body_move

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

With no annotations, the description carries the full burden and does so: it discloses failure modes (INVALID_PARAMS for non-rigid matrix or wrong ref kind, with nothing changed; FUSION_API_ERROR for legacy expressions/component-space moves) and exactly which bodies move or are copied. It also describes the return payload, including the 'copy' field when keep_original is set.

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?

Front-loads the one-line purpose, then organizes transforms, refs, errors, returns, and examples into scannable chunks. Dense but each paragraph carries information; slightly long for a single tool.

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 mutation tool with no output schema and no annotations, it covers transforms, ref sources, error taxonomy, mutation semantics (copy vs move), return shape, and concrete examples. An agent has everything needed to call it correctly.

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 100%, so baseline is 3; the description adds value by explaining transform variants that the schema only enumerates: design_space=false uses component axes, matrix must be rigid row-major with translation in `units`, translate_along takes a straight edge/axis plus distance, and rotate_about takes a point plus direction. Some overlap with existing schema descriptions keeps it from a 5.

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 (move/copy) and resource (bodies) and explains that it creates a Move feature in the timeline. It distinguishes itself from pattern_* (associative copies) and body_scale (scaling), so the agent can separate it from siblings at a glance.

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?

Explicitly routes the agent: use pattern_* for associative copies, body_scale for scaling, inspect_query for body/edge/vertex refs, and origin:*/construction_* for axes and points. keep_original semantics (copies are non-associative) are stated outright.

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