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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint. The description adds behavioral context: it handles off-calendar fiscal years correctly, sorts results by primary metric, and returns citation URIs. It does not contradict annotations and provides useful operational details beyond the structured fields.

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 example queries and key preference guidance. Every sentence adds value: usage patterns, data sources, sorting, output format. While somewhat long, the complexity of the tool (two entity types, multiple metrics) justifies the length. Minor redundancy with schema constraints could be trimmed.

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 thoroughly explains what each entity type returns: for companies, specific financial metrics from SEC EDGAR; for drugs, FAERS adverse-event counts, approval counts, trial counts. It mentions sorting, citation URIs, and off-calendar handling. For a comparison tool replacing many lookups, this is complete and actionable.

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 the baseline is 3. The description enriches parameter meaning by explaining that 'type' determines the data source (company vs drug) and giving concrete examples for 'values' (tickers/CIKs for company, drug names for drug). It also reiterates the 2–5 range and adds sorting behavior, providing more context than the schema alone.

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 opens with concrete usage examples like 'Compare X and Y' and 'X vs Y', clearly stating it performs side-by-side comparison of 2–5 entities. It distinguishes between 'company' (financial data from SEC EDGAR) and 'drug' (FAERS data), and explicitly prefers this tool over sequential lookups, differentiating it from sibling tools 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?

The description explicitly says 'ALWAYS PREFER over sequential single-pack lookups when comparing entities', giving clear when-to-use guidance. It also implies alternatives by naming the sequential approach, and describes data sources and constraints, helping the agent decide when this tool is appropriate.

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