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

Annotations already declare readOnlyHint=false, idempotentHint=false, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds nothing beyond that – no note on where the draft lands, whether it is persisted server-side, or what happens with replyToMessageId. It contributes no behavioral context of its own.

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?

A single short sentence that is front-loaded and free of padding, so it is structurally clean. But the brevity here reflects under-specification rather than disciplined conciseness, since it omits information an 11-parameter tool needs.

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?

For an 11-parameter, zero-required, mutation tool with no output schema and no per-parameter descriptions, this description is far too thin. An agent cannot tell what a draft requires, what the reply fields do, or how attachments and account targeting work.

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% across 11 parameters, including non-obvious ones like replyAll, replyToMessageId, accountId, and the attachment content/contentId/disposition fields. The description compensates for none of this, leaving half the schema's semantics (boolean and id relationships) undocumented.

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?

States a specific verb and resource ('Create a draft'), so the operation is unambiguous. However, it does nothing to distinguish itself from siblings like update_draft, preview_send, or send_email, which an agent must choose between.

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?

There is no when-to-use guidance, no mention of prerequisites (e.g. accountId selection), and no reference to alternatives such as update_draft for editing or send_email for dispatching. The agent is left to infer the workflow entirely.

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