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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world. The description adds real context beyond them by naming the required auth scope (`cuenta:read`) and that an account is required, which is the key operational gating detail.

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 tight sentences with no filler; the returned content is front-loaded and the auth prerequisite is a single trailing clause. Every part earns its place.

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?

An output schema exists to explain the return shape, so the description need not detail return values. It covers what the tool provides and the auth gate, which is everything an agent needs for a no-parameter read tool.

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 are no parameter semantics to document; the baseline for a parameterless tool is 4. The description correctly adds no spurious 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?

Enumerates concretely what the tool returns for the account: plan, report quota, available features, token scopes, usage limits, and useful URLs. The resource (account) is clear and no sibling in the list covers account-level information, so it is effectively distinguishable, though the sentence is a noun list rather than an explicit verb+resource statement.

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?

States a prerequisite (requires an account with `cuenta:read` scope), which helps an agent confirm eligibility before calling. However, it gives no explicit when-to-use guidance or exclusions, and with no competing sibling it relies on implied usage.

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