getCapacity

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

With no annotations, the description carries the behavioral burden. The verb "Return" strongly implies a read-only operation and there are no parameters that could mutate state, but the description does not explicitly confirm read-only behavior, side effects, authorization needs, or rate limits.

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 a single front-loaded sentence that states the return scope immediately. The enumerated storage layers earn their place by making the output scope concrete, with no wasted wording.

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 tool with an output schema, the description is largely complete: it explains what gets returned and the output schema can define the exact response shape. The only gap is the lack of explicit read-only or safety framing, which is more noticeable because annotations are empty.

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 has zero parameters, so there is no parameter semantics for the description to explain. The schema coverage is 100%, and the baseline for no-parameter tools is a 4.

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 uses a specific verb and resource: it returns on-disk byte totals by storage layer. It enumerates the exact layers covered plus free disk, which makes the tool's scope unambiguous and distinguishable from the sibling tools.

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 description states what the tool returns but gives no explicit guidance on when to use it, when not to use it, or what alternative to prefer. Usage is only indirectly implied by the tool name and the capacity-related return fields.

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