set_mixer

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

Annotations already declare write/idempotent/non-destructive, so the bar is lower. The description adds genuinely useful behavior beyond that: it returns the resulting mixer state (no output schema exists), notes 'solo is not exclusive', and flags which params are master-only. It does not contradict any annotation.

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?

Front-loads the purpose, then provides a dense but well-ordered parameter reference, ending with a concrete example. The block is long but every clause earns its place given the 0% schema coverage; only minor structural improvement (e.g., explicit list formatting) is missing.

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 14-parameter mutation with no output schema and no schema-level parameter descriptions, the definition covers the target, all value formats, master-only constraints, and the return behavior. Nothing an agent needs to call it correctly is missing.

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 coverage is 0%, so the description carries the full burden and does so well: it specifies ranges and formats for volume_db ('up to +6', '-inf'), volume (raw 0..1), pan ('-1..1' or '25L'/'C'/'50R'), sends syntax, crossfade values ('A'/'none'/'B'), pan_mode, and the master-only crossfader/cue_volume_db. This is meaning no agent could derive from the bare schema.

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 and resource ('Set a track's mixer') plus scope ('in one call') and return behavior ('get the resulting mixer state back'). This clearly distinguishes it from the sibling get_mixer, which only reads state.

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?

The phrase 'in one call' implies batching for efficiency and the example shows a concrete invocation, but the description never explicitly says when to use this versus get_mixer or set_track, nor any when-not conditions. Usage is implied rather than stated.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.