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. It discloses the sorting behavior, which is useful, but lacks critical details such as pagination, rate limits, authentication needs, error conditions, or what 'all emails' entails (e.g., time range, limit). For a read operation with zero annotation coverage, this is insufficient.

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 a single, efficient sentence with zero waste. It front-loads the core purpose and includes essential behavioral detail (sorting), making it appropriately sized and well-structured for its purpose.

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 no annotations and no output schema, the description is incomplete. It lacks information on return values (e.g., email format, fields), error handling, and operational constraints. For a tool with one parameter but unknown output complexity, this leaves significant gaps for an AI agent.

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%, with the parameter 'email' documented as 'The inbox email address'. The description adds no additional meaning beyond this, as it doesn't clarify parameter usage or constraints. Baseline 3 is appropriate since the schema handles parameter documentation adequately.

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 ('List all emails') and resource ('received in an inbox'), with specific sorting behavior ('sorted by date, newest first'). It distinguishes from siblings like 'wait_for_email' by focusing on listing rather than waiting, but doesn't explicitly differentiate from potential overlapping functions with other tools.

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?

No guidance is provided on when to use this tool versus alternatives like 'wait_for_email' or 'list_inboxes'. The description implies usage for retrieving emails from a specific inbox but doesn't mention prerequisites, exclusions, or comparative contexts with sibling tools.

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