Retrieve and list Klaviyo tracked event metrics using a private API key, enabling you to inspect available events for reporting and automation workflows.
List Klaviyo metrics (tracked events).
| 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=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds only the semantic gloss that "metrics" means tracked events; it says nothing about pagination, result volume, or whether the full account metric set is returned at once - the main behavioral unknowns for a list endpoint.
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?
One short sentence, front-loaded with verb and resource, with zero filler. It is arguably too terse for the domain rather than padded, so the brevity is efficient rather than wasteful.
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 one-parameter, read-only list endpoint with full schema coverage and no output schema, everything an agent needs to invoke it correctly is present; annotations supply the safety profile and the description supplies the domain gloss for "metrics". Nothing needed for a correct call is missing.
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% for the single api_key parameter, so the schema already carries parameter meaning. The description adds no information about the key's scope or permissions, which is the baseline-3 outcome when structured fields do the work.
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 and resource ("List Klaviyo metrics") and clarifies jargon with "(tracked events)" so an agent unfamiliar with Klaviyo knows these are event definitions, not analytics numbers. It is distinguishable from klaviyo_list_profiles/lists/segments by the resource noun itself, though it never names those siblings explicitly.
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?
Usage is only implied: an agent infers this is the discovery call for metric/event definitions, but there is no statement of when to prefer it over klaviyo_list_profiles or klaviyo_list_segments, and no mention of typical follow-on use (e.g., fetching metric-based reporting). No exclusions of any kind.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.