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

The description explicitly guarantees no mutation of the application or drafts, which is valuable because the annotation readOnlyHint is false)Skip this valuable context is not carried by annotations. It also reinforces the idempotent and non-destructive nature already hinted at by idempotentHint and destructiveHint. No contradictions with annotations.

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 sentence, concise and front-loaded with the action 'Preview'. It avoids redundancy and effectively clarifies the non-mutating behavior. It could be slightly more structured, but there is no unnecessary content.

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 there is no output schema, the description should explain what the preview returns (e.g., email subject, body, recipient) but does not. It also leaves parameter semantics unexplained. While the tool is simple and the required application_id is implied, an agent cannot know the exact request construction or response format, making the description insufficient for correct invocation without additional 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?

The description provides zero information about the parameters. Schema description coverage is 0%, so the description must compensate, but it mentions neither application_id nor the optional request_id and idempotency_key. The only hint is the word 'application' in the tool name, which is not enough to clarify parameter semantics. There is no added meaning beyond the schema's structural definitions.

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 tool previews the candidate email for an application status change alerting the agent to the fact that nothing is sent. It explicitly says it does not mutate the application or drafts, which distinguishes it from the sibling 'yardstick_applications_email_decision_apply' and related transition tools. The verb 'Preview' and the resource (candidate email for application status change) are specific and unambiguous.

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 phrase 'without mutating the application or drafts' implicitly conveys that this is for previewing before applying a change rather than executing it. However, it does not explicitly name alternatives like yardstick_applications_email_decision_apply or yardstick_applications_transition_preview, nor does it state when to use this tool versus those siblings. The context is clear enough for a knowledgeable agent but lacks explicit routing.

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