# Build brief — a focused alternative to Thrumble

> **Verdict:** Partly, if you narrow it · **Buildability:** 53/100 · **Category:** Voice AI
> **Source:** https://www.canitbevibecoded.com/thrumble
> Independent editorial assessment from Can It Be Vibe Coded? Not affiliated with, endorsed by, or derived from Thrumble. Verify current pricing and capabilities before acting.

## Context

**Thrumble** — Voice AI platform for inbound and outbound business phone calls. It currently costs $99/mo.

A single inbound receptionist agent is a credible focused build with LiveKit Agents or Pipecat plus a SIP trunk. Thrumble as a product is larger: agent config UI, knowledge bases, tools, call transfer, outbound campaigns, phone numbers, transcripts, and production telephony. You can DIY the core conversation loop; you still own carriers, media ports, failed calls, and ops.

This brief describes a focused, single-operator replacement for the part of Thrumble that is genuinely reproducible. It is deliberately narrower than the product it replaces, and it says so in writing. Build the useful core; do not pretend to have rebuilt the rest.

## What you are building

Answer one inbound number with a realtime STT → LLM → TTS agent, look something up, and log the call outcome.

- Turn supplied scripts into speech or avatars through documented model APIs.
- A responsive interface with real empty, loading, success, and error states.

## Requirements

### Functional

- Public VM with TLS and correctly opened SIP / WebRTC / RTP ports.
- SIP trunk and phone number (e.g. Telnyx).
- Consent and recording rules for your country before real traffic.

### Data and integrations

- STT, LLM, and TTS API keys.

Each of these needs a real account, credential, or quota. Set them up before writing feature code.

### Non-functional

- Accessibility: semantic markup, labelled controls, visible focus, and reduced-motion support.
- Security: server-side secrets, validated input, and no credentials in the client bundle.
- Reliability: retries with backoff on external calls, and a clear failure state when a provider is down.
- Portability: the operator can export their data and leave without losing it.

## Implementation brief

Build me a focused self-hosted alternative to Thrumble for one inbound business number.
Requirements:

- Python 3.12 + livekit-agents with one AgentServer worker.
  Direct provider plugins only · no managed agent host.
- Docker Compose: LiveKit Server, Redis, LiveKit SIP, Caddy for HTTPS/WSS.
  Expose only documented SIP and UDP media ports.
- One Telnyx DID + credential SIP trunk. Checked-in inbound-trunk and
  dispatch-rule JSON that routes calls to receptionist-agent.
- AgentSession: Silero VAD, Deepgram STT, gpt-4.1-mini (OpenAI plugin),
  Cartesia TTS. Secrets only from .env.
- Narrow receptionist prompt: answer FAQs from a local knowledge.md,
  book a callback into SQLite after confirmation, transfer is out of scope.
- Persist call id, timestamps, transcript, and outcome to SQLite.
  JSON logs + /healthz. Recording off by default.
- Unit tests for FAQ lookup and callback confirmation; scripted agent tests
  for interruption and refusal to invent facts.
- make setup / make dev / make smoke + docker compose up -d.
  Smoke test must pass in the LiveKit agent console before a real PSTN call.
- README: DNS, TLS, firewall, Telnyx, trunk, keys, test-call steps,
  and common one-way-audio / SIP auth failures.
- Out of scope: outbound campaigns, multi-tenant dashboard, knowledge-base
  crawler, tool marketplace, call transfer, billing, HA, compliance claims.

## Delivery standard

- Inspect the repository first, then write a short implementation plan before writing code.
- Deliver the smallest complete end-to-end workflow first; every primary control must work against persisted data.
- Use real validation and storage; never substitute fake dashboards, decorative controls, hard-coded success states, or mock integrations.
- Include responsive layouts plus genuine empty, loading, success, validation, and failure states.
- Keep secrets server-side in environment variables, provide .env.example, and never commit credentials or user data.
- Add structured logs around every external call and return actionable errors without leaking sensitive details.
- Write unit tests for the core logic and one automated test of the main user journey.
- Finish with a README covering setup, architecture, data location, backups, tests, deployment, and known limitations.

## Acceptance criteria

- [ ] A clean install starts the app using only the README and .env.example.
- [ ] The primary journey works from first visit through saved result, reload, edit, export, and deletion where applicable.
- [ ] Invalid input, missing configuration, provider failure, and an empty database each have a usable state.
- [ ] The interface works at 390px and 1440px, is keyboard navigable, and shows visible focus on every control.
- [ ] Tests, type checking, linting, and a production build all pass with no ignored failures.
- [ ] No part of the interface implies a live integration, security guarantee, or scale capability that was not actually built and verified.

## Non-goals

Do not build these, and do not claim to have replaced them:

- Hosted agent builder, knowledge bases, tools, and transfer destinations.
- Outbound campaign dialer and contact workflows.
- Managed phone numbers, concurrency, and telephony debugging.
- Call logs, recordings, post-call extraction, and analytics.
- Uptime, support, and multi-tenant workspace polish.

## What you still own after launch

- Secure credentials, rotate secrets, and handle provider rate limits.
- Run migrations, backups, restores, and dependency updates.
- Test the critical journey after every model, API, or hosting change.
- Monitor failures and fix the edge cases a first prompt will miss.
- Maintain every third-party integration as APIs and OAuth rules change.

## Risk

**Operational risk.** The code is achievable; dependable data, integrations, and ongoing operations are the real cost.

Editorial confidence in this assessment: high. No reviewed project implementation is linked yet.

## Prior art

Working open-source software you can read, fork, or borrow from before starting:

- [LiveKit Agents + SIP](https://github.com/livekit/agents) — Realtime agent framework; pair with LiveKit Server + SIP for a self-hosted phone stack
- [Pipecat](https://github.com/pipecat-ai/pipecat) — Composable voice pipelines with telephony integrations; you still own deploy and carriers

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