Memory for voice agents on Retell.

pip install 'niadra[retell]'   # no framework dependency

"""The server side of a Retell voice agent: inbound webhook, custom functions and call events.

Run: uvicorn retell_server:app. On the Retell phone number, set the inbound webhook to
/retell/inbound; add the tools from tool_configs() to the Retell LLM's general_tools; set the
agent's webhook to /retell/events. Put {{niadra_agent_memory}} and {{niadra_context}} in the
prompt, after your instructions.
"""

import os

from fastapi import FastAPI, Request, Response

from niadra import AsyncNiadra
from niadra.integrations.retell import RetellWebhooks, tool_configs

niadra = AsyncNiadra(channel="voice")
retell = RetellWebhooks(niadra, api_key=os.environ["RETELL_API_KEY"], agent_memory=True)
app = FastAPI()
TOOLS = tool_configs("https://agent.example.com/retell/tools", agent_memory=True)


def answer(result) -> Response:
    return Response(result.text(), result.status, media_type=result.content_type)


@app.post("/retell/inbound")
async def inbound(request: Request) -> Response:
    return answer(await retell.inbound(await request.body(), request.headers))


@app.post("/retell/tools")
async def tools(request: Request) -> Response:
    return answer(await retell.custom_function(await request.body(), request.headers))


@app.post("/retell/events")
async def events(request: Request) -> Response:
    return answer(await retell.webhook(await request.body(), request.headers))


async def call_out(to_number: str) -> dict:
    """What to pass to Retell's create_phone_call for an outbound call to a customer."""
    return await retell.outbound(to_number)

npm install @niadra/sdk   # @niadra/sdk/retell needs only web APIs

// The three Retell endpoints on Hono. Every handler takes the raw body: the signature covers the exact bytes.
import { Hono } from "hono";
import { Niadra } from "@niadra/sdk";
import { retell } from "@niadra/sdk/retell";

const niadra = new Niadra();
const handlers = retell({ niadra, apiKey: process.env.RETELL_API_KEY ?? "" });
const respond = (c, { status, body }) => c.json(body, status);

const app = new Hono();
app.post("/retell/inbound", async (c) => respond(c, await handlers.inbound(await c.req.text(), c.req.raw.headers)));
app.post("/retell/webhook", async (c) => respond(c, await handlers.webhook(await c.req.text(), c.req.raw.headers)));
app.post("/retell/tools", async (c) => respond(c, await handlers.tool(await c.req.text(), c.req.raw.headers)));

// For the Retell LLM's general_tools.
export const TOOLS = handlers.toolConfigs({ url: "https://agent.example.com/retell/tools" });
export default app;