fusion_loft

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

With no annotations, the description must disclose behavioral traits. It explains the lofting operation morphs between cross-sections, but does not disclose whether the operation consumes the source sketches, modifies existing bodies, or has any side effects on the model tree. The default operation 'new_body' is in the schema, not the description, so it misses the chance to clarify that it creates a new body unless combined. It is decent but not fully transparent.

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 exactly two sentences, with the first delivering the primary purpose and usage distinction, and the second providing essential parameter detail. It is front-loaded, concise, and every word contributes to understanding the tool. No unnecessary verbiage.

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 modeling operation with three parameters and no annotations or output schema, the description covers the core behavior and the most complex parameter (profiles) well. It also adds a valuable constraint ('2+ profiles') and the flexibility that planes need not be parallel. It lacks details about the operation semantics (e.g., how `operation` affects behavior) and the return value, but these are inferable from the schema defaults. Overall, it is nearly complete for its complexity.

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 compensate for parameter meaning. It provides a substantial explanation of the key parameter `profiles`: 'Each entry in `profiles` is {"sketch_id": ..., "profile_index": ...}, given in loft order.' This adds structure and ordering semantics not visible in the schema (which only says array of objects). The other parameters (operation, target_body_id) are not explained, but their names and defaults are self-explanatory. Given the low coverage, this is a solid contribution.

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 clearly states the tool's purpose: 'Loft through 2+ sketch profiles to build a shape that tapers/morphs between cross-sections.' It uses a specific verb (loft) and resource (sketch profiles), and distinguishes it from extrude by noting when to use it instead. This is above the baseline of many tool descriptions, which often just repeat the name.

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 explicitly says 'use this instead of extrude when the profile isn't constant along its length,' providing a clear alternative selection rule. It also notes that profiles are 'given in loft order (they don't need to be parallel planes),' which clarifies sequencing and geometric flexibility. This offers strong guidance for when to invoke the tool versus siblings like fusion_extrude or fusion_revolve.

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