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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false, and destructiveHint=false, so the safety profile is fully covered. The description adds the useful detail that results are measured in bytes against the plan, but says nothing about scope (per-site vs account) or freshness, which is a modest contribution beyond the annotations.

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?

One tight sentence that front-loads the verb and enumerates the returned metrics with units. No filler, though it is quite terse given the tool takes a site argument.

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 simple read-only metric tool with a fully documented single parameter and no output schema, the description tells the agent what data comes back, which is the key missing piece. Only minor gaps (per-site scope, currency of data) remain.

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?

Schema coverage is 100% and there is a single 'site' parameter already documented in the schema. The description adds no parameter-level detail, so the schema carries the load — the baseline 3 for high coverage.

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?

States a specific verb ('Shows') and resource set (storage, files and folders, and traffic) scoped against the account's plan, with units (bytes). Clear purpose, though it does not explicitly differentiate itself from siblings like list_files or list_sites that touch overlapping resources.

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?

Usage is implied by the name and content — an agent can infer this is for checking consumption against a plan — but there is no explicit when-to-use, when-not-to-use, or alternative routing. Adequate but with an obvious gap.

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