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

Annotations already establish read-only, idempotent, closed-world behavior, and the description adds quota mechanics the annotations cannot express: free layers unlimited, premium layers counted once per UTC day with per-tier caps (1/3/30/none) and a same-day re-fetch being free. It does not clarify the returned medium (raw text vs structured), but the quota disclosure is significant context an agent needs before spending a daily credit.

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 sentences, front-loaded with what the tool returns, then the directive ('Follow it as the build brief'), then the cost rules. The long quota sentence is dense but every clause carries a distinct, actionable constraint.

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 100% schema coverage and no output schema, the remaining burden is return-shape and cost semantics; the description covers the cost side thoroughly and implies a text prompt deliverable via 'the full prompt' and 'follow it as the build brief'. Slightly more on the return format would make it complete.

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, and the description adds real value beyond it: it characterizes palette as covering templates, sections, pages, elements and gradients, and variant as covering 3D scenes, backgrounds and vectors, and frames them as an 'or' choice between two families. That classification is absent from the schema and disambiguates the two integer parameters.

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 resource (the full build prompt for a layer) and enumerates what it spans (framework, palette families, variant families), so an agent knows it returns a build brief rather than layer metadata. It does not explicitly name get_layer as the contrasting sibling, leaving that distinction to be inferred from the schema's 'from get_layer' references.

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?

'Follow it as the build brief' implies the intended downstream use, and the quota paragraph helps an agent decide whether to re-fetch. However, there is no explicit statement of when to call this versus get_layer (metadata) or how to pick target/palette/variant sequences; usage is implied rather than prescribed.

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