list_layers

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

With no annotations, the description carries the transparency burden. It discloses the key runtime behavior: an empty map_name falls back to the active map, and it lists all layers rather than a filtered subset. It does not describe invalid-map-name behavior, but the simple list operation and existence of an output schema mitigate this.

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 two short sentences with parameter details clearly split out. No filler or redundant restatement of the tool name.

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 optional-parameter list operation with an output schema already present, the description covers the essential context: what is listed and how the single parameter behaves. Nothing critical is missing for an agent to invoke it 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?

The description adds significant meaning beyond the bare schema: it explains that map_name is optional, that it selects a specific map, and that leaving it empty uses the active map. This fully compensates for the 0% schema description coverage.

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 states the specific action ('List all layers') and the resource scope ('active map or specific map by name'). It clearly differentiates from sibling list tools like list_fields or list_feature_classes by targeting map layers.

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 implies the appropriate context by mentioning the active map and optional named map, but it does not explicitly state when to prefer this over sibling layer/feature-class listing tools. There are no exclusions or alternative tool references.

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