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

Annotations already indicate readOnly, idempotent, open-world, and non-destructive behavior. The description adds substantial behavioral context: internal cascading through multiple endpoints, graceful degradation for LEI/FIGI when upstream sources fail, explicit listing of unresolved identifiers, candidate disambiguation when multiple matches exist, and source labeling for every identifier. This goes well beyond what annotations convey.

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 long but dense; nearly every clause adds operational value, and important guidance is front-loaded ('Use FIRST whenever...'). The parentheticals and repeated emphasis on non-equity handling make it slightly heavier than strictly necessary, but it avoids fluff and promotional 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?

With no output schema, the description carries the burden of explaining what the tool returns, and it does: for companies it names CIK, ticker, company name, LEI with ownership, FIGI, source labels, and unresolved fields; for drugs it names RxCUI, ingredient, brand, and a citation. Candidate behavior and graceful degradation are also covered, making the tool fully callable and interpretable.

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%, but the description adds significant meaning beyond the schema. It gives concrete examples for 'value' (ticker, CIK, ISIN, brand/generic name), clarifies that only the entity name should be passed with a specific bond-issuer warning, and explains how the 'type' enum maps to different lookup behaviors. This is much more than a restatement of the 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 states a specific verb and resource: resolve a user-spoken name to canonical/official identifiers. It enumerates supported types ('company', 'drug') and explicitly frames its role as the first-stop lookup ('Use FIRST whenever you have a name but need an ID'), clearly distinguishing it from sibling tools like entity_profile and compare_entities.

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 gives explicit usage context: 'Use FIRST whenever you have a name but need an ID.' It also clarifies edge cases, such as when a bond issuer name does not identify a single instrument, and explains that non-equity instruments DO resolve here. It does not name specific alternative tools or give when-not-to-use exclusions, but the guidance is strong.

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