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

Annotations already establish read-only, non-destructive, non-open-world behavior. The description adds meaningful behavioral context beyond that: the status lifecycle includes active, trial, 3-day renewal grace, and expired read-only, and it explains that a limit of 0 means unlimited.

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?

The description is front-loaded with the resource and then the returned data, with a clear final usage instruction. It is dense as a single long sentence, but nearly every clause carries useful information; the status parenthetical is slightly run-on but not wasteful.

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 tool with no output schema, the description explains the return shape thoroughly, including status values, limit semantics, usage meters, and the can-do summary. It also supplies the critical preflight instruction, so an agent has what it needs 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?

The tool takes no parameters, so there are no parameter semantics for the description to document. The baseline for a zero-parameter tool is 4, and the description correctly avoids unnecessary parameter discussion.

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 states a specific resource, the founder's current subscription, and enumerates exactly what it returns: plan name and price, status, abilities and limits, usage against meters, and a can-do summary. It is not tautological and clearly distinguishes this from the product/keyword/report tools listed as siblings.

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?

It gives an explicit routing instruction: call this FIRST before using any other tool to check which features the plan allows. That is a clear when-to-use rule tied to the tool's role as a preflight authorization check.

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