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

With no annotations provided, the description carries full behavioral disclosure. It transparently explains the two-step payment requirement and details what each view computes, including 'skipping weekends and holidays' for settle. It does not cover return formats or error handling, but the key behavioral traits are clearly stated.

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 front-loaded with the primary purpose, then condenses view behaviors into a single semicolon-separated sentence, followed by the payment flow and a pointer to a free sibling. Every sentence contributes unique information with no redundancy, making it both concise and well-structured.

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 tool with 8 parameters and a payment gate, the description covers all views, the payment two-step, and the free alternative. While no output schema exists, an agent receives sufficient guidance to select the correct view and invoke the tool correctly, including how to handle the paid flow.

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 coverage is 100%, setting baseline 3. The description adds relational semantics by connecting parameters to views (e.g., `days` as N in T+N for settle, from/to for business_days, year for year, date for is_open). This integration goes beyond the static schema descriptions, which already partially reference views, by clarifying how the parameters interact and what the view outputs mean.

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 'Is a market open on a date, and why not if it isn't,' clearly stating the tool's core purpose. It then enumerates the four views (next_session, settle, business_days, year) with specific outputs, making it distinct from siblings like `pricing` which is explicitly called out as the pricing tool.

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 explicitly points users to the `pricing` tool for price listings ('The free `pricing` tool lists every price at once'), providing a direct alternative. It also gives a step-by-step payment workflow (call without x_payment, sign terms, call again with x_payment), telling the agent exactly how to proceed for paid access.

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