Read draft

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered elsewhere. The description adds nothing beyond that: it does not say what happens if the draft ID is unknown, whether sending state or scheduled info is included, or how it behaves when multiple accounts are connected.

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 twelve-word sentence with the resource and key front-loaded and no filler. It is not padded, though the brevity leaves gaps that other dimensions penalize.

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 read-only single-resource getter with an output schema and annotations, the essentials are covered. Missing are the failure behavior for a bad draft ID and any mention of the optional accountId scope, which matters given the tool operates in a multi-account context.

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 50%: accountId is documented in the schema ('Optional when exactly one account is connected'), while draftId is only named. The description's 'by its draft ID' confirms the required parameter's role but adds no format or lookup semantics, so the schema is doing most of the work.

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 (read) and resource (draft) with the retrieval key (draft ID), which cleanly separates it from create_draft, update_draft, and delete_draft in the sibling list. It does not explicitly name those siblings or contrast itself with them, so it stops short of a 5.

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 word 'existing' implies this is for retrieving a draft you already have an ID for, but there is no explicit when-to-use or when-not statement. No alternative is named, even though update_draft and preview_send operate on the same object and an agent must infer which to call.

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