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

Annotations already establish readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds rich behavioral detail beyond annotations: ambiguous matches 'assert nothing' and return figi_candidates, unresolved identifiers are explicitly listed, LEI/FIGI enrichment 'degrades gracefully', and the call cascades through multiple endpoints internally. This is exactly the kind of non-obvious runtime behavior an agent needs.

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, but it is organized with front-loaded question examples, a clear 'Use FIRST' directive, and labeled SUPPORTED TYPES sections. The parenthetical edge-case detail is substantial and mostly earns its place, though a few clauses (e.g., the extensive FIGI coverage exegesis) could be tightened without losing meaning.

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 must explain what the tool returns, and it does: each identifier is labeled with its source, unresolved identifiers are listed explicitly under `unresolved`, ambiguous matches return `figi_candidates`, and enrichment failures still yield EDGAR identifiers. This gives an agent a complete mental model of the tool's behavior across success, ambiguity, and partial-failure paths.

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 the baseline is 3, but the description substantially enriches parameter meaning. It clarifies the exact format for value (ticker, CIK, ISIN, or name; brand or generic for drug) and adds a critical pitfall warning: pass only the entity name, never the full noun phrase, because 'trailing security-class words match nothing'. It also explains that an ISIN resolves to the legal entity that issued the security, which the schema alone does not convey.

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 defines a specific action ('resolve a user-spoken NAME to the canonical/official identifiers') and clearly distinguishes the tool from siblings like compare_entities and entity_profile by positioning it as the prerequisite step that 'other tools require as input'. The two supported types, 'company' and 'drug', are enumerated with exact identifier outputs.

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 trigger conditions ('Use FIRST whenever you have a name but need an ID') and realistic user phrasings, which makes when-to-use highly clear. It does not explicitly state when not to use it or name alternative tools to prefer instead, but the context is strong enough that exclusions are not necessary for safe invocation.

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