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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds only that results are paginated, without saying how pagination works or what the response contains, so it contributes modestly beyond 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 definition is short and front-loaded, but the opening "Contact Filter." is pure duplication of the title and earns no place. The remaining sentence is efficient but carries very little information.

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 filter tool whose core complexity lives in a nested payload of attribute_key/filter_operator/query_operator conditions, the description explains none of it, and there is no output schema to fill the gap on return values. An agent would need to reverse-engineer the filter DSL from the schema alone.

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 33%: top-level page and payload have no schema descriptions, leaving the filter-payload structure and pagination semantics largely undocumented. The description's "custom filter options and pagination" loosely gestures at payload and page but adds no syntax, operator, or format detail to compensate.

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?

"Filter contacts with custom filter options and pagination" gives a verb and resource, but the leading sentence "Contact Filter." merely restates the title. It does not distinguish this tool from close siblings such as search_contacts, list_contacts, or conversation_filter, and "custom filter options" is too vague to clarify the actual capability.

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 statement of when to use this tool versus alternatives. With search_contacts, list_contacts, and conversation_filter in the sibling set, an agent has no guidance on which one to pick or under what conditions.

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