feat(coding-agent): add user_bash event and theme API extensions

- user_bash event for intercepting ! and !! commands (#528)
- Extensions can return { operations } or { result } to redirect/replace
- executeBashWithOperations() for custom BashOperations execution
- session.recordBashResult() for extensions handling bash themselves
- Theme API: getAllThemes(), getTheme(), setTheme() on ctx.ui
- mac-system-theme.ts example: sync with macOS dark/light mode
- Updated ssh.ts to use user_bash event

packages/coding-agent/CHANGELOG.md

@@ -8,8 +8,10 @@
 
 ### Added
 
+- `ctx.ui.getAllThemes()`, `ctx.ui.getTheme(name)`, and `ctx.ui.setTheme(name | Theme)` methods for extensions to list, load, and switch themes at runtime ([#576](https://github.com/badlogic/pi-mono/pull/576))
 - `--no-tools` flag to disable all built-in tools, allowing extension-only tool setups ([#557](https://github.com/badlogic/pi-mono/pull/557) by [@cv](https://github.com/cv))
 - Pluggable operations for built-in tools enabling remote execution via SSH or other transports ([#564](https://github.com/badlogic/pi-mono/issues/564)). Interfaces: `ReadOperations`, `WriteOperations`, `EditOperations`, `BashOperations`, `LsOperations`, `GrepOperations`, `FindOperations`
+- `user_bash` event for intercepting user `!`/`!!` commands, allowing extensions to redirect to remote systems ([#528](https://github.com/badlogic/pi-mono/issues/528))
 - `setActiveTools()` in ExtensionAPI for dynamic tool management
 - Built-in renderers used automatically for tool overrides without custom `renderCall`/`renderResult`
 - `ssh.ts` example: remote tool execution via `--ssh user@host:/path`

packages/coding-agent/docs/extensions.md

@@ -523,6 +523,28 @@ pi.on("tool_result", async (event, ctx) => {
 
 **Examples:** [git-checkpoint.ts](../examples/extensions/git-checkpoint.ts), [plan-mode.ts](../examples/extensions/plan-mode.ts)
 
+### User Bash Events
+
+#### user_bash
+
+Fired when user executes `!` or `!!` commands. **Can intercept.**
+
+```typescript
+pi.on("user_bash", (event, ctx) => {
+  // event.command - the bash command
+  // event.excludeFromContext - true if !! prefix
+  // event.cwd - working directory
+
+  // Option 1: Provide custom operations (e.g., SSH)
+  return { operations: remoteBashOps };
+
+  // Option 2: Full replacement - return result directly
+  return { result: { output: "...", exitCode: 0, cancelled: false, truncated: false } };
+});
+```
+
+**Examples:** [ssh.ts](../examples/extensions/ssh.ts)
+
 ## ExtensionContext
 
 Every handler receives `ctx: ExtensionContext`:
@@ -1256,6 +1278,16 @@ const current = ctx.ui.getEditorText();
 // Custom editor (vim mode, emacs mode, etc.)
 ctx.ui.setEditorComponent((tui, theme, keybindings) => new VimEditor(tui, theme, keybindings));
 ctx.ui.setEditorComponent(undefined);  // Restore default editor
+
+// Theme management
+const themes = ctx.ui.getAllThemes();  // [{ name: "dark", path: "/..." | undefined }, ...]
+const lightTheme = ctx.ui.getTheme("light");  // Load without switching
+const result = ctx.ui.setTheme("light");  // Switch by name
+if (!result.success) {
+  ctx.ui.notify(`Failed: ${result.error}`, "error");
+}
+ctx.ui.setTheme(lightTheme!);  // Or switch by Theme object
+ctx.ui.theme.fg("accent", "styled text");  // Access current theme
 ```
 
 **Examples:**
@@ -1264,6 +1296,7 @@ ctx.ui.setEditorComponent(undefined);  // Restore default editor
 - `ctx.ui.setFooter()`: [custom-footer.ts](../examples/extensions/custom-footer.ts)
 - `ctx.ui.setHeader()`: [custom-header.ts](../examples/extensions/custom-header.ts)
 - `ctx.ui.setEditorComponent()`: [modal-editor.ts](../examples/extensions/modal-editor.ts)
+- `ctx.ui.setTheme()`: [mac-system-theme.ts](../examples/extensions/mac-system-theme.ts)
 
 ### Custom Components
 

packages/coding-agent/examples/extensions/mac-system-theme.ts

@@ -0,0 +1,25 @@
+/**
+ * Syncs pi theme with macOS system appearance (dark/light mode).
