OpenAI Realtime API Voice Agent

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\n\n \n \n",[18,68],"pulls","branches","forks","envVars",{"_176":178,"_179":26},"connections",{"_176":26,"_177":26},"count","unfilledCount",2,"emptyCount",{"_33":157,"_13":18,"_66":74,"_43":-5,"_35":36,"_158":40,"_159":24,"_37":250,"_39":26,"_69":75,"_161":-5,"_70":30,"_162":-5,"_195":251,"_17":252},{"_33":165,"_13":68,"_66":67,"_43":74,"_35":36,"_158":40,"_159":24,"_37":247,"_39":26,"_69":21,"_161":167,"_70":30,"_162":-5,"_195":248,"_17":249},{"_33":243,"_13":214,"_66":208,"_43":-5,"_35":36,"_158":40,"_159":24,"_37":244,"_39":26,"_69":75,"_161":-5,"_70":30,"_162":-5,"_195":245,"_17":246},{"_33":236,"_13":237,"_66":238,"_43":208,"_35":36,"_158":111,"_159":24,"_37":239,"_39":178,"_69":193,"_161":240,"_70":30,"_162":-5,"_195":241,"_17":242},{"_33":229,"_13":230,"_66":231,"_43":208,"_35":36,"_158":40,"_159":24,"_37":232,"_39":26,"_69":210,"_161":233,"_70":30,"_162":-5,"_195":234,"_17":235},{"_33":222,"_13":223,"_66":224,"_43":208,"_35":36,"_158":40,"_159":24,"_37":225,"_39":26,"_69":210,"_161":226,"_70":30,"_162":-5,"_195":227,"_17":228},{"_33":215,"_13":216,"_66":217,"_43":208,"_35":36,"_158":40,"_159":24,"_37":218,"_39":26,"_69":210,"_161":219,"_70":30,"_162":-5,"_195":220,"_17":221},{"_33":205,"_13":206,"_66":207,"_43":208,"_35":36,"_158":40,"_159":24,"_37":209,"_39":26,"_69":210,"_161":211,"_70":30,"_162":-5,"_195":212,"_17":213},{"_33":198,"_13":199,"_66":200,"_43":-5,"_35":36,"_158":40,"_159":24,"_37":201,"_39":26,"_69":21,"_161":202,"_70":30,"_162":-5,"_195":203,"_17":204},{"_33":190,"_13":191,"_66":87,"_43":-5,"_35":36,"_158":40,"_159":24,"_37":192,"_39":26,"_69":193,"_161":194,"_70":30,"_162":-5,"_195":196,"_17":197},"59f073e4-ebfc-11f0-bb01-42dde27851f2","main.tsx",["D",1767812952099],"http","import { Hono } from \"npm:hono\";\nimport { blob } from \"https://esm.town/v/std/blob\";\nimport { parseVal, serveFile } from \"https://esm.town/v/std/utils/index.ts\";\n// import mcp from \"./routes/mcp.ts\";\nimport rtc from \"./routes/rtc.ts\";\nimport sip from \"./routes/sip.ts\";\nimport observer from \"./routes/observer.ts\";\n\nconst SOURCE_URL = parseVal(Deno.env.get(\"VALTOWN_ENTRYPOINT\")).links.self.val;\n\nconst app = new Hono();\napp.route(\"/rtc\", rtc);\napp.route(\"/sip\", sip);\napp.route(\"/observer\", observer);\n// app.route(\"/mcp\", mcp);\napp.get(\"/source\", (c) => c.redirect(SOURCE_URL));\n\napp.get(\"/\", () => serveFile(\"/frontend/index.html\", import.meta.url));\napp.get(\"/favicon.ico\", async (c) => {\n const entry = parseVal(Deno.env.get(\"VALTOWN_ENTRYPOINT\"));\n const file = await blob.get(`${entry.name}/favicon.ico`);\n if (!file) {\n return c.text(\"favicon not found\", 404);\n }\n return new Response(file.body, {\n headers: {\n \"Content-Type\": \"image/x-icon\",\n \"Cache-Control\": \"public, max-age=31536000, immutable\",\n },\n });\n}); \n \nexport default app.fetch;","children",[],[191],"59f066c4-ebfc-11f0-bb01-42dde27851f2","README.md","019b99dc-f052-7178-bca5-43dcbffd23e5",["D",1767812952099],"# hello-realtime\n\n**Hello Realtime** is a OpenAI Realtime app that supports both WebRTC and SIP\n(telephone) users. You can access the app via WebRTC at\n[hello-realtime.val.run](https://hello-realtime.val.run), or via SIP by calling\n425-800-0042.\n\nThis demo shows off the new SIP API, the new all-in-one WebRTC API, and the new\nserver-side websocket interface.\n\nIf you remix the app, you'll just need to pop in your own `OPENAI_API_KEY` (from\n[platform.openai.com](https://platform.openai.com)), and if you want SIP, the\n`OPENAI_SIGNING_SECRET`.