update_elements

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

With no annotations, the description carries the full burden, and it does disclose key merge semantics: partial updates leave the other ~25 fields untouched. It says nothing about permissions, behavior on unknown ids, or whether the change is reversible/snapshot-able (the snapshot/history system is only alluded to in the `label` schema, not the description).

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?

Three tight sentences: verb+resource first, a concrete example of partial-update semantics second, the two input modes third. No filler, and the most important constraint (send only what changes) is front-loaded.

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 mutation tool with nested objects, no output schema, and no annotations needs the description to cover error/edge behavior, which it does not. It is adequate for a competent caller — both input patterns are clear — but leaves the boundary with move_elements and failure modes unspecified.

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 60%, and the description adds genuine meaning beyond it by contrasting the `elements` list form with the `ids` + `patch` bulk form, which the bare schemas do not explain (`patch` has no schema description at all). It does not enumerate which element fields are patchable, only that there are ~26 of them.

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 ('Change named fields on existing elements') and the word 'existing' implicitly separates it from add_elements/delete_elements. However it never distinguishes itself from move_elements, even though its own example ({id, x: 40}) is a move operation — a real overlap an agent would need resolved.

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 explains two invocation shapes (a list in `elements` vs `ids` + `patch`), which is useful routing between input forms. It gives no guidance on when to prefer this tool over move_elements, replace_scene, or add_elements, so the when-to-use question is only implied.

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