OneSeq

Practical manual

Start making patterns in OneSeq

This manual covers the path that matters first: install, launch, choose a project, enter steps, edit sound, connect MIDI, and recover when a device or setting is off.

Install

Choose MSI or ZIP

  1. Download the MSI installer or the portable ZIP.
  2. Verify the file against SHA256SUMS.txt.
  3. Run the MSI to install to C:\Program Files\OneSeq, or extract the ZIP and run oneseq.exe.
Unsigned release: Windows may warn because this early build is not code-signed yet. Verify the checksum before installing.

First launch

New project or recall

On startup, OneSeq asks whether to create a new kit project or recall the last state. A new project starts with KICK, SNARE, HAT, CLAP, TOM, BASS, PLUCK, MIDI, and MASTER tracks. Recall is the hardware-style path for continuing where you stopped.

First pattern

Put sound on the grid

  1. Use Up/Down to select a track and Left/Right to select a step.
  2. Press Enter to toggle the step.
  3. Press Space to start or stop pattern playback.
  4. Use Ctrl+Up/Down to change pitch, Shift+Up/Down for velocity, and Ctrl+Left/Right for step length.
  5. Press Tab to enter parameter edit mode, then use number keys 1-8 and arrows to choose and edit parameters.

Core shortcuts

The first keys to remember

Key Action
SpaceToggle pattern playback.
Ctrl+SpaceToggle Song playback.
EnterToggle the selected Grid step, or lock the selected parameter in param edit mode.
TabToggle Grid parameter edit mode.
H heldShow help overlay.
T heldShow track operations.
O heldShow pattern operations.
R or N heldShow randomization overlays.
F12Open Project Launcher.

MIDI output

Send notes to external gear

  1. Open Config.
  2. Enable MIDI output and choose an output port.
  3. Use the C3 test-note action to confirm the port is reachable.
  4. Enable send per track and choose channel behavior: Auto maps track number to MIDI channel, or choose a fixed channel.
  5. Use a MIDI utility track when you want a track dedicated to external gear.

MIDI input

Use hardware as a control surface

  1. Open Config and enable the MIDI input monitor.
  2. Select the input port. Recent input should show notes, CCs, channel, and values.
  3. Choose a built-in profile or clone one into a custom profile.
  4. Use Learn latest when you want OneSeq to bind the last incoming MIDI control.
  5. Disable Control Surface Follow when you want hardware changes without auto-focusing the UI.

Device-specific setup is listed on the MIDI controller page.

MCP bridge

Enable agent-assisted live control

The OneSeq app does not need Python for normal use or for hosting the bridge. Python is needed only by the MCP stdio adapter used by Codex, MetaMCP, or another MCP client. That adapter uses Python 3 standard-library modules only: no pip install, virtualenv, Rust toolchain, or extra Python libraries are required.

  1. Open Config and enable MCP.
  2. Select the interface addresses the bridge should listen on. Use loopback for same-OS clients; use a private Windows LAN address when a WSL client must reach the Windows app.
  3. Choose a port if the default 41731 is already in use.
  4. For MCP logs, enable session logging and choose the logs folder. OneSeq does not pick a default log destination.
  5. Start your MCP client adapter after OneSeq is running. The adapter can read OneSeq's mcp_config.json token, while ONESEQ_MCP_CONFIG, ONESEQ_MCP_ENDPOINT, and ONESEQ_MCP_TOKEN may override config discovery for WSL/Windows or advanced setups.

Troubleshooting

Common fixes

Problem Check
No audio Check Windows output device, Config audio output, and whether Auto default-device follow is enabled.
MIDI input visible but not controlling Confirm the active profile, channel/source match, binding target, and Control Surface Follow preference.
MIDI output not sounding Confirm output port, track send enabled, MIDI channel, receiving device channel, and transport state.
Download blocked directly Open the download from the OneSeq page. Direct and external hotlinks are intentionally blocked.