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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. The description still adds real value by calling out that the call is 'free' — meaningful for a tool whose subject matter is credit consumption — and implies no side effects on the account.

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?

A single tight sentence that front-loads the resource and then enumerates the three pricing categories, with the cost/safety qualifier last. No filler.

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 no output schema, the description does the work of naming what is returned (three pricing components), which is adequate for a zero-param read tool. Exact response shape and currency/format details are left unspecified, a minor gap for an informational tool.

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. There is nothing param-related the description could add or omit.

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 (returns Wozapi prices) and enumerates exactly what pricing is covered: per-credit lookup pricing by quantity, address-list pricing by size, and trial terms. This is clearly distinguishable from siblings like get_account_balance (balance, not prices) and create_credit_payment_link (a mutation, not a read).

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 implies usage by noting it is 'read-only and free', which tells the agent it is safe to call without cost, but it never says when to call this instead of get_account_balance or the payment-link tools. Usage is inferable rather than stated.

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