Side-by-side comparison of two or more campaigns. Shows performance metrics, scores, grades, identifies the winner for each metric, and provides recommendations based on what worked best.
| Name | Required | Description | Default |
|---|---|---|---|
| campaign_ids | Yes | Two or more campaign IDs to compare | |
| cost_per_email | No | Optional cost per email in dollars for cost-per-open and cost-per-click calculations |
Changes observed during successful MCP inspections.
Input schema / properties / campaign_ids / descriptionPrevious value: -"Two or more campaign IDs to compare,required"New value: +"Two or more campaign IDs to compare"Input schema / properties / api_keyRemoved value: -{
- "description": "MailerCloud API key",
- "type": "string"
-}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the tool as read-only, idempotent, and non-destructive, so the safety profile is covered. The description adds meaningful behavioral context by describing what the tool computes: side-by-side metrics, scores, grades, per-metric winners, and recommendations based on what worked best. It stops short of describing output format or pagination, but that is a minor gap given 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?
Two tightly written sentences with no filler. The primary purpose is front-loaded, followed by a compact enumeration of outputs.
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 analytical tool with fully documented parameters and no output schema, the description provides enough context about what the tool returns and how it is used. A small gap remains: the role of cost_per_email in shaping the results is not mentioned, though the schema covers it.
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 coverage is 100%, and both parameters are well described in the schema itself. The description adds no parameter-level detail beyond the schema—it only implies the campaign_ids requirement via 'two or more campaigns' and does not mention the optional cost_per_email parameter at all.
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?
The description states a specific verb and resource ('side-by-side comparison of two or more campaigns') and enumerates the outputs (metrics, scores, grades, winner, recommendations). It implicitly distinguishes itself from single-campaign tools like analyze_campaign by requiring two or more campaigns, but it does not explicitly name any sibling alternatives.
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 'two or more campaigns' framing implies when to use it, but there is no explicit guidance on when to prefer it over analyze_campaign, campaign_health_dashboard, or analyze_latest_campaigns. No exclusions or prerequisites are stated.
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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