List Layers

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

Annotations already declare readOnlyHint=true. The description adds behavioral detail about the return value (name, visibility, layer type), which is helpful. It does not contradict 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?

One concise sentence covering purpose and return structure. Very efficient, though slightly more structure (e.g., bullet list) could improve readability.

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?

Given the tool's simplicity, readOnlyHint annotation, and existing output schema, the description adequately covers return contents and usage context. It could mention that it lists all layers without filtering, but overall sufficient.

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 clarifies the single parameter map_name by explaining that an empty value corresponds to the active map, while a named map is used otherwise. This adds meaning beyond the schema's simple 'Map Name' string and default=''.

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 tool lists layers in the active or named map, specifying the returned attributes (name, visibility, type). This distinguishes it from sibling tools like add_raster_layer or remove_layer.

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 explicit guidance is given on when to use this tool versus alternatives. The description only says what it does, not when it is appropriate or when to use other list tools like list_fields or list_feature_classes.

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