option_list_expirations

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

With no annotations, the description carries the transparency burden. It adds useful context: '[FREE]' indicates no cost and 'Updated overnight' signals data freshness. However, it does not disclose output format, pagination, or any special behaviors or limitations, leaving the agent partly guessing.

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 extremely compact: two short sentences front-load the primary purpose and then a second sentence conveys update frequency and cost. Every word earns its place; there is no redundancy or filler.

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 this is a simple list tool with one parameter and no output schema, the description covers the essential purpose and freshness. It does not state the return format, but for a straightforward list of dates that is likely predictable. Overall, it is reasonably complete for the tool's complexity.

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?

The input schema provides a detailed description for the single 'symbol' parameter, including wildcard and comma-separated syntax, achieving 100% coverage. The description adds no additional parameter-level details, so the baseline of 3 is appropriate.

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 uses a specific verb 'List' and clearly identifies the resource: 'available expiration dates for an option symbol.' It is unambiguous and distinguishes from similar sibling tools like option_list_strikes or option_list_contracts. Even though option_list_dates exists, 'expiration dates' adds clarity.

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 implies usage: use it when you need expiration dates for an option symbol. However, it does not explicitly state when not to use it or mention alternatives among the many sibling listing tools. No exclusions or comparison to option_list_dates or other list tools is provided.

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