select_layer_alpha

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

With no annotations, the description carries full behavioral burden. It states that the existing selection is replaced, which is a key side effect, but it does not disclose other important behaviors such as requiring the image and layer to exist, potential error conditions, or whether the operation can be undone. This is minimal transparency for a mutating tool.

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?

The description is a single sentence with no wasted words. It is front-loaded with the action and resource, making it immediately scannable.

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?

The tool has a simple signature with two required parameters and an output schema, so the description partially suffices. However, it lacks context about how this selection operation relates to other selection methods and omits prerequisites for safe invocation, leaving noticeable gaps for an agent.

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 0%, so the description must compensate for explaining parameters. It only implies that 'layer_id' refers to the layer whose alpha is used, but it does not explain 'image_id' or the relationship between the two parameters. The schema titles alone are insufficient.

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 uses a specific verb ('Replace'), a clear resource ('the selection'), and a distinguishing source ('a layer's alpha'). This clearly differentiates it from shape-based selection tools like select_rectangle and select_ellipse, and from global selections like select_all and select_none.

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 gives no guidance on when to use this tool versus alternatives. It does not mention selection operation modes (e.g., add, subtract, intersect) or provide examples of when this should be chosen over other selection tools.

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