Zeltor Labs MCP server

• Registry namecom.zeltorlabs/music-toolsverified in the MCP registry

The registry name sits under zeltorlabs.com. The registry only lets a publisher use that namespace after proving control of the domain through DNS or HTTP.

• Stateanswerschecked 2026-10-31
• Tools6
• Server calls itselfzeltor-music-tools
• Server version1.1.0
• Protocol version2025-06-18

On 2026-10-31 the server answered initialize and tools/list without a sign-in. First answer in 125 ms.

• Its tools do check whether two songs share a key and tempo; find the tempo or key change needed to mix two tracks, but not preview a mashup before opening it in a DAW.
• Checked on 5 of the 7 days it takes to judge reliability.

Said by rules from the measurements above. The likely first call is a model's pick from the tool list; read its description before relying on it.

• INITE MCP scoreafter a weeka score needs 7 daily checks: 5 so far
• What an agent can do with it2 of 3 use cases
• Answeredmeasuring5 of the 7 daily checks it takes to print a share
• Median first answer241 ms
• Space in an agent's context≈ 1,047 tokensthe definitions of all its tools (6), which an agent carries on every turn
• Tool definitionsA · 100 of 100
• Typed results0 of 6 toolsdeclared outputSchema: results come typed, read once

• Every tool passes all six checks.

A program checks the server once a day: initialize and tools/list, no model. Tokens are the definitions' length at about four characters a token. The grade averages six checks of every tool's name, description, schema and annotations; it says how well the tools are described, not whether they work. The score weighs what was measured and nothing else: answering (25%), doing the product's job (25%), definitions (20%), context (10%), use (10%) and how readily a client connects (10%). A part that was not measured is left out, and a hidden instruction caps the score at 40. The state of vendors' MCP servers: method and numbers →

• check_mix

  Decides whether two songs will mix well, from their keys and BPMs, using the Camelot wheel and DJ tempo limits (about 3% sounds natural, up to about 16% is usable, half and double time count). Returns a verdict, the tempo change in…

• camelot

  Gives the Camelot wheel code for a key and the three other keys that mix cleanly with it (one step either way with the same letter, and the relative major or minor).

• tempo_change

  Percent change and playback rate to go from one BPM to another, how noticeable it will sound, the pitch change if it is not time-stretched, and the half and double time of the target.

• speed_pitch

  For a nightcore (faster and higher) or slowed (slower and lower) version: the pitch change in semitones for a speed, the new BPM if given, and typical settings. Defaults: nightcore 1.25x, slowed 0.80x.

• transpose

  Moves a key up or down by semitones and gives the new key name and Camelot code, with a note on how natural the shift will sound.

• song_report

  Reads the song DNA from a MusicMind report the person made on zeltorlabs.com and shared: key and Camelot code with the keys that mix with it, BPM, genre mix, section structure with energy, and production DNA (energy profile, mood…