/**
* Dynamic Tools Extension
*
* Demonstrates registering tools after session initialization.
*
* - Registers one tool during session_start
* - Registers additional tools at runtime via /add-echo-tool <name>
*/
import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
import { Type } from "typebox";
const ECHO_PARAMS = Type.Object({
message: Type.String({ description: "Message to echo" }),
});
function normalizeToolName(input: string): string | undefined {
const trimmed = input.trim().toLowerCase();
if (!trimmed) return undefined;
if (!/^[a-z0-9_]+$/.test(trimmed)) return undefined;
return trimmed;
}
export default function dynamicToolsExtension(pi: ExtensionAPI) {
const registeredToolNames = new Set<string>();
const registerEchoTool = (name: string, label: string, prefix: string): boolean => {
if (registeredToolNames.has(name)) {
return false;
}
registeredToolNames.add(name);
pi.registerTool({
name,
label,
description: `Echo a message with prefix: ${prefix}`,
promptSnippet: `Echo back user-provided text with ${prefix.trim()} prefix`,
promptGuidelines: ["Use echo_session when the user asks for exact echo output."],
parameters: ECHO_PARAMS,
async execute(_toolCallId, params) {
return {
content: [{ type: "text", text: `${prefix}${params.message}` }],
details: { tool: name, prefix },
};
},
});
return true;
};
pi.on("session_start", (_event, ctx) => {
registerEchoTool("echo_session", "Echo Session", "[session] ");
ctx.ui.notify("Registered dynamic tool: echo_session", "info");
});
pi.registerCommand("add-echo-tool", {
description: "Register a new echo tool dynamically: /add-echo-tool <tool_name>",
handler: async (args, ctx) => {
const toolName = normalizeToolName(args);
if (!toolName) {
ctx.ui.notify("Usage: /add-echo-tool <tool_name> (lowercase, numbers, underscores)", "warning");
return;
}
const created = registerEchoTool(toolName, `Echo ${toolName}`, `[${toolName}] `);
if (!created) {
ctx.ui.notify(`Tool already registered: ${toolName}`, "warning");
return;
}
ctx.ui.notify(`Registered dynamic tool: ${toolName}`, "info");
},
});
}