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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=false, so the mutation profile is partly covered without the description. However, the description does not explain that a required idempotency_key implies replay-safe writes, that expected_version implies optimistic-concurrency conflict failures, or how 'simulate' differs behaviorally from an applied edit. For a 13-parameter mutation with nested op payloads, this is a significant gap.

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?

It is a single short, front-loaded sentence with no filler, which is structurally efficient. But the brevity comes at the cost of under-specification rather than genuine economy, so it does not earn a top score.

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 13 parameters at 0% description coverage, nested object payloads, a 19-value op enum, and no output schema, the description is far too thin for an agent to call this correctly without external lookup. The delegation to guides_get is the only thing preventing a 1.

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 description coverage is 0% across 13 parameters, including a 19-value op enum, two free-form objects (preview, template), and an array of untyped nested items. The description does not compensate; it only redirects to guides_get, without explaining action semantics, the role of item_keys vs items, or what simulate_days affects.

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 pairs a verb ('Edit/simulate') with a resource ('checkout drafts'), which is better than a tautology, but 'drafts' does not match the tool name's 'plan' or the sibling checkout_plan_submit, leaving the agent unsure whether this operates on plans, drafts, or both. It also fails to distinguish itself from other checkout siblings such as checkout_manage and commerce_draft_apply.

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 clause 'guides_get checkout/plans defines payloads' is a useful pointer for constructing inputs, but nothing states when to use this tool instead of checkout_plan_submit, checkout_manage, or commerce_draft_apply. No preconditions, no exclusions, and no guidance on choosing among the nine action values.

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