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TypeScript

Remote

Estimate tempo from taps or a BPM

estimate_tempo

Read-onlyIdempotent

Estimate BPM from tap timestamps with a steadiness spread, or convert a known tempo to beat and 4/4 bar lengths in milliseconds for cutting edits on the beat.

Instructions

Tempo arithmetic for editing to music: pass tap timestamps (ms) to estimate BPM, with a spread figure that shows how steady the taps were, or pass a known bpm to get the beat and 4/4 bar length in ms for cutting on the beat. It works on numbers you supply and does not analyse audio. Taps more than 2.5 s apart restart the count, and outlier intervals (a missed or doubled tap) are discarded. Errors when neither input is given, fewer than two usable taps remain, or bpm is outside 20-400.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "estimate_tempo"
  }
}

Input Schema

Name	Required	Description	Default
`bpm`	No	Known tempo in beats per minute. Used instead of the estimate when both are given.
`timestampsMs`	No	Tap times in ms from a monotonic clock (performance.now()), in order.

Output Schema

Name	Required	Description	Default
`bpm`	Yes
`barMs4_4`	Yes
`estimate`	Yes
`quarterNoteMs`	Yes
`referenceToolUrl`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed7 schema fields changedv1.0.0Oct 24, 2026

addedInput schema / additionalProperties
```
Added value: +false
```

changedInput schema / properties / bpm / description

Previous value: -"Optional known BPM to calculate quarter-note beat duration in ms."New value: +"Known tempo in beats per minute. Used instead of the estimate when both are given."

addedInput schema / properties / bpm / maximum
```
Added value: +400
```
addedInput schema / properties / bpm / minimum
```
Added value: +20
```

changedInput schema / properties / timestampsMs / description

Previous value: -"Optional list of monotonic tap timestamps in milliseconds."New value: +"Tap times in ms from a monotonic clock (performance.now()), in order."

addedInput schema / properties / timestampsMs / minItems
```
Added value: +2
```

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "barMs4_4": {
+      "type": "number"
+    },
+    "bpm": {
+      "type": "number"
+    },
+    "estimate": {
+      "anyOf": [
+        {
+          "properties": {
+            "bpm": {
+              "type": "number"
+            },
+            "discarded": {
+              "type": "integer"
+            },
+            "spreadMs": {
+              "type": "number"
+            },
+            "taps": {
+              "type": "integer"
+            }
+          },
+          "required": [
+            "bpm",
+            "taps",
+            "spreadMs",
+            "discarded"
+          ],
+          "type": "object"
+        },
+        {
+          "type": "null"
+        }
+      ]
+    },
+    "quarterNoteMs": {
+      "type": "number"
+    },
+    "referenceToolUrl": {
+      "type": "string"
+    }
+  },
+  "required": [
+    "estimate",
+    "bpm",
+    "quarterNoteMs",
+    "barMs4_4",
+    "referenceToolUrl"
+  ],
+  "type": "object"
+}

First observedv0.3.0Oct 23, 2026

TDQS

A4.7/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds real behavioral detail beyond them: a 2.5 s gap restarts the tap count, outlier intervals from missed or doubled taps are discarded, and the exact error conditions (no input, fewer than two usable taps, bpm outside 20-400). The 'spread figure' also discloses what the estimate reports about tap steadiness.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tight sentences, front-loaded with the tool's purpose and the two usage modes, then the edge-case rules, then errors. Every clause carries information an agent would otherwise have to guess at.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need not be enumerated, yet the description still tells the agent what the outputs mean (spread = tap steadiness, bar length for cutting on the beat). Combined with the disclosed restart rule and error cases, an agent has everything needed to call it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3; the description earns above that by explaining what each mode yields (BPM plus spread vs. beat and bar length in ms) rather than just restating the field names. It leaves the precise formula and spread units implicit, which keeps it just short of a 5.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource ('Tempo arithmetic') and immediately distinguishes its two input modes: tap timestamps to BPM, or a known bpm to beat/4-4 bar length in ms. This is clearly differentiated from every sibling (aspect ratios, bitrate, safe area, subtitles), none of which overlap.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly says which input to pass for which outcome and notes that it works on supplied numbers rather than audio, which heads off a plausible misuse. It does not name an alternative tool, but no sibling is a real substitute, so the omission is minor rather than a gap.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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