list_emails

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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely useful context beyond them: emails are not marked as read (an important side effect for a read-only listing) and each result carries an automated-mail heuristic, which an agent could not otherwise anticipate.

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 tight sentences, front-loaded with the operation and ordering, then the return shape and the read-status caveat. No filler or redundancy.

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, the description compensates by enumerating the returned fields (sender, subject, date, read status, automated flag) and the non-marking-as-read behavior. For a four-parameter read-only listing tool this is sufficient to call it correctly.

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% and every parameter (count, since, folder, unreadOnly) already carries a description with defaults, so the baseline is 3. The description adds no syntax or format detail beyond what the schema supplies, though it does echo the folder scoping.

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?

States a specific verb and resource ('List recent emails in a folder') plus ordering (newest first) and the fields returned, so the agent knows exactly what it gets. It does not name or contrast with the sibling search_emails, so the boundary between listing and searching is left to inference.

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 word 'recent' plus the folder/count framing implies the intended browsing use case, but there is no explicit statement of when to prefer this over search_emails or read_email, and no exclusions. Usage is inferable but not guided.

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