feat(coding-agent): add ExtensionAPI.getCommands() (#1210)

packages/coding-agent/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Added
+
+- Added `ExtensionAPI.getCommands()` to let extensions list available slash commands (extensions, prompt templates, skills) for invocation via `prompt` ([#1210](https://github.com/badlogic/pi-mono/pull/1210) by [@w-winter](https://github.com/w-winter))
+
 ## [0.51.2] - 2026-02-03
 
 ### New Features

packages/coding-agent/docs/extensions.md

@@ -942,6 +942,31 @@ pi.registerCommand("deploy", {
 });
 ```
 
+### pi.getCommands()
+
+Get the slash commands available for invocation via `prompt` in the current session. Includes extension commands, prompt templates, and skill commands.
+The list matches the RPC `get_commands` ordering: extensions first, then templates, then skills.
+
+```typescript
+const commands = pi.getCommands();
+const bySource = commands.filter((command) => command.source === "extension");
+```
+
+Each entry has this shape:
+
+```typescript
+{
+  name: string; // Command name without the leading slash
+  description?: string;
+  source: "extension" | "template" | "skill";
+  location?: "user" | "project" | "path"; // For templates and skills
+  path?: string; // Files backing templates, skills, and extensions
+}
+```
+
+Built-in interactive commands (like `/model` and `/settings`) are not included here. They are handled only in interactive
+mode and would not execute if sent via `prompt`.
+
 ### pi.registerMessageRenderer(customType, renderer)
 
 Register a custom TUI renderer for messages with your `customType`. See [Custom UI](#custom-ui).

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

@@ -67,6 +67,7 @@ import { expandPromptTemplate, type PromptTemplate } from "./prompt-templates.js
 import type { ResourceExtensionPaths, ResourceLoader } from "./resource-loader.js";
 import type { BranchSummaryEntry, CompactionEntry, SessionManager } from "./session-manager.js";
 import type { SettingsManager } from "./settings-manager.js";
+import { BUILTIN_SLASH_COMMANDS, type SlashCommandInfo, type SlashCommandLocation } from "./slash-commands.js";
 import { buildSystemPrompt } from "./system-prompt.js";
 import type { BashOperations } from "./tools/bash.js";
 import { createAllTools } from "./tools/index.js";
@@ -1775,6 +1776,45 @@ export class AgentSession {
 	}
 
 	private _bindExtensionCore(runner: ExtensionRunner): void {
+		const normalizeLocation = (source: string): SlashCommandLocation | undefined => {
+			if (source === "user" || source === "project" || source === "path") {
+				return source;
+			}
+			return undefined;
+		};
+
+		const reservedBuiltins = new Set(BUILTIN_SLASH_COMMANDS.map((command) => command.name));
+
+		const getCommands = (): SlashCommandInfo[] => {
+			const extensionCommands: SlashCommandInfo[] = runner
+				.getRegisteredCommandsWithPaths()
+				.filter(({ command }) => !reservedBuiltins.has(command.name))
+				.map(({ command, extensionPath }) => ({
+					name: command.name,
+					description: command.description,
+					source: "extension",
+					path: extensionPath,
+				}));
+
+			const templates: SlashCommandInfo[] = this.promptTemplates.map((template) => ({
+				name: template.name,
+				description: template.description,
+				source: "template",
+				location: normalizeLocation(template.source),
+				path: template.filePath,
+			}));
+
+			const skills: SlashCommandInfo[] = this._resourceLoader.getSkills().skills.map((skill) => ({
+				name: `skill:${skill.name}`,
+				description: skill.description,
+				source: "skill",
+				location: normalizeLocation(skill.source),
+				path: skill.filePath,
+			}));
+
+			return [...extensionCommands, ...templates, ...skills];
+		};
+
 		runner.bindCore(
 			{
 				sendMessage: (message, options) => {
@@ -1810,6 +1850,7 @@ export class AgentSession {
 				getActiveTools: () => this.getActiveToolNames(),
 				getAllTools: () => this.getAllTools(),
 				setActiveTools: (toolNames) => this.setActiveToolsByName(toolNames),
+				getCommands,
 				setModel: async (model) => {
 					const key = await this.modelRegistry.getApiKey(model);
 					if (!key) return false;

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

@@ -2,6 +2,7 @@
  * Extension system for lifecycle events and custom tools.
