List emails

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

With no annotations, the description carries the full burden of behavioral disclosure. It conveys read-only behavior through 'List' and tells the agent what is returned, including flags/seen. It does not explicitly state that nothing is modified or marked as read, and it omits the POP3-only-INBOX limitation that appears in the schema.

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 two sentences with no filler. It front-loads the core action and ordering, then gives the concrete return-field list, making every sentence informative.

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?

There is no output schema, so the description appropriately lists the returned summary fields. Combined with the schema's defaults and folder constraints, the tool is reasonably complete for a simple listing operation, though it could add a note about non-mutating behavior or protocol limits.

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 for the undocumented limit and unread_only parameters. The phrase 'newest messages' adds slight ordering context, but it does not explain how limit or unread_only change the result beyond what their names and schema defaults already imply.

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 verb and resource: it lists the newest messages in a folder and returns summaries with specific fields. It is distinct from obvious siblings by indicating summaries rather than full messages, but it does not explicitly contrast itself with sibling tools like get_email or search_emails.

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 intended use is implied: use this when you want newest message summaries for a folder. However, the description gives no explicit guidance on when to choose search_emails, get_email, or mark_read instead, and it does not state exclusions such as not being for full-message retrieval.

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