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

With no annotations provided, the description carries the full burden and does meaningful work: it discloses the HTTP method and path, the $0.04 x402 price, a docs URL, the ranking behavior, and that results include volume surge ratios. It omits return/pagination shape and any auth or rate-limit notes, which keeps it short of a 5 for an unannotated tool.

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-loads the purpose in the first sentence, then adds the ranking mechanism and the sibling-shape note, and relegates transport metadata to a bracketed footer. Every clause is informative; the HTTP/pricing bracket is verbose but genuinely useful for invocation.

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?

There is no output schema and no annotations, so the description must cover behavior; it conveys what the response contains conceptually (ranked markets plus volume surge ratios) but not its shape. Given a 4-param tool at 25% schema coverage, explaining limit/category/min_liquidity behavior is the missing piece.

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 description coverage is only 25% (just min_liquidity), so the description must compensate, and it largely does not. It echoes the window options ('1h/6h/24h') already in the enum, but says nothing about limit, the category enum, min_liquidity, or why a soccer-scoped tool still exposes non-soccer categories.

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 ('Biggest soccer probability moves'), the exact ranking metric ('absolute probability change'), the enhancement ('volume surge ratios'), and the scope pre-filter ('soccer markets'). It also explicitly positions itself against the generic sibling ('Same shape as /v1/movers, pre-filtered to soccer markets'), so an agent can distinguish it from probability_movers and probability_movers_sports-mlb/nba/nfl.

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?

It supplies a usage context ('the fastest way to see where news is landing in soccer') and implies routing versus the generic movers endpoint via 'pre-filtered to soccer markets'. However, it never names a sibling tool explicitly nor states when NOT to use it (e.g., vs probability_board_sports-soccer or probability_movers with a sports filter), leaving the agent to infer the alternative.

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