set_mpci_parent_collection

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

Annotations already declare destructiveHint=true and idempotentHint=true, and the description adds substantial non-obvious context: overrides are lost, other collections' instances are untouched, it is runtime-only, and nothing is saved with no undo. This is exactly the extra behavioral detail annotations cannot convey.

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-loaded with the core action, then the crucial 'cannot move parent' caveat, then runtime constraints, then the return shape. Dense but every clause carries decision-relevant information; the trailing Returns block is mildly verbose but justified since no output schema exists.

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 destructive mutation with no output schema, the description covers effect, scope of side effects, persistence/undo behavior, and the return payload shape. An agent has everything needed to call it correctly and predict the outcome.

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%, so both parameters are already documented by the schema. The description reinforces the editor-world default and the collection-keyed semantics of collection_path, but adds little format or syntax meaning beyond what the schema fields already state. 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?

Names a specific verb and resource (rebuild the MPCI for collection_path) and immediately flags the counter-intuitive scope: despite the 'set parent' name, it cannot reparent and instead resets the instance to collection defaults. It explicitly distinguishes itself from siblings by equating the effect with create_material_parameter_collection_instance, so an agent can pick between them without opening schemas.

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?

Gives clear context for when this applies (rebuilding a transient per-world instance, editor world by default) and names an equivalent sibling call. It stops short of stating explicit when-to-use / when-not-to-use conditions against alternatives like get_mpci_info or clear_mpci_parameter_overrides, so it is clear but not fully routing.

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