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

Annotations declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior. The description goes far beyond these: it explains graceful degradation when GLEIF/OpenFIGI are unavailable, the cascading lookup behavior, how unresolved identifiers are explicitly listed under `unresolved`, and that multiple matches yield no assertion but candidates. It also clarifies that non-equity instruments without tickers still resolve. No contradiction with annotations.

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 but densely packed with valuable information, front-loaded with example queries and the 'Use FIRST' directive. It is well-structured with a supported-types breakdown. While slightly verbose, every sentence contributes meaning—no filler. A minor trim could improve, but it remains appropriately detailed for 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?

For a complex tool with no output schema, the description covers almost everything an agent needs: inputs, expected outputs per type, error handling (ambiguous matches, unresolved identifiers, service degradation), source labelling, and even non-US issuer coverage. It preempts common mistakes (e.g., passing full noun phrases for bonds). Nothing critical is missing.

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?

Schema coverage is 100% (both params have descriptions), but the description enriches meaning substantially. For `value`, it adds concrete examples, distinguishes input types, and warns about the pitfall of passing full noun phrases instead of entity names. For `type`, it explains each enum value's output and edge cases like ISIN-to-LEI resolution. This goes well beyond the base 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 states a precise verb-object purpose: resolving a spoken name to canonical identifiers. It enumerates concrete example queries and explicitly names the resource types (company, drug) and the specific identifiers returned (CIK, LEI, FIGI, RxCUI). This clearly distinguishes it from generic search tools and from sibling comparison tools like compare_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 gives an explicit directive: 'Use FIRST whenever you have a name but need an ID.' It also details when each type applies, explains the cascade of internal lookups replacing manual steps, and outlines what happens in ambiguous matches (returns figi_candidates). This is excellent guidance for an agent deciding when to invoke this tool versus alternatives.

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