+ *
+ * Usage:
+ *   pi -e examples/extensions/mac-system-theme.ts
+ */
+
+import { execSync } from "node:child_process";
+import type { ExtensionAPI } from "@mariozechner/pi-coding-agent";
+
+function isDarkMode(): boolean {
+	try {
+		execSync("defaults read -g AppleInterfaceStyle", { encoding: "utf-8" });
+		return true; // Returns "Dark" if dark mode
+	} catch {
+		return false; // Throws if light mode
+	}
+}
+
+export default function (pi: ExtensionAPI) {
+	pi.on("session_start", (_event, ctx) => {
+		const theme = isDarkMode() ? "dark" : "light";
+		ctx.ui.setTheme(theme);
+	});
+}

packages/coding-agent/examples/extensions/ssh.ts

@@ -199,6 +199,13 @@ export default function (pi: ExtensionAPI) {
 		}
 	});
 
+	// Handle user ! commands via SSH
+	pi.on("user_bash", (_event) => {
+		const ssh = getSsh();
+		if (!ssh) return; // No SSH, use local execution
+		return { operations: createRemoteBashOps(ssh.remote, ssh.remoteCwd, localCwd) };
+	});
+
 	// Replace local cwd with remote cwd in system prompt
 	pi.on("before_agent_start", async (event) => {
 		const ssh = getSsh();

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

@@ -24,7 +24,7 @@ import type {
 import type { AssistantMessage, ImageContent, Message, Model, TextContent } from "@mariozechner/pi-ai";
 import { isContextOverflow, modelsAreEqual, supportsXhigh } from "@mariozechner/pi-ai";
 import { getAuthPath } from "../config.js";
-import { type BashResult, executeBash as executeBashCommand } from "./bash-executor.js";
+import { type BashResult, executeBash as executeBashCommand, executeBashWithOperations } from "./bash-executor.js";
 import {
 	type CompactionResult,
 	calculateContextTokens,
@@ -50,6 +50,7 @@ import type { ModelRegistry } from "./model-registry.js";
 import { expandPromptTemplate, type PromptTemplate } from "./prompt-templates.js";
 import type { BranchSummaryEntry, CompactionEntry, NewSessionOptions, SessionManager } from "./session-manager.js";
 import type { SettingsManager, SkillsSettings } from "./settings-manager.js";
+import type { BashOperations } from "./tools/bash.js";
 
 /** Session-specific events that extend the core AgentEvent */
 export type AgentSessionEvent =
@@ -1617,51 +1618,63 @@ export class AgentSession {
 	 * @param command The bash command to execute
 	 * @param onChunk Optional streaming callback for output
 	 * @param options.excludeFromContext If true, command output won't be sent to LLM (!! prefix)
+	 * @param options.operations Custom BashOperations for remote execution
 	 */
 	async executeBash(
 		command: string,
 		onChunk?: (chunk: string) => void,
-		options?: { excludeFromContext?: boolean },
+		options?: { excludeFromContext?: boolean; operations?: BashOperations },
 	): Promise<BashResult> {
 		this._bashAbortController = new AbortController();
 
 		try {
-			const result = await executeBashCommand(command, {
+			const result = options?.operations
-				onChunk,
+				? await executeBashWithOperations(command, process.cwd(), options.operations, {
-				signal: this._bashAbortController.signal,
+						onChunk,
-			});
+						signal: this._bashAbortController.signal,
-
+					})
-			// Create and save message
+				: await executeBashCommand(command, {
-			const bashMessage: BashExecutionMessage = {
+						onChunk,
-				role: "bashExecution",
+						signal: this._bashAbortController.signal,
-				command,
+					});
-				output: result.output,
-				exitCode: result.exitCode,
-				cancelled: result.cancelled,
-				truncated: result.truncated,
-				fullOutputPath: result.fullOutputPath,
-				timestamp: Date.now(),
-				excludeFromContext: options?.excludeFromContext,
-			};
-
-			// If agent is streaming, defer adding to avoid breaking tool_use/tool_result ordering
-			if (this.isStreaming) {
-				// Queue for later - will be flushed on agent_end
-				this._pendingBashMessages.push(bashMessage);
-			} else {
-				// Add to agent state immediately
-				this.agent.appendMessage(bashMessage);
-
-				// Save to session
-				this.sessionManager.appendMessage(bashMessage);
-			}
 
+			this.recordBashResult(command, result, options);
 			return result;
 		} finally {
 			this._bashAbortController = undefined;
 		}
 	}
 
+	/**
+	 * Record a bash execution result in session history.