\n\n## Architecture\n\n1. **WebRTC Flow**:\n - Browser connects to frontend\n - creates WebRTC offer\n - `/rtc` endpoint handles SDP negotiation with OpenAI\n - observer established to monitor session\n2. **SIP Flow**:\n - Phone calls triggers webhook\n - `/sip` endpoint verifies webhook and accepts call\n - observer established to monitor session\n\n## API Endpoints\n\n- `GET /` - serves the WebRTC-based app\n- `POST /rtc` - creates a new WebRTC-based Realtime API session\n - Supports optional `model` URL parameter to override the default model\n - Example: `POST /rtc?model=gpt-4o-realtime-preview`\n- `POST /sip` - handles an incoming Realtime API SIP call\n- `POST /observer` - internal endpoint to establish a Realtime API websocket for\n session control\n\n## Project Structure\n\n```\n├── frontend/ \n│ └── index.html # HTML/JS application for WebRTC\n├── main.tsx # Main entrypoint for the val.town app\n└── routes/\n |\n ├── agent.ts # Realtime API session configuration and tools\n ├── observer.ts # Server-side session control for SIP & WebRTC\n ├── rtc.ts # WebRTC session setup\n ├── sip.ts # SIP webhook handling and session setup\n └── utils.ts # Various HTTP helpers\n```\n\n## File Links\n\n- [`frontend/index.html`](./frontend/index.html)\n- [`main.tsx`](./main.tsx)\n- [`routes/agent.ts`](./routes/agent.ts)\n- [`routes/observer.ts`](./routes/observer.ts)\n- [`routes/rtc.ts`](./routes/rtc.ts)\n- [`routes/sip.ts`](./routes/sip.ts)\n- [`routes/utils.ts`](./routes/utils.ts)",[],[199],"59f05f76-ebfc-11f0-bb01-42dde27851f2","utils.ts","019b99dc-f052-7178-bca5-38ef91935ebb","019b99dc-f052-7178-bca5-3cbe94c358d5",["D",1767812952099],"script","const REALTIME_BASE_URL = \"https://api.openai.com/v1/realtime\";\nconst OPENAI_API_KEY = Deno.env.get(\"OPENAI_API_KEY\");\nif (!OPENAI_API_KEY) {\n throw new Error(\"🔴 OpenAI API key not configured\");\n}\n\n// Builds the URL for a Realtime API endpoint.\nexport function makeUrl(callId?: string, action?: string) {\n let url = REALTIME_BASE_URL;\n if (!callId) {\n // start call (POST)\n url += \"/calls\";\n } else if (action) {\n // accept, reject, hangup (POST)\n url += `/calls/${callId}/${action}`;\n } else {\n // observer (web socket)\n url += `?call_id=${callId}`;\n }\n return url;\n}\n\n// Builds the headers for a Realtime API endpoint.\nexport function makeHeaders(contentType?: string) {\n const obj: Record = {\n Authorization: `Bearer ${OPENAI_API_KEY}`,\n };\n if (contentType) obj[\"Content-Type\"] = contentType;\n return obj;\n}\n\n// Debug helper for printing Realtime API errors.\nexport async function getErrorText(resp: Response) {\n const errBody = await resp.text().catch(() => \"\");\n return `${resp.status} ${resp.statusText}: ${errBody}`;\n}",[],[214,206],"routes","59f051de-ebfc-11f0-bb01-42dde27851f2","sip.ts","019b99dc-f052-7178-bca5-37c2d6d827d0",["D",1767812952099],"import { Hono } from \"npm:hono\";\nimport { Webhook } from \"npm:svix\";\nimport { makeSession } from \"./agent.ts\";\nimport { getErrorText, makeHeaders, makeUrl } from \"./utils.ts\";\n\nconst sip = new Hono();\n\n// POST /sip : webhook endpoint\nsip.post(\"/\", async (c) => {\n // Verify the webhook.