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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, and idempotentHint=false, so the safety profile is covered. The description adds that results are distinct values rather than raw activity records, but it does not explain filtering behavior, result limits/ordering, or why a read query is marked non-idempotent. It does not contradict the 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 a single front-loaded sentence with no filler. The use of the internal method name GetPropertyValues is slightly redundant, but overall it is appropriately concise.

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?

The output schema exists, so return values need not be described, and annotations cover safety. However, for a tool with four optional filters and a near-identical insights sibling, the description omits selection guidance and filter semantics, leaving it under-complete for an agent choosing and invoking it.

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 only 25%, and the description explains only the property_key role. It provides no meaning for source, event_kind, or project_id beyond what is already in the schema, so it does not compensate for the low 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 a specific action and result: returns distinct values for a given property key. The tool name identifies it as activity-related, but the description itself does not distinguish it from the near-identical get_insights_property_values sibling, so it falls short of a 5.

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?

There is no when-to-use or when-not guidance, and no alternative tool is mentioned. The only implied context is that it applies to a property key, leaving the agent to infer how this differs from get_insights_property_values.

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