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

The description adds no behavioral context beyond what the annotations already provide. Annotations indicate idempotent and non-destructive, but the description does not clarify whether highlighting is temporary, whether it affects layer state, or how it interacts with the rendered scene.

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 concise sentence with no redundancy. It is appropriately short for the tool's simplicity, though it could include a bit more detail without becoming verbose.

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 highlight operation with full schema parameter coverage and idempotent annotation, the description is minimally viable. However, it lacks usage context such as when to apply highlighting, how specified layers are identified, or what happens when no featureIndex is provided.

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 descriptions cover all three parameters (color, layerId, featureIndex), providing baseline semantics. The description itself adds no additional parameter context, so it stays at the 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 clearly states the action (highlight) and target (features of the specified layer). It distinguishes from sibling add*/remove* tools by focusing on highlighting existing features rather than creating or removing them.

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?

No guidance is provided on when to use this tool versus alternatives. The description does not mention prerequisites, selection criteria, or how it relates to other tools like setLayerVisibility or updateLayerStyle.

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