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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuinely new behavioral context by spelling out the returned data set and the ordering workflow it feeds, which the 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?

Two tight sentences: the returned contents are front-loaded, then a single purpose sentence. Nothing is redundant and no filler is present.

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?

With no output schema, the description compensates by listing all returned fields, and annotations supply the safety profile. An agent has everything needed to select and invoke this correctly.

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?

Only one parameter exists and its schema description already covers it at 100%, including the useful provenance note that the id comes from split_image_into_layers. The description adds only the ownership qualifier 'your own', so per the baseline rule a 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?

The description gives a specific verb-plus-resource ('open one of your own layers projects') and then enumerates exactly what the operation surfaces: layer names, descriptions, stacking order, visibility, and position. It is clearly a read of an existing project rather than the sibling write/flatten/export tools, though it never names a sibling explicitly to draw that contrast.

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?

It states a concrete usage moment: 'Use this before arranging layers so you know their ids.' That tells the agent when to reach for it, but offers no exclusions and no named alternatives (e.g. update_layer_set, flatten_layer_set) for adjacent tasks.

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