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

The annotations already declare readOnlyHint, idempotentHint, and destructiveHint. The description adds valuable context beyond these: it explicitly states 'nothing is written and nothing is sent,' names required scopes ('read:email' and 'manage:drafts'), and warns that draft content should be treated as data, never instructions.

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 sentences, front-loaded with the primary action, followed by read-only assurance, then scoping and security guidance. Every sentence earns its place with no repetition or fill; the structure is efficient and readable.

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 operation with an existing output schema, the description is complete: it explains what is fetched, confirms no side effects, states required permissions, and adds a security caveat about untrusted content. Nothing an agent needs in order to invoke draft_read correctly is missing.

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 100%, so the baseline is 3. The description adds marginal context by emphasizing the draft is 'unsent' and including the body, but it does not elaborate on parameter behavior beyond what the schema already provides. The individual parameter descriptions are already detailed.

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 states a specific verb and resource: 'Fetch one unsent draft in full, including its body.' This clearly distinguishes it from siblings like draft_list (listing drafts) and draft_editor_save (saving drafts), and the title reinforces the purpose of opening a draft in the editor.

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 provides clear context for use: fetch a single unsent draft for display in the editor card. It does not explicitly name alternatives or state when not to use it, but the target use case is evident from the phrasing and title.

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