Merge PR #8423: fix(extensions): populate runtime mode in context (@roboomp)

packages/coding-agent/src/modes/acp/acp-agent.ts

@@ -2419,6 +2419,7 @@ export class AcpAgent implements Agent {
 				compact: instructionsOrOptions => runExtensionCompact(record.session, instructionsOrOptions),
 			},
 			uiContext,
+			"rpc",
 		);
 		await extensionRunner.emit({ type: "session_start" });
 		record.extensionsConfigured = true;

packages/coding-agent/src/modes/controllers/extension-ui-controller.ts

@@ -283,7 +283,7 @@ export class ExtensionUiController {
 			},
 		};
 
-		extensionRunner.initialize(actions, contextActions, commandActions, uiContext);
+		extensionRunner.initialize(actions, contextActions, commandActions, uiContext, "tui");
 
 		// Subscribe to extension errors
 		extensionRunner.onError((error: ExtensionError) => {
@@ -512,7 +512,7 @@ export class ExtensionUiController {
 			},
 		};
 
-		extensionRunner.initialize(actions, contextActions, commandActions, uiContext);
+		extensionRunner.initialize(actions, contextActions, commandActions, uiContext, "tui");
 	}
 
 	/**

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

@@ -118,6 +118,7 @@ export async function runPrintMode(session: AgentSession, options: PrintModeOpti
 	}
 	// Set up extensions for print mode (no UI, no command context)
 	await initializeExtensions(session, {
+		mode: mode === "json" ? "json" : "print",
 		reportSendError: (action, err) => {
 			process.stderr.write(
 				`Extension ${action === "extension_send" ? "sendMessage" : "sendUserMessage"} failed: ${err.message}\n`,

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

@@ -933,6 +933,7 @@ export async function runRpcMode(
 
 	// Set up extensions with RPC-based UI context
 	await initializeExtensions(session, {
+		mode: "rpc",
 		reportSendError: (action, err) => {
 			output(error(undefined, action, err.message));
 		},

packages/coding-agent/src/modes/runtime-init.ts

@@ -8,7 +8,7 @@
  */
 import { runExtensionCompact, runExtensionSetModel } from "../extensibility/extensions/compact-handler";
 import { getSessionSlashCommands } from "../extensibility/extensions/get-commands-handler";
-import type { ExtensionError, ExtensionUIContext } from "../extensibility/extensions/types";
+import type { ExtensionError, ExtensionMode, ExtensionUIContext } from "../extensibility/extensions/types";
 import type { AgentSession } from "../session/agent-session";
 import { USER_INTERRUPT_LABEL } from "../session/messages";
 
@@ -22,6 +22,8 @@ export interface InitializeExtensionsOptions {
 	reportRuntimeError: (error: ExtensionError) => void;
 	/** Optional shutdown hook (rpc mode signals its loop; print mode is a no-op). */
 	onShutdown?: () => void;
+	/** Pi-compatible mode exposed to extension contexts. Defaults to `"print"`. */
+	mode?: ExtensionMode;
 	/** Optional UI context (rpc supplies one; print runs headless). */
 	uiContext?: ExtensionUIContext;
 	/** Optional lifecycle hook for extension-originated messages that can start an agent turn. */
@@ -44,6 +46,7 @@ export async function initializeExtensions(session: AgentSession, options: Initi
 		reportSendError,
 		reportRuntimeError,
 		onShutdown,
+		mode = "print",
 		uiContext,
 		markAgentInvokingMessage,
 		trackAgentInvokingMessage,
@@ -137,6 +140,7 @@ export async function initializeExtensions(session: AgentSession, options: Initi
 			compact: instructionsOrOptions => runExtensionCompact(session, instructionsOrOptions),
 		},
 		uiContext,
+		mode,
 	);
 
 	runner.onError(reportRuntimeError);