create_mailbox

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

No annotations, so description must fully cover behavior. Only states creation action and constraint; missing details on error handling, idempotency, or side effects. Does not disclose return value or potential failures.

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?

Single sentence, front-loaded with action and key constraint. No unnecessary words.

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?

No output schema, so description should explain return value or success indication, but does not. Lacks context about error handling, prerequisites (e.g., project existence), and behavioral expectations for a creation tool.

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?

Input schema already describes both parameters (project_id and slug) with format constraints. Description adds no extra meaning beyond schema, so baseline 3 is 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?

Clearly states 'Create a project-scoped email mailbox' with specific email format. Distinguishes from siblings like delete_mailbox and get_mailbox by specifying creation and the unique constraint 'One mailbox per project'.

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?

Implies usage by stating 'One mailbox per project', but does not explicitly mention when not to use or provide alternatives. Lacks prerequisites or error scenarios.

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