List sent emails

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

There are no annotations, so the description carries the behavioral burden. It discloses ordering ('newest first') and result fields ('delivery status and open/click counts'), which is useful, but doesn't mention pagination defaults, filtering semantics, or that the operation is read-only beyond the word 'List.'

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?

Two sentences convey the resource, ordering, result contents, and the intended use case without waste. The key purpose is front-loaded and the use case 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?

The tool is simple, but with no output schema and no annotations, the description should cover more ground. It names key return fields and the use case, yet omits pagination behavior, default limits, and possible status filter values, leaving gaps an agent must infer.

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 only 33%, and the description does not compensate: it never explains limit, offset, or status filtering behavior. Status is documented in the schema, but limit and offset remain undocumented, and the description only hints at ordering rather than parameter usage.

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?

Description uses a specific verb ('List') with a clear resource ('emails previously sent through Maillog') and adds ordering and output fields. It clearly distinguishes from the sibling tool send_email by focusing on checking whether a message went out.

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?

Explicitly says 'Use this to check whether a message actually went out,' which gives a concrete condition for selecting this tool. It doesn't spell out when-not-to-use or name the sibling explicitly, but the description frames this as the read-side counterpart to sending.

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