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

Annotations already declare destructiveHint=true, idempotentHint=true and readOnlyHint=false, so the safety profile is largely covered. The description adds real value beyond them: changes save immediately, they run through the same validation checks the Switch workspace uses, and 'reset' implicitly discards prior manual arrangement. It does not say whether a multi-entry 'changes' array is atomic on partial failure, which is the remaining behavioral unknown.

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?

Compact, front-loaded, and every clause maps to a real capability or behavioral fact. The long first sentence packs four operations but remains readable, and the second sentence adds the persistence/validation note rather than padding.

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 two-parameter mutation tool with no output schema and full annotation coverage, the description supplies what an agent needs: the supported change types, coordinate format, persistence behavior, and validation parity with the Switch workspace. Return-value detail is unnecessary since no output schema exists and the tool's effect is self-evident.

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%, including the box, order, reset, visible and layer_id sub-fields, so the schema already carries the parameter semantics. The description restates the box format ('[left, top, right, bottom] in the base picture's pixels') without adding coordinate conventions, units or constraints beyond the schema. 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 (arrange/update) on a specific resource (layers project / layer set) and enumerates the exact operations supported: show/hide, move/resize, reorder, reset. It is clearly separable from siblings like get_layer_set (read), split_image_into_layers (create), flatten_layer_set and export_layer_set.

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 implies when to use it (mutating 'your own layers project' after a split) but never names an alternative tool or an exclusion condition. There is no guidance on reading the current state with get_layer_set first, or on when flatten/export are the better choice, so usage is left to inference for a sibling set this large.

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