Set a design choice directly

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

No annotations are provided, so the description carries the full burden. It thoroughly describes valid choiceIds and custom JSON formats, giving insight into expected behavior. However, it does not disclose side effects (e.g., whether it overwrites existing choices), reversibility, error handling, or return values, leaving some behavioral ambiguity.

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 description is long but information-dense, covering all necessary validity lists and usage context. It is front-loaded with purpose and use case. A bulleted format could improve scannability, but every sentence serves a functional purpose with no fluff.

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?

The description thoroughly covers input semantics, allowed values, and special cases, which is the core of correct invocation. However, it lacks information about return values or potential errors, which would help an agent verify success. For a setter tool this is a minor gap, but the complexity warrants that information.

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 only 25% (customValue has a description). The description compensates by enumerating all valid choiceIds for each category and providing detailed JSON structures for colors and layout, adding far more semantic meaning than the schema alone.

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 explicitly states it 'Sets one design category choice directly' and frames it as a fallback when the browser gallery cannot be used or the user stated a preference in chat, clearly distinguishing it from gallery-related sibling tools.

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 provides explicit when-to-use guidance: 'Fallback for when the browser gallery cannot be used (e.g. headless environment) or the USER stated their preference in chat.' This clearly defines the context and excludes other scenarios.

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