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

Annotations already declare read-only, idempotent, open-world, non-destructive, so the safety profile is covered. The description adds genuinely new behavioral context: results are cached 1-3 hours, it costs no third-party call when warm, the text comes back in the issuing service's language, and it should be quoted rather than translated.

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 core definition, then provider details, then the language contract and cost note; every sentence carries information. It is slightly longer than strictly necessary, but no sentence is filler.

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 carries the return contract and does so well: bulletin text, publishing language, quoting guidance, and caching cost. It omits the failure case (what is returned when no service covers the point), which is the main remaining gap for a 3-param open-world lookup.

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, and it does so for the highest-risk param: it enumerates the exact accepted `provider` values (mf, aemet, meteoam, metoffice) and explains that omitting it triggers automatic matching. Latitude/longitude semantics are only implied by 'the zone containing a point', leaving their coordinate order/format undocumented in both places.

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 and resource ('official marine forecast bulletin for the maritime zone containing a point') and explicitly distinguishes itself from model output, which is exactly the boundary against sibling get_forecast. An agent knows what this returns and how it differs from the numerical forecast tool without opening the 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?

Gives clear context: providers are auto-matched to the point, and `provider` can be passed to force one. The 'not a model output' contrast implies when to prefer it over get_forecast, but it never names the alternative or states an explicit condition, so routing is left partly to inference.

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