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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds context annotations cannot: contact happens on honestdog.de and never through this tool, the returned fields are listed, and there is a special Qualzucht caution-instead-of-results behavior. That is exactly the kind of non-obvious behavior an agent needs.

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 a clear 'Use when...' clause, which is good, but the trailing German sentence largely restates the English content and inflates length for an agent-facing tool. The return-value list is useful, yet the overall text could shed the duplication.

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 (kennel name, photo, city/region/country, score, profile URL) and explains contact flow and the Qualzucht edge case. Nothing an agent needs to call or interpret this tool correctly is missing.

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 75% and the description adds genuinely new semantics the schema lacks: breed_slug accepts only exact breeds (crosses like Labradoodle are not listed under a parent breed) and state uses German spelling with English names mapped. The limit parameter gets no mention, and the state/city spelling guidance largely duplicates the schema, so it falls slightly short of 5.

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 ('Searches HonestDog's directory of vetted, APPROVED dog breeders') and immediately distinguishes itself from siblings by naming search_breeds as the source of the breed slug and contrasting with shelter adoption implicitly. The geographic scope (Germany/Austria/other Europe) further sharpens what this tool is versus a generic search.

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 concrete when-to-use triggers with real example queries in two languages. However, it never explicitly names an alternative to route to (e.g. search_shelter_dogs for adoption) or states when NOT to use it, so the routing guidance stops just short of the top score.

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