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

With readOnlyHint/idempotentHint already covering safety, the description adds real behavioral context: output differs by date path, future dates additionally return cumulative risk from the data date, and past dates use archived rather than modeled data. It stops short of describing the ladder's level structure or result shape.

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 sentences, front-loaded with the core scope before the past/future branching and the optional what-if note. Dense but every sentence carries information; only minor tightening is possible.

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 7-parameter read-only tool with no output schema, the description covers the date-range constraint, the two data paths, and the extra cumulative-risk output for future dates. It does not explain what the risk 'levels' are or how the what-if parameters interact, but the essentials for correct invocation are present.

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 100%, so the schema already documents all seven parameters, including the scenario enum/number union and each what-if percentage. The description only adds the grouping concept ('optional what-if assumptions'), which is a mild aid, not new parameter meaning — baseline 3 applies.

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 ('annual risk of each level') and scopes it precisely to a date window relative to the data date, which is more than a restatement of the title. It does not, however, explicitly distinguish itself from sibling tools such as get_forecast_history, even though past dates pull from the 'published forecast archive' — a boundary an agent would need spelled out.

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 clearly states the internal routing rule (past dates -> forecast archive, future dates -> scenario model) and notes that what-if assumptions are optional, which is the main decision an agent faces. It offers no guidance on when to prefer this over sibling tools like get_forecast_history or get_other_forecasts.

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