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

Annotations already cover read-only, idempotent, and non-destructive behavior, so the bar is lower. The description still adds useful context beyond them: the result ordering by block count and the fact that free/paid counts and a page URL are included per registry.

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, both doing work: the first packs purpose, ordering, and return contents; the second routes to the sibling tool. Slightly dense but front-loaded and free of filler.

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 compensates by enumerating the returned fields, and annotations carry the safety profile. Only minor gaps remain, such as whether there is a cap on the number of registries returned.

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?

There is only one optional parameter and the schema documents it at 100% coverage, including examples ('dashboard or animated'). The description itself never mentions the query filter, so it adds nothing over the schema; baseline 3 is appropriate.

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 and resource ('List the public shadcn/ui registries'), plus the ordering ('most blocks first') and the fields returned (free/paid counts, description, page). This clearly separates it from sibling search_blocks, which it explicitly names.

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 an explicit routing rule: pass a registry id to search_blocks to scope a search to that registry. It establishes the discover-then-search workflow without stating an explicit 'do not use this when…' exclusion, so it falls just short of a full 5.

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