List emails at an address

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

With no annotations, the description carries the full burden. It usefully discloses ordering ('newest first'), the exclusion of bodies, and scope ('currently stored'), but says nothing about pagination, result limits, permissions, or what 'One operation' actually means — which reads as cryptic rather than informative.

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?

One sentence, front-loaded with the core action and result shape, with the ordering and body-exclusion constraints trailing compactly. No filler.

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?

With no output schema and no annotations, the description does the important work of describing the return set (emails, newest first, bodies omitted). The main gaps are pagination/limits and the meaning of the trailing 'One operation', which are not explained.

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 0% for the single 'address' parameter; the schema only declares type=string/format=email. The description adds that the address selects the mailbox whose emails are listed, which is minimal but consistent with the schema's format hint.

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?

Specific verb+resource ('List the emails') scoped to 'an address', and it distinguishes itself from read_email by noting there are 'no bodies'. It does not name siblings explicitly, but the resource and result shape are unambiguous.

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?

Usage is implied rather than stated: the '(no bodies)' note hints that read_email is the tool for message content, and 'newest first' signals a listing/scan use case. There is no explicit when-to-use or when-not-to-use guidance against wait_for_email, delete_emails, or list_domains.

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