Backend status

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

The annotation already marks the tool as read-only, idempotent, and non-destructive, so the description does not need to repeat those. It adds useful behavioral context by revealing that the tool can explain cost-per-call and availabe optional features, which matters for deciding whether an unavailable action is actually impossible or merely unsupported.

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. The first sentence lists exactly the information returned, and the second gives the precise moment to call the tool. Everything in the description 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?

The tool takes no inputs, has an output schema, and has unambiguous read-only annotations. The description is sufficient for an agent to know when and why to call it, and because there is an output schema, the description need not enumerate return fields.

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 input schema requires no parameters, so the description has no parameter meanings to add. The tool's whole purpose is self-contained, and the description adequately conveys that calling it requires no arguments.

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 what the tool reports: the active backend, per-call cost implications, and available optional features. This distinguishes it from the ad-focused sibling tools, which all operate on ads or advertisers rather than on backend configuration.

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 condition: call this when another tool reports something unavailable, and just before informing the user that something cannot be done. This is concrete, actionable usage guidance and there are no alternative sibling tools that compete with this purpose.

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