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

Annotations already mark the operation read-only, and the description adds meaningful context: the tool reports tier, quota usage, and the special meaning of a null cap (unlimited). It does not describe exact response fields, but for a simple read-only status tool the added context is adequate.

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 core purpose is front-loaded, followed by a concrete usage trigger and the one non-obvious semantic detail (null cap). Every sentence 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?

For a parameterless read-only tool with no output schema, the description covers what it reports (tier and quota usage), why to call it (pre-flight check), and how to interpret an important value (null cap). It is complete enough for an agent to decide when to call it, though exact response fields are not enumerated.

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?

There are zero parameters, so there is no schema burden. The description goes beyond schema by explaining the meaning of the cap field (null means unlimited), which helps interpret results.

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?

Description clearly identifies the tool as reporting this account's tier and quota usage, with a specific use case (checking before large batch uploads). It distinguishes itself from sibling tools, none of which report account status or quota.

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?

Explicitly states when to check it: before large batch uploads, to warn at the quota wall rather than failing midway, and to answer 'how much room do I have left'. No exclusion or alternative is needed since no sibling tool serves this role.

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