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

Even with annotations already declaring readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, the description adds substantial behavioral context: it cascades through multiple lookup endpoints, degrades gracefully when GLEIF or OpenFIGI is unavailable, returns figi_candidates rather than asserting on ambiguous matches, and explicitly lists unresolved identifiers under 'unresolved'. None of this contradicts the 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 front-loaded, opening with concrete query examples before immediately stating the tool's purpose. It is long and contains many nested clauses and parentheticals, so it could be tightened, but nearly every clause adds real information about resolution behavior, supported types, and edge cases.

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 return behavior, and it does thoroughly: it names the identifier components (CIK, ticker, company_name, LEI, FIGI, RxCUI, ingredient, brand, citation), covers ambiguity via figi_candidates, and explains unresolved and degraded-enrichment cases. For a tool with this complexity, both entity types and failure modes are addressed.

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 materially enriches both parameters: company accepts ticker, CIK, ISIN, or company name, with ISIN resolving via GLEIF to the issuing legal entity; drug accepts brand or generic names with examples. It also provides crucial formatting guidance that the schema lacks, such as passing the entity name only and why trailing security-class words break FIGI lookup.

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: it resolves user-spoken names to canonical/official identifiers that other tools require as input, with explicit supported types ('company' and 'drug') and concrete example queries. It conceptually distinguishes itself from likely siblings like entity_profile and compare_entities by framing its output as the identifier inputs those tools consume, rather than as a profile or comparison tool itself.

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 an explicit trigger condition: 'Use FIRST whenever you have a name but need an ID,' along with example user phrasings such as 'what's the CIK for…' and 'is X a subsidiary of Y'. It does not name sibling alternatives or state when not to use this tool, so exclusions are missing, but the context is clear enough for an agent to route to it.

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