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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint. Description adds valuable behavioral context: results sorted by primary metric, returns citation URIs, handles off-calendar fiscal years for companies, pulls latest 10-K data. No contradictions.

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?

Description is dense but highly efficient. Front-loaded with common query examples. Every sentence adds unique value: examples, type behaviors, output characteristics, and usage preference. 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?

Despite no output schema, description explains return format (paired data + citation URIs), sorting behavior, and data sources for both types. Covers constraints, parameter details, and use cases. Comprehensive for a comparison 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?

Both parameters (type, values) are fully described in schema (100% coverage). Description adds meaning: explains enum values (company pulls financials, drug pulls FAERS data), values format (tickers/CIKs vs drug names), and constraints (2-5 items). Significantly enhances usability.

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?

Description clearly states the tool compares 2-5 entities in parallel. Lists example queries like 'X vs Y' and specifies comparisons for companies or drugs. Distinguishes from sequential lookups and siblings by explicitly saying 'ALWAYS PREFER over sequential single-pack lookups'.

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 advises preferring this tool over sequential lookups for comparisons. Provides context for when to use company vs drug type. Does not explicitly state when not to use or alternatives like entity_profile for single entities, but the guidance is clear enough.

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