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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint. The description adds useful behavioral context: the data is public, prices are in USD, both one-time and monthly options exist, and the response includes inclusions, exclusions, and a purchase page. This goes beyond the annotations without contradicting them.

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 no filler. The main return content is front-loaded, and the parameter behavior is stated clearly and efficiently.

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?

This is a simple tool with one optional parameter and no output schema. The description sufficiently explains what the response contains and how to get all plans versus a specific one. Nothing critical is missing for an agent to call it correctly.

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?

Schema coverage is 100% and the schema already describes plan_id as 'Return only this plan or add-on.' The description adds meaningful behavior by stating 'Omit plan_id to get everything,' clarifying the default behavior when the optional parameter is not provided.

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 identifies the resource: public plans and add-ons with prices in USD, billing frequency, inclusions/exclusions, and purchase page. It does not explicitly differentiate from sibling tools like list_services, but the resource is specific enough that an agent can understand what this tool returns.

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 no guidance on when to use this tool versus siblings such as list_services or get_contact_options. It only explains the optional plan_id parameter behavior with 'Omit plan_id to get everything,' which is parameter usage rather than tool-selection guidance.

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