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

The description adds meaningful behavioral context beyond annotations by stating that no API key is required, which directly affects invocation. It also discloses that signup URLs are included. The annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered; there is no contradiction.

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 concise sentences, with the core purpose front-loaded and the key invocation detail ('No API key required') placed at the end. Every sentence adds value and there is no redundancy with the schema or annotations.

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?

For a zero-parameter, read-only, idempotent tool, the description provides comprehensive needed context: what data is returned, which plans are included, and authentication requirements. No output schema exists, but the return content is sufficiently described for an agent to invoke the tool and interpret the result.

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 has zero parameters, so the description does not need to explain parameter meaning. The baseline of 4 applies because there are no parameters to document, and the description appropriately focuses on what the tool returns rather than inventing parameter details.

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 ('Get') and resource ('Scriptivox pricing information') and enumerates concrete contents: subscription plans (Free, Pro, Team), API pay-as-you-go rates, and signup URLs. This makes the tool's purpose immediately clear and distinct from broader siblings like get_product_info.

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 gives clear context for when to call the tool ('Get pricing information') and explicitly says 'No API key required,' which is an important usage qualifier. It does not explicitly rule out alternatives such as get_product_info or purchase_plan, but for a simple zero-parameter read tool the guidance is adequate.

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