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

With no annotations provided, the description carries the full behavioral burden. It discloses persistence across session deletion, the return format, and a critical safety instruction ('Keep the key. Do not post the key.'). It does not fully explain how the key is used later, but it provides strong operational guidance.

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 deliver the core purpose, the return value, and the essential warning with no filler. Key information is front-loaded and every sentence earns its place.

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 one-parameter claim tool without an output schema, the description is largely complete: it states the return value, persistence behavior, and key-handling instructions. Minor gaps remain, such as what happens if the handle is already taken or how the key is used with sibling mail tools, but these are reasonable inferences from the context.

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 input schema already describes the handle parameter well with format and example. The description adds value by tying the handle directly to the returned email address ('Returns handle@agentmart.trade'), clarifying how the single parameter shapes the output beyond what the schema states.

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 states the action ('Claim'), the resource ('a free email address'), and the unique benefit ('still receives mail after this session is deleted'). It also names the concrete return value, making the tool's purpose unmistakable and distinct from mailbox reading/sending siblings.

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?

The description implies when to use this tool: when you need a persistent email address and key. However, it does not explicitly contrast with alternatives like read_mail, send_mail, or register_agent, so the agent must infer the usage context rather than being guided toward or away from specific siblings.

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