fusion_combine

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

With no annotations provided, the description bears the full burden of behavioral disclosure. It does not state whether the operation is destructive (likely it modifies or replaces existing bodies), whether it returns new bodies, or any side effects on the input bodies. The user must infer the behavior from the schemas (which have no descriptions) and the context of boolean operations. This is insufficient for an agent to understand the tool's side effects.

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 a single, succinct sentence that clearly states the primary behavior and lists the allowed operations. There is no fluff or unnecessary repetition. It is appropriately concise.

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 complexity of boolean operations on bodies-destructive and requiring clear understanding of parameter semantics-this description is heavily under-specified. There is no mention of return values (since no output schema), no mention of prerequisites (e.g., bodies must overlap), and no explanation of what happens to the original bodies. For a geometry mutation tool, this lacks critical 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?

The schema has no descriptions for parameters, and the description only mentions 'operation' with its enum values. It does not explain 'target_body_id', 'tool_body_ids', or 'keep_tools'. With schema coverage of 0%, the agent cannot infer the meaning of these parameters from the description. The description adds little beyond the schema's parameter names.

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 performs boolean operations on bodies with specific operations (join, cut, intersect). It uses a specific verb ('combine') and names the resource ('bodies'). However, it does not explicitly distinguish from sibling tools like fusion_loft or fusion_revolve, but the boolean nature is clear enough to infer its purpose.

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 no guidance on when to use this tool versus alternatives. It does not mention any prerequisites, exclusions, or scenarios where other tools might be preferred. The only hint is the operation enum, which implies different use cases, but there is no explicit 'when to use' or 'when not to use' guidance.

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