Price your own 3D file and get a checkout link

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

Annotations already say readOnlyHint=false and openWorldHint=true, and the description adds real context: it calls out to Hark Tech for slicing, saves the priced item to a basket on harktech.co.uk (an external side effect), and returns checkout_url without charging or ordering. It also discloses the host-restriction behavior and failure mode for unsupported links.

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?

The core behavior, return values, and non-goals are front-loaded before the Args section, and the Args block is justified because the schema has zero parameter descriptions. It is slightly verbose in places (repeated 'person's own'/'own file' phrasing), but no sentence is 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 mutating, externally-dependent tool with no output schema, the description supplies everything an agent needs: required input format and hosts, all four parameter meanings, side effects on the basket, the returned fields (summary, price, size, postage, checkout_url), and the explicit limitation that no order/payment occurs.

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 0%, so the description must carry the burden, and it does: file_url is defined as a public share link plus accepted hosts and formats, material enumerates all eleven options, quantity gives the 1-999 range, and lead_time explains standard/express/bulk with concrete price modifiers and a free-upgrade condition.

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 and resource: price a user's own STL/3MF/STEP file from a share link, naming the accepted formats and inputs. This is clearly distinct from siblings like search_models (discovery) and get_quote (retrieval), and the line 'does not place an order or take payment' further separates it from checkout/order tools.

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 concrete use conditions: a public share link from Drive/OneDrive/Dropbox/GitHub/Discord, and states that links from other hosts are refused with an explanation. It also clarifies the tool does not place orders or take payment, implying the boundaries, but it never names a sibling tool to use instead when the user actually wants to order or check a quote.

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