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

Annotations already establish read-only, idempotent, non-destructive, closed-world behavior. The description adds useful behavioral context by naming the returned fields and explaining the workspace id/null relationship with list_mailboxes.

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?

Three short sentences with no wasted language. The resource concept is front-loaded, followed by return information and the cross-tool relationship.

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 list tool with rich annotations, the description is complete enough. It covers what is returned and how workspace ids relate to mailboxes, with no output schema required.

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 are no parameter semantics to document. The schema is empty and fully described, making the baseline score 4 appropriate.

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 clearly identifies the resource as client workspaces and states the returned fields (id, name, mailbox count). It does not use an explicit action verb like "list," but the tool name and return statement make the purpose clear and distinguish it from list_mailboxes.

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?

It implies usage by explaining that each mailbox in list_mailboxes has a workspace id and that null means My mailboxes. However, it does not explicitly say when to call this tool versus siblings like get_workspace_report, create_workspace, or list_mailboxes.

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