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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is fully covered. The description adds genuine domain context (prices are included, the current plan is returned, the first space is a free private preview), but says nothing about ordering, pagination, or auth requirements for a pricing call.

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 short sentences with no padding, and the content of the response is front-loaded before the usage trigger. The second sentence is slightly muddled in its referent ('show them' — show the plans), which keeps it from a 5.

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 listing tool with no output schema, the description covers what is returned and when to surface it. Missing details like result ordering or how the current plan is marked are minor given the simplicity of the call.

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 and the schema coverage is 100%, so there is nothing for the description to disambiguate. Baseline of 4 applies for a no-parameter tool.

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 identifies the resource unambiguously — hosting plans with prices plus the account's current plan — which tells an agent what it will get back. It never states an action verb (the listing behavior is inferred from the name/title), but there is no sibling that could be confused with it, since the other tools are about tours, spaces, uploads, and account linking.

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 second sentence gives an explicit trigger: show these when the person wants to publish or keep a space. That is real when-to-use guidance rather than implied context. It stops short of naming an alternative tool or a when-not condition, so it is not a 5.

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