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

With no annotations, the description carries the full burden and does disclose the meaningful cost signal ('$0.001 USDC per call') plus the returned fields. It omits payment/auth mechanics, rate limits, data freshness, and unit conventions, which matter for an unpriced-looking paid endpoint.

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 with zero filler: purpose and output first, cost last. Every clause carries information the agent uses.

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 3-parameter read tool with no output schema, it covers purpose, outputs, and cost, which is most of what an agent needs. Minor gaps remain in unit system and whether 'location' alone can substitute for coordinates.

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 three parameters; the description only restates that lookup is by latitude/longitude. It does not clarify whether the optional 'location' name is an alternative to coordinates or merely annotative, which is the one genuinely ambiguous point.

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 ('Get current weather and 7-day forecast') and enumerates the returned measurements, so the agent knows exactly what comes back. No sibling tool covers weather, so there is no ambiguity to resolve against the list.

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?

The phrase 'for any location by latitude/longitude' implies the input mode and scope, but there is no explicit statement of when this tool should be preferred over anything else, nor any prerequisites. Acceptable, but the usage context is inferred rather than stated.

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