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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds useful behavioral context beyond annotations: the data source (Yahoo Finance via yfinance), that no API key is required, and that it returns date and amount/ratio for each event. No contradiction with 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 compact and well-structured: a clear first sentence, three focused use-case bullets, and a source note. Every sentence earns its place and the core purpose is front-loaded.

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?

Given the output schema and annotations, the description covers the core usage well: what data is returned, when to use it, and the source. The main gap is that it does not clarify the period parameter or acknowledge the many unrelated-looking schema fields, though those are partially documented in the schema itself.

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 0%, so the description carries the burden of explaining parameters. It only mentions 'a ticker' and 'full history' and does not explain the period parameter, symbol format, or which of the many schema fields are actually relevant. The schema has nested descriptions, but the description itself adds little parameter-level meaning.

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 a specific verb and resource: 'Fetch the full history of cash dividends, stock splits, and combined corporate actions for a ticker.' This clearly distinguishes it from sibling tools like GetPriceHistory or GetEarningsHistory by naming the exact data domain.

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 provides explicit 'Use this tool when' bullets covering dividend history, yield calculations, dividend growth research, and split verification. It does not name alternative tools or state when not to use it, but the context is clear enough for an agent to route correctly.

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