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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description usefully adds that the payload is usage/plan data with percentage metrics, but discloses nothing further about auth requirements, rate limits, or freshness of the usage numbers.

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 front-loaded sentence naming the resource and its returned fields, followed by the raw endpoint. No filler or redundancy.

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, read-only tool with no output schema, the description covers what the agent gets back (plan, add-ons, contact usage) and how it is fetched. Only minor gaps remain, such as whether account context is implicit from credentials.

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, which is the baseline-4 case; the schema is empty and fully covered. Nothing in the description is needed to compensate for a parameter gap.

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?

Namespace (email plan, add-ons, contact usage) is a specific resource, and the parenthetical enumerates exactly what is returned (active/account/total contacts, percent used), plus the underlying endpoint. It is clear on its own, though it never explicitly contrasts itself with neighbors like benchmark_get_account or benchmark_get_settings that an agent might confuse it with.

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 when-to-use guidance, no prerequisites, and no mention of alternative tools for related account information. The only implicit cue is that it is a read endpoint (GET /Client/Plan).

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