swap_material_layer_parameters

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

Annotations already declare the mutation profile (readOnlyHint=false, destructiveHint=true, idempotentHint=false), so the safety burden is lifted. The description adds real behavioral context the annotations cannot: per-layer parameters travel with the slot, previously recorded indices become stale, and the agent should re-read via get_material_layer_stack. That is genuine side-effect disclosure, not a restatement.

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-loads the operation, then the sibling alternative, then the index-invalidation gotcha, then the return shape. Three tight sentences with no filler; every clause is load-bearing.

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 three-parameter mutation tool, the description covers the action, the alternative, the side effect on existing indices, and the exact return shape (no output schema exists, so including it here is correct). Nothing needed to invoke it correctly is missing.

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 100%, so baseline would be 3. The description goes further by explaining that indices denote layer slots and that any index recorded earlier now points at the other layer, which clarifies what original_index/new_index actually mean beyond the schema's one-line glosses.

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 concrete verb ('Exchange two layer slots') on a specific resource ('layered material instance'), and explicitly distinguishes itself from set_material_layer_stack, a real sibling. An agent can tell what this does and how it differs from the rebuild path without opening a 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?

Names the alternative (set_material_layer_stack) and frames the choice ('without rebuilding the whole stack'), which is clear usage direction. It stops short of stating prerequisites or when the tool should not be used, so it isn't a full 5.

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