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

Beyond the readOnlyHint and idempotentHint annotations, the description discloses data sources (SEC EDGAR/XBRL, FAERS/FDA), handling of off-calendar fiscal years, sorting by primary metric, and the return format (paired data with citation URIs). No contradictions 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 information-dense but every sentence earns its place: query patterns, data sources, fiscal-year edge cases, sort behavior, return format, and efficiency claim. It is front-loaded with the main purpose and remains readable.

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?

Given the tool's complexity, no output schema, and two distinct entity types, the description fully explains what the agent can expect: paired data, citation URIs, and sorted results. It also covers edge cases like off-calendar fiscal years and explicitly states the number of lookups replaced.

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 already covers the two parameters, but the description adds substantial meaning: exactly what data each 'type' value retrieves, the expected format for values (tickers/CIKs for company, drug names for drug), and the cardinality (2–5). This goes well beyond the bare schema.

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 query examples and then states the core function: side-by-side comparison of 2–5 companies or drugs in ONE parallel call. It clearly distinguishes from sequential lookups by explicitly preferring itself for comparisons and noting it replaces 8–15 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?

It explicitly says 'ALWAYS PREFER over sequential single-pack lookups when comparing entities,' providing an unambiguous when-to-use rule and an implied alternative. It also separates usage by entity type (company vs drug) with data source specifics.

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