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

Annotations cover the safety profile (readOnlyHint=false, destructiveHint=false, non-idempotent), and the description adds two non-obvious facts: the return value is an opaque handle used by every later call, and the call creates nothing chargeable. It does not say whether repeated calls produce distinct jobs, which matters given idempotentHint=false.

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 short sentences, front-loaded with the action, then the return contract, then the billing caveat. 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?

Complete for a zero-param starter tool: action, output handle, and the no-charge guarantee are all present, and safety is carried by annotations. It leaves the handoff to sibling tools implicit, which is a minor gap in a 10-tool checkout/job workflow.

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 baseline is 4. The description correctly implies all configuration happens elsewhere (via the returned handle path), adding meaning about where state lives, though it could name the follow-up tool that supplies job details.

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+resource ('Start a print-and-mail job'), and the title mirrors it. Distinguished from siblings like hip_quote and hip_update_job by the explicit 'start' action and the returned job handle that threads into later calls.

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?

Usage is implied by the workflow (start a job, then use the returned handle with hip_update_job / hip_complete_payment), but the description never names an alternative or states when not to call this tool. An agent must infer ordering from the sibling list rather than the text.

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