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

Annotations already say readOnlyHint=false, destructiveHint=false, so the key added value is 'Onhand takes no payment' plus the approval-before-confirm pattern and the fact that non-Square/Shopify shops hand off a provider-hosted URL. Useful context beyond the hints, though it never addresses the required idempotency_key or what happens on retry 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, no filler: scope first, provider-variant behavior second, return value and payment posture last. Every sentence adds information an agent needs.

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?

With no output schema, the description still says it returns listed price and destination for approval, and it clarifies the two funnel paths and that no payment occurs. What's missing is error/failure behavior and the meaning of the idempotency key, but the core decision path is covered.

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%, so the description must carry the params, and it explains only offering_id indirectly ('one currently available item'). business_id and especially idempotency_key (which is required while the annotation says idempotentHint=false) are never explained, leaving a real gap.

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 ('Prepare checkout') and constrains scope to 'one currently available item', which separates it from the confirm_* siblings. It stops short of naming an alternative tool, so it is clear but not fully differentiated.

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 mention that eligible Square/Shopify connections 'create hosted checkouts on confirm' implies this is the pre-step to confirm_checkout_handoff, but the link is never stated explicitly and no when-not-to-use guidance is given (e.g., what to do if the item is no longer available).

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