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

No annotations are provided, so the description carries the full burden and does reasonably well: it discloses the ranking methodology (absolute probability change over the window), the volume surge ratio enrichment, the HTTP GET transport, and the x402 $0.04 cost. It does not mention auth, rate limits, or pagination behavior, which are real gaps 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 the core purpose and the window options, and the bracketed HTTP/pricing/docs line is compact and useful. Minor redundancy from repeating 'NFL football' three times, but no wasted sentences.

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?

With no output schema and no annotations, the description steps in to describe the return shape (ranked active markets with volume surge ratios) and the transport/cost. It is nearly complete for invocation, losing a point only for not clarifying the mismatched category/min_liquidity parameters.

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 only 25% (just min_liquidity), so the description should compensate. It states the window options (1h/6h/24h) and the ranking/window concept, and limit is implied by 'ranked' lists, but category and min_liquidity are not explained beyond the schema, and category is especially confusing on an NFL-scoped tool.

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?

Names a specific verb (ranked moves) and resource (NFL football probability markets) with explicit scope: 'pre-filtered to NFL football markets.' This cleanly differentiates it from the sibling family probability_movers_sports-mlb/-nba/-soccer and from the general probability_movers.

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 fastest way to see where news is landing in NFL football' gives a use case context, and the pre-filtering statement implicitly signals when to prefer it over the unfiltered probability_movers. However, no explicit alternative is named and no when-not guidance is offered, so usage is only implied.

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