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

Goes well beyond the annotations by disclosing a real side effect ('the file is kept privately by the studio'), the accepted formats and 25 MB cap, and the fallback behavior when a file can't be auto-quoted. The revelation that a file is retained is consistent with readOnlyHint=false rather than contradicting it.

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?

Front-loaded with purpose, then the upload alternative, retention note, return values, and fallback in a logical order — every sentence carries information. It is dense, and the second sentence is a long run-on bundling endpoint, formats, size limit, and key prefix, which slightly hurts scannability.

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 10-parameter tool with a nested file object and no output schema, the description covers the essentials: which input form is required, what comes back (price, size, turnaround, checkout_item) and the handoff to create_checkout, plus what happens on unsupported files. An agent could invoke this correctly without further context.

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 already 100%, so the schema carries the per-parameter burden (color, units, infill, quality, material). The description still adds value the schema only hints at: the upload endpoint, the format/size constraints that govern 'file' vs 'file_key', and the meaning of the returned file_key prefix. It adds context but doesn't walk through the optional parameters.

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 ('exact instant-quote price for printing a person's 3D model file') and pins the source of truth ('same engine and same measurements as the instant quote page'). This clearly separates it from print_price_examples and request_quote, which are the nearest siblings.

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?

Explicitly names both input paths (pass the attached file, or upload first via POST /api/upload with kind=printiq and pass the returned key) and states exactly which cases this tool will NOT handle: painted multicolor, STEP, oversized-in-one-piece, and model links from Printables/Thingiverse/MakerWorld, routing those to request_quote. Nothing is left to inference.

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