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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true, covering the safety profile. The description adds no behavioral context beyond that, such as whether filters are combined with AND/OR, default ordering, or pagination behavior. Since annotations carry the safety burden and the description does not contradict them, a 3 is appropriate – it adds minimal but not insufficient value.

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 a single, efficient sentence that front-loads the action and resource, then mentions the optional filters. There is zero waste; every word contributes to the meaning. It is appropriately concise for a simple listing operation.

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?

Given the absence of an output schema and 0% schema coverage, the description leaves critical details unstated: pagination via starting_after, limit behavior, what 'candidate' means in this domain, and the return format. The tool is not fully self-contained; an agent would need additional context or documentation to use it correctly beyond a basic list call.

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?

With 0% schema description coverage, the description must compensate for all five parameters. It only mentions 'status' and 'email-type' filters, leaving 'limit', 'starting_after', and 'request_id' undocumented. The description does not explain pagination, default limits, or the role of request_id, so an agent cannot correctly invoke the tool with full parameter awareness.

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 clearly states the action 'List' and the resource 'candidate email drafts'. It distinguishes from sibling tools by the verb 'list' versus 'send', 'update', 'preview', etc., though it does not explicitly name alternatives. The purpose is unambiguous and specific enough for an agent to understand the core function.

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 no guidance on when to use this tool versus other email draft tools (e.g., read, preview, send). It does not mention any context like 'use this to see all drafts' or 'when you need a collection of drafts'. There is no mention of alternatives or when not to use it, leaving the agent to infer usage from the verb alone.

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