object_group

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

Annotations already declare readOnlyHint=false with destructiveHint=false and openWorldHint=false, so a non-destructive mutation is established. The description adds only that naming is optional, which implies a default auto-naming behavior, but never says whether objects are moved out of their current parent, whether existing group membership is replaced, or what happens on failure.

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?

A single front-loaded sentence with zero filler, and the optional-naming qualifier is placed after the core action. It is appropriately sized for a two-parameter tool, though the brevity borders on under-specification.

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?

Although an output schema exists and annotations cover the safety profile, the description leaves essential operational questions unanswered for a scene-graph mutation: what a ref resolves to, whether grouping reparents or copies, and whether selection state is affected. For a mutation tool with 0% schema coverage this is inadequate.

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 carries the full burden. It clarifies only that 'name' is optional; the required 'refs' parameter, which accepts an int, string, or array of either, is never explained as to what a ref actually is (object id, object name, path).

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 (grouping) and resource (objects) in a scene-graph sense, so the agent knows it creates a container and places objects in it. It does not distinguish itself from the near-sibling object_set_parent, which could be an alternative way to restructure the hierarchy.

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?

There is no guidance on when to group versus reparent (object_set_parent) or create a fresh scene (scene_new), nor any prerequisite about selection state or existing groups. 'Optionally named' hints at the optional parameter but says nothing about choosing between this tool and its alternatives.

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