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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is known. The description adds a useful caveat that keyword search works only 'when available' in extracted text, but it does not disclose response shape or further behavioral constraints. No contradiction with annotations.

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 two sentences: the first states the core purpose, the second lists the facets available. It is front-loaded, concise, and every sentence contributes useful information without redundancy.

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 covers the data source and all major filter dimensions, including a caveat about keyword text availability. It does not explain pagination or return fields, but the schema already documents limit/offset and the search intent is clear, making it reasonably complete for a read-only search tool.

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% coverage with descriptions for all 8 parameters. The description restates the filter categories in natural language, but adds no semantic details beyond what the schema already provides, so it receives the baseline score.

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 uses a specific verb ('Search') and names a precise resource ('official FDA OPDP untitled letters') with a clear domain ('pharmaceutical promotion and advertising issues'). This clearly distinguishes it from sibling tools like fda_search_warning_letters.

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 by enumerating filter dimensions (company, product, issue date, close-out availability, keyword), which implies when it is useful. However, it does not explicitly name alternatives or state when not to use this tool, so it stops short of full guidance.

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