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

Annotations already assert readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds real context beyond that: the output is a link the user opens rather than an action performed here, and presets are applied "where possible" — clarifying that not every option maps to every 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?

Two sentences, zero filler; the return-value nature and the usage trigger are both front-loaded, and the examples are compact.

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?

No output schema, but the description explains what comes back (a ready-to-open link) and how options are applied. With annotations covering the safety profile, enum-heavy params documented in the schema, and only one required parameter, nothing essential 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 description coverage is 80% and already labels bpm/beats/frequency/instrument as tool-specific, so baseline is 3. The description adds the presetting model (tool + its applicable options become pre-configured state), which helps an agent understand why options are conditional on the tool enum.

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+resource: returns a ready-to-open link to a MusoKit tool, with examples of preset behavior (tuner for an instrument, metronome at a tempo, tone at a frequency). It implicitly separates itself from the informational siblings (chord_info, scale_info, bpm_to_ms) but never names them explicitly.

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?

"Use when the user needs to actually tune, keep time or hear something" gives a clear triggering condition and implicitly contrasts with the lookup/calculation siblings, which only supply information rather than a usable tool. No explicit when-not or named alternatives.

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