Plan usage

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds useful behavioral scope by pinning the measurement to a monthly billing window and a plan limit, but says nothing about reset timing, overage behavior, or whether the count is live or cached.

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?

A single short sentence with no filler, and the key qualifier (this month against plan limit) is front-loaded. It reads as a fragment without a leading verb, which is slightly less scannable than an imperative form.

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 and annotations cover safety, so return shape and side-effect risk need not be restated. For a no-parameter, no-side-effect tool the description supplies everything needed to decide to call it, short of a policy on when quota checks are warranted.

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?

Zero parameters, so there is nothing for the description to disambiguate; baseline is 4. The description correctly avoids inventing inputs, implicitly confirming the tool needs no arguments.

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 names the specific resource (scan usage) and the exact measurement (this month's consumption against the plan limit), which is more precise than the bare name get_usage. It lacks an explicit verb, but the intent is unambiguous. Differentiation from the scan/findings siblings is clear by subject matter alone.

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?

There is no explicit when/when-not guidance or named alternative, but for a zero-argument quota read the intent is self-evident: check remaining allowance before calling start_scan. Usage is implied rather than stated.

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