Register a custom email sending domain for an organization via Resend. Returns DNS records that must be configured in the domain provider before verification. Replaces any previously configured domain. After adding DNS records, call email_domain_verify to check status.
| Name | Required | Description | Default |
|---|---|---|---|
| apiKey | No | ||
| domain | Yes | ||
| orgSlug | Yes |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden. It discloses a critical behavioral trait: 'Replaces any previously configured domain,' and also explains that DNS records are returned for external configuration. It does not mention authentication requirements or rate limits, but the disclosed side effects and follow-up step provide solid transparency beyond the raw schema.
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 three sentences long, with each sentence adding value: the registration action, the DNS records requirement, and the replacement warning plus verification step. It is front-loaded with the purpose and avoids unnecessary detail.
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 tool with no output schema, the description explains the return value ('Returns DNS records') and the essential workflow. It also highlights the destructive replacement behavior and directs users to the verification tool. It could elaborate on the DNS record structure or prerequisites, but it is sufficiently complete for a straightforward registration tool.
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 schema has 0% description coverage for its 3 parameters (apiKey, domain, orgSlug), and the description adds no information about them. It does not explain the meaning, format, or purpose of any parameter. The description mentions 'domain' and 'organization' only indirectly via prose, but fails to compensate for the complete lack of schema-level documentation.
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 states the tool's function with a specific verb ('Register'), a resource ('custom email sending domain'), and a scope ('for an organization via Resend'). It distinguishes itself from sibling tools like email_domain_delete, email_domain_get, and email_domain_verify by focusing on the registration action.
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 provides a clear workflow: register