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

Annotations already declare readOnlyHint=true, and 'Changes nothing' reinforces rather than contradicts that. The description adds real value by enumerating the returned cost components (item, print, shipping, tax, retail totals) and the underlying endpoint, useful since no output schema exists.

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 key distinction (pricing without creation), and every clause carries information. No filler, no restating of the title.

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 5-parameter tool with nested objects and full schema coverage but no output schema, the description covers purpose, side-effect profile, return categories, and the API route. It could say a bit more about the shape of the returned totals, but an agent has enough to call it correctly.

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 100%, so the baseline is 3, but 'Same item shape as printful_create_draft_order' is a genuinely useful semantic pointer that lets an agent reuse the item payload structure from a known sibling. It stops short of noting the shipping/store_id/recipient specifics already covered by the schema.

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?

Specific verb (price/estimate) plus resource (order costs) and an explicit negative scope: 'WITHOUT creating it.' It also enumerates what is priced (item, print, shipping, tax, retail totals) and names the sibling it mirrors, so it is unmistakable against printful_create_draft_order or printful_calculate_shipping_rates.

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?

'Price an order WITHOUT creating it' gives clear context for when to reach for this tool (pre-order cost preview). It does not name an alternative or exclusion case, and the closest sibling relationship (shipping-only estimates via printful_calculate_shipping_rates) is only hinted at through the schema, not the description.

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