6 +581,10 @@ export class ExtensionRunner {
 				runner.assertActive();
 				return runner.uiContext;
 			},
+			get mode() {
+				runner.assertActive();
+				return runner.mode;
+			},
 			get hasUI() {
 				runner.assertActive();
 				return runner.hasUI();

packages/coding-agent/src/core/extensions/types.ts

@@ -295,10 +295,14 @@ export interface CompactOptions {
 /**
  * Context passed to extension event handlers.
  */
+export type ExtensionMode = "tui" | "rpc" | "json" | "print";
+
 export interface ExtensionContext {
 	/** UI methods for user interaction */
 	ui: ExtensionUIContext;
-	/** Whether UI is available (false in print/RPC mode) */
+	/** Current run mode. Use "tui" to guard terminal-only UI such as custom components. */
+	mode: ExtensionMode;
+	/** Whether dialog-capable UI is available (true in TUI and RPC modes) */
 	hasUI: boolean;
 	/** Current working directory */
 	cwd: string;