MIDIRestyle

Or just ask — MIDIRestyle speaks MCP

The same .exe doubles as a Model Context Protocol server. Point Claude — or any MCP client — at it, and your agent can search the scale library, read your MIDI, restyle it and export the result. Nothing extra to install, and your files never leave your machine.

Three lines in claude_desktop_config.json:

{ "mcpServers": {
  "midirestyle": { "command": "C:\\Tools\\MIDIRestyle.exe", "args": ["--mcp"] }
} }

Or one line in Claude Code:

claude mcp add midirestyle -- "C:\Tools\MIDIRestyle.exe" --mcp

Help ▸ Agent access (MCP)… inside the app shows both snippets with this exe's real path already filled in — worth using, because a portable exe can live anywhere and be renamed.

An agent host spawns the server; you never run --mcp by hand. It speaks over stdin/stdout only — no window, no network, no second copy of the app installed.

You — take ballad_sketch.mid and try it in a few Middle Eastern styles. Keep whichever one holds the melody's shape best.

inspect_midi   ballad_sketch.mid          →  148 notes · D minor · 72 bpm · 4 tracks
list_scales    query: "maqam"             →  16 scales
describe_scale middleeast.arabic.maqam-rast  →  7 degrees · ±50¢ from 12-TET · 2 bend clusters
restyle_midi   → Maqam Rast               →  ballad_sketch.middleeast.arabic.maqam-rast.mid
restyle_midi   → Maqam Hijaz              →  ballad_sketch.middleeast.arabic.maqam-hijaz-notated.mid

Agent — Hijaz is the one: its lowered 2nd lands right on your hook, and the descending motif in bars 5–8 survives intact. Rast smoothed it out too much. Written with per-channel pitch bend, so the tuning holds up in your DAW.

The tools it exposes

Tool	What it does
inspect_midi	Tracks, notes, tempo, time signature and the detected key of a file on disk, as structured data.
list_scales	Browse and filter all 171 scales — by tradition, degree count, whether they notate, how far they sit from 12-TET.
describe_scale	One scale in detail: degrees in cents, its spelling, its deviation, and what it will cost in MIDI channels.
restyle_midi	Runs the desktop app's own pipeline and writes the restyled .mid, pitch bend included.
export_musicxml	Writes notation, for scales that can honestly be spelled on a staff.

Plus a choose_a_style prompt that walks a user to a scale one question at a time.

Every path passed to the tools must be absolute. Outputs default to <input>.<scale-id>.mid beside the input, and an existing file is never overwritten unless overwrite is true.

How it works

Three steps, no theory homework.

01 · Drop in a MIDI file — anything you already have: a sketch, a stem, a full arrangement. MIDIRestyle reads the tracks, detects the key, and shows you what it found.

02 · Choose the target style — search the library by name or tradition: maqam, melakarta, gamelan, wǔshēng, koto tunings, the church modes. Arrow-key down the list and the transform re-runs per keystroke.

03 · Hear it converted — play it back in the app, switch between original and restyled on the fly, then keep it, tweak it, or try another.

What's in it

More than a converter — somewhere to look at the result.

• Piano roll and staff view — see the file as a piano roll with a keyboard and bar ruler, or as wrapped systems of real engraved notation with a playhead that follows playback. Click the staff to seek.
• Scale wheel — the degree view lays the scale out as a wheel, with degrees at their true cents angle against the twelve equal-tempered ticks. That gap is the whole point: Maqam Rast's neutral third sits visibly between a major and a minor one. Its furniture stays put while playback recolours it, so you can watch which degrees the music actually leans on.
• A/B the original — switch between the source and the restyled version mid-playback, without leaving for a DAW.
• Microtonal-accurate export — scales that don't sit on 12-TET (maqam, dastgāh, slendro, pelog, Thai 7-equal) are exported with per-channel pitch bend, one channel per distinct cent-offset rather than per voice, so the tuning survives the round trip. Preview and exported file come out of the same code path and can't disagree.
• MIDI and MusicXML out — save the result as a MIDI file, or export MusicXML to carry the notation into Sibelius, MuseScore or Dorico.
• Portable and private — one self-contained .exe. No installer, no account, no upload. Copy it to a USB stick and run it.

Restyling is pitch remapping only — it never touches rhythm, ornamentation or articulation.