  */
 
+export type { SlashCommandInfo, SlashCommandLocation, SlashCommandSource } from "../slash-commands.js";
 export {
 	createExtensionRuntime,
 	discoverAndLoadExtensions,
@@ -68,6 +69,7 @@ export type {
 	FindToolResultEvent,
 	GetActiveToolsHandler,
 	GetAllToolsHandler,
+	GetCommandsHandler,
 	GetThinkingLevelHandler,
 	GrepToolCallEvent,
 	GrepToolResultEvent,

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

@@ -119,6 +119,7 @@ export function createExtensionRuntime(): ExtensionRuntime {
 		getActiveTools: notInitialized,
 		getAllTools: notInitialized,
 		setActiveTools: notInitialized,
+		getCommands: notInitialized,
 		setModel: () => Promise.reject(new Error("Extension runtime not initialized")),
 		getThinkingLevel: notInitialized,
 		setThinkingLevel: notInitialized,
@@ -228,6 +229,10 @@ function createExtensionAPI(
 			runtime.setActiveTools(toolNames);
 		},
 
+		getCommands() {
+			return runtime.getCommands();
+		},
+
 		setModel(model) {
 			return runtime.setModel(model);
 		},

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

@@ -200,6 +200,7 @@ export class ExtensionRunner {
 		this.runtime.getActiveTools = actions.getActiveTools;
 		this.runtime.getAllTools = actions.getAllTools;
 		this.runtime.setActiveTools = actions.setActiveTools;
+		this.runtime.getCommands = actions.getCommands;
 		this.runtime.setModel = actions.setModel;
 		this.runtime.getThinkingLevel = actions.getThinkingLevel;
 		this.runtime.setThinkingLevel = actions.setThinkingLevel;

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

@@ -53,6 +53,7 @@ import type {
 	SessionEntry,
 	SessionManager,
 } from "../session-manager.js";
+import type { SlashCommandInfo } from "../slash-commands.js";
 import type { BashOperations } from "../tools/bash.js";
 import type { EditToolDetails } from "../tools/edit.js";
 import type {
@@ -973,6 +974,9 @@ export interface ExtensionAPI {
 	/** Set the active tools by name. */
 	setActiveTools(toolNames: string[]): void;
 
+	/** Get available slash commands in the current session. */
+	getCommands(): SlashCommandInfo[];
+
 	// =========================================================================
 	// Model and Thinking Level
 	// =========================================================================
@@ -1154,6 +1158,8 @@ export type ToolInfo = Pick<ToolDefinition, "name" | "description">;
 
 export type GetAllToolsHandler = () => ToolInfo[];
 
+export type GetCommandsHandler = () => SlashCommandInfo[];
+
 export type SetActiveToolsHandler = (toolNames: string[]) => void;
 
 export type SetModelHandler = (model: Model<any>) => Promise<boolean>;
@@ -1188,6 +1194,7 @@ export interface ExtensionActions {
 	getActiveTools: GetActiveToolsHandler;
 	getAllTools: GetAllToolsHandler;
 	setActiveTools: SetActiveToolsHandler;
+	getCommands: GetCommandsHandler;
 	setModel: SetModelHandler;
 	getThinkingLevel: GetThinkingLevelHandler;
 	setThinkingLevel: SetThinkingLevelHandler;

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

@@ -88,6 +88,9 @@ export type {
 	ExtensionCommandContext,
 	ExtensionContext,
 	ExtensionFactory,
+	SlashCommandInfo,
+	SlashCommandLocation,
+	SlashCommandSource,
 	ToolDefinition,
 } from "./extensions/index.js";
 export type { PromptTemplate } from "./prompt-templates.js";

packages/coding-agent/src/core/slash-commands.ts

@@ -0,0 +1,37 @@
+export type SlashCommandSource = "extension" | "template" | "skill";
+
+export type SlashCommandLocation = "user" | "project" | "path";
+
+export interface SlashCommandInfo {
+	name: string;
+	description?: string;
+	source: SlashCommandSource;
+	location?: SlashCommandLocation;
+	path?: string;
+}
+
+export interface BuiltinSlashCommand {
+	name: string;
+	description: string;
+}
+
+export const BUILTIN_SLASH_COMMANDS: ReadonlyArray<BuiltinSlashCommand> = [
+	{ name: "settings", description: "Open settings menu" },
+	{ name: "model", description: "Select model (opens selector UI)" },
+	{ name: "scoped-models", description: "Enable/disable models for Ctrl+P cycling" },
+	{ name: "export", description: "Export session to HTML file" },
+	{ name: "share", description: "Share session as a secret GitHub gist" },
+	{ name: "copy", description: "Copy last agent message to clipboard" },
+	{ name: "name", description: "Set session display name" },
+	{ name: "session", description: "Show session info and stats" },
+	{ name: "changelog", description: "Show changelog entries" },
+	{ name: "hotkeys", description: "Show all keyboard shortcuts" },
+	{ name: "fork", description: "Create a new fork from a previous message" },
+	{ name: "tree", description: "Navigate session tree (switch branches)" },
+	{ name: "login", description: "Login with OAuth provider" },
