hotato

The open-source flight recorder for production voice agents.

Find where your voice agent talks over callers, and pin the failure to a portable contract with audio, timing, traces, trust checks, human labels, and CI gates. Recapture the call against your changed agent, and the same contract shows whether the fresh recapture passes it without regressing the paired hold guard. MIT.

Start here (no account, no keys, no network)

uvx hotato start --demo

That sweeps two bundled recorded calls a provider's default agent failed, writes the dashboard, and turns one real missed-interruption candidate into a demo failure contract it immediately verifies:

[start] demo: swept 2 bundled calls, 5 candidate moments;
        wrote hotato-sweep.json, hotato-sweep.html, hotato-no-single-threshold.svg
        wrote contracts/demo-missed-interruption.hotato; verified contract: FAIL as expected

Open hotato-sweep.html for the ranked candidate moments with a hear-the-bug playhead. One of them is the failure below: the agent missed a real interruption in one call and false-stopped on a backchannel in another, so no single sensitivity dial fixes both. That is the card start --demo renders for you:

A real failure became a candidate, became a portable .hotato contract, and contract verify catches it. Hotato prints the exact next commands to promote it into a permanent fixture, run it in CI, and re-verify.

Choose your path

Every command above takes a two-channel recording (caller on one channel, agent on the other). A mono file or a bad export is marked NOT SCORABLE, never turned into a confident but meaningless verdict.

contract verify and a promoted fixture in CI are two different guarantees, depending on which recording goes in:

A contract bundle contains call audio. Do not commit a raw customer contract to a public repository; use sanitized fixtures for anything public. See docs/CONTRACTS.md.

The loop

Catch it, confirm it, gate it, then prove it holds:

1. Sweep surfaces candidate talk-over and false-stop moments across your recent calls, ranked by how far the timing missed.
2. You label one (yield = stop for the caller, hold = keep talking through a backchannel) and fixture promote saves it as a permanent regression test.
3. CI runs that fixture on every change and exits non-zero if the recorded evidence stops matching your policy -- a change to the evidence, thresholds, or scorer is caught on every push. Catching the AGENT itself regressing needs a fresh recapture through the same fixture: see docs/RECAPTURE.md.

Hotato measures whether the agent stopped talking when the caller started, how many seconds that took, and how many seconds both were talking at once. It reports what it measured, never a guess at intent.

Connect a production stack

The demo needs nothing. To point Hotato at real calls, connect once, then sweep on a schedule:

hotato connect vapi                                             # credentials stored 0600, local only
hotato sweep --stack vapi --since 7d --out hotato-sweep.html    # cron, CI, wherever

Run sweep on a timer and it becomes a scheduled batch scanner. Your audio stays on your machine unless you explicitly pull it from your stack. Full guide: docs/SET-AND-FORGET.md · runnable examples/set-and-forget/.

What Hotato is not

• Not a full QA platform. It does not grade the whole conversation, task success, or content. See docs/COMPARE.md for where Hamming, Cekura, Coval, Bluejay, Roark, Vapi, and Retell fit instead.
• Not transcript scoring. It measures audio timing, not what was said.
• Not speaker ID. Channels are anonymous; nothing identifies who a person is.
• Not semantic intent detection. It produces candidate timing evidence. Humans label intent. CI enforces confirmed contracts.
• Not a hand on production config. It never sits in the live audio path and never changes a running agent.

Install

uvx hotato runs any command with zero install. To add it to a project:

pip install hotato                 # core: stdlib-only, zero dependencies
pip install 'hotato[neural]'       # optional Silero VAD cross-check
pip install 'hotato[livekit]'      # LiveKit live capture
pip install 'hotato[pipecat]'      # Pipecat live capture

Depth

• Set-and-forget monitoring (connect once, sweep on a schedule, promote confirmed bugs into fixtures): docs/SET-AND-FORGET.md · runnable examples/set-and-forget/
• Bad call to CI regression test, step by step: docs/BAD-CALL-TO-CI.md · runnable examples/bad-call-to-ci/
• What it measures (the three timing signals, re-derivable by hand): METHODOLOGY.md · Python API docs/API.md
• The fix ladder (each failure names a likely fix class; when the evidence maps cleanly to stack config, Hotato names the setting family and direction): docs/FIX-PLANS.md
• Rule out the non-turn-taking bugs first (STT, buffering, verbosity, refusals, wrong-language): docs/WHY.md
• Pull a call from your stack (Vapi, Twilio, Retell, LiveKit, Pipecat): adapters/README.md · status docs/ADAPTER-STATUS.md
• CI gates: GitHub Action docs/CI.md · pytest plugin docs/PYTEST.md
• Recorded-call battery: 12 scripted calls against a live voice agent on its provider's default settings, where a missed interruption and a false stop on a backchannel fail in the same run, so diagnose refuses to name one threshold: corpus/vapi-defaults/README.md
• Failure contracts and traces: turn a labelled candidate into a portable, CI-verified bundle and attach observability evidence: docs/CONTRACTS.md · docs/TRACE.md · docs/OTEL.md
• Proving the CURRENT agent, not just the frozen recording: the recapture walkthrough: docs/RECAPTURE.md
• Egress: a per-command network table derived from the code -- what's local, what reaches your vendor, what optional extras add a hosted call: docs/EGRESS.md
• Root-cause evidence and a before/after fix trial: hotato explain turns a failing result into root-cause-by-layer evidence, and hotato fix trial tests a candidate change before/after, fail-closed: docs/EXPLAIN.md · docs/FIX-TRIAL.md · docs/APPLY.md · docs/FIX-LOOP.md
• Evidence: what Hotato validates, the input-condition trust matrix, every card and CLI block reproducible, and where Hotato does and doesn't fit next to Hamming/Cekura/Coval/Bluejay/Roark/Vapi/Retell: docs/VALIDATION.md · docs/TRUST-MATRIX.md · docs/GALLERY.md · docs/EVIDENCE-PACK.md · docs/COMPARE.md
• For coding agents: AGENTS.md · llms.txt · llms-full.txt · MCP server docs/MCP.md · Security SECURITY.md
• Contributing: the highest-value PR is a labelled call fixture: docs/SUBMITTING.md

Why "hotato": good turn-taking is a game of hot potato. Speak, then pass the turn the moment the caller wants it. MIT licensed (LICENSE); the open core stays open.

mcp-name: io.github.attenlabs/hotato