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

Annotations already establish the safe read-only, idempotent, non-destructive profile, so the description's burden is lighter. It usefully adds what the caller actually receives — a 16-day daily detail plus a weekly monthly outlook, barrier/cleanup program information, and model source and held-out skill — which is meaningful behavioral context in the absence of an output schema.

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?

One dense sentence that is front-loaded with the core purpose (forecast horizon) before enumerating supplementary returns. It is efficient, though the trailing item list ('barrier and cleanup programs, the model's source and held-out skill') is somewhat tacked on.

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?

For a two-parameter read-only tool with no output schema, the description covers the return content well enough that an agent knows what it will get, and annotations cover the safety profile. The main gap is the missing tie-breaker against the closely related sargassum_model_skill sibling.

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%, so both 'resort' and 'weeks' are already documented in the schema, making the baseline 3. The description's '16 days in detail plus a weekly outlook' implicitly clarifies the daily-vs-weekly granularity that the 'weeks' parameter controls, adding marginal value but no syntax or format detail beyond the schema.

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 names a specific resource (sargassum/seaweed outlook) and scope (next 16 days in detail plus a weekly outlook for coming months) plus supplementary content like barrier/cleanup programs and model skill. It is clear what the tool returns, but it does not distinguish itself from the sibling sargassum_model_skill, which the 'model's source and held-out skill' clause appears to overlap with.

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 only implied through the description of output content; there is no explicit when-to-use statement, no exclusions, and no routing guidance versus alternatives such as beach_conditions, sargassum_model_skill, or plan_trip. The mention of model source/skill even creates ambiguity about which sibling to pick.

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