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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds valuable non-obvious behavior: the semantic distinction between 'submitted' and 'delivered', and the warning against retry/duplication for specific statuses. This goes beyond what annotations convey.

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 three compact sentences with no wasted words. The first sentence states the core purpose, the second clarifies a key status term, and the third gives actionable safety guidance. Each sentence earns its place and the most important information is front-loaded.

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 simple one-parameter read-only tool, the description covers the essential semantics: what is retrieved, status meaning, and what actions to avoid. It lacks an explicit enumeration of all possible statuses or return shape, but annotations cover safety and no output schema is expected, so the main gaps are minor.

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%, so the description must compensate for documenting the draftId parameter. But the description never mentions draftId, how to obtain it, or how it identifies the target draft. The parameter name is self-explanatory, but the description adds no meaning beyond the schema and fails to compensate for the low coverage.

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 a specific verb and resource: 'Get the current draft and submission status.' This clearly distinguishes the tool from siblings like read_message (reading messages) and prepare_draft/revise_draft (creating/modifying drafts). The added clarification about 'submitted' meaning accepted-not-delivered further pins down its purpose.

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 gives clear behavioral context: if the status is 'submitting' or 'delivery_unknown', do not create another copy or retry sending, and instead direct the user to check Sent in webmail. This effectively tells the agent when not to use sending/duplication actions, though it does not explicitly name alternative sibling tools.

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