+	 * Used by executeBash and by extensions that handle bash execution themselves.
+	 */
+	recordBashResult(command: string, result: BashResult, options?: { excludeFromContext?: boolean }): void {
+		const bashMessage: BashExecutionMessage = {
+			role: "bashExecution",
+			command,
+			output: result.output,
+			exitCode: result.exitCode,
+			cancelled: result.cancelled,
+			truncated: result.truncated,
+			fullOutputPath: result.fullOutputPath,
+			timestamp: Date.now(),
+			excludeFromContext: options?.excludeFromContext,
+		};
+
+		// If agent is streaming, defer adding to avoid breaking tool_use/tool_result ordering
+		if (this.isStreaming) {
+			// Queue for later - will be flushed on agent_end
+			this._pendingBashMessages.push(bashMessage);
+		} else {
+			// Add to agent state immediately
+			this.agent.appendMessage(bashMessage);
+
+			// Save to session
+			this.sessionManager.appendMessage(bashMessage);
+		}
+	}
+
 	/**
 	 * Cancel running bash command.
 	 */

packages/coding-agent/src/core/bash-executor.ts

@@ -13,6 +13,7 @@ import { join } from "node:path";
 import { type ChildProcess, spawn } from "child_process";
 import stripAnsi from "strip-ansi";
 import { getShellConfig, killProcessTree, sanitizeBinaryOutput } from "../utils/shell.js";
+import type { BashOperations } from "./tools/bash.js";
 import { DEFAULT_MAX_BYTES, truncateTail } from "./tools/truncate.js";
 
 // ============================================================================
@@ -177,3 +178,98 @@ export function executeBash(command: string, options?: BashExecutorOptions): Pro
 		});
 	});
 }
+
+/**
+ * Execute a bash command using custom BashOperations.
+ * Used for remote execution (SSH, containers, etc.).
+ */
+export async function executeBashWithOperations(
+	command: string,
+	cwd: string,
+	operations: BashOperations,
+	options?: BashExecutorOptions,
+): Promise<BashResult> {
+	const outputChunks: string[] = [];
+	let outputBytes = 0;
+	const maxOutputBytes = DEFAULT_MAX_BYTES * 2;
+
+	let tempFilePath: string | undefined;
+	let tempFileStream: WriteStream | undefined;
+	let totalBytes = 0;
+
+	const onData = (data: Buffer) => {
+		totalBytes += data.length;
+
+		// Sanitize: strip ANSI, replace binary garbage, normalize newlines
+		const text = sanitizeBinaryOutput(stripAnsi(data.toString("utf-8"))).replace(/\r/g, "");
+
+		// Start writing to temp file if exceeds threshold
+		if (totalBytes > DEFAULT_MAX_BYTES && !tempFilePath) {
+			const id = randomBytes(8).toString("hex");
+			tempFilePath = join(tmpdir(), `pi-bash-${id}.log`);
+			tempFileStream = createWriteStream(tempFilePath);
+			for (const chunk of outputChunks) {
+				tempFileStream.write(chunk);
+			}
+		}
+
+		if (tempFileStream) {
+			tempFileStream.write(text);
+		}
+
+		// Keep rolling buffer
+		outputChunks.push(text);
+		outputBytes += text.length;
+		while (outputBytes > maxOutputBytes && outputChunks.length > 1) {
+			const removed = outputChunks.shift()!;
+			outputBytes -= removed.length;
+		}
+
+		// Stream to callback
+		if (options?.onChunk) {
+			options.onChunk(text);
+		}
+	};
+
+	try {
+		const result = await operations.exec(command, cwd, {
+			onData,
+			signal: options?.signal,
+		});
+
+		if (tempFileStream) {
+			tempFileStream.end();
+		}
+
+		const fullOutput = outputChunks.join("");
+		const truncationResult = truncateTail(fullOutput);
+		const cancelled = options?.signal?.aborted ?? false;
+
+		return {
+			output: truncationResult.truncated ? truncationResult.content : fullOutput,
+			exitCode: cancelled ? undefined : (result.exitCode ?? undefined),
+			cancelled,
+			truncated: truncationResult.truncated,
+			fullOutputPath: tempFilePath,
+		};
+	} catch (err) {
+		if (tempFileStream) {
+			tempFileStream.end();
+		}
+
+		// Check if it was an abort
+		if (options?.signal?.aborted) {
+			const fullOutput = outputChunks.join("");
+			const truncationResult = truncateTail(fullOutput);
+			return {
+				output: truncationResult.truncated ? truncationResult.content : fullOutput,
+				exitCode: undefined,
+				cancelled: true,
+				truncated: truncationResult.truncated,
