Pre-send quality audit for a campaign draft. Checks subject line length and spam triggers, sender configuration, list selection, content presence, preheader text, and provides a pass/fail checklist with specific fix-it recommendations before you hit send. Use this before scheduling any campaign.
| Name | Required | Description | Default |
|---|---|---|---|
| campaign_id | Yes | Campaign ID to audit |
Changes observed during successful MCP inspections.
Input schema / properties / campaign_id / descriptionPrevious value: -"Campaign ID to audit,required"New value: +"Campaign ID to audit"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 readOnly, idempotent, non-destructive, so the safety profile is covered. The description adds genuine context beyond that: it describes what the tool returns (pass/fail checklist plus specific fix-it recommendations) and the pre-send constraint, which is exactly the value-add expected when annotations carry the safety load.
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 sentences, zero filler, and the core purpose is front-loaded before the check list and the call to action. Every clause carries either scope or usage 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?
With a single required parameter, no output schema, and annotations covering the safety traits, this description is complete: it covers what is checked, what is returned (checklist and recommendations), and when to call it. Nothing an agent needs to invoke it correctly 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?
Only one parameter and schema coverage is 100%, so the schema fully documents campaign_id. The description contributes the nuance that the ID should point at a draft, but gives no format or eligibility details beyond that; baseline 3 is appropriate.
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 ('audit') and resource ('campaign draft') and then enumerates exactly what is checked: subject line length, spam triggers, sender config, list selection, content, preheader. An agent can tell this apart from analyze_campaign or campaign_health_dashboard because the audit is explicitly pre-send and gated on a draft.
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?
'Use this before scheduling any campaign' gives a clear trigger condition, which is the main usage decision an agent needs. It does not contrast itself against the analytic siblings (analyze_campaign, campaign_health_dashboard), so the agent still infers the boundary.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.