add_assembly_instance

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It conveys that the operation mutates an assembly by adding an instance, but it does not explain side effects, required ownership, relationship between the two element IDs, or what happens if the part studio or assembly is already instanced. This is a meaningful gap for a mutating CAD operation.

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, efficient sentence with no filler or redundancy. It is appropriately front-loaded, though it omits useful context that could make it more informative without much added length.

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?

This tool has six parameters, no output schema, and no annotations, yet the description provides only a one-line summary. It does not help an agent understand the document/workspace/element ID structure, the optional partId behavior, or how this operation differs from other assembly-related tools. The context is insufficient for confident correct 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 parameters are already well documented in the schema. The description adds only a high-level hint ('part or sub-assembly') that maps loosely to isAssembly, but it does not clarify the relationships among documentId, workspaceId, elementId, and partStudioElementId. Baseline 3 is appropriate given the schema's completeness.

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 action ('Add') and the resource ('a part or sub-assembly instance to an assembly'), which is more specific than a mere restatement of the name. It implies differentiation from siblings like create_assembly, but does not explicitly name alternatives.

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 gives no guidance about when to use this tool versus alternatives such as create_assembly, transform_instance, or set_instance_position. There are no stated prerequisites, exclusions, or decision criteria, so an agent must infer usage from the tool name and schema alone.

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