mixer_set_return

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

Annotations already declare readOnly=false, idempotent=true, destructive=false, so the safety profile is covered. The description adds one genuinely useful trait not in the annotations — 'Undoable' — but says nothing about prerequisites (does the return bus need to exist?), how out-of-range values are handled, or how it relates to mixer_get.

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?

Two short fragments with zero waste, but the terseness tips into under-specification rather than crispness — a missing verb and missing object ('Fader of a return bus in dB' is not a sentence).

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 mutation tool that changes audio levels, the description omits what the return bus is in this session model, whether the bus must already exist, and the audible consequence of the wide -200..6 dB range. Annotations cover reversibility, but the core operational context is thin.

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%, with both 'bus' and 'volume_db' documented including min/max ranges, so the baseline is 3. The description restates 'return bus' and 'dB' without adding units, defaults, or the -200..6 dB range implications.

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?

The fragment names the resource (a return bus) and the quantity (fader in dB), so an agent can infer it sets a return bus level. But there is no verb and no differentiation from siblings such as mixer_set_send or mixer_set_master, which also set levels in dB.

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 guidance on when to use this versus mixer_set_send (per-track sends), mixer_set_master (master fader), or mixer_add_return. The agent must infer the distinction from the tool name alone.

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