Send one approved reply

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

With no annotations provided, the description carries full disclosure burden. It discloses key behaviors: marks source as read, threads the send, appends Gmail signature and quoted original, and supports legacy 'html' parameter. However, it omits details like whether sending is immediate, error handling, or rate limits, which would improve transparency. Still, the coverage is solid.

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 paragraph of about 4 sentences, which is concise. It front-loads the core purpose and key parameter behaviors. However, the structure could be improved by separating parameter details from flow instructions, and the sentence about legacy `html` could be merged. Still, it is efficient and readable.

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?

Given the complexity (12 params, 3 required, no output schema, no annotations), the description covers the essential purpose and parameter behaviors but lacks explanation for several optional params and does not describe the return value or error behavior after sending. For a critical action like sending email, this is a gap, making it incomplete.

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 must compensate. It explains `messageId`, `body`, `format`, `quoteOriginal`, `appendSignature`, and legacy `html`. However, it does not explain `to`, `subject`, `cc`, `bcc`, `accountAlias`, or `chatScope`, leaving 6 out of 12 parameters undocumented. While some are self-explanatory, the missing explanation for `accountAlias` and `chatScope` lowers the score.

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 starts with 'Send one approved **reply**' and explicitly contrasts with 'send_new' for new outbound/campaigns, clearly distinguishing the tool's purpose as a reply-only function. The verb 'send' and resource 'reply' are specific, and the sibling tool 'send_new' is named for differentiation.

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 states 'Requires `messageId` (marks source read, threads send)' and 'For new outbound / campaigns use `send_new` instead.' It also warns 'Never run without explicit approval.' This provides explicit when-to-use and when-not-to-use guidance, including an alternative tool.

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