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

The description goes well beyond the readOnly/idempotent annotations: it documents ambiguity handling (`figi_candidates`), explicit `unresolved` output, graceful degradation when GLEIF/OpenFIGI are unavailable, and internal endpoint cascading. These traits are context an agent could not infer from annotations alone.

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 it is front-loaded with purpose, structured by entity type, and every major clause carries useful information. It slightly exceeds minimal conciseness due to heavy parentheticals, but this is justified by the tool's complexity.

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 thoroughly covers what the agent should expect: returned identifier fields, candidate selection on ambiguity, explicit unresolved fields, ownership data, and graceful degradation. An agent has enough context to call the tool correctly and interpret its 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 schema coverage is 100%, the description adds substantial meaning: ticker/CIK/ISIN/name accepted for company, brand/generic accepted for drug, and a critical warning to pass only the issuer name for bonds, not the full noun phrase. This materially improves correct invocation beyond 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 opens with concrete user phrasings ('What's the ticker for…', 'find the CIK for…') and states the core action: resolving a name to canonical/official identifiers. It explicitly contrasts itself with 'other tools require as input,' so an agent can distinguish it from sibling lookup tools like entity_profile or validate_claim.

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 directive: 'Use FIRST whenever you have a name but need an ID.' It also explains that the tool replaces 2-3 manual lookups. However, it does not explicitly name alternative tools or state when NOT to use it, stopping short of a full 5.

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