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

The description adds behavioral detail beyond the readOnly/idempotent annotations by noting that the returned URL is time-limited and that a single surface file is returned. It does not exhaustively describe all error or expiry behaviors, but the annotations already cover side-effect transparency.

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 two concise sentences with no unnecessary wording. It front-loads the primary purpose and then gives a single actionable prerequisite.

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?

The description is sufficient for an agent to understand what the tool does, what input context is needed (exact slug from list_market_data), and what kind of output to expect (time-limited URL). With an output schema present, no further return-value explanation is 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?

All parameters already have descriptive schema entries, and the description adds extra practical guidance for the slug parameter via list_market_data. This is a useful supplement to the schema, though the meaning of optional parameters like expires and timeframe is left to their existing 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?

The description clearly states the tool returns a time-limited download URL for a single volatility surface file, using a specific verb and resource. It also distinguishes this from the broader data-listing workflow by instructing users to call list_market_data first for the correct slug.

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 gives clear usage context by directing users to list_market_data (md_type=surface) before calling this tool. It does not explicitly contrast it with sibling tools like get_download_url, but the specialization to volatility surface files makes the intended use clear.

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