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

Beyond the readOnly/idempotent/non-destructive annotations, the description discloses data sources (SEC EDGAR/XBRL and FAERS), specifics like off-calendar fiscal year handling, and that results are sorted by primary metric. It also mentions citation URIs, adding behavioral context not present in 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 longer than ideal but front-loaded with trigger phrases and the core purpose. Every sentence contributes functional detail, such as data sources, sorting, and replacement value, but the density makes it slightly less concise than a 5.

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?

Even without an output schema, the description explains what the response contains (paired data, citation URIs, sorted results) and the data types involved. It addresses all essential aspects for invoking the tool correctly, especially given the rich annotations.

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 already covers both parameters with 100% coverage, but the description adds significant meaning by explaining what each type ('company' vs 'drug') retrieves and providing concrete examples for values. This goes beyond the schema's minimal descriptions, though the schema remains the primary reference.

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 is explicitly action-oriented: "side-by-side comparison of 2–5 companies or drugs in ONE parallel call," with trigger phrases like 'X vs Y' and 'rank these companies.' It clearly distinguishes itself from sibling tools like entity_profile by focusing on multi-entity comparison.

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 states "ALWAYS PREFER over sequential single-pack lookups when comparing entities," giving a direct when-to-use instruction. It also notes that it replaces 8–15 sequential lookups, reinforcing the preference and implying when not to use it.

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