move_to_contact

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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the write/mutation nature is covered. The description adds genuinely useful behavioral context beyond that: the whole object moves including children, overlapping parts are a no-op, and `depth` sinks the part to hide seams. It does not detail permissions or reversibility, but for a local mesh transform that is a minor gap.

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?

Purpose is front-loaded and every sentence carries actionable information (mechanism, axis behavior, depth values, sibling routing, the long-part caveat). It is dense rather than padded, though the single long block could be tightened slightly for scanning.

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 4-parameter mutation tool with no output schema, the description covers mechanism, parameter meaning, no-op behavior, and alternatives. What an agent needs to invoke it correctly is present; only permission/reversibility context is 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 description coverage is 0%, so the description must carry the load, and it does: `a` is the part that slides with its children, `to` is the contact target, `axis` is explained functionally ('without axis it takes the shortest way; with an axis it slides along that axis only, so other coordinates stay'), and `depth` gets units plus a concrete range (0.005..0.02 for limbs and necks).

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 and resource up front: 'Close a gap by surfaces: slide `a` (with children) until its mesh touches the mesh of `to`'. It immediately distinguishes itself from the nearest siblings by contrasting the mechanism ('attach aligns boxes instead, place_on drops by a ray'), so an agent can route correctly without opening any schema.

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?

Explicit when-to-use and when-not-to-use guidance: names `attach` for bounding-box alignment, `place_on` for ray drops, `combine` for merging, and `set_dimensions`/`limb` for the case where a long part must stay anchored. It also states the no-op condition ('if the parts already overlap nothing moves'), leaving nothing to inference.

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