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

Beyond the readOnly/openWorld/idempotent annotations, the description discloses several runtime behaviors: it cascades through multiple lookup endpoints internally, returns `figi_candidates` to pick from, labels identifiers by source, reports unresolved IDs explicitly, and degrades gracefully if GLEIF/OpenFIGI is unavailable. This is far more than the annotations alone 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 is front-loaded with user-phrase examples, the core purpose, and a clear 'Use FIRST' directive. However, the `company` section is one extremely long parenthetical-filled run-on that would benefit from bullets; each clause adds value, but the structure is harder to parse than necessary.

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 two-parameter tool with no output schema, the description covers the important operational details: input varieties, output resolution behavior, unresolved handling, and fallback degradation. It gives enough information for an agent to know exactly when and how to invoke it and what to expect back.

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 substantially extends parameter meaning: it adds ISIN as an accepted company input, details the entity-name-only rule for bonds, and warns against trailing security-class words that break FIGI matching. It also clarifies drug input accepts brand or generic names.

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 verb and resource: resolving user-spoken names to canonical identifiers needed by other tools, with explicit supported types (`company`, `drug`) and example inputs. It also positions itself against siblings by saying 'Use FIRST whenever you have a name but need an ID,' which distinguishes it from profile/entity tools.

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 an explicit trigger condition: 'Use FIRST whenever you have a name but need an ID,' and explains that it replaces 2-3 manual lookups. It does not explicitly name sibling tools like entity_profile or compare_entities as alternatives or state when not to use it, so it lacks exclusions/alternatives.

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