bb_duplicate_elementsCopy selected Blockbench elements, including group children, then optionally repeat and offset each duplicate to build patterns or arrays.
Copy elements (groups copy their children too). Optionally repeat and offset each copy.
| Name | Required | Description | Default |
|---|---|---|---|
| axis | No | ||
| count | No | ||
| offset | No | ||
| vector | No | ||
| targets | Yes |
Changes observed during successful MCP inspections.
v2.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full behavioral burden and does disclose one real trait: groups bring their children along. But it says nothing about how axis and vector interact, whether copies are linked/instanced, whether the operation is undoable, or what is returned.
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?
Two short sentences, front-loaded with the core action and the group caveat. No filler, though it is arguably too sparse for the parameter surface it fronts.
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?
A five-parameter mutation tool with no annotations, no output schema, and zero schema descriptions requires far more from the description than this. The group-copy note is the only substantive detail; axis/vector/targets handling is entirely absent.
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% across five parameters, so the description must compensate and largely does not. 'Repeat and offset' loosely gestures at count/offset, but axis vs vector, the numeric meaning of offset, and the shape of 'targets' are all undocumented.
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 (copy/duplicate) and resource (elements), plus a useful nuance that groups copy their children. However, it does not distinguish itself from closely related siblings like bb_array_elements or bb_mirror_elements, which plausibly cover the same repeat/offset territory.
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?
No when-to-use guidance, no prerequisites, and no alternatives named. The phrase 'optionally repeat and offset each copy' describes capability, not when an agent should pick this tool over bb_array_elements or bb_mirror_elements.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.