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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and a closed world, so the safety profile is fully covered. The description adds the useful fact that only public (non-account-scoped) plans are returned and that pricing/request counts are included, but says nothing about auth requirements or pagination.

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 with no filler: the first defines the resource and payload, the second routes the agent to the consuming tool. Front-loaded and fully earned.

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?

An output schema exists, so return-value documentation is not required, and the description covers scope and payload. It stops short of noting that this listing is unauthenticated/public, which would be the last useful behavioral detail for an agent deciding whether it can call it in a bare context.

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 the baseline is 4 and there is nothing for the description to disambiguate. The mention of a 'plan' value refers to output consumed by subscribe_to_plan, not to an input parameter.

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 identifies the exact resource ('publicly available AudD subscription plans') and the payload ('pricing and included requests'), so an agent knows precisely what comes back. The 'publicly available' qualifier implicitly separates it from account-scoped siblings like get_billing_history or get_account_status, though no sibling is named explicitly.

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 gives a concrete downstream usage rule — feed the 'plan' value into subscribe_to_plan — which is genuinely actionable context. However, it never states when to call this tool versus the billing siblings, nor any prerequisites, so guidance is implied rather than enumerated.

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