setLayerVisibility

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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds the 'managed layer' scoping and the standard return envelope, but does not disclose additional behavioral details (e.g., persistence, error conditions). No contradiction with annotations.

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 front-loaded sentence followed by the return shape. It is waste-free and appropriately sized for the tool's simplicity; no filler or repetition.

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 three-parameter tool with full schema coverage, annotations, and an output schema, the description is nearly sufficient. It clearly states the core action and returns. Minor gap: no mention that this affects only managed layers, but that is inherent in the phrase 'managed layer' and the tool's scope is otherwise complete.

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%, with each parameter having a concise description ('Layer ID', 'Whether visible', 'Target browser session ID for multi-browser routing (optional)'). The description adds no extra meaning beyond the schema, so the baseline 3 applies.

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 and resource: 'Show or hide a managed layer.' This clearly distinguishes it from layer-deletion tools like removeLayer and styling tools like updateLayerStyle. The action is unambiguous and directly tied to the tool's name.

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 usage through its purpose—use when you need to change a layer's visibility—but it does not explicitly state when to use it versus alternatives, and no sibling tools are referenced. For a simple tool, this is adequate but not exemplary.

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