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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false). The description adds real behavioral context beyond that: the data is measured from the LIVE DOM rather than guessed, and it discloses fallback behavior ('returns the available component types if the requested one isn't found').

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?

Front-loaded with the core purpose, then the use case, then the caveat. The long enumerated field list is informative rather than filler, though it makes the middle sentence dense; every sentence still 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?

With no output schema, the description carries the return burden and does so (anatomy fields, image_url, design tokens), and it covers the not-found error path. Complete enough to call correctly, though parameter value formats remain unspecified.

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 0%, so the description must compensate, and the example get_component('Linear', 'Button') maps positionally to site='Linear' (a product name) and component_type='Button', clarifying both required params' expected values. It still doesn't define what forms 'site' accepts (name vs domain) or list valid component_type values.

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 ('Get one product's UI component fully specified') and enumerates exactly what comes back (anatomy from the live DOM, image_url, design tokens). It is clearly about a single component, which separates it from get_screen/get_section, though it never explicitly names a sibling to contrast against.

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?

Gives a concrete trigger use case ('build a <component> like <product>') plus an example invocation, so the agent knows when to reach for it. It stops short of naming alternatives or stating when-not-to-use (e.g., versus get_design_system or compare_components).

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