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 |
|---|---|---|---|
| api_key | No | MailerCloud API key | |
| campaign_id | Yes | Campaign ID to audit,required |
Does 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 useful behavioral context (pre-send audit, fix-it recommendations) beyond annotations, but it doesn't disclose details like whether it sends any data externally or if there are rate limits. Acceptable but not rich.
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?
The description is a single, comprehensive sentence front-loaded with the core purpose, followed by specific checks and outcome. Every clause earns its place; no filler or repetition.
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 audit tool with a single required parameter and no output schema, the description adequately covers what it checks and what it returns (checklist with recommendations). It could mention whether it returns results synchronously or any limitations, but nothing critical is missing given the annotations cover non-destructiveness.
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 both parameters (api_key and campaign_id), so schema already documents them. The description does not add additional meaning beyond what's in the schema; it merely implies campaign_id is needed. 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?
Description clearly states a specific verb ('audit') and resource ('campaign draft'), enumerates the exact checks performed (subject line, spam triggers, sender config, list selection, content, preheader) and outputs a pass/fail checklist with recommendations. It is distinct from sibling tools like analyze_campaign since it is explicitly pre-send and quality-focused.
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 description says to use it 'before scheduling any campaign,' which gives a clear temporal trigger. It does not explicitly name alternatives or when not to use it, but the pre-send context is strong enough to separate it from analysis or scheduling tools.
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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Tool purposes are largely distinct, with clear separation between CRUD operations, analytics, and deliverability tools. Some overlap exists between get_campaign, analyze_campaign, and campaign_health_dashboard, but descriptions clarify scope sufficiently.
Most tools follow a consistent verb_noun pattern (list_, get_, create_, update_, delete_, send_). Minor exceptions like campaign_health_dashboard and engagement_funnel are descriptive but break the pattern.
With 47 tools, this is a very large surface area. While the variety reflects the breadth of email marketing operations, the count exceeds what is typically manageable and suggests potential redundancy or over-scoping.
The tool set covers most core workflows: contact/list management, campaign lifecycle, templates, webhooks, analytics, and transactional email. Minor gaps like no delete for templates or tags are acceptable but not fatal.
