Weather Forecast

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

Annotations already declare readOnly, idempotent, non-destructive, open-world behavior, so the bar is lower. The description adds genuinely useful behavior beyond them: US-only coverage via NWS, the shape of the response (named periods with temperature, wind, short + detailed forecast), and the existence of a different mode. It does not mention rate limits or data staleness, keeping it out of 5 territory.

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?

Two sentences, zero filler. Purpose and scope come first, the response shape second, and the geocode routing hint last, so the most decision-relevant information is front-loaded.

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 read-only, open-world lookup with a full output schema and 100% parameter coverage, the description supplies everything an agent needs: what it returns, the coverage limitation, and the prerequisite for address-based input. No material gap remains.

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 lat/lon/hourly are fully documented in the schema, establishing the baseline of 3. The description reinforces the lat/lon and US-coverage semantics but adds no format or constraint detail the schema does not already carry, and never mentions the hourly toggle.

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 (multi-day weather forecast), the required inputs (latitude/longitude), and the data source (National Weather Service). The 'multi-day' scope plus the returned named periods distinguish it from weather_current, and it names geocode as the sibling to use for addresses.

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?

Explicitly gives the prerequisite routing rule: 'Use geocode first if you only have an address.' That is clear context plus an alternative. It stops short of stating when to prefer weather_current or weather_alerts, so it is not a full when/when-not/alternatives treatment.

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