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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior, and the description adds substantial value beyond those. It discloses pagination mechanics via `next_page_token`, the exact fields returned on each draft, the distinction between preview-only list items and full content, and the fact that drafts are not sent until the send endpoint is called. This gives an agent accurate expectations for downstream behavior.

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 compact yet information-dense, with the core function front-loaded in the first sentence. Every subsequent sentence earns its place by explaining output shape, list-item limitations, related follow-up tools, and the account-wide alternative.

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?

The description covers what an agent needs: scope, returned fields, pagination, the preview/full-content distinction, the send relationship, and the sibling tool for account-wide drafts. The output schema exists, so return-value details are reinforced structurally, and no critical behavioral gap remains.

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?

Input schema coverage is 100%, so the baseline of 3 applies; the schema already documents each parameter. The description mentions pagination via `next_page_token`, which indirectly relates to `page_token`, but does not add new semantic meaning for `after`, `before`, `labels`, or `limit`. It does not need to compensate, so 3 is appropriate.

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 opens with the specific verb 'Lists' and the precise resource 'unsent drafts in one inbox,' making the tool's function immediately clear. It also distinguishes itself from the account-wide `get_agentmail_drafts` and the single-draft `get_agentmail_inbox_draft`, which is critical given the large sibling list.

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 clearly states this is scoped to one inbox and explicitly points to `get_agentmail_drafts` as the account-wide alternative, giving an agent useful routing context. It also mentions that full `text` and `html` content comes from `get_agentmail_inbox_draft`, which guides follow-up calls. The guidance is implicit rather than an explicit 'use when / use instead' rule, so it falls just short of a 5.

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