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

Annotations already declare readOnlyHint=true and idempotentHint=true, and the description adds value by specifying the return fields (license number, company name, full address, establishment type, divisions, subsidiaries) and the covered facility types. This goes beyond what annotations alone provide, though it doesn't mention rate limits or pagination behavior.

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 description is three sentences: the first states the purpose and filters, the second lists the return fields, and the third covers scope and a related tool. Every sentence earns its place with no redundancy or 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 return fields, which is crucial for an agent to know what to expect. It also defines the domain (vaccine manufacturers, diagnostic kit producers) and links to a related tool. The main gap is not specifying geographic coverage or data provenance, but overall it is sufficiently complete for a search tool with optional filters.

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?

The input schema has 100% description coverage, with each parameter clearly documented (e.g., 'Company name (fuzzy search)', 'State code (e.g., CA, NY)'). The description merely references 'company, state, or establishment type' without adding any new syntax or format details, so the baseline of 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?

The description clearly states the tool's function: 'Search APHIS veterinary biologics establishments' with specific filters (company, state, establishment type). It distinguishes from siblings by focusing on this niche domain and lists relevant facility categories (vaccine manufacturers, diagnostic kit producers), leaving no ambiguity.

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 provides clear context: it searches establishments, not adverse events, and explicitly names a related tool (fda_vet_events) for the latter. However, it does not explicitly exclude other search tools like fda_search_facilities or provide when/when-not guidance, so it falls 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.