Get Unique Values

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

Annotations declare readOnlyHint=true, so description focuses on additional behavior: 'limit caps the number of values returned.' No contradictions; adds value beyond annotations by clarifying the limit's effect.

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?

Two sentences, front-loaded with the main action and purpose. No redundant words, every sentence earns its place.

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?

With an output schema present, return values are covered. The description clearly states the tool's purpose and key parameter behavior, adequate for a simple read tool. Could mention required parameters but implicit given context.

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 0%, so description is expected to add meaning. It explains 'limit' (default 100, caps values), but does not elaborate on 'layer' or 'field' parameters. Minimal added value beyond naming.

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 returns distinct values of a field, with a specific use case ('useful before building where-clauses or categorized symbology'). It differentiates from sibling tools like describe_data or get_layer_features by focusing on unique values for a single field.

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 provides clear context on when to use ('useful before building where-clauses or categorized symbology'), but does not explicitly state when not to use or mention alternatives among siblings.

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