\n const OPENAI_SIGNING_SECRET = Deno.env.get(\"OPENAI_SIGNING_SECRET\");\n if (!OPENAI_SIGNING_SECRET) {\n console.error(\"🔴 webhook secret not configured\");\n return c.text(\"Internal error\", 500);\n }\n const webhook = new Webhook(OPENAI_SIGNING_SECRET);\n const bodyStr = await c.req.text();\n let callId: string | undefined;\n let toNumber: string | undefined;\n try {\n const headers = Object.fromEntries(c.req.raw.headers.entries());\n const payload: any = webhook.verify(bodyStr, headers);\n callId = payload.data.call_id;\n toNumber = getToNumber(payload.data.sip_headers);\n const fromNumber = getFromNumber(payload.data.sip_headers);\n console.log(\"✅ verified webhook:\", callId, fromNumber, toNumber);\n } catch (error) {\n console.error(`🔴 verify failed: ${error}`);\n return c.text(\"Invalid signature\", 401);\n }\n\n // Accept the call.\n const model = getModelForNumber(toNumber);\n const url = makeUrl(callId, \"accept\");\n const headers = makeHeaders(\"application/json\");\n const body = JSON.stringify(makeSession(model));\n const opts = { method: \"POST\", headers, body };\n const resp = await fetch(url, opts);\n if (!resp.ok) {\n console.error(`🔴 accept failed: ${await getErrorText(resp)}`);\n return c.text(\"Internal error\", 500);\n }\n console.log(\"✅ call accepted:\", callId);\n\n // Kick off observer in the background (fire-and-forget).\n const selfUrl = new URL(c.req.url);\n fetch(`${selfUrl.origin}/observer/${callId}`, { method: \"POST\" })\n .catch((e) => console.error(\"observer start failed:\", e));\n\n return c.newResponse(null);\n});\n\nconst getToNumber = headers => getNumberFromSipHeader(headers, \"to\");\nconst getFromNumber = headers => getNumberFromSipHeader(headers, \"from\");\n\nfunction getNumberFromSipHeader(headers: any, name: string) {\n const header = getSipHeader(headers, name);\n const match = header?.match(/sip:\\+?(\\d+)@/);\n return match ? `+${match[1]}` : undefined;\n}\n\nfunction getSipHeader(headers: any, name: string) {\n return headers.find((h) => h.name.toLowerCase() === name)?.value;\n}\n\nfunction getModelForNumber(number: string) {\n const map = { \"+14258000074\": \"gpt-realtime-mini\" };\n return map[number];\n}\n\nexport default sip;",[],[214,216],"59f04a36-ebfc-11f0-bb01-42dde27851f2","rtc.ts","019b99dc-f052-7178-bca5-31773a7b679c",["D",1767812952099],"import { Hono } from \"npm:hono\";\nimport { makeSession } from \"./agent.ts\";\nimport { getErrorText, makeHeaders, makeUrl } from \"./utils.ts\";\n\nconst rtc = new Hono();\n\n// POST /rtc : create a new call\nrtc.post(\"/\", async (c) => {\n // Extract model parameter from URL if provided\n const model = c.req.query(\"model\");\n if (model !== undefined) {\n console.log(\"🔧 Model parameter received:\", model);\n }\n \n // Create the call.\n const fd = new FormData();\n fd.set(\"sdp\", await c.req.text());\n fd.set(\"session\", JSON.stringify(makeSession(model)));\n const opts = { method: \"POST\", headers: makeHeaders(), body: fd };\n const resp = await fetch(makeUrl(), opts);\n if (!resp.ok) {\n console.error(`🔴 start call failed: ${await getErrorText(resp)}`);\n return c.text(\"Internal error\", 500);\n }\n\n const contentType = resp.headers.get(\"Content-Type\");\n const location = resp.headers.get(\"Location\");\n const callId = location?.split(\"/\").pop();\n console.log(\"✅ call created:\", callId);\n\n // Kick off observer in the background (fire-and-forget).\n const selfUrl = new URL(c.req.url);\n fetch(`${selfUrl.origin}/observer/${callId}`, { method: \"POST\" })\n .catch((e) => console.error(\"observer start failed:\", e));\n\n const responseHeaders = {\n \"Content-Type\": contentType,\n \"Location\": location,\n };\n return c.newResponse(resp.body, { headers: responseHeaders });\n});\n\nexport default rtc;",[],[214,223],"59f03a1e-ebfc-11f0-bb01-42dde27851f2","observer.ts","019b99dc-f052-7178-bca5-2ce8dc7693bf",["D",1767812952099],"import { Hono } from \"npm:hono\";\nimport WebSocket from \"npm:ws\";\nimport { createHandler } from \"./agent.ts\";\nimport { makeHeaders, makeUrl } from \"./utils.ts\";\n\nexport interface ObserverHandler {\n onInit(): void;\n onTool(name: string, args: any): void;\n onOutputAudioStarted(): void;\n onOutputAudioStopped(): void;\n onOutputAudioCleared(): void;\n}\n\nexport class ObserverClient {\n private ws: WebSocket;\n private closeResolve: () => void;\n private closePromise: Promise;\n private handler: ObserverHandler;\n\n constructor(callId: string) {\n const url = makeUrl(callId);\n this.ws = new WebSocket(url, { headers: makeHeaders() });\n this.ws.on(\"open\", () => this.handleOpen());\n this.ws.on(\"message\", (data) => this.handleMessage(JSON.parse(data)));\n this.ws.on(\"error\", (err) => this.handleError(err));\n this.ws.on(\"close\", (ev) => this.handleClose(ev));\n this.closePromise = new Promise((resolve) =>\n this.closeResolve = resolve\n );\n this.handler = createHandler(this, callId);\n }\n createResponse() {\n this.sendMessage({ type: \"response.create\" });\n }\n async waitForClose() {\n await this.closePromise;\n }\n private sendMessage(message: any) {\n this.ws.send(JSON.stringify(message));\n }\n private handleOpen() {\n console.log(\"✅ websocket connected\");\n this.handler.onInit();\n }\n private async handleMessage(message: any) {\n if (!message.type.endsWith(\".delta\")) { // ignore verbose messages\n console.log(message);\n }\n switch (message.type) {\n case \"response.function_call_arguments.done\":\n this.handler.onTool(message.name, message.arguments);\n break;\n case \"output_audio_buffer.started\":\n this.handler.onOutputAudioStarted();\n break;\n case \"output_audio_buffer.stopped\":\n this.handler.onOutputAudioStopped();\n break;\n case \"output_audio_buffer.cleared\":\n this.handler.onOutputAudioCleared();\n break;\n }\n }\n private handleError(err: Error) {\n console.error(`🔴 websocket failed: ${err.message}`);\n this.closeResolve();\n }\n private handleClose(e: Event) {\n console.log(`websocket closed: ${e}`);\n this.closeResolve();\n }\n}\n\nconst observer = new Hono();\n\n// POST /observer/:callId : self-connect to establish a web socket\nobserver.post(\"/:callId\", async (c) => {\n const callId = c.req.param(\"callId\");\n const client = new ObserverClient(callId);\n await client.waitForClose();\n return c.newResponse(null);\n});\n\nexport default observer;",[],[214,230],"27e2af34-ec06-11f0-a6bb-42dde27851f2","agent.ts","019b99dc-f052-7178-bca5-2a32ce9ded24",["D",1767817163154],"import { ObserverClient, ObserverHandler } from \"./observer.ts\";\nimport { getErrorText, makeHeaders, makeUrl } from \"./utils.ts\";\n\nconst MODEL = \"gpt-realtime\";\nconst TRANSCRIBE_MODEL = \"gpt-4o-transcribe\";\nconst NR_TYPE = \"near_field\";\nconst INSTRUCTIONS = `\n #Role\nYou are the museum tour guide for the Barrett-Byam Homestead in Chelmsford, Massachusetts. \n#Rules\n**Do**\nProvide fact-based comprehensive tours of the homestead with as much detail as possible as time permits. \n**Don’t**\nThere is no need to introduce yourself.\n ;\nconst VOICE = \"marin\";\nconst HANGUP_TOOL = {\n type: \"function\",\n name: \"end_call\",\n description: `\n Use this function to hang up the call when the user says goodbye \n or otherwise indicates they are about to end the call.`,\n};\n\n// Builds the declarative session configuration for a Realtime API session.