instruments_list

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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered. The description adds useful return-shape context: builtins are listed first, plugins appear in a 'Plugin' group with vendor and format, and each entry carries name/family/URI. It says nothing about output format, ordering guarantees beyond 'after the builtins', or how missing plugins are handled, which is the remaining gap for an annotation-covered read tool.

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 core purpose is buried mid-sentence behind 'Instruments that tracks.create can load', and the plugin clause is tacked on with a semicolon. The family taxonomy is long, though it earns some of its space by helping the agent pick instruments; a leading 'List all loadable instruments' would have front-loaded the meaning.

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?

With zero parameters, no output schema, and annotations covering safety, the description's job is to convey the return shape, which it does: builtin entries with name/family/URI, plus a Plugin group with vendor/format, and the family taxonomy. What's missing is only format specifics (e.g., exact URI scheme) that the agent can't infer.

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?

The tool takes no parameters, so there is nothing to disambiguate and the 4 baseline applies. The description helpfully explains that the 'instrument' URI it returns is what the agent should pass to tracks.create, which connects the output to downstream parameter usage.

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 description identifies the resource (instruments loadable via tracks.create) and the fields returned (name, family, URI used as the 'instrument' argument), which makes the tool's function inferable. It never states a verb like 'list', and leads with a purpose clause rather than an action, so the purpose is clear but not stated crisply.

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?

Referencing 'the URI to pass as instrument' and tracks.create implies the use case: call this before creating a track. However, it never explicitly says 'use before tracks_create' nor distinguishes this from instruments_presets / instruments_load_preset, which is the most likely sibling confusion.

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