Filter values

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety and external access are covered. The description adds valuable context by specifying the content categories returned and advising pre-filtering use, though it does not describe the return format or any limitations.

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 short sentences, front-loaded with the tool's output categories followed by a concise usage recommendation. No wasted words.

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 the simple lookup nature, no parameters, and annotations covering safety, the description is nearly complete. It could optionally clarify the return structure (e.g., arrays per category), but the listed categories make the tool's behavior sufficiently clear for correct 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?

The tool takes no parameters, so there is nothing for the description to document beyond the schema. Baseline score of 4 applies as no parameter semantics are needed.

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 clearly states the tool returns valid values for stats filters, explicitly listing the covered dimensions (countries, categories, OS, browsers, platform). It distinguishes itself from a generic filter getter, though it does not explicitly name a sibling tool for contrast.

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 description gives a clear usage trigger: 'Call this before filtering if unsure of exact spelling.' This tells the agent when to invoke it, but does not state when not to use it or name alternative tools for known values.

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