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

packages/coding-agent/CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Fixed
 
 - Fixed the status-line git branch display freezing on the previous branch after the first branch switch, caused by the HEAD watcher binding to a file inode that git unlinks on its atomic HEAD rename ([#8412](https://github.com/can1357/oh-my-pi/issues/8412)).
+- Fixed Pi extension contexts omitting the runtime `mode`, which made documented TUI guards silently disable extension UI ([#8419](https://github.com/can1357/oh-my-pi/issues/8419)).
 
 ## [17.3.0] - 2026-08-13
 

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

@@ -42,6 +42,7 @@ import type {
 	ExtensionError,
 	ExtensionEvent,
 	ExtensionFlag,
+	ExtensionMode,
 	ExtensionRuntime,
 	ExtensionShortcut,
 	ExtensionUIContext,
@@ -342,6 +343,7 @@ interface ToolRegistrationScope {
 
 export class ExtensionRunner {
 	#uiContext: ExtensionUIContext;
+	#mode: ExtensionMode = "print";
 	#toolApprovalPreviewWaiter?: (toolCallId: string) => Promise<void>;
 	#errorListeners: Set<ExtensionErrorListener> = new Set();
 	#getModel: () => Model | undefined = () => undefined;
@@ -525,6 +527,7 @@ export class ExtensionRunner {
 		contextActions: ExtensionContextActions,
 		commandContextActions?: ExtensionCommandContextActions,
 		uiContext?: ExtensionUIContext,
+		mode: ExtensionMode = "print",
 	): void {
 		// Copy actions into the shared runtime (all extension APIs reference this)
 		this.runtime.sendMessage = actions.sendMessage;
@@ -573,6 +576,7 @@ export class ExtensionRunner {
 		}
 
 		this.#uiContext = uiContext ?? noOpUIContext;
+		this.#mode = mode;
 		this.#initialized = true;
 
 		// Drain events buffered by emitCredentialDisabled() before initialize ran. The
@@ -953,6 +957,7 @@ export class ExtensionRunner {
 		const getModel = model ? () => model : this.#getModel;
 		return {
 			ui: this.#uiContext,
+			mode: this.#mode,
 			getContextUsage: () => this.#getContextUsageFn(),
 			compact: instructionsOrOptions => this.#compactFn(instructionsOrOptions),
 			getAsyncJobSnapshot: () => this.#getAsyncJobSnapshotFn(),

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

@@ -434,9 +434,14 @@ export interface ExtensionModelQuery {
 	family(model: Model): string;
 }
 
+/** Runtime host mode exposed to Pi-compatible extensions. */
+export type ExtensionMode = "tui" | "rpc" | "json" | "print";
+
 export interface ExtensionContext {
 	/** UI methods for user interaction */
 	ui: ExtensionUIContext;
+	/** Current run mode. Use `"tui"` to guard terminal-only UI such as custom components. */
+	mode: ExtensionMode;
 	/** Get current context usage for the active model. */
 	getContextUsage(): ContextUsage | undefined;
 	/** Get a read-only snapshot of async jobs owned by this session. */

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);

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

@@ -5647,6 +5647,7 @@ export class AgentSession {
 
 		return {
 			ui: noOpUIContext,
+			mode: "print",
 			hasUI: false,
 			cwd: this.sessionManager.getCwd(),
 			sessionManager: this.sessionManager,

packages/coding-agent/test/extensions-runner.test.ts

@@ -104,6 +104,53 @@ describe("ExtensionRunner", () => {
 		expect(runner.createContext().cwd).toBe(dirB);
 	});
 
+	it("exposes the initialized host mode to extension contexts", async () => {
+		const result = await loadTestExtensions();
+		const runner = new ExtensionRunner(
+			result.extensions,
+			result.runtime,
+			tempDir.path(),
+			sessionManager,
+			modelRegistry,
+		);
+		const actions = {
+			sendMessage: () => {},
+			sendUserMessage: () => {},
+			appendEntry: () => {},
+			setLabel: () => {},
+			getActiveTools: () => [],
+			getAllTools: () => [],
+			setActiveTools: async () => {},
+			getCommands: () => [],
+			setModel: async () => false,
+			getThinkingLevel: () => undefined,
+			setThinkingLevel: () => {},
+			getSessionName: () => undefined,
+			setSessionName: async () => {},
+		};
+		const contextActions = {
+			getModel: () => undefined,
+			isIdle: () => true,
+			abort: () => {},
+			hasPendingMessages: () => false,
+			shutdown: () => {},
+			getContextUsage: () => undefined,
+			compact: async () => {},
+			getSystemPrompt: () => [],
+		};
+
+		expect(runner.createContext().mode).toBe("print");
+
+		runner.initialize(actions, contextActions, undefined, undefined, "rpc");
+		expect(runner.createContext().mode).toBe("rpc");
+
+		runner.initialize(actions, contextActions, undefined, undefined, "json");
+		expect(runner.createContext().mode).toBe("json");
+
+		runner.initialize(actions, contextActions, undefined, undefined, "tui");
+		expect(runner.createContext().mode).toBe("tui");
+	});
+
 	describe("shortcut conflicts", () => {
 		it("warns when extension shortcut conflicts with built-in", async () => {
 			const extCode = `