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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=false, so safety and determinism are covered. The description adds a worked example ($50 stock / $0.50 quarterly = 4%) that aids interpretation, but does not disclose anything further about behavior, limits, or return shape.

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 worked example, then purpose, then output scope, then a link. Every clause is doing work except the trailing 'Web page' URL, which is promotional filler rather than agent-relevant content.

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 simple, read-only, no-output-schema calculator with full schema coverage and complete annotations, the description covers inputs implied, computation, and the extra income output. It is sufficiently complete; only the missing return-shape detail (given no output schema) keeps it short of 5.

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%, so all five parameters are already documented in the schema. The description's reference to monthly/quarterly/annual payers loosely maps to the frequency parameter but adds no syntax or enum detail beyond what the schema provides; baseline 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?

States a specific verb and resource ('Get the dividend yield') and names the added output ('the cash income your shares produce'), so the agent knows exactly what is computed. It doesn't explicitly differentiate from any sibling, but no sibling tool overlaps with dividend yield, so the purpose is unambiguous.

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 signals applicability across 'monthly, quarterly or annual payers', which implicitly frames when the tool fits, but gives no when-not guidance or prerequisites. With no sibling alternative to route away from, the omission is not costly, leaving it at implied usage.

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