update_instrument

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

This goes beyond the annotations (readOnlyHint=false, destructiveHint=false, openWorldHint=false) by disclosing a cross-entity side effect — every pattern using the instrument changes — and a real data-loss hazard when switching to a drumkit. That is exactly the kind of consequence hints cannot express. It is docked one point for not saying whether the change is reversible (an undo sibling exists) or what happens when only the instrument index is supplied with no settings.

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?

Three short sentences, zero filler, and the edit's scope is front-loaded before the caveats. Each sentence carries distinct information: action, blast radius, failure mode.

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 5-parameter mutation tool with full schema descriptions, no output schema, and existing annotations, this covers what changes, what else it affects, and the main hazard. Only the reversibility question and the no-op case (instrument index alone) are left open.

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 100%, so the baseline is 3; each parameter already carries a range, default, and cross-reference to list_voices. The description's "voice or settings" loosely maps to voice/cutoff/volume/resonance but adds no format, default, or interaction detail beyond the 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?

"Changes an instrument's voice or settings" pairs a specific verb with a specific resource and even names the mutable facets, so an agent knows this is a mutator on an existing instrument rather than a creator/remover. It stops short of explicitly distinguishing itself from siblings like add_instrument or update_pattern, but the model is unambiguous.

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?

Usage is implied rather than stated: the propagation and drumkit notes give context for what happens when you call it, but the description never says when to prefer this over update_pattern or add_instrument, nor that instrument (index) must identify an existing instrument. Useful signal, no explicit routing.

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