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

Goes well beyond the annotations by disclosing graceful degradation ('LEI/FIGI enrichment degrades gracefully'), candidate disambiguation ('returns `figi_candidates` to pick from'), and explicit unresolved reporting ('stated explicitly under `unresolved`'). These are important behavioral traits not captured by readOnly/idempotent hints.

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 a clear purpose and usage rule, then explains supported types. It is long and dense, especially the 'company' section with nested parentheticals, but each clause contributes behavior that is hard to express briefly. Minor redundancy exists in the closing remark about cascading lookups.

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 covers return shape (figi_candidates, unresolved, source labels), input variants, type-specific behavior, and failure handling. An agent can successfully invoke it and interpret results without needing additional context.

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 description coverage is 100% already, and the schema's value description is detailed with examples and instructions about entity name formats. The tool description reinforces this by mentioning accepted inputs (ticker, CIK, ISIN, name) and the bond issuer caveat, but adds little beyond what the schema already provides.

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?

Description states a specific verb-resource pair ('resolve a user-spoken NAME to the canonical/official identifiers other tools require as input') and explicitly lists supported types (company, drug). It distinguishes from siblings by positioning itself as the first step whenever a name needs an ID, which separates it from tools like entity_profile or 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?

Provides explicit guidance: 'Use FIRST whenever you have a name but need an ID.' It gives example user phrasings and notes that it replaces 2-3 manual lookups. It does not explicitly name sibling alternatives or state when not to use it, but the context is clear.

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