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

No annotations, so the description carries the burden. It discloses useful context: HTTP method, the x402 price ($0.01), a docs URL, and the return shape (date-ordered forward calendar with blended probabilities). Missing: what 'blended probability' means, pagination, and any rate-limit behavior for a paid endpoint.

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?

Front-loaded with purpose and scope in the first two clauses. The HTTP/pricing/docs footer is B-heavy but genuinely useful for an agent that must decide whether to spend on a paid call.

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?

No output schema exists, but the description partially compensates by describing the return shape ('date order with current blended probabilities'). Combined with the endpoint having a required 'days' param and an unused-looking 'category' enum, an agent still lacks full guidance on parameter behavior.

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 0%, so the description must compensate for two undocumented params. It mentions 'upcoming' (implying a future-window filter) but never explains the 'days' window or its 1-90 bounds, nor what the 'category' enum does on a pre-filtered NFL endpoint.

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?

States a specific verb+resource: upcoming NFL event/market resolutions in date order with blended probabilities. Distinguishes itself from siblings (probability_calendar_sports-nba, -mlb, -soccer), which are the same shape pre-filtered to different leagues.

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?

Description explicitly says 'Same shape as /v1/calendar, pre-filtered to NFL football markets,' which tells an agent when to use this vs the unfiltered probability_calendar. It does not name the sibling by tool name or say when to prefer probability_board_sports-nfl, but the routing intent is clear.

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