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

Even with annotations already declaring readOnly, openWorld, idempotent, and non-destructive behavior, the description adds substantial behavioral detail: cross-source identity spine, source labelling, explicit `unresolved` identifiers, `figi_candidates` on ambiguous matches, graceful degradation when GLEIF or OpenFIGI is unavailable, and internal cascading lookups. There is no contradiction with the 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 dense and long, but nearly every clause carries useful information and it is front-loaded with example queries and the 'Use FIRST' directive. The heavy use of nested parentheticals makes it harder to scan, but the content is not wasted.

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 adequately covers what the agent will receive: EDGAR identifiers, LEI plus ownership, FIGI with candidates on ambiguity, RxCUI with citation, and explicit unresolved fields. It also covers edge cases like non-US issuers, non-ticker instruments, and service outages, so the agent can set expectations and handle responses 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?

Although the schema covers both parameters, the description adds critical usage nuance beyond the schema: exact input examples like 'AAPL', '0000320193', and 'ozempic', the requirement to pass the entity name only, and the warning that trailing security-class words like 'revenue bonds' will fail FIGI lookup. This materially improves correct invocation.

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 example queries and states the core job: resolving a user-spoken NAME to canonical/official identifiers other tools require as input. It explicitly differentiates itself by saying 'Use FIRST whenever you have a name but need an ID' and by listing the two supported entity types, making its role distinct from sibling tools like entity_profile.

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 strong when-to-use guidance: 'Use FIRST whenever you have a name but need an ID.' It also explains the cascade and how it replaces multiple manual lookups. However, it does not explicitly name sibling alternatives or state when one of those should be chosen instead, so it falls short of full when-not/alternative coverage.

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