Backend status

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered structurally. The description adds no behavioral traits beyond that (no side effects, auth needs, or rate limits), and the return content it names is already captured by the existing output schema. No contradiction, but limited added value.

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 tight sentences with no filler. The purpose is front-loaded and the call condition follows immediately, so 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?

With an output schema documenting return values and annotations covering safety, the description only needs to convey purpose and when to invoke it, and it does both. Nothing an agent needs to call a zero-parameter diagnostic 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, so there is nothing for the description to disambiguate; baseline 4 applies. The description correctly implies a no-argument diagnostic call.

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 first sentence states exactly what the tool reports: the serving backend, per-call cost, and available optional features in the current configuration. This is a distinct diagnostic/config resource that cannot be confused with any ad-related sibling tool, so an agent can identify its role without opening the schema.

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 gives an explicit trigger: 'Call this when a tool reports something unavailable, before telling the user it cannot be done.' That is a clear, actionable condition. It does not name when-not-to-call or alternatives, but the siblings are unrelated ad tools with no overlapping function, so there is little to exclude.

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