reply_to_email

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

Even though no annotations are provided, the description discloses notable behaviors: prior approval is required, and attachments over 3MB go through an internal draft-then-send step while reaching the same result. This goes beyond basic schema info and sets accurate expectations.

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 concise sentence with one clarifying parenthetical. It conveys the primary purpose and key constraints without unnecessary detail, making it easy to parse.

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?

There is no output schema and no explicit return-value description, but for a send-type action, the absence may be acceptable. The description covers what the tool does and important edge cases (attachment size limits and internal handling), giving enough context for an agent to call it correctly.

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 57%; emailId, body, and replyAll lack descriptions. While their meanings are fairly obvious from the tool name and context, the description does not add further semantics for these missing fields. The attachment constraints are well documented, but overall parameter clarity is moderate.

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?

Description states a specific verb and object: 'Reply to an existing email thread.' It clearly distinguishes from sending a new email or creating a draft, though it does not explicitly name the sibling alternatives. The sibling list includes create_reply_draft and send_email, making the intent reasonably clear.

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 it via 'existing email thread' but does not explicitly state 'use this instead of send_email for replies' or compare with create_reply_draft. The 'Requires prior approval' note gives a condition, but usage guidance is left implicit.

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