+				fullOutputPath: tempFilePath,
+			};
+		}
+
+		throw err;
+	}
+}

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

@@ -103,6 +103,9 @@ export type {
 	TreePreparation,
 	TurnEndEvent,
 	TurnStartEvent,
+	// Events - User Bash
+	UserBashEvent,
+	UserBashEventResult,
 	WriteToolResultEvent,
 } from "./types.js";
 // Type guards

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

@@ -5,7 +5,7 @@
 import type { AgentMessage } from "@mariozechner/pi-agent-core";
 import type { ImageContent, Model } from "@mariozechner/pi-ai";
 import type { KeyId } from "@mariozechner/pi-tui";
-import { theme } from "../../modes/interactive/theme/theme.js";
+import { type Theme, theme } from "../../modes/interactive/theme/theme.js";
 import type { ModelRegistry } from "../model-registry.js";
 import type { SessionManager } from "../session-manager.js";
 import type {
@@ -33,6 +33,8 @@ import type {
 	ToolCallEvent,
 	ToolCallEventResult,
 	ToolResultEventResult,
+	UserBashEvent,
+	UserBashEventResult,
 } from "./types.js";
 
 /** Combined result from all before_agent_start handlers */
@@ -89,6 +91,9 @@ const noOpUIContext: ExtensionUIContext = {
 	get theme() {
 		return theme;
 	},
+	getAllThemes: () => [],
+	getTheme: () => undefined,
+	setTheme: (_theme: string | Theme) => ({ success: false, error: "UI not available" }),
 };
 
 export class ExtensionRunner {
@@ -399,6 +404,35 @@ export class ExtensionRunner {
 		return result;
 	}
 
+	async emitUserBash(event: UserBashEvent): Promise<UserBashEventResult | undefined> {
+		const ctx = this.createContext();
+
+		for (const ext of this.extensions) {
+			const handlers = ext.handlers.get("user_bash");
+			if (!handlers || handlers.length === 0) continue;
+
+			for (const handler of handlers) {
+				try {
+					const handlerResult = await handler(event, ctx);
+					if (handlerResult) {
+						return handlerResult as UserBashEventResult;
+					}
+				} catch (err) {
+					const message = err instanceof Error ? err.message : String(err);
+					const stack = err instanceof Error ? err.stack : undefined;
+					this.emitError({
+						extensionPath: ext.path,
+						event: "user_bash",
+						error: message,
+						stack,
+					});
+				}
+			}
+		}
+
+		return undefined;
+	}
+
 	async emitContext(messages: AgentMessage[]): Promise<AgentMessage[]> {
 		const ctx = this.createContext();
 		let currentMessages = structuredClone(messages);

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

@@ -18,6 +18,7 @@ import type { ImageContent, Model, TextContent, ToolResultMessage } from "@mario
 import type { Component, EditorComponent, EditorTheme, KeyId, TUI } from "@mariozechner/pi-tui";
 import type { Static, TSchema } from "@sinclair/typebox";
 import type { Theme } from "../../modes/interactive/theme/theme.js";
+import type { BashResult } from "../bash-executor.js";
 import type { CompactionPreparation, CompactionResult } from "../compaction/index.js";
 import type { EventBus } from "../event-bus.js";
 import type { ExecOptions, ExecResult } from "../exec.js";
@@ -31,6 +32,7 @@ import type {
 	SessionEntry,
 	SessionManager,
 } from "../session-manager.js";
+import type { BashOperations } from "../tools/bash.js";
 import type { EditToolDetails } from "../tools/edit.js";
 import type {
 	BashToolDetails,
@@ -147,6 +149,15 @@ export interface ExtensionUIContext {
 
 	/** Get the current theme for styling. */
 	readonly theme: Theme;
+
+	/** Get all available themes with their names and file paths. */
+	getAllThemes(): { name: string; path: string | undefined }[];
+
+	/** Load a theme by name without switching to it. Returns undefined if not found. */
+	getTheme(name: string): Theme | undefined;
+
+	/** Set the current theme by name or Theme object. */
+	setTheme(theme: string | Theme): { success: boolean; error?: string };
 }
 
 // ============================================================================
@@ -378,6 +389,21 @@ export interface TurnEndEvent {
 	toolResults: ToolResultMessage[];
 }
 
+// ============================================================================
+// User Bash Events
