Apply Prefab Overrides

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

Annotations already declare readOnly=false, destructive=false, idempotent=true, but the description adds genuinely new context: that the operation is Undo-able and that it propagates to all instances once saved, plus a specific failure mode. That side-effect disclosure is exactly the kind of behavioral value annotations don't carry.

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 front-loaded sentences: the main action with its caveat first, then the argument note. It is tight and wastes little, though the parenthetical caveat slightly interrupts the flow.

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 single-parameter mutation tool with no output schema, the description covers purpose, side effect, reversibility, and failure behavior, which is nearly everything an agent needs. Only explicit sibling routing 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 100% with the single parameter fully documented, including an example path, so the schema does the heavy lifting. The description restates the same 'Level/Enemy_1' example without adding format or constraint details beyond it, so baseline 3 is appropriate.

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 ('Apply') and resource ('an instance's overrides back to its prefab source'), clearly distinguishing it from siblings like unity_instantiate_prefab. An agent can immediately tell this pushes instance-level changes up to the prefab asset.

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?

Provides a clear precondition ('Fails with hint if the object is not a prefab instance') and a consequence warning ('affects all instances once saved'), which frames when the tool is appropriate. It stops short of naming an alternative sibling or an explicit when-not scenario, so it lands at 4 rather than 5.

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