Reply to an email

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

Annotations indicate non-read-only and non-destructive. Description adds behavioral detail: threading headers are preserved, and reply_all/include_quote toggle CC and quoting. These go beyond annotations to specify side effects of optional parameters.

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?

Two concise sentences: first sentence states core functionality, second covers key options. No wasted words; information is 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?

Moderate complexity (6 params, no output schema). Explains threading and two booleans, but omits that the reply is sent immediately, the role of html vs text, and how mailbox affects the target folder. Could be more explicit about the action's result.

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?

With 0% schema description coverage, the description must compensate. It explains reply_all and include_quote, but leaves uid, html, text, and mailbox unelaborated. Over half of parameters lack semantic clarity.

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 tool replies to an existing message while preserving threading headers (In-Reply-To, References). It uses specific verbs and resource, distinguishing it from sending new emails or forwarding, especially due to threading emphasis.

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 usage when replying to an existing message but does not explicitly contrast with alternatives like 'proton_send_email' for new messages or 'proton_forward_email'. No guidance on when not to use it.

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