[bot] Instrument Retell AI (202,911 weekly downloads)

[braintrust-bot]

Summary

Retell AI publishes an official server-side TypeScript/Node.js SDK, retell-sdk on npm (latest v5.64.0, actively maintained, typed clients generated from Retell's REST API spec). It provides execution APIs for creating and managing real-time voice AI agent calls (phone and web), plus agent/LLM configuration. This repository has zero instrumentation for any retell-sdk surface — no wrapper, no diagnostics channel, no plugin, no auto-instrumentation config, no e2e scenario. Voice agent execution is squarely in scope: this repo already instruments other agent-execution SDKs (Google ADK, Strands Agent SDK, Cloudflare Agents), but has no coverage for voice-agent call orchestration.

What instrumentation is missing

The retell-sdk npm package exposes these execution surfaces, none of which are instrumented:

SDK Method	Description
client.call.createPhoneCall({ from_number, to_number, ... })	Initiates an outbound AI voice agent phone call — the primary execution entrypoint
client.call.createWebCall({ agent_id, ... })	Creates a web-based voice agent call session, returns an access_token/call_id
client.call.retrieve(call_id)	Retrieves call transcript, recording, and structured analysis of a completed agent call
client.chat.create(...) / client.chat.createChatCompletion(...)	Text-based chat agent execution (non-voice)

These are the core execution paths for running a Retell voice/chat agent — analogous in kind to the google-adk and strands-agent-sdk agent-execution plugins already present in this repo, but for a different (voice-first) agent runtime. The SDK has its own generated HTTP client (API-key auth) and does not depend on openai or any already-instrumented package.

No coverage in any instrumentation layer:

• No wrapper function (e.g. wrapRetell()) in js/src/wrappers/
• No diagnostics channels or plugin in js/src/instrumentation/plugins/
• No auto-instrumentation config in js/src/auto-instrumentations/configs/ (not listed in all.ts)
• No e2e test scenario under e2e/scenarios/
• Full repo grep for retell (case-insensitive) returns zero real matches (only unrelated binary cassette blobs from other providers' recorded HTTP fixtures, not instrumentation)

Weekly downloads

Weekly downloads: 202,911 (as of 2026-08-31; window 2026-08-23 to 2026-08-29; https://api.npmjs.org/downloads/point/last-week/retell-sdk)

Braintrust docs status

not_found. Retell / Retell AI does not appear anywhere on the Braintrust integrations index — https://www.braintrust.dev/docs/guides/tracing/integrations — which lists Tracing integrations (OpenTelemetry, Vercel AI SDK, LangChain, LlamaIndex, Cloudflare Workers AI, etc.), Agent frameworks (OpenAI Agents SDK, Claude Agent SDK, Google ADK, LiveKit Agents, Mastra, Pipecat, Strands Agents SDK, Cloudflare Agents/AI Chat, etc.), Eval frameworks, and Testing frameworks. There is no Retell entry in any category and no gateway/proxy workaround documented.

Upstream references

• retell-sdk npm package: https://www.npmjs.com/package/retell-sdk
• Official SDK GitHub: https://github.com/RetellAI/retell-sdk-node (published as retell-sdk)
• Retell AI SDK docs (TypeScript/Python): https://docs.retellai.com/get-started/sdk
• Retell API reference (create phone call): https://docs.retellai.com/api-references/create-phone-call

Braintrust docs sources checked

• https://www.braintrust.dev/docs/guides/tracing/integrations

Local files inspected

• js/src/wrappers/*.ts — full directory listing — no retell.ts wrapper
• js/src/instrumentation/plugins/*.ts — full directory listing — no Retell channels or plugin file
• js/src/auto-instrumentations/configs/all.ts — full config group list (openai, anthropic, bedrock, ai-sdk, claude-agent-sdk, cloudflare-*, cursor-sdk, openai-agents, google-genai, huggingface(+transformers), langchain/langgraph, langsmith, openrouter(+agent), mistral, ollama, google-adk, cohere, groq, genkit, github-copilot, pi-coding-agent, strands-agent-sdk, flue, voyageai) — no Retell entry
• e2e/scenarios/ — no Retell test scenario
• Full repo grep for retell (case-insensitive) — zero real matches (only incidental hits inside unrelated recorded-cassette binary blobs for other providers)