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

The annotations already establish read-only/idempotent/non-destructive behavior. The description adds substantial behavioral context beyond that: graceful degradation of LEI/FIGI enrichment, explicit unresolved identifiers rather than omission, ambiguity handling via figi_candidates, and internal cascading of multiple lookup endpoints. No annotation contradiction is present.

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 and dense, but nearly every sentence carries operational content: trigger phrases, supported types, resolution behavior, and identifier sources. It is front-loaded with the core purpose; the main deduction is the wall-of-text formatting and some redundant clarifications that keep it from being maximally concise.

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: company results include CIK, ticker, company_name, LEI, ownership, and FIGI; drug results include RxCUI, ingredient, and brand; ambiguous matches produce figi_candidates; unresolved identifiers are explicit. This is sufficient for an agent to call the tool and interpret results.

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?

Although the schema already documents both parameters well (100% coverage), the description enriches them further: it explains ISIN input for company type, the distinction between instruments with and without tickers, and the bond issuer-name caveat about trailing security-class words. This materially improves the agent's ability to supply valid values.

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 names a specific action and resource: resolving a user-spoken name to the canonical/official identifiers other tools require. It enumerates supported types (company, drug), the identifier sources, and example user phrasings, making its purpose unmistakable even among many siblings.

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 gives a clear positive trigger: 'Use FIRST whenever you have a name but need an ID.' It does not explicitly list when not to use it or name alternative tools (e.g., entity_profile, compare_entities), so the when-not side of the guidance is missing.

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