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

With no annotations provided, the description carries the full burden. It discloses the return fields and mentions pricing at /.well-known/x402, but does not describe error handling for invalid tickers, rate limits, authentication requirements, or any side effects. Useful context, but significant behavioral details remain uncovered.

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 somewhat long with a comprehensive list of use cases, but every sentence adds relevant information. It is front-loaded with the core action and return values, and the pricing note is a useful contextual detail. Minor redundancy in the list of return items, but overall efficient.

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 single-parameter tool with no output schema, the description thoroughly covers the return values (CIK, registrant name, SIC code and description, exchanges, fiscal year end) and provides clear context for when to use it. It does not address invalid-ticker behavior or other edge cases, but the tool is simple enough that this is a minor gap.

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%, and the schema already documents the ticker parameter format (case-insensitive, pattern, max length). The tool description adds no additional semantic meaning beyond what the schema provides, so the baseline of 3 applies.

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 clearly states the tool resolves an exchange ticker to its SEC filer and returns specific reference data (CIK, registrant name, SIC code and description, exchanges, fiscal year end). It uses a specific verb-resource pair and is easily distinguished from sibling tools like get_financials or list_filings.

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 explicitly enumerates use cases ('confirm a ticker is a real SEC filer', 'resolve it to a CIK', 'establish industry or sector context', 'choose peers', 'learn a filer's fiscal calendar') and positions itself as 'reach for this first'. It lacks explicit exclusions or alternative tool references, so it does not fully meet the 'when-not' criterion.

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