Email List Messages

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

Annotations already establish that this is read-only, non-destructive, idempotent, and open-world. The description adds 'newest' ordering and lists returned message fields, but it does not mention body_text truncation or that body content is included by default, though the schema documents those details. Overall this is safe and non-contradictory, with only moderate added behavioral context.

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 a single front-loaded sentence: it states the action and scope first, then gives a compact enumeration of returned fields. There is no filler, repetition, or unnecessary context.

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?

Given the rich input schema, output schema, and read-only annotations, the description orients an agent well for a simple folder-listing call. It could be more complete by suggesting when to use email_search or email_get_message instead, but nothing essential for invoking this tool correctly is missing.

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?

The input schema fully documents all four parameters with descriptions, defaults, and constraints (100% coverage), so the description does not need to compensate. The description's field list is about output, not parameters, and adds no meaning beyond what the schema already provides.

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 states a specific action ('List') on a concrete resource ('newest messages in a folder') and names the main returned fields. It is clear and unambiguous, but it does not explicitly differentiate from sibling tools like email_search or email_get_message(s), so it stops short of the top score.

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 phrasing implies this tool is for browsing recent folder contents, and the folder parameter references email_list_folders for valid folder names. However, there is no explicit guidance on when to choose this over email_search or email_get_message(s), nor any exclusions for search-style lookups.

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