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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description's 'Read-only and free' largely restates that, though 'free' adds a small piece of cost information not present in structured fields; it adds no detail on caching, freshness, or response shape.

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?

One sentence, front-loaded with the resource and immediately followed by the enumerated return categories, then closed with the safety/cost note. No filler or redundancy.

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 input parameters, no output schema, and annotations covering the safety profile, the description carries the full burden of explaining returns - which it does by naming the three price categories. It stops short of format/currency or unit details, but is adequate for a parameterless read of a small price table.

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; the baseline of 4 applies. Describing the returned price categories is a bonus but not parameter semantics.

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 (Returns) plus the exact resource (WozApi prices) and enumerates the three price categories returned: credit cost per single lookup quantity, address-list price by size, and trial terms. This is far more specific than siblings like get_account_balance or get_address_list, so an agent can distinguish it without opening a 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?

Usage is only implied by the content: an agent can infer this is the tool to consult before buying credits or starting a trial. However, no sibling is named as an alternative and there is no explicit when-to-use/when-not-to-use guidance (e.g., use get_account_balance for current credits instead).

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