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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and a closed-world catalog, so safety needs no restating. The description adds real behavioral detail beyond them: fuzzy matching ('close matches') and a hard result ceiling of 8. It does not say what happens on zero matches or how matches are ranked.

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 short sentences with the purpose first, the result shape second, and the routing condition last. Every sentence carries distinct information, with only mild overlap between the stated 8-match ceiling and the schema's limit note.

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 only two simple, fully documented parameters, rich annotations, and an output schema that already describes the returned domain/name/logo URL, the description is nearly sufficient. The remaining gaps are the no-match behavior and result ordering, both minor for a read-only lookup.

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% and the schema already spells out the limit bounds, the catalog's 8-result cap, and the query format with an example. The only meaning the description adds is that matching is fuzzy as well as exact, which is a modest increment over an already self-documenting schema.

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 gives a specific verb and resource ('Find brands in the catalog') plus the match key ('by company name or domain') and the match mode ('exact and close matches'). It implicitly separates itself from get_logo/get_favicon via the last sentence, but never names those siblings, so the differentiation is inferred rather than stated.

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?

The closing sentence 'Use it when you know the name but not the domain' gives a genuine selection condition, and 'exact and close matches' tells the agent near-miss queries are acceptable. It stops short of explicitly naming get_logo as the alternative when the domain is already known, and says nothing about when not to use it.

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