+	{ name: "logout", description: "Logout from OAuth provider" },
+	{ name: "new", description: "Start a new session" },
+	{ name: "compact", description: "Manually compact the session context" },
+	{ name: "resume", description: "Resume a different session" },
+	{ name: "reload", description: "Reload extensions, skills, prompts, and themes" },
+];

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

@@ -66,6 +66,7 @@ import { createCompactionSummaryMessage } from "../../core/messages.js";
 import { resolveModelScope } from "../../core/model-resolver.js";
 import type { ResourceDiagnostic } from "../../core/resource-loader.js";
 import { type SessionContext, SessionManager } from "../../core/session-manager.js";
+import { BUILTIN_SLASH_COMMANDS } from "../../core/slash-commands.js";
 import type { TruncationResult } from "../../core/tools/truncate.js";
 import { getChangelogPath, getNewEntries, parseChangelog } from "../../utils/changelog.js";
 import { copyToClipboard } from "../../utils/clipboard.js";
@@ -288,56 +289,41 @@ export class InteractiveMode {
 
 	private setupAutocomplete(fdPath: string | undefined): void {
 		// Define commands for autocomplete
-		const slashCommands: SlashCommand[] = [
+		const slashCommands: SlashCommand[] = BUILTIN_SLASH_COMMANDS.map((command) => ({
-			{ name: "settings", description: "Open settings menu" },
+			name: command.name,
-			{
+			description: command.description,
-				name: "model",
+		}));
-				description: "Select model (opens selector UI)",
-				getArgumentCompletions: (prefix: string): AutocompleteItem[] | null => {
-					// Get available models (scoped or from registry)
-					const models =
-						this.session.scopedModels.length > 0
-							? this.session.scopedModels.map((s) => s.model)
-							: this.session.modelRegistry.getAvailable();
 
-					if (models.length === 0) return null;
+		const modelCommand = slashCommands.find((command) => command.name === "model");
+		if (modelCommand) {
+			modelCommand.getArgumentCompletions = (prefix: string): AutocompleteItem[] | null => {
+				// Get available models (scoped or from registry)
+				const models =
+					this.session.scopedModels.length > 0
+						? this.session.scopedModels.map((s) => s.model)
+						: this.session.modelRegistry.getAvailable();
 
-					// Create items with provider/id format
+				if (models.length === 0) return null;
-					const items = models.map((m) => ({
-						id: m.id,
-						provider: m.provider,
-						label: `${m.provider}/${m.id}`,
-					}));
 
-					// Fuzzy filter by model ID + provider (allows "opus anthropic" to match)
+				// Create items with provider/id format
-					const filtered = fuzzyFilter(items, prefix, (item) => `${item.id} ${item.provider}`);
+				const items = models.map((m) => ({
+					id: m.id,
+					provider: m.provider,
+					label: `${m.provider}/${m.id}`,
+				}));
 
-					if (filtered.length === 0) return null;
+				// Fuzzy filter by model ID + provider (allows "opus anthropic" to match)
+				const filtered = fuzzyFilter(items, prefix, (item) => `${item.id} ${item.provider}`);
 
-					return filtered.map((item) => ({
+				if (filtered.length === 0) return null;
-						value: item.label,
+
-						label: item.id,
+				return filtered.map((item) => ({
-						description: item.provider,
+					value: item.label,
-					}));
+					label: item.id,
-				},
+					description: item.provider,
-			},
+				}));
-			{ name: "scoped-models", description: "Enable/disable models for Ctrl+P cycling" },
+			};
-			{ name: "export", description: "Export session to HTML file" },
+		}
-			{ name: "share", description: "Share session as a secret GitHub gist" },
-			{ name: "copy", description: "Copy last agent message to clipboard" },
-			{ name: "name", description: "Set session display name" },
-			{ name: "session", description: "Show session info and stats" },
-			{ name: "changelog", description: "Show changelog entries" },
-			{ name: "hotkeys", description: "Show all keyboard shortcuts" },
-			{ name: "fork", description: "Create a new fork from a previous message" },
-			{ name: "tree", description: "Navigate session tree (switch branches)" },
-			{ name: "login", description: "Login with OAuth provider" },
-			{ name: "logout", description: "Logout from OAuth provider" },
-			{ name: "new", description: "Start a new session" },
-			{ name: "compact", description: "Manually compact the session context" },
-			{ name: "resume", description: "Resume a different session" },
-			{ name: "reload", description: "Reload extensions, skills, prompts, and themes" },
-		];
 
 		// Convert prompt templates to SlashCommand format for autocomplete
 		const templateCommands: SlashCommand[] = this.session.promptTemplates.map((cmd) => ({