Slice a 3D model (G-code, print time, preview)

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

With no annotations, the description carries the full burden of behavioral disclosure. It transparently states the paid nature, the exact price tiers for outputs, that omitting payment returns a 402 challenge, and that optional preview/G-code outputs are included only if requested. It does not mention potential timeouts or size limits, but the critical behavioral traits (payment gating, challenge response, optional outputs) are clearly disclosed.

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 description is reasonably concise (about 120 words) and well-structured: payment notice, core function, optional outputs, pricing table, input instructions, and auth behavior. Every sentence contributes useful information. The pricing detail is verbose but necessary for a paid tool; it could be slightly trimmed, but overall it is efficient.

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 the tool's complexity (12 parameters, no output schema, no annotations), the description is quite complete. It explains the main return values (print time, filament grams, etc.), optional outputs (preview/G-code), input file formats, and the payment/challenge flow. It does not detail the exact JSON response structure, but that is partly covered by the listed outputs and is not mandatory for basic invocation.

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. The description adds high-level context (e.g., file types, price implications of include_preview/include_gcode) but does not provide parameter-specific syntax or details beyond what the schema already documents. It adds marginal value over 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?

The description uses a specific verb ('slice') and resource ('3D model') and enumerates the concrete outputs (print time, filament grams, layer count, geometry, fits-on-bed). It clearly distinguishes from sibling tools like list_printers, analyze_model, and get_print_quote by focusing on the slicing action and its result.

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 description provides clear context on when to use the tool (to slice a 3D model on a specific printer) and includes essential usage prerequisites (payment via x402, upload STL/3MF/OBJ/STEP). It does not explicitly name alternatives, but the workflow is well explained with the payment challenge behavior, making the intended usage unambiguous.

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