reply_email

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

No annotations are provided, so the description must fully disclose behavioral traits, but it only says 'reply' without explaining whether it sends immediately, opens a compose window, or requires additional input. This omission is significant for a mutation tool.

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 sentence starting with 'Use this when...', which is front-loaded and direct. However, it appears truncated, reducing its effectiveness. Assuming completion, it would be concise, but the cut-off warrants a moderate score.

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 lack of annotations and output schema, the description should provide a complete picture. It only mentions the platform and basic action, omitting details on behavior, prerequisites, or return values. The tool's simplicity does not fully compensate for missing context.

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 has no parameters, but the description implies a required 'message ID' from list_emails, creating confusion. With 0 parameters, the schema coverage is 100% trivially, but the description contradicts the schema by suggesting an unlisted parameter.

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 states the action (reply) and the specific resource (Apple Mail emails), distinguishing it from sibling tools like m365_reply_email. The truncated reference to 'list_...' slightly reduces clarity but still conveys the context.

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 explicitly specifies when to use the tool (to reply to Apple Mail emails), providing clear usage context. It does not explicitly state when not to use it, but the platform specificity inherently excludes other email services.

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