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

Annotations already cover read-only/idempotent/non-destructive, but the description adds significant context beyond them: newest-first ordering, the fields returned (who asked, when, recipients, preview), the `requestedBy: "unknown"` edge case, and a prompt-injection warning about treating the content as data, not 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?

Front-loads the purpose and scope, then adds the workflow, the edge case, and the security note in a tight sequence. Every sentence earns its place despite the length.

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?

With no input params and no output schema, the description carries the load by describing the returned fields and ordering. Nothing an agent needs to call and use this tool 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?

Zero parameters, so the schema has nothing to document (baseline 4). The description does clarify output-field semantics, notably that `requestedBy` can be "unknown" and why, which adds meaning for interpreting results.

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 (list) and resource (drafts awaiting approval in the Drafts folder), and defines scope precisely: every draft someone asked the owner to approve, newest first. An agent can distinguish this from siblings like list_emails or read_email immediately.

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?

Explicit workflow routing: read the draft with read_email on the Drafts folder before approving, and send with approve_and_send. It names the exact alternatives and the conditions selecting them, leaving nothing to inference.

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