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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful context by enumerating the returned data fields, which is valuable beyond the annotations. It does not disclose behavioral details like pagination behavior, result-limit defaults, or how partial matches are handled, but with the safety profile fully covered by annotations, a 3 is appropriate.

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 economical sentences. The first front-loads the action and search scope; the second enumerates return fields. No filler, no repetition of schema content, and every clause adds information an agent needs.

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?

Strongly complete for a search tool: it covers what can be searched, what is returned, and an output schema exists so return structures need no further explanation. Minor gaps remain — no guidance on combining query with application_number, and no note on result-limit behavior — but these are covered partly by the schema, so they only mildly detract from completeness.

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 all four parameters (limit, query, application_number, include_discontinued) are already documented in the schema. The description's 'ingredient, trade name, applicant, or application number' loosely maps to query and application_number but adds no new format or usage detail beyond what the schema states (including the substring vs exact-match distinction already present in the schema). Baseline 3 applies.

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 ('Search'), a specific resource ('FDA Orange Book products'), enumerates the search keys (ingredient, trade name, applicant, application number), and lists the returned fields (NDA/ANDA status, TE codes, RLD/reference-standard flags, etc.). This clearly distinguishes it from siblings like orange_book_application_detail and purple_book_product_search, since the Orange Book scope and search-oriented behavior are explicit.

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 phrase 'Search FDA Orange Book products by...' implies when to use it, and the Orange Book vs Purple Book scope in sibling names gives natural context. However, there is no explicit when-to-use vs alternatives guidance (e.g., when to prefer orange_book_application_detail for a single application, or purple_book_product_search for biologics), and no mention that this is the general-purpose entry point versus the more specialized orange_book_* siblings.

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