List Emails

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=true, so the safety profile is clear. The description adds behavioral context by specifying the default folder (inbox) and the folder parameter's scope, which goes beyond the annotations. It does not disclose details like pagination or ordering, but the output schema likely covers return structure.

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 with no filler. Every word contributes to understanding the tool's core behavior, making it highly 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?

For a simple list tool with two optional parameters, an output schema, and strong annotations (read-only, idempotent), the description covers the essential context: the action (list), the subject (emails), and the key default (inbox). The output schema handles return values, and annotations handle safety, making the description sufficient.

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 100%, so the parameter descriptions already document count and folder. The description adds value by explicitly stating the default folder as 'inbox', which is not present in the folder property's description. This enriches parameter understanding beyond the schema.

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 is specific: 'Lists emails from a folder (default: inbox)' clearly identifies the verb (List), resource (emails), and scope (folder-based). It distinguishes from sibling tools like read-email (single email) and search-emails (filtered search) by stating the folder-based listing behavior.

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 implies when to use the tool (when listing emails from a folder) but does not explicitly state when not to use it or mention alternatives such as search-emails for filtered queries. The guidance is derived from the tool's name and behavior rather than stated directly.

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