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

Annotations already establish this as a safe, idempotent read. The description adds real context: results are relevance-ordered ('best first'), and each result carries an id, description, install command or purchase location, and a live-preview page. The key matching rule ('every word of the query has to be in a block's name, title, description or registry') is behavior an agent cannot infer elsewhere.

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 paragraph is dense and front-loaded: what it searches, then when to use, then result shape, then query constraints. The enumerated section examples (heroes, pricing tables, login forms, dashboards, footers, FAQs) partly duplicate the category enum, which is the one stretch that does not fully earn 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 takes on the burden of describing return contents, and it does: ordering, id, description, install command versus where to buy, and preview page. Combined with the explicit query-matching rule and the six fully documented parameters, an agent can call this correctly on the first try.

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. The description still contributes the AND-matching semantics of query and the advice to use 'one or two words, and the category for the kind of section', which meaningfully changes how an agent should combine query with category.

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?

A specific verb plus resource, with the resource itself defined: 'ready-made sections of a page' from 'every public shadcn registry, free and paid'. It also implicitly distinguishes itself from siblings by naming the block id '(for get_block)' and pointing to the category/registry fields.

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 it when the user is building a page or a screen with shadcn/ui and wants a section to start from, or asks what blocks exist for something' gives a clear trigger condition. The split from get_block (detail lookup) and list_categories/list_registries (enumeration) is only implied through field references rather than stated as an alternative, so it falls short of a 5.

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