+// ============================================================================
+
+/** Fired when user executes a bash command via ! or !! prefix */
+export interface UserBashEvent {
+	type: "user_bash";
+	/** The command to execute */
+	command: string;
+	/** True if !! prefix was used (excluded from LLM context) */
+	excludeFromContext: boolean;
+	/** Current working directory */
+	cwd: string;
+}
+
 // ============================================================================
 // Tool Events
 // ============================================================================
@@ -481,6 +507,7 @@ export type ExtensionEvent =
 	| AgentEndEvent
 	| TurnStartEvent
 	| TurnEndEvent
+	| UserBashEvent
 	| ToolCallEvent
 	| ToolResultEvent;
 
@@ -497,6 +524,14 @@ export interface ToolCallEventResult {
 	reason?: string;
 }
 
+/** Result from user_bash event handler */
+export interface UserBashEventResult {
+	/** Custom operations to use for execution */
+	operations?: BashOperations;
+	/** Full replacement: extension handled execution, use this result */
+	result?: BashResult;
+}
+
 export interface ToolResultEventResult {
 	content?: (TextContent | ImageContent)[];
 	details?: unknown;
@@ -598,6 +633,7 @@ export interface ExtensionAPI {
 	on(event: "turn_end", handler: ExtensionHandler<TurnEndEvent>): void;
 	on(event: "tool_call", handler: ExtensionHandler<ToolCallEvent, ToolCallEventResult>): void;
 	on(event: "tool_result", handler: ExtensionHandler<ToolResultEvent, ToolResultEventResult>): void;
+	on(event: "user_bash", handler: ExtensionHandler<UserBashEvent, UserBashEventResult>): void;
 
 	// =========================================================================
 	// Tool Registration

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

@@ -11,7 +11,7 @@ export {
 	type PromptOptions,
 	type SessionStats,
 } from "./agent-session.js";
-export { type BashExecutorOptions, type BashResult, executeBash } from "./bash-executor.js";
+export { type BashExecutorOptions, type BashResult, executeBash, executeBashWithOperations } from "./bash-executor.js";
 export type { CompactionResult } from "./compaction/index.js";
 export { createEventBus, type EventBus, type EventBusController } from "./event-bus.js";
 

packages/coding-agent/src/index.ts

@@ -83,6 +83,8 @@ export type {
 	ToolResultEvent,
 	TurnEndEvent,
 	TurnStartEvent,
+	UserBashEvent,
+	UserBashEventResult,
 } from "./core/extensions/index.js";
 export {
 	createExtensionRuntime,

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

@@ -75,12 +75,15 @@ import { UserMessageComponent } from "./components/user-message.js";
 import { UserMessageSelectorComponent } from "./components/user-message-selector.js";
 import {
 	getAvailableThemes,
+	getAvailableThemesWithPaths,
 	getEditorTheme,
 	getMarkdownTheme,
+	getThemeByName,
 	initTheme,
 	onThemeChange,
 	setTheme,
-	type Theme,
+	setThemeInstance,
+	Theme,
 	theme,
 } from "./theme/theme.js";
 
@@ -937,6 +940,20 @@ export class InteractiveMode {
 			get theme() {
 				return theme;
 			},
+			getAllThemes: () => getAvailableThemesWithPaths(),
+			getTheme: (name) => getThemeByName(name),
+			setTheme: (themeOrName) => {
+				if (themeOrName instanceof Theme) {
+					setThemeInstance(themeOrName);
+					this.ui.requestRender();
+					return { success: true };
+				}
+				const result = setTheme(themeOrName, true);
+				if (result.success) {
+					this.ui.requestRender();
+				}
+				return result;
+			},
 		};
 	}
 
@@ -3140,6 +3157,50 @@ export class InteractiveMode {
 	}
 
 	private async handleBashCommand(command: string, excludeFromContext = false): Promise<void> {
+		const extensionRunner = this.session.extensionRunner;
+
+		// Emit user_bash event to let extensions intercept
+		const eventResult = extensionRunner
+			? await extensionRunner.emitUserBash({
+					type: "user_bash",
+					command,
+					excludeFromContext,
+					cwd: process.cwd(),
+				})
+			: undefined;
+
+		// If extension returned a full result, use it directly
+		if (eventResult?.result) {
+			const result = eventResult.result;
+
+			// Create UI component for display
