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

Annotations already mark the tool as read-only, idempotent, open-world, and non-destructive, and the description adds substantial behavioral context: it cascades through multiple lookup endpoints, degrades gracefully when GLEIF or OpenFIGI is unavailable, returns figi_candidates for ambiguous matches, labels each identifier with its source, and explicitly lists unresolved identifiers rather than omitting them.

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 with its purpose and the 'Use FIRST' directive, and most of the long parentheticals convey edge-case behavior rather than filler. It is dense and could be tightened, but the extra length is largely earned by explaining ambiguity handling, graceful degradation, and input pitfalls.

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?

For a tool with no output schema and cross-source complexity, the description covers input variants, ambiguous matches, source unavailability, identifier provenance, and explicit unresolved-identifier semantics. It also explains what is returned for each supported type, leaving no critical gap for an agent deciding whether and how to call it.

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?

Even though schema coverage is 100%, the description adds real value beyond the schema: concrete examples such as AAPL, 0000320193, and ozempic; the instruction to pass only the entity name or issuer exactly as printed; and the warning that trailing security-class words will fail FIGI matching. These details directly improve the agent's ability to construct correct parameter 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 states a precise verb and resource: resolve a user-spoken name to canonical/official identifiers (CIK, LEI, FIGI, RxCUI) that other tools require. It distinguishes itself from sibling tools by saying 'Use FIRST whenever you have a name but need an ID' and enumerates supported entity types and identifier sources.

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 usage rule: use this tool first whenever the user has a name but needs an ID, and notes that one call replaces 2-3 manual lookups. However, it does not name sibling alternatives or state when not to use it, such as once an ID is already known and a profile is needed.

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