What the application's email has sent

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

With readOnlyHint and openWorldHint already declared, the description still adds real behavioural context: ordering (newest first), the deliberate absence of subject/body/address, and the rule that `outcome` is null until Resend reports and while `reporting` is false. It omits retention window and any rate/volume limits, which keeps it from a 5.

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?

Front-loaded with what the log is, then use cases, then the data-absence caveat, then the null/pagination mechanics — every sentence carries information an agent needs and none repeats the schema verbatim.

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 exists, so the description carries the return-value burden, and it does: the row contents, ordering, and the `next` cursor are all described well enough to write a correct query and interpret the response. The `reporting` flag is referenced, which fills a gap the input schema leaves open.

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 coverage is 100%, so the baseline is 3; the description earns above that by explaining the null-until-reported semantics of `outcome` (telling the agent that outcome filters will miss pending rows) and by restating the cursor contract for `before` in operational terms ('the `next` of the last answer'). It does not clarify `limit` behaviour or defaults beyond the schema.

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 names a specific resource and scope: the relay's log for this application, newest first, with the fields it carries (timestamp, address count, relay status, report outcome, reason). An agent can distinguish it from general settings tools, but it never explicitly contrasts itself with near-neighbours like email_status, email_overview or email_deliverability, so the sibling boundary is inferred rather than stated.

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?

It gives concrete triggering questions ('did my email go out', 'why did that one not arrive'), which is clearer than most definitions. It does not say when to prefer email_deliverability or email_status, and names no exclusions, so it falls short of a 5.

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