Retrieves all Klaviyo lists using your private API key, letting you identify and select the audience segments needed for email and SMS campaigns or further automation workflows.
List Klaviyo lists.
| Name | Required | Description | Default |
|---|---|---|---|
| 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, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds nothing beyond them: no mention of pagination, result volume, rate limits, or the authorization/permission scope required by the private API key.
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 four-word sentence with no wasted clauses, but its brevity comes from omission rather than discipline. There is no front-loaded scope statement or qualifier to anchor it.
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?
A one-parameter read tool is simple and annotations cover the safety profile, but with no output schema the description should at least sketch what a returned list contains or how results are returned. It leaves the agent with only the tool name to work from.
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% and there is a single required api_key parameter documented in the schema, so the baseline of 3 applies. The description contributes no additional meaning about the key's scope or expected format.
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?
"List Klaviyo lists" is a verb+resource restatement of the tool name klaviyo_list_lists, adding no distinguishing detail. Nothing tells an agent how a Klaviyo "list" (an audience/subscriber list) differs from the segments, metrics, or profiles returned by sibling tools.
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-to-use guidance, and the three sibling Klaviyo tools (klaviyo_list_segments, klaviyo_list_metrics, klaviyo_list_profiles) are never mentioned as alternatives. The agent must infer the choice from the tool name alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.