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

Beyond the readOnly/idempotent/openWorld annotations, the description discloses important behavior: internal cascading through several lookup endpoints, graceful degradation when GLEIF/OpenFIGI are unavailable, ISIN-to-LEI resolution for non-US issuers, and the explicit handling of unresolved identifiers under `unresolved`. This is exactly the kind of behavioral context that annotations do not provide.

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 contains a lot of detail, but it is front-loaded with the core purpose and 'Use FIRST' guidance, and the rest is organized by supported type. Some parentheticals are dense, but every sentence contributes useful semantic or behavioral information rather than 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?

For a tool with no output schema, the description is remarkably complete: it explains acceptable inputs per type, the identifiers returned, how non-equity instruments resolve, unresolved-id handling, graceful degradation, and cites the replace-2-3-lookups value. An agent has enough information to call the tool correctly in almost any target scenario.

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?

The schema already covers both parameters fully. The description adds meaningful beyond schema by documenting that ISIN is accepted for company type, describing type-specific resolution outputs, and giving explicit input examples such as 'ozempic' and 'metformin'. It also clarifies the INPUt should include only the entity name, which reduces misuse.

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 clearly states the tool's purpose: resolving user-spoken names to canonical/official identifiers that other tools require. It enumerates supported entity types and concrete identifier examples, and distinguishes the tool as the first step when a name but not an ID is available. This clearly separates it from sibling tools like entity_profile or compare_entities, which operate on already-identified 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 explicitly says 'Use FIRST whenever you have a name but need an ID,' giving a clear invocation trigger. It does not explicitly name alternatives or state when not to use this tool, but the guidance is specific enough to route correct selection in most cases.

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