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

No annotations are provided, so the description carries full burden; it discloses the non-obvious evergreen roll-forward behavior and that the response adds current_slug and rolls_to_next_at beyond the standard shape. It does not state rate limits, auth, or pricing caveats beyond the HTTP/x402 line, but the core behavioral surprise is well covered.

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 question is repeated twice in near-identical form, which wastes space, and the HTTP/pricing/docs line adds non-descriptive boilerplate. The evergreen semantics are front-loaded, but the duplication keeps it from being tight.

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, so the description rightly explains the extended response fields and the roll-forward behavior, which is what an agent most needs. It stops short of documenting the full standard probability response shape, but the tool-specific additions are complete.

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?

Zero parameters, which sets the baseline at 4; the description correctly documents the parameterless call and describes the extra response fields (current_slug, rolls_to_next_at) even though no output schema exists.

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?

Specific verb (probability) plus the exact recurring question 'Will Atlantic named storms run above normal this season?', and it is clearly distinguished from the other evergreen siblings by naming this particular real-world question. An agent can route correctly without opening another schema.

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?

States the evergreen behavior (auto-resolves to current market instance and rolls forward on resolution), which implies when to use this versus a dated market lookup, but never names an alternative tool or gives explicit when-not guidance. 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.