gmail_reply

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

With no annotations provided, the description must disclose behavioral traits. It mentions the need to obtain IDs via gmail_read but does not describe side effects, authentication requirements, or what happens on success/failure. Some additional behavior context would improve transparency.

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 concise with two efficient sentences. It front-loads the core purpose and immediately provides actionable guidance, earning its length with no redundant information.

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 tool's complexity (12 parameters), the description provides essential workflow guidance but omits the return value or output format. Since there is no output schema, the agent lacks information about what the tool returns (e.g., sent message ID or draft ID), leaving the description somewhat 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 coverage is 100%, so the baseline is 3. The description adds value beyond the schema by explaining how to obtain threadId, inReplyTo, and references from gmail_read, and clarifies the isDraft parameter's usage for draft-only accounts. This extra context enhances semantic understanding.

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's purpose: 'Reply to an email within its existing thread.' It uses a specific verb (reply) and resource (email thread), and the context of sibling tools like gmail_send and gmail_draft distinguishes it from sending a new message or creating a draft.

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 explicitly instructs to use gmail_read first to obtain threadId, messageId, and references, providing clear prerequisites and usage context. This helps the agent understand when and how to invoke this tool.

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