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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds substantial behavioral context beyond that: currency handling per exchange, that date filters bind to the ex-dividend date, that future ex-dates may appear post-declaration, and the non-inheritance rule across share classes and fund series. This is genuinely useful value, though it omits pagination/return-format notes.

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?

Front-loaded with the core action, then the return format, then the semantics and edge cases. Sentences are dense but each carries distinct information; the listing-isolation rule is verbose but earns its place by preventing a common misinterpretation.

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 carries the burden of describing returns and does so (ex-div date + cash amount per share, ordering, currency). Safety is covered by annotations. Only minor gaps remain around pagination behavior, which offset/maxResults in the schema partially address.

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. The description goes further by explaining that startDate/endDate filter on the ex-dividend date specifically and how the ticker format (MIC:TICKER) works, adding meaning beyond the schema's field 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?

States a specific verb and resource: 'Get the stored declared cash dividends of an exact stock or ETF listing, newest first.' The scope (declared cash dividends, exact listing, newest-first ordering) is precise enough that an agent can distinguish it from siblings like GetStockPrices or GetFundProfile without opening the schema.

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?

It clarifies scope and edge cases (per-listing isolation, future ex-dates) but never explicitly says when to choose this tool over a sibling or names an alternative. Usage is implied rather than stated.

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