Set the global musical scale and root note in Ableton Live 12 so generated or edited MIDI follows the intended key.
Sets the global musical scale and root note in Ableton Live 12 (Song.scale_information). Root note is 0 for C, 1 for C#, ..., 11 for B.
| Name | Required | Description | Default |
|---|---|---|---|
| root_note | Yes | Pitch class integer for root note: 0=C, 1=C#, 2=D, 3=D#, 4=E, 5=F, 6=F#, 7=G, 8=G#, 9=A, 10=A#, 11=B. | |
| scale_name | Yes | Name of the musical scale. |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. It states that the scale is global and references Song.scale_information, but it does not say whether the operation overwrites existing scale data, how it affects existing clips, whether permissions or a loaded set are required, or what a successful call returns.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is two short sentences and front-loads the core purpose. The second sentence duplicates the root-note mapping already present in the schema and therefore does not fully earn its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple two-parameter setter, the description is minimally adequate: it names the resource, the global scope, and the backing LOM property. However, with no annotations and no output schema, it leaves behavioral gaps about mutation effects and prerequisites unaddressed.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so the schema already documents both parameters, including the full 0–11 root-note mapping and the scale_name enum. The description repeats the root-note mapping but adds no meaningful semantics beyond what the schema provides, making the baseline 3 appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb ('Sets') and resource ('global musical scale and root note') and anchors it to Ableton's Song.scale_information. It is clear what the tool does, but it does not explicitly distinguish itself from the related sibling live12_song_set_tuning_system.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No when-to-use guidance is given, and no alternative is named. An agent must infer that this tool is for setting the song's musical scale rather than for tuning systems, clip scales, or other related operations.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.