list_styles

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

readOnlyHint=true already establishes this is a safe read, so the description's job is to add context — and it does, disclosing the return shape (numbered, grouped by purpose, includes a picture sheet). That is genuinely useful given there is no output schema. It does not mention size limits or whether styles can be filtered, but for a simple enumerator that is a minor gap.

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, no waste, and the behavioural intent ('show this when...') is front-loaded right after the content summary. Every clause earns its place.

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 zero-required-parameter read tool with no output schema, the description supplies the essential missing piece — what the result looks like. It could add pagination or scale hints if the style catalogue is large, but nothing needed to call it correctly is absent.

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?

With a single parameter at 100% schema description coverage, the baseline is 3. The phrase 'with a picture sheet' echoes the picture parameter's effect but does not explain that it is an optional toggle (default true) or why an agent might turn it off.

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 names the resource precisely — 'every look' — and characterises the output as a 'numbered menu ... grouped by purpose, with a picture sheet'. That distinguishes it from the singular sibling get_style without needing to name it. The verb is implied by 'menu' rather than stated, so it falls just short of a perfect verb+resource framing.

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?

It gives an explicit trigger: 'Show this when the user has not picked a look or asks what is available.' That covers the common ambiguous case well. It does not explicitly say to use get_style instead once a look is chosen, so the routing to the alternative is left to inference.

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