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

With no annotations provided, the description carries the full burden of disclosing behavior. It explains the conditional behavior (no filter → category tree with counts; filter → filtered slice), which is meaningful context beyond what the schema alone conveys. It doesn't explicitly state read-only, but 'Return' and 'browsing' strongly imply a non-destructive operation.

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 sentences with no wasted words. The first sentence front-loads the core behavior, the second clarifies use cases, and the third names the alternative. Every sentence 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?

There is no output schema and no annotations, but the description gives enough context for an agent to select and invoke the tool correctly: it covers the main output shapes (filtered slice vs. category tree with counts) and points to the sibling for product-specific searches. It could mention return-field details or explicit read-only status, but for a browsing tool this is largely sufficient.

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 description coverage is 100%, so the schema already documents all four parameters. The description adds only the high-level 'no filter' vs 'filter' distinction, which does not exceed what the schema implies. Baseline 3 is appropriate because the schema carries the parameter documentation burden.

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 states a specific verb ('Return') and a clear resource ('catalogue') with two well-defined modes: a filtered slice or, with no filter, the full category tree with counts. It also explicitly contrasts with search_products, which helps an agent distinguish it from a sibling tool without opening schemas.

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 description explicitly says when to use this tool ('for browsing and for questions about the catalogue's shape and size') and when not to ('Use search_products when the request names specific products'). This gives the agent concrete routing criteria rather than leaving inference up to it.

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