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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds that results include WOEIDs, which is useful content context, but says nothing about response size, truncation, or the format parameter's effect on output.

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?

A single sentence, front-loaded with the resource, with no redundant or filler text. Every clause earns its place by naming the resource, its content, and the downstream consumer.

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 simple two-optional-param read tool with no output schema, the description tells the agent what comes back (locations and their WOEIDs) and what they're for. Coverage of output shape is adequate, though it doesn't mention whether the list is exhaustive or truncated.

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 both parameters (format, max_chars) are fully documented in the schema itself. The description adds no parameter guidance beyond the schema, so the baseline 3 applies.

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 (List) and resource (locations — countries and cities) and clarifies the payload's purpose: WOEIDs for get_trends. This cleanly separates it from the sibling get_trends, which consumes those identifiers rather than listing them.

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?

Frames the tool as the lookup step feeding get_trends, which implies when to use it (to discover valid location identifiers). It doesn't state exclusions or explain what to do if a location isn't listed, but the workflow context is clear.

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