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

Annotations only declare readOnlyHint and openWorldHint; the description goes well beyond them by documenting the return shape (UTC ISO 8601 timestamps), the 0-3 risk score scale, and the non-obvious omission semantics ('risks missing from a time don't apply then'). It also proactively states what is NOT returned (safety tips) and where to get it.

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?

Four short sentences, front-loaded with purpose then routing then return semantics. Every sentence carries distinct information; nothing is repeated from the schema or annotations.

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 compensates by explaining the return structure, timezone, score encoding and omission rules. For a bounded read-only forecast tool with full schema coverage, nothing an agent needs to call or interpret it is missing.

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 latitude, longitude, risk_ids, forecast_type and include_summaries are all already documented in the schema. The description's 'next 8 days' phrasing loosely reinforces forecast_type's daily default but adds no syntax or constraint 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?

States a specific verb and resource ('Forecast outdoor environmental health risks at a location') with the data basis (weather and air quality forecasts). It explicitly distinguishes itself from the sibling get_environmental_risk by time horizon, so an agent can route without opening either 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 explicit when-to-use ('plans later today or in the next 8 days') and names the alternative for the opposing case ('use get_environmental_risk for right now'). It also routes a second need (safety tips) to the sibling, covering both selection and follow-up.

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