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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and a closed-world scope, so the safety profile is fully covered. The description adds value by disclosing the shape of the result (dimensions with their valid values), but says nothing about caching, stability of slugs, or whether the list is exhaustive/fixed.

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, no filler, and the primary purpose is front-loaded before the cross-reference to search_ads. Every clause earns its place.

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?

There is no output schema, so the description correctly compensates by stating what the tool returns (taxonomy dimensions plus their valid values) and why that matters. For a zero-parameter read-only lookup, nothing an agent needs is missing.

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 zero parameters, which sets the baseline at 4. Schema coverage is 100% and there is nothing for the description to clarify, so no adjustment is warranted.

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 and resource ('Lists the taxonomy dimensions of the Ad Radar library') and enumerates examples of what those dimensions are, so the agent knows exactly what comes back. It also ties itself to a sibling by naming the 'tags filter of search_ads', which no other tool in the list would do.

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 second sentence establishes the reason to call it: these slugs are what the tags filter of search_ads accepts, implying it should be used to discover valid filter values before searching. It stops short of an explicit when-to-use/when-not-to-use statement or naming a fallback if the taxonomy is already known.

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