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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive. The description adds substantial context beyond these: graceful degradation of LEI/FIGI enrichment, behavior on ambiguous name matches (asserts nothing, returns candidates), explicit listing of unresolved identifiers, and the ISIN-to-LEI mapping for non-US issuers. This is rich behavioral disclosure that exceeds the annotation baseline.

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 necessary context. It front-loads with usage examples and then structures the supported types and key behaviors. Every sentence contributes; there is no filler. The length is justified by the tool's complexity and the need to explain enrichment and edge cases. Slight deduction for not being shorter, but it's well-organized.

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 of this complexity (multiple entity types, multiple identifier sources, enrichment, fallback, ambiguous cases), the description covers all essential aspects. It explains what inputs are accepted, how each type resolves, what happens when resolution is incomplete, and even mentions the replacement of manual lookups. No critical missing information for an agent to use it correctly.

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%, so baseline is 3. The description adds meaningful parameter guidance: for 'value' it clarifies accepted formats (ticker, CIK, ISIN for company; brand/generic for drug) and provides a critical warning about passing only the entity name for bonds, not the full noun phrase. This goes well beyond the schema's terse description.

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 concrete purpose: resolve a spoken name to canonical identifiers required by other tools. It lists specific example queries and supported entity types (company, drug), and explicitly differentiates from siblings by framing it as the lookup tool that feeds other tools. This is a specific verb+resource with clear scope.

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?

Explicit guidance is given: 'Use FIRST whenever you have a name but need an ID.' This establishes a clear triggering condition. It does not name alternative tools or provide exclusions, but the instruction is unambiguous and context-rich, noting that it replaces 2-3 manual lookups. Slight deduction for not explicitly contrasting with sibling tools like entity_profile.

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