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set_mix

Idempotent

Adjust volume, pan, sends, mute, and solo on a single track in one request. Set absolute mixer values with optional parameters for quick, focused mixing changes.

Instructions

Set volume, pan, sends, mute and solo on one track in a single round trip.

Every argument is optional and only the ones given are written, so this is the
cheap way to change several mixer controls at once. Read the current state with
get_track first, since the values here are absolute and not relative.

Returns:
    Dictionary reporting each write with its before and after value, and the dB
    display where Live offered one.

Note:
    Volume and pan are normalised, so 0.85 is 0 dB (measured) rather than 85 per
    cent of anything. Read ``display`` in the answer for Live's own dB reading
    instead of converting the normalised number yourself.

    The master track has no mute and no solo. Both are refused there rather than
    silently ignored, and ``track`` is not read at all when kind is master.

    This is the mixer only. For a knob on a device in the chain use
    set_parameter, and for the tempo use set_tempo. To make a mixer control move
    over time rather than jump, write an envelope with write_automation.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
panNoPan position from -1.0 hard left through 0.0 centre to 1.0 hard right. Omit to leave it alone.
kindNoWhich collection the track index counts in: 'track' for song.tracks, 'return' for song.return_tracks, 'master' for the master track, where the track index is ignored.track
muteNoTrue mutes the track, False unmutes it. Not supported on the master track. Omit to leave it alone.
soloNoTrue solos the track, which silences the others rather than changing anything on this one. Not supported on the master track. Omit to leave it alone.
sendsNoSend levels to write, keyed by send letter as Live labels it ('A', 'B') or by index as a string ('0', '1'), with normalised values 0.0 to 1.0. Only the sends named are written. Omit to leave every send alone.
trackYesTrack index in song.tracks, counted from 0.
volumeNoFader position, normalised 0.0 to 1.0, not decibels. 0.85 is 0 dB (measured) and the scale between is not linear, so 0.425 is not half the level. Omit to leave the fader alone.

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault

No arguments

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

  1. Changed8 schema fields changedv0.1.1
    • addedInput schema / properties / kind / description
      Added value: +"Which collection the track index counts in: 'track' for song.tracks, 'return' for song.return_tracks, 'master' for the master track, where the track index is ignored."
    • addedInput schema / properties / kind / enum
      Added value: +[
      +  "track",
      +  "return",
      +  "master"
      +]
    • addedInput schema / properties / mute / description
      Added value: +"True mutes the track, False unmutes it. Not supported on the master track. Omit to leave it alone."
    • addedInput schema / properties / pan / description
      Added value: +"Pan position from -1.0 hard left through 0.0 centre to 1.0 hard right. Omit to leave it alone."
    • addedInput schema / properties / sends / description
      Added value: +"Send levels to write, keyed by send letter as Live labels it ('A', 'B') or by index as a string ('0', '1'), with normalised values 0.0 to 1.0. Only the sends named are written. Omit to leave every send alone."
    • addedInput schema / properties / solo / description
      Added value: +"True solos the track, which silences the others rather than changing anything on this one. Not supported on the master track. Omit to leave it alone."
    • addedInput schema / properties / track / description
      Added value: +"Track index in song.tracks, counted from 0."
    • addedInput schema / properties / volume / description
      Added value: +"Fader position, normalised 0.0 to 1.0, not decibels. 0.85 is 0 dB (measured) and the scale between is not linear, so 0.425 is not half the level. Omit to leave the fader alone."
  2. First observedv0.1.0

TDQS

A4.8/5.0
Behavior5/5

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

Annotations declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false; the description adds meaningful context beyond these: master-track mute/solo 'are refused there rather than silently ignored,' 'track is not read at all when kind is master,' values are absolute rather than relative, volume/pan use a non-linear normalised scale ('0.85 is 0 dB (measured)'), and the return dictionary reports before/after values plus Live's dB display. The description is consistent with the annotations, so there is no contradiction.

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

Conciseness4/5

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

The description is front-loaded with purpose and core behavior, then returns, then normalization notes, then sibling routing. It is longer than average, but the tool genuinely has the complexity to justify it (7 parameters, normalization traps, master-track exceptions). The Note paragraph slightly overlaps the schema's volume description, though it earns its place by extending normalization context to pan and pointing at the display field.

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?

For a 7-parameter mutable mixer tool with an output schema and annotations present, nothing an agent needs is missing: prerequisites (get_track first), edge cases (master refusal, track ignored), exclusions (mute/solo unsupported), alternatives (set_parameter, set_tempo, write_automation), and return behavior are all covered. The output schema carries the detailed return structure.

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 description coverage is 100%, so the baseline is 3. The description adds genuine cross-parameter meaning beyond the schema: pan shares the same normalised 0.85=0 dB semantics as volume, the 'display' field in the answer is the authoritative dB reading rather than converting the normalised number, and master rejects mute/solo rather than silently ignoring them. This lifts it above the baseline.

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?

The opening sentence states a specific verb and resource: 'Set volume, pan, sends, mute and solo on one track in a single round trip.' It is scoped precisely to the mixer of one track and is immediately distinguishable from siblings like set_parameter, set_tempo, and get_track without opening their schemas.

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

Usage Guidelines5/5

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

The description explicitly tells the agent when to use this tool ('the cheap way to change several mixer controls at once'), states a prerequisite ('Read the current state with get_track first, since the values here are absolute and not relative'), and names alternatives with routing conditions: 'For a knob on a device in the chain use set_parameter, and for the tempo use set_tempo... write an envelope with write_automation.' Nothing is left to inference.

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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