attributes_unique_values

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

The description mentions the cap of 20 and total distinct count, which are behavioral details. However, without annotations, it does not disclose other behaviors such as performance or prerequisites. The cap explanation is helpful but incomplete.

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 sentences, front-loads the cap and total count, and provides a clear alternative. Every sentence adds value with no fluff.

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 tool with only two parameters and an output schema, the description covers what the tool does, its cap, and relationship to a sibling. It is fully adequate for an agent to select and invoke the tool 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?

With 0% schema description coverage, the description must compensate. It does not explicitly describe the two parameters (layer_id and field_name), but the tool name and context make their meaning clear. The description adds some implicit understanding but not explicit detail.

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 it lists distinct values of a field with a cap of 20 and total distinct count. It distinguishes itself from the sibling get_layer_schema by specifying when to use this tool instead.

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 explicitly says to use this tool when you only need one field's distinct values without the rest of the schema, referencing the sibling get_layer_schema. It provides clear context but does not exclude other siblings.

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