AgentMail

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

No annotations are provided, so the description carries full burden for behavioral disclosure. 'List messages' reveals nothing about permissions, rate limits, pagination behavior, or response format. It fails to describe what 'list' entails operationally.

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 extremely concise with two words, but this brevity results in under-specification rather than effective communication. Every word earns its place, but the description is too minimal to be helpful.

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 3 parameters with 0% schema coverage, no annotations, and no output schema, the description is completely inadequate. It provides no context about the tool's behavior, parameters, or output, leaving critical gaps for agent understanding.

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 0%, meaning parameters (inbox_id, limit, offset) are undocumented in the schema. The description adds no parameter information beyond what the schema provides, offering no clarification on usage, constraints, or relationships between parameters.

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 'List messages' is a tautology that restates the tool name without adding meaningful context. It specifies the verb 'list' and resource 'messages' but lacks any distinguishing details about scope, format, or relationship to sibling tools like listThreads or getMessage.

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?

No guidance is provided on when to use this tool versus alternatives. With siblings like listThreads, getMessage, and getThread available, the description offers no context about selection criteria, prerequisites, or typical use cases.

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