reply_email

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

With no annotations, the description carries full burden but only says 'Reply to an existing email.' It does not disclose behavior such as whether it includes the original message, supports CC/BCC, or sends immediately. This is insufficient for an agent to understand side effects.

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 one short phrase with no unnecessary words. However, it may be too brief, sacrificing completeness for conciseness.

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 no parameters, output schema, or annotations, the description is incomplete. It does not explain how the agent should specify which email to reply to or what the tool returns, leaving significant gaps in usability.

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 0 parameters, so description coverage is 100% trivially. The description does not explain how the target email is identified (e.g., via context from a prior read). Baseline for 0 params is 4, but ambiguity lowers it to 3.

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 resource ('an existing email'), which is specific and distinct from creating a new email. However, it does not differentiate from the sibling 'send_email' tool, which might also have reply capabilities.

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 provides no guidance on when to use this tool versus alternatives like 'send_email' or 'move_email'. It does not specify prerequisites or context, such as requiring a previously read email thread.

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