Retrieve Klaviyo subscriber profiles with an API key, then apply filter expressions and set return limits to target specific audience segments.
List Klaviyo profiles (subscribers).
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | Profiles to return (max 100, default 20) | |
| filter | No | Klaviyo filter expression (e.g. equals(email,'a@b.com')) | |
| api_key | Yes | Klaviyo private API key |
Changes observed during successful MCP inspections.
v0.1.11Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds only the small semantic clarification that profiles are subscribers; it says nothing about pagination, result caps (the schema notes max 100), or rate limiting. With annotations carrying the weight, a 3 is appropriate.
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?
A single short sentence with the core verb and resource front-loaded and zero filler. The brevity is efficient, though it borders on under-specification for a listing tool.
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?
There is no output schema, so the description is the only place return shape could be described, yet it says nothing about what a profile record contains or how pagination works. Given the fully documented input schema and the read-only annotations, it is barely adequate but leaves meaningful gaps.
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 100%, so limit, filter, and api_key are all documented in the schema, which sets the baseline of 3. The description adds only the gloss that profiles equal subscribers and contributes nothing about filter expression syntax or pagination behavior beyond what the schema already says.
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?
States a specific verb (List) and resource (Klaviyo profiles/subscribers), which is unambiguous on its own. However it never distinguishes itself from sibling Klaviyo tools such as klaviyo_list_lists, klaviyo_list_segments, or klaviyo_list_metrics, so an agent must infer from the name alone which object type it returns.
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 no when-to-use guidance, no prerequisites beyond the api_key in the schema, and no mention of alternatives. An agent has to decide between this and the other Klaviyo list_* tools with no stated criteria.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.