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

The annotations already declare read-only, idempotent, non-destructive behavior, while the description adds useful context: no prices, settlement/rule semantics, token estimates for line/table/all-cities output, and a fallback city-list behavior. It does not mention permissions or rate limits, but it adds behavior beyond the annotations without contradicting them.

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 dense but front-loaded: it leads with the resource and content, then states constraints, fallback behavior, and token-cost implications. Every clause carries operational information, including the no-prices exclusion and size-cost estimates.

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?

Because there is no output schema, the description carries the return-content burden and does so by listing the market fields and forecast values. It also explains fallback behavior and output size costs, though 'credits' remains undocumented and the exact output shape is only partially described.

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 83%, and the schema already documents enums and defaults for date, place, family, size, and format. The description adds useful meaning for place/family requirement and size token costs, but it omits the 'credits' parameter entirely and adds little detail for date/format 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?

The description names the resource (weather markets) and enumerates the returned content: settlement station and rule, the observed number, our value, the official result, and forecast daily max/min. It also explicitly excludes prices, making the purpose specific enough to distinguish it from a generic forecast tool, though it does not directly name sibling alternatives.

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 states the key input constraint, 'Needs place or family,' and explains the fallback when neither is supplied: the list of market cities. It also ties size defaults to whether a place is provided, but it does not compare this tool with forecast/history/search or state when not to use it.

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