Create Safe Inbox Reply Draft

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

Annotations indicate idempotency and non-destructiveness. The description adds context by clarifying that the tool creates a draft without sending, which aligns with the idempotentHint. No contradictions with annotations.

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 concise sentence that directly states the action and a key behavioral note. While efficient, it could be slightly expanded to include parameter hints without losing clarity.

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 (7 parameters, required fields, output schema not described), the description is too minimal. It omits important context like the purpose of `expected_reply_version`, the relationship to the thread, and what the output represents.

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 low (29%), and the description does not explain any parameters. For a tool with 7 parameters, including critical ones like `thread_id` and `expected_reply_version`, the description should provide context to aid correct usage.

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 explicitly states the action ('create'), the resource ('reply draft'), and the key constraint ('does not send email'), making the tool's purpose clear. It also distinguishes from siblings like `shipmail_send_inbox_reply_draft` which sends the 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 does not provide any guidance on when to use this tool versus alternatives such as `shipmail_send_inbox_reply_draft` or `shipmail_reply_to_inbox_thread`. It only notes what the tool does not do, without explaining the typical workflow.

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