+			this.bashComponent = new BashExecutionComponent(command, this.ui, excludeFromContext);
+			if (this.session.isStreaming) {
+				this.pendingMessagesContainer.addChild(this.bashComponent);
+				this.pendingBashComponents.push(this.bashComponent);
+			} else {
+				this.chatContainer.addChild(this.bashComponent);
+			}
+
+			// Show output and complete
+			if (result.output) {
+				this.bashComponent.appendOutput(result.output);
+			}
+			this.bashComponent.setComplete(
+				result.exitCode,
+				result.cancelled,
+				result.truncated ? ({ truncated: true, content: result.output } as TruncationResult) : undefined,
+				result.fullOutputPath,
+			);
+
+			// Record the result in session
+			this.session.recordBashResult(command, result, { excludeFromContext });
+			this.bashComponent = undefined;
+			this.ui.requestRender();
+			return;
+		}
+
+		// Normal execution path (possibly with custom operations)
 		const isDeferred = this.session.isStreaming;
 		this.bashComponent = new BashExecutionComponent(command, this.ui, excludeFromContext);
 
@@ -3162,7 +3223,7 @@ export class InteractiveMode {
 						this.ui.requestRender();
 					}
 				},
-				{ excludeFromContext },
+				{ excludeFromContext, operations: eventResult?.operations },
 			);
 
 			if (this.bashComponent) {

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

@@ -456,6 +456,36 @@ export function getAvailableThemes(): string[] {
 	return Array.from(themes).sort();
 }
 
+export interface ThemeInfo {
+	name: string;
+	path: string | undefined;
+}
+
+export function getAvailableThemesWithPaths(): ThemeInfo[] {
+	const themesDir = getThemesDir();
+	const customThemesDir = getCustomThemesDir();
+	const result: ThemeInfo[] = [];
+
+	// Built-in themes
+	for (const name of Object.keys(getBuiltinThemes())) {
+		result.push({ name, path: path.join(themesDir, `${name}.json`) });
+	}
+
+	// Custom themes
+	if (fs.existsSync(customThemesDir)) {
+		for (const file of fs.readdirSync(customThemesDir)) {
+			if (file.endsWith(".json")) {
+				const name = file.slice(0, -5);
+				if (!result.some((t) => t.name === name)) {
+					result.push({ name, path: path.join(customThemesDir, file) });
+				}
+			}
+		}
+	}
+
+	return result.sort((a, b) => a.name.localeCompare(b.name));
+}
+
 function loadThemeJson(name: string): ThemeJson {
 	const builtinThemes = getBuiltinThemes();
 	if (name in builtinThemes) {
@@ -532,6 +562,14 @@ function loadTheme(name: string, mode?: ColorMode): Theme {
 	return createTheme(themeJson, mode);
 }
 
+export function getThemeByName(name: string): Theme | undefined {
+	try {
+		return loadTheme(name);
+	} catch {
+		return undefined;
+	}
+}
+
 function detectTerminalBackground(): "dark" | "light" {
 	const colorfgbg = process.env.COLORFGBG || "";
 	if (colorfgbg) {
@@ -596,6 +634,12 @@ export function setTheme(name: string, enableWatcher: boolean = false): { succes
 	}
 }
 
+export function setThemeInstance(themeInstance: Theme): void {
+	theme = themeInstance;
+	currentThemeName = "<in-memory>";
+	stopThemeWatcher(); // Can't watch a direct instance
+}
+
 export function onThemeChange(callback: () => void): void {
 	onThemeChangeCallback = callback;
 }

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

@@ -15,7 +15,7 @@ import * as crypto from "node:crypto";
 import * as readline from "readline";
 import type { AgentSession } from "../../core/agent-session.js";
 import type { ExtensionUIContext, ExtensionUIDialogOptions } from "../../core/extensions/index.js";
-import { theme } from "../interactive/theme/theme.js";
+import { type Theme, theme } from "../interactive/theme/theme.js";
 import type {
 	RpcCommand,
 	RpcExtensionUIRequest,
@@ -229,6 +229,19 @@ export async function runRpcMode(session: AgentSession): Promise<never> {
 		get theme() {
 			return theme;
 		},
+
+		getAllThemes() {
+			return [];
+		},
+
+		getTheme(_name: string) {
+			return undefined;
+		},
+
+		setTheme(_theme: string | Theme) {
+			// Theme switching not supported in RPC mode
+			return { success: false, error: "Theme switching not supported in RPC mode" };
+		},
 	});
 
 	// Set up extensions with RPC-based UI context