customerio_get_campaign_metricsGet delivery/engagement metrics for a campaign over time. App API: GET /v1/campaigns/{campaign_id}/metrics.
| Name | Required | Description | Default |
|---|---|---|---|
| type | No | Metric type filter (e.g. email, push, sms). | |
| steps | No | Number of periods to return. | |
| period | No | Bucket size. Default days. | |
| campaign_id | Yes | Campaign id. |
Changes observed during successful MCP inspections.
Input schema / $schemaPrevious value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"Input schema / properties / campaign_id / anyOfRemoved value: -[
- {
- "type": "string"
- },
- {
- "type": "number"
- }
-]Input schema / properties / campaign_id / typeAdded value: +[
+ "string",
+ "number"
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, so safety is covered. The description adds the underlying REST endpoint (GET /v1/campaigns/{campaign_id}/metrics), which is genuinely useful for a REST-backed tool, but it omits any rate-limit, pagination, or empty-result behavior. With annotations carrying the safety profile, 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?
Two tight sentences with the purpose front-loaded and no filler. The endpoint sentence is defensible as a disambiguator for a REST-backed API, though it is the one part that could be trimmed without losing capability 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 read-only, single-required-parameter tool with a fully documented schema and no output schema, the description covers what the tool returns at a conceptual level (delivery/engagement metrics over time) and how to reach it. Only the absence of any discovery path to campaign_id keeps it from being fully self-sufficient.
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 the schema already documents type, steps, period, and campaign_id in full, making 3 the baseline. The phrase 'over time' loosely corroborates the period/steps bucketing semantics but adds no format or default detail beyond what the schema states.
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 ('Get delivery/engagement metrics for a campaign') plus the scope ('over time'), so the agent can distinguish it from customerio_get_campaign, which retrieves campaign configuration rather than performance data. It stops short of naming any sibling explicitly, so it lands at 4 rather than 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?
The purpose implies when it applies (you want metrics, not campaign metadata), but there is no explicit when-to-use, no prerequisite conditions, and no mention of alternatives such as customerio_list_campaigns for discovering campaign ids. Usage is inferable but not guided.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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