Source: https://guthlabs.ai/docs/instruments/bpm-tap-tempo/implementation/

instrument implementation / implementation-contract

# BPM Tap Tempo implementation

A source-bound implementation contract for BPM Tap Tempo; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t4-073

**Effect**: Computation or source lookup only

## Input and validation requirements

Coincident timestamps produce a zero denominator and therefore an undefined BPM, with no specified rejection behavior. The specification also leaves timestamp units and handling of out-of-order taps insufficiently defined, allowing materially different outputs.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "timestamps": [
      1000,
      1500,
      2000,
      2500
    ],
    "timestamp_unit": "ms"
  },
  "expected_outputs": {
    "BPM": 120
  },
  "working": "Intervals: 1500-1000=500 ms, 2000-1500=500 ms, 2500-2000=500 ms. Average interval=(500+500+500)/3=1500/3=500 ms. BPM=60000/500=120 BPM."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/bpm-tap-tempo/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/bpm-tap-tempo/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/bpm-tap-tempo/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche4/tranche4-results.json`