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

Annotations already declare destructiveHint=true, openWorldHint=true and idempotentHint=false, so the safety profile is covered. The description adds the nonce requirement, but it never says what is destroyed or overwritten (e.g., the existing draft body) — for a destructive mutation, that context would be valuable beyond the 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?

It is short and front-loaded, but the brevity is under-specification rather than efficiency — one of the three sentences (the create_draft pointer) is the only high-value line, while the parameter and effect gaps go unfilled.

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 a destructive, non-idempotent write tool with six undocumented parameters and no output schema, the description is far too thin. It omits what the call replaces, what happens to omitted optional fields, and what a successful response looks like.

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 six parameters, so the description must compensate — but it only names 'nonce' and says nothing about to, subject, body, cc, or bcc. An agent gets no semantic guidance on the email fields or on whether omitted cc/bcc are cleared or preserved.

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 says 'used by the draft card when the person saves an edit', which gives the context and effect, but doesn't state clearly what resource is being updated (the draft? the message?) or what the resulting state is. It distinguishes this from create_draft only via the usage hint, not by describing the operation itself.

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?

It explicitly tells agents to use create_draft instead, which is a clear alternative and exclusion. It also states a prerequisite ('needs the card's approval nonce'). Missing only a positive statement of when an agent (not a card) would ever legitimately call this.

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