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

Annotations already mark it read-only, idempotent, and non-destructive, so the bar is lower. The description adds substantial behavior: data sources (SEC EDGAR/XBRL, FAERS/FDA), handling of off-calendar fiscal years, sorting by primary metric, and return format (paired data + citation URIs). 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 front-loaded with examples and the core purpose. Each sentence earns its place: trigger phrases, scope, type-specific behavior, sorting, output, and efficiency gain. It is dense but not padded, covering all key aspects 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?

Despite no output schema, the description explains return content and format sufficiently. It addresses the two entity types, data sources, sorting, and the efficiency advantage. For a comparison tool with this complexity, it leaves no major gaps in understanding when and how to use it.

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 100%, so baseline is 3. The description enriches parameter understanding by explaining what each 'type' value pulls (latest 10-K financials vs adverse-event/trial counts) and explicitly mentions the 2–5 count and ticker/CIK/name formats. It adds meaning beyond the schema's short descriptions.

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 the tool's purpose with a specific verb ('compare'), resource ('companies or drugs'), and scope ('2–5 ... in ONE parallel call'). It distinguishes from alternatives by noting it replaces 8–15 sequential lookups and gives concrete trigger phrases. This clearly separates it from siblings like entity_profile.

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?

Explicitly says 'ALWAYS PREFER over sequential single-pack lookups when comparing entities,' and provides example triggers like 'X vs Y' and 'rank these companies.' It also explains the two type-specific use cases (company vs drug), giving clear context for when to invoke this tool.

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