\nexport function makeSession(modelOverride?: string) {\n const model = modelOverride || MODEL;\n const instructions = INSTRUCTIONS.replace(\"{{model}}\", model);\n return {\n type: \"realtime\",\n model,\n instructions,\n audio: {\n input: {\n noise_reduction: { type: NR_TYPE },\n transcription: { model: TRANSCRIBE_MODEL },\n },\n output: { voice: VOICE },\n },\n tools: [HANGUP_TOOL],\n };\n}\n\n// AgentHandler implements the agent runtime behavior (tool calling, etc).\nclass AgentHandler implements ObserverHandler {\n private audioActive = false;\n private callEnding = false;\n constructor(private client: ObserverClient, private callId: string) {}\n onInit() {\n // Trigger a response immediately.\n this.client.createResponse();\n }\n async onTool(name: string, _args: any) {\n // If audio is playing, defer the hangup until it finishes.\n // Otherwise, end the call now.\n if (name == HANGUP_TOOL.name) {\n if (this.audioActive) {\n this.callEnding = true;\n } else {\n await this.hangup();\n }\n }\n }\n async onOutputAudioStarted() {\n this.audioActive = true;\n }\n async onOutputAudioStopped() {\n // Shut down the call and websocket once audio has finished spooling.\n this.audioActive = false;\n if (this.callEnding) {\n await this.hangup();\n }\n }\n async onOutputAudioCleared() {\n this.audioActive = false;\n }\n private async hangup() {\n const url = makeUrl(this.callId, \"hangup\");\n const resp = await fetch(url, { method: \"POST\", headers: makeHeaders() });\n if (!resp.ok) {\n console.error(`🔴 end call failed: ${await getErrorText(resp)}`);\n return;\n }\n\n console.log(\"✅ call ended\");\n }\n}\n\n// Creates the runtime handler for the session.\nexport function createHandler(client: ObserverClient, callId: string) {\n return new AgentHandler(client, callId);\n}",[],[214,237],"59f06584-ebfc-11f0-bb01-42dde27851f2",["D",1767812952099],[183,184,185,186,187],[214],["D",1767812952099],[],[18,68],["D",1767812952099],[181],[18],["D",1767812952099],{"_11":12,"_125":73},{"_11":12,"_121":-5,"_72":73,"_31":71,"_122":123,"_124":30},{"_39":111,"_13":16,"_33":36,"_112":77,"_113":63,"_114":40,"_115":81,"_116":117,"_118":42,"_119":14,"_120":12},"ctx",{"_52":-5,"_146":290,"_291":292,"_293":294,"_295":30,"_296":30,"_297":30,"_298":24,"_299":-5,"_300":-7,"_301":-7,"_302":26,"_303":30,"_304":30,"_305":-5,"_306":30,"_307":30,"_308":30,"_309":-5},"ENV",{"_261":262,"_263":264,"_265":16,"_266":267,"_268":269,"_270":271,"_272":273,"_274":275,"_276":277,"_278":279,"_280":281,"_282":283,"_284":285,"_286":287,"_288":289},"REACT_APP_SENTRY_DSN","https://586020d86f05489db63a554690acf1e9@o1398359.ingest.sentry.io/6724499","RENDER_GIT_COMMIT","e87eb04e707cf64e7e532c8e8ec395f209e17f15","RENDER_GIT_BRANCH","POSTHOG_API_TOKEN","phc_nmoyuAkStEZuUp69rYlg1DZgrIt19Gx0Y4Hwf8tGgJP","POSTHOG_API_HOST","https://wart.val.town","WEB_API_TEMPLATE","https://{val}.web.val.run","APP_URL","https://www.val.town","MODULE_URL","https://esm.town","VANITY_WEB_API_TEMPLATE","https://{label}.val.run/","DENOLS_URL","https://lsp.val.town","NODE_ENV","production","CLOUDFLARE_TURNSTILE_SITE_KEY","0x4AAAAAACtaIZJH7s9rBMZ6","GOOGLE_CLIENT_ID","875989696899-jtsqkhlbdv5jrlsk8631p7ipjg3c6o62.apps.googleusercontent.com","STRIPE_PUBLISHABLE_KEY","pk_live_51N2zvWEpZTTLipIkVEwXrUG9AT0yeOOEYxszarZT1jpsZV58Ly6wlg3SltZpHN26CUalOBmUSY7adQRQiSkCZz2500qSXNkf8Y","API_URL","https://api.val.town",[],"preferencesKeybindings","default","preferencesTheme","light","preferencesFixers","preferencesCopilot","preferencesSelectionAi","preferencesCloseBrackets","preferencesChatPanelState","preferencesDprint","preferencesDenofmt","notificationCount","flagDenols","isBusinessOrgMember","businessOrgHandle","isBusinessOrgAdmin","isHigherTownieTier","navCollapsed","currentOrgId"]

Realtime Agent

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