List subscriber attributes

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

Beyond the readOnlyHint annotation, the description adds useful behavioral context: it clarifies that attributes are custom keys set via the JS SDK, notes that results are paginated with `has_more`, and mentions that it operates on the current site. This adds value beyond the structured 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 two sentences, front-loaded with the action, and every clause adds value: the resource, the data source, pagination behavior, and the concrete use case. No wasted words.

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 read-only list tool with good annotations, a full output schema, and detailed parameter descriptions, the description covers the essential aspects: what it lists, the pagination flag, and why you'd use it. Nothing critical is missing for the agent to select and invoke this 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?

The schema already covers all four parameters with detailed descriptions (100% coverage), so the description carries no burden to explain parameters. The baseline of 3 applies because the description does not add any additional parameter semantics beyond the schema.

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 ('Lists') and a specific resource ('subscriber attributes'), with scope ('on the current site') and a distinguishing feature (paginated with `has_more`). It clearly differentiates from sibling tools like list_segments or list_audience_groups.

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 gives explicit guidance: 'Use this to discover attribute `key` values before constructing an audience-group filter rule with field="attributes".' This clearly states a key use case, but does not mention alternatives or when not to use the tool. It falls just short of the 'explicit when/when-not/alternatives' standard.

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