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

Annotations already flag destructiveHint/readOnlyHint/idempotentHint, and the description adds the operationally critical context they don't carry: the exact failure conditions, that the mailing is stopped permanently, that user confirmation is required, and the underlying endpoint. That is meaningful disclosure beyond the structured hints.

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?

Three compact sentences with the write classification, the restriction, the safety gate, and the alternative all front-loaded; the endpoint hint at the end. No filler.

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 2-param destructive mutation with no output schema, it covers the safety profile, failure modes, prerequisite approval, and the sibling to use instead. Nothing an agent needs in order to call it 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 coverage is 100% and already constrains confirm to true, so the schema does the heavy lifting. The description still contributes intent by framing confirm as a user-approval gate ('get the user's explicit go-ahead first'), which is more actionable than the schema's terse 'user approved' wording.

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?

Opens with an explicit verb and resource plus a state qualifier: 'WRITE: cancel a SUBMITTED job.' It also names the sibling for the adjacent-but-different operation (drafts → click2mail_delete_job), so an agent can discriminate it from delete_job and from submit_job without opening a schema.

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?

Gives both when-to-use and when-not: it states the vendor restriction (invoice-paid jobs only, only before mailing processing starts, otherwise it fails) and redirects draft removal to click2mail_delete_job. It also names a prerequisite (explicit user approval) before invocation.

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