set_layer_mode

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

No annotations are present, so the description carries the full burden for behavioral transparency. It only states the action ('Set') without disclosing side effects, prerequisites (e.g., layer must exist), whether the operation is reversible, or how invalid mode strings are handled. For a mutation tool, this is a significant gap.

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 that states the action, target, and examples. Every word earns its place with no redundancy or unnecessary detail.

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 simple two-parameter setter with an output schema, the description is close to sufficient. However, the lack of behavioral transparency (no annotations, no side-effect disclosure) and the absence of a full list of valid modes leaves some gaps. It meets the minimum viable standard but is not richly comprehensive.

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. It adds value by providing two concrete valid values for the 'mode' parameter, which helps the agent infer the expected string format. The 'layer_id' parameter is self-explanatory from its name. While it doesn't enumerate all possible modes, the examples provide a meaningful baseline.

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 ('Set') and identifies the exact resource ('GIMP layer mode'), with concrete examples (LAYER-MODE-NORMAL, LAYER-MODE-MULTIPLY). This clearly distinguishes it from sibling layer tools that set opacity, visibility, or position.

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 usage context is implied: use it when you want to change a layer's compositing mode. However, the description provides no explicit 'when to use vs alternatives' or exclusionary guidance, such as noting that this is not for opacity or blending adjustments. This is minimal but not misleading.

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