get_etf_history

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

With no annotations, the description carries the burden of behavioral disclosure. It explains important default behavior for start_date, end_date, and months (e.g., 'Defaults to the latest day with data'), which goes beyond the raw schema. It does not explicitly declare read-only status, but the tool's purpose makes that obvious, and the output schema covers return structure.

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 concise and well-structured: a one-line purpose followed by a compact argument list. Every sentence adds value, and the main 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 tool's simplicity, the presence of an output schema, and thorough parameter documentation, the description is complete for an agent to use it effectively. No critical information appears missing, and an example is optional rather than necessary.

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 fully compensates by defining each parameter meaningfully: code as a '6-digit short code,' date formats as YYYYMMDD, and the roles of start_date, end_date, and months with their default relationships. This adds substantial clarity beyond the bare schema.

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 provides 'Daily closing-price history for one ETF,' which is a specific data product and scope. It naturally distinguishes from siblings like get_etf_quote (current quote) and compare_etf (comparison), even without naming them.

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?

No guidance is given on when to use this tool versus alternatives. The description does not mention sibling tools, prerequisites, or exclusions, leaving the agent to infer usage solely from the tool name and the description's first line.

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