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

On top of the readOnlyHint annotation, the description adds meaningful behavior: the output shape and the consequence of a null cik (prices/indicators work, issuer-level events do not). It also clarifies the optionality of resolution, which is behavioral context the annotation alone cannot convey.

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?

Three sentences, no filler, with the main action in the first sentence and the most important caveat (null cik) last. Every sentence earns its place.

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 one-parameter resolver with an output schema and readOnly annotation, this fully covers when, why, and what the result means. The null-cik caveat is exactly the kind of domain nuance an agent needs to route output appropriately.

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?

The schema only says `query` is a required string, and schema coverage is 0%, but the description compensates by stating the accepted free-text inputs (ticker, company name, or CIK). It stops short of giving example formats or confirming that `query` is the free-text field, so it is not quite a 5.

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?

Opens with a specific verb and resource: 'Resolve a ticker, company name, or CIK to the canonical entity {figi, cik, ticker, name}.' It also positions the tool relative to the 36 siblings by noting that every other tool takes the same free-text form, so this is the disambiguation step rather than a data-return tool.

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?

Explicitly states calling this first is optional and gives the exact reason: confirm WHICH company a name resolved to before trusting downstream results. This tells an agent when to call it and why, without needing to inspect siblings.

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