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

With no annotations provided, the description carries the full burden of disclosing behavior, but it only mentions an external data source. It does not disclose whether the call is read-only, what side effects or network dependencies exist, rate limits, or what happens to the input values beyond the schema's discarded-after-call notes.

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?

The description is a single front-loaded sentence with no filler. It states the core action and data source efficiently, earning its place without redundancy.

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?

Given a complex 9-parameter schema, no annotations, and no output schema, one sentence is far too thin. An agent cannot determine the expected return format, units, parameter selection rules, or why the schema contains many non-weather fields, so the description is not complete enough for reliable invocation.

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 the schema already documents all nine parameters. The description adds the useful context that city is the weather input and Open-Meteo is the source, but it does not clarify how the many unrelated parameters relate to the weather call or which parameter is actually required, so the value added is moderate.

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 action ('current temperature') and a specific resource ('city via Open-Meteo'), making the tool's core purpose immediately clear. It also differentiates from sibling tools like geo-hint by naming the data source.

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?

There is no guidance about when to use weather-hint versus sibling tools, nor any mention of when not to use it. The description only states what the tool does, leaving the selection criteria entirely to inference.

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