SandMail — Disposable Email API for AI Agents

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes the blocking behavior and timeout mechanism, which are key traits. However, it lacks details on permissions, rate limits, error handling, or what happens after timeout (e.g., returns null or error), leaving gaps for a tool with potential real-time implications.

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?

The description is front-loaded with the core purpose in the first sentence and adds essential behavioral detail in the second. Both sentences earn their place by providing critical information without redundancy, making it highly efficient and well-structured.

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?

Given the tool's moderate complexity (blocking wait with timeout), no annotations, and no output schema, the description is partially complete. It covers the basic operation but omits details like return values (e.g., email content or timeout status), error conditions, or dependencies on other tools (e.g., requires an existing inbox from 'create_inbox'), leaving room for improvement.

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?

Schema description coverage is 100%, so the schema already documents both parameters ('email' as inbox address and 'timeout' with range/default). The description adds no additional meaning beyond what the schema provides, such as clarifying parameter interactions or usage nuances, resulting in a baseline score.

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 specific action ('wait for a new email to arrive'), the resource ('inbox'), and distinguishes it from siblings like 'get_emails' (which likely retrieves existing emails) by emphasizing the blocking/waiting behavior. It precisely communicates the tool's function without being tautological.

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 usage context by specifying it blocks until an email arrives or timeout is reached, suggesting it's for real-time monitoring rather than historical retrieval. However, it doesn't explicitly state when to use this versus alternatives like 'get_emails' or 'wait_for_otp', nor does it provide exclusions or prerequisites, leaving some ambiguity.

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