mail_reply_to_email

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

The description discloses key behaviors: preserving threading headers, quoting the original message, and the effect of reply_all. With no annotations, this is good transparency. However, it does not mention whether the reply is sent immediately or any side effects like marking the original as replied.

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 concise with a brief opening sentence followed by a clean Args list. Every sentence is informative and there is no redundant information. It is well-structured and front-loaded.

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 description covers the main parameters and behavior adequately for a reply action. With an output schema present, it need not explain return values. However, it could mention that the reply is sent immediately and any error conditions (e.g., invalid email_id) to be fully complete.

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%, so the description fully compensates. It explains each parameter: email_id as 'ID of the email to reply to', text_body including that the original is quoted below, reply_all as CC all recipients, identity_id with auto-selection logic. This adds significant meaning beyond the schema titles.

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 'Reply to an email, preserving threading headers and quoting the original.' This is a specific verb+resource combination, and it distinguishes this tool from siblings like mail_send_email (new email) and mail_forward_email (forwarding) by emphasizing the reply action and threading 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 (when replying to an email) and provides context for parameters like identity_id ('auto-selects first if omitted'). However, it does not explicitly state when not to use or mention prerequisites (e.g., the email must exist), which would improve guidance.

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