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

Beyond the readOnlyHint/openWorldHint annotations, the description discloses the upstream data source and license (MET Norway, CC BY 4.0), that the flags are heuristics rather than safety advice, that thresholds are returned alongside the flags, and that invocation is paid ($0.001, x402). The cost and reliability caveats are exactly the extra context an agent needs; only return shape/pagination is unaddressed.

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?

Three dense sentences, front-loaded with what it returns and followed by the two things that most affect an agent's decision to call it: heuristic caveat and price. No filler clauses.

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, the description correctly compensates by naming the returned flags and their categories (event_risk low/moderate/high) and stating thresholds are included. Coverage is strong; actual threshold values and units are still unknown until invocation, which is a minor gap.

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%, with lat/lon ranges and the hours window already documented in the schema, so the baseline is 3. The description adds no syntax or format detail beyond noting that the hours window scopes the flags, which is already the schema's wording.

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 states a specific verb+resource (current weather and hourly forecast for a lat/lon) and then enumerates the derived outputs (drone_safe, event_risk, rain_expected, frost_risk, high_wind). No sibling tool competes in this domain, and the combination of raw forecast plus decision flags is unambiguous.

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?

Usage is implied by the input (supply a lat/lon and get forecast + risk flags) but there is no explicit when-to-use/when-not guidance, no alternative routing, and no statement of when the heuristics are or aren't appropriate beyond the disclaimer. It is adequate but leaves the agent to infer the triggering conditions.

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