The scale library

171 scales ship with the app, grouped by tradition:

Tradition	Scales	A few of them
South Asia	82	The ten thaats, plus all 72 Carnatic melakarta — generated from the Ri/Ga, Dha/Ni and Ma positions rather than hand-typed
Middle East	16	Maqam Rast, Bayati, Hijaz, Saba — in quarter-tone notated and just-intonation tunings
Türkiye	15	Makam Rast, Uşşak, Hüseyni, Buselik (AEU)
East Asia	13	Gong, Shang, Jiao, Zhi, Yu (wǔshēng); Japanese in, yō, hirajōshi, iwato, kumoi; Korean p'yŏngjo, kyemyŏnjo
Europe	12	The seven church modes, harmonic and melodic minor, double harmonic, Hungarian minor, Ukrainian Dorian
Southeast Asia	11	Slendro and pelog as measured from named gamelan, plus Thai 7-tone, idealised and measured
Persia	10	Dastgāh-e Shur, Homāyun, Māhur and others, on Farhat's intervals
Africa	9	Ethiopian kiñit (tizita, bati, ambassel, anchihoye), equiheptatonic, equipentatonic, bow-music overtones
Americas	3	Blues hexatonic, minor and major pentatonic

Every hand-authored scale carries a source citation, and a test fails the build if one is missing — wrong cents values make a wrong app, and that is not the kind of error a mechanical test would ever catch. You can also author your own in the scale editor, or bring in Scala .scl files.

Getting it

Download MIDIRestyle.exe from the latest release — a single self-contained file, 51.2 MB, Windows x64, no installer. Copy it anywhere (including a USB stick) and run it.

Settings and the writable scale library live in a scales/ folder written beside the exe on first run, falling back to %APPDATA% when that location isn't writable (a read-only stick, Program Files). Setting MIDIRESTYLE_DATA_ROOT to an absolute path overrides both.

Building from source

Requires the .NET 10 SDK (pinned in global.json).

dotnet build                                    # whole solution
dotnet test                                     # all tests - do NOT add --nologo, see below
dotnet run --project src/MidiRestyle.App        # launch the app

A single test or class:

dotnet test --filter "FullyQualifiedName~ChannelAllocatorTests"
dotnet test --filter "FullyQualifiedName~ChannelAllocatorTests.RastAllocatesTwoChannels"

Never pass --nologo to dotnet test. The .NET 10 SDK forwards unrecognised arguments to the underlying test application, which rejects the flag and reports "Zero tests ran" even when every test passed. If dotnet test ever reports zero, read the per-assembly Standard output: block — that's where the real error is.

The portable release

dotnet publish src/MidiRestyle.App -c Release -r win-x64 --self-contained true `
  -p:PublishSingleFile=true `
  -p:IncludeNativeLibrariesForSelfExtract=true `
  -p:EnableCompressionInSingleFile=true

The publish folder must end up holding exactly one file — that's the whole portability promise. This is enforced automatically: a gate built into MidiRestyle.App.csproj runs after every publish and fails the build loudly if a second file shows up (a stray native library, a debug symbol, anything). It caught a real bug during development — see the csproj comments for the mechanism, and CLAUDE.md for the full history.

Project status

v1 is complete, with five releases on top of it. All twelve build phases are done — the domain model, the 171-scale library, key detection, the restyle engine, channel allocation for microtonal export, audio playback with an A/B switch, and the portable single-file publish — as are the three features v1 deferred: MusicXML export, the staff view and the degree view.

Since then: v1.2 rebuilt the notation as a wrapped page of systems with a following playhead and turned the degree view into a scale wheel; v1.3 added click-to-seek on the staff and real clef and rest glyph outlines; v1.4 added the About window and bundled the third-party licence notices; v1.5 put bar counts in the file pane, a keyboard and a bar ruler on the piano roll, and rebuilt the degree wheel so its furniture stays put and playback only recolours it; and v1.6 added the embedded MCP server, so the same exe can be driven by an agent.

Last verified green at v1.6.0: 1572 tests, 0 warnings, and a portable publish of exactly one 51.2 MB file.

Where the real documentation lives

This README is the shop window. For anything deeper:

• .claude/plan/PLAN-midi-restyle.md — the authoritative spec
• .claude/STRUCTURE.md — map of the repository layout
• .claude/PROGRESS.md — phase-by-phase implementation state and handover notes
• CLAUDE.md — architecture and the load-bearing invariants behind the design

Licence

MIDIRestyle is released under the MIT License.

The shipped .exe is self-contained, so it also redistributes its dependencies and the .NET runtime. Their licences and copyright notices are reproduced in full in THIRD-PARTY-NOTICES.txt — MIT for most of them, BSD for ANGLE and Skia, and the SIL Open Font License for the Inter typeface, which requires that its licence be distributed along with the font.

That last requirement is why the notices are embedded in the executable as well as published here. A single-file build leaves no room for a companion file beside the .exe, so the text travels inside it and can be read from About → third-party notices; a copied .exe carries its notices with it.