reply_to_email

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

Annotation only sets destructiveHint=true; description adds meaningful context: immediate sending, correct header threading, and the required permission PROTONMAIL_ALLOW_SEND. It does not explicitly state irreversibility, but 'Immediately send' plus destructive hint cover the core risk.

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 sentences, all essential: first states purpose, second gives usage trigger, third provides alternatives and a requirement. No filler or repetition.

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?

Covers the key decision points for a 13-parameter destructive tool: when to use, what it does with headers, and permission requirements. It lacks explicit mention of confirmation/cancellation and return behavior, but those are partially covered by destructiveHint and schema, respectively.

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 describes all 13 parameters with detailed comments (100% coverage), so the baseline of 3 applies. The description adds no extra parameter-level semantics, instead focusing on tool selection.

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 states a specific verb-resource pair ('Immediately send a reply to an existing email'), clarifies threading behavior, and distinguishes from siblings by naming alternatives for draft creation and reply-all cases.

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?

Explicitly says when to use ('when you have an emailId and want to send the reply right away'), and provides clear alternative tools (create_reply_draft, create_thread_reply_draft, reply_all_email) with conditions for each.

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