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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, and the description adds substantial behavioral context beyond those: it reports unresolved identifiers explicitly under 'unresolved', returns 'figi_candidates' on ambiguous matches, labels identifiers with their source, and degrades gracefully when GLEIF or OpenFIGI is unavailable. No contradiction with annotations exists.

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 and dense, with heavy parenthetical nesting in the company-type section, but it is front-loaded with purpose and clear first-use guidance. Nearly every sentence adds operational detail—sources, failure behavior, input caveats—so the length is mostly justified despite some editorializing like 'replaces 2-3 manual 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?

With no output schema, the description does the work of explaining what the tool returns: CIK, ticker, company_name, LEI, FIGI, RxCUI, ingredient, and brand, plus the 'unresolved' field and 'figi_candidates' ambiguity behavior. It also covers edge cases like ISIN-to-LEI mapping, non-US issuers, and degraded enrichment, making it complete for an agent to select and invoke the tool 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?

Even though schema coverage is 100%, the description adds meaning the schema lacks: the 'value' parameter gets crucial guidance to pass the entity name only, with the counter-example 'NEW YORK ST DORM AUTH revenue bonds' explaining why trailing security-class words fail. It also documents accepted input forms for company (ticker, CIK, ISIN, name) and drug (brand or generic), going well beyond the schema's enum and one-line descriptions.

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 opens with concrete user phrasings ('What's the ticker for…', 'find the CIK for…') and then states a specific verb+resource action: resolve a user-spoken name to canonical/official identifiers. It clearly scopes the tool to company and drug entity types, which differentiates it from siblings like entity_profile and compare_entities even without naming them.

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 explicit usage guidance: 'Use FIRST whenever you have a name but need an ID.' It also explains when the tool is appropriate versus when it returns candidates rather than asserting an answer. However, it does not explicitly name alternatives or state when not to use this tool, so it misses the top-tier 'when-not/alternatives' bar.

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