Create a new webhook to receive event notifications.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | Webhook URL,required | |
| name | Yes | Webhook name,required | |
| events | Yes | Events to subscribe to,required | |
| api_key | No | MailerCloud API key |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate this is a write operation that is not idempotent and not destructive. The description adds a minimum of context by saying the webhook will 'receive event notifications', which discloses its ongoing side effect. However, it does not mention authentication requirements or possible duplicate-creation behavior in more detail, despite those being relevant to a create call.
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, front-loaded sentence that states the core action and its purpose with no redundant or irrelevant content. Every word adds meaning.
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?
The description is inadequate for a mutate tool without an output schema. It does not specify what the tool returns (e.g., the webhook object or an ID), nor does it explain the allowed values for 'events' or when the optional 'api_key' is required. An agent cannot fully anticipate the result or constraints of calling create_webhook from this description alone.
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?
The input schema has 100% parameter description coverage; each parameter (url, name, events, api_key) already has a description. The tool description itself adds no parameter-level meaning, so it remains at the baseline score of 3.
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 clearly identifies the verb 'Create' and the resource 'new webhook', and explains its purpose: 'to receive event notifications'. This distinguishes it from sibling webhook tools such as update_webhook, delete_webhook, or toggle_webhook, as it is the only one explicitly creating a new webhook.
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 gives no guidance on when to select this tool over alternatives. There is no mention of prerequisites, exclusions, or distinction from update_webhook/list_webhooks. The phrase 'to receive event notifications' is a statement of purpose, not a usage rule.
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.
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.
