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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior. The description adds that the data belongs to the authenticated user and enumerates the account dimensions returned, which is useful context beyond what the annotations alone provide.

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 short sentences with the primary return value front-loaded and the actionable use case in the second sentence. No wasted or redundant 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?

With no parameters, a read-only/idempotent annotation set, and an output schema available, the description plus annotations fully cover what an agent needs to select and safely invoke the tool. The use-case sentence resolves the common pre-call decision.

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 parametersorestation; the description need not document inputs. The enumeration of plan, storage, site count, and limits aligns with the expected output and clarifies what account state is being reported.

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 the tool returns account-level data (plan, storage used, site count, plan limits) with a specific verb and resource. The data domain is clearly distinct from the sibling file/site management tools, so an agent can disambiguate without opening schemas.

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 ties the tool to a decision point: checking whether a new site can be created or how much storage remains, which is exactly when to call it before create_site. No alternative account-info tool exists among siblings, so not naming one is acceptable.

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