List emails

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

No annotations are provided, so the description carries the full transparency burden. It discloses the newest-first ordering and the search option, but it does not state what the returned messages contain (e.g., metadata vs. full content), pagination behavior, or the role of the account parameter. This leaves key behavioral details unspecified.

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 that conveys the essential action and key modifiers without redundancy. It is concise and well-structured.

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?

The tool is simple with three optional parameters, but there is no output schema. The description covers the action, ordering, and search option, but it omits what the list returns (e.g., message summaries vs. full bodies) and what happens if no account is specified. This is a notable gap given the lack of output schema, yet the description still suffices for basic use.

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 only mentions the query being optional, which is already evident from the schema (no required fields). It adds no extra meaning for the account or maxResults parameters beyond what the schema already describes.

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 specifies the verb 'List', the resource 'messages from the inbox', and the ordering 'newest first', which distinguishes it from sibling tools like get, send, or modify. It also notes the optional Gmail search query, making the purpose 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?

The description gives clear context when to use this tool: to list inbox messages, optionally filtered by a search query. However, it does not explicitly mention alternatives or when not to use it (e.g., when a full message body is needed, use get), so it stops 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.