feat(coding-agent): add commands.ts example and export SlashCommandInfo types

- Add example extension demonstrating pi.getCommands() API
- Export SlashCommandInfo, SlashCommandLocation, SlashCommandSource from main index.ts

Follow-up to #1210

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

@@ -0,0 +1,72 @@
+/**
+ * Commands Extension
+ *
+ * Demonstrates the pi.getCommands() API by providing a /commands command
+ * that lists all available slash commands in the current session.
+ *
+ * Usage:
+ * 1. Copy this file to ~/.pi/agent/extensions/ or your project's .pi/extensions/
+ * 2. Use /commands to see available commands
+ * 3. Use /commands extensions to filter by source
+ */
+
+import type { ExtensionAPI, SlashCommandInfo } from "@mariozechner/pi-coding-agent";
+
+export default function commandsExtension(pi: ExtensionAPI) {
+	pi.registerCommand("commands", {
+		description: "List available slash commands",
+		getArgumentCompletions: (prefix) => {
+			const sources = ["extension", "template", "skill"];
+			const filtered = sources.filter((s) => s.startsWith(prefix));
+			return filtered.length > 0 ? filtered.map((s) => ({ value: s, label: s })) : null;
+		},
+		handler: async (args, ctx) => {
+			const commands = pi.getCommands();
+			const sourceFilter = args.trim() as "extension" | "template" | "skill" | "";
+
+			// Filter by source if specified
+			const filtered = sourceFilter ? commands.filter((c) => c.source === sourceFilter) : commands;
+
+			if (filtered.length === 0) {
+				ctx.ui.notify(sourceFilter ? `No ${sourceFilter} commands found` : "No commands found", "info");
+				return;
+			}
+
+			// Build selection items grouped by source
+			const formatCommand = (cmd: SlashCommandInfo): string => {
+				const desc = cmd.description ? ` - ${cmd.description}` : "";
+				return `/${cmd.name}${desc}`;
+			};
+
+			const items: string[] = [];
+			const sources: Array<{ key: "extension" | "template" | "skill"; label: string }> = [
+				{ key: "extension", label: "Extensions" },
+				{ key: "template", label: "Templates" },
+				{ key: "skill", label: "Skills" },
+			];
+
+			for (const { key, label } of sources) {
+				const cmds = filtered.filter((c) => c.source === key);
+				if (cmds.length > 0) {
+					items.push(`--- ${label} ---`);
+					items.push(...cmds.map(formatCommand));
+				}
+			}
+
+			// Show in a selector (user can scroll and see all commands)
+			const selected = await ctx.ui.select("Available Commands", items);
+
+			// If user selected a command (not a header), offer to show its path
+			if (selected && !selected.startsWith("---")) {
+				const cmdName = selected.split(" - ")[0].slice(1); // Remove leading /
+				const cmd = commands.find((c) => c.name === cmdName);
+				if (cmd?.path) {
+					const showPath = await ctx.ui.confirm(cmd.name, `View source path?\n${cmd.path}`);
+					if (showPath) {
+						ctx.ui.notify(cmd.path, "info");
+					}
+				}
+			}
+		},
+	});
+}

packages/coding-agent/src/index.ts

@@ -97,6 +97,9 @@ export type {
 	SessionStartEvent,
 	SessionSwitchEvent,
 	SessionTreeEvent,
+	SlashCommandInfo,
+	SlashCommandLocation,
+	SlashCommandSource,
 	ToolCallEvent,
 	ToolDefinition,
 	ToolInfo,