reply_to_email

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

With no annotations, the description carries the full behavioral burden, and it does disclose the important two-step preview/confirm safety gate before a mutation occurs. However, it omits side effects (does it mark the thread read, send immediately on confirm, apply to all recipients with reply_all) and failure behavior.

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?

Three short sentences with no filler; the core action and the confirm flow are front-loaded. Nothing is redundant.

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?

This is a mutating, five-parameter tool with no annotations, no output schema, and zero schema descriptions, so the description needs to work harder than it does. It covers the confirm flow but leaves most parameters and the preview payload's shape unexplained.

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% across five parameters, and the description only explains `account` ('an email or alias') and implicitly `confirm_token` via the two-step flow. `message_id`, `body`, and `reply_all` receive no semantic explanation anywhere.

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 opens with a specific verb and resource: 'Reply in-thread to a message,' which distinguishes it from send_email (new message) and forward_email (forward). It doesn't explicitly contrast with the sibling create_reply_draft, so the agent must infer the draft-vs-send distinction.

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?

It gives concrete invocation guidance: the first call yields a preview plus confirm_token, and a second call with that token actually sends. That is a clear usage protocol. It does not state when to prefer this over create_reply_draft/send_draft or what to do if message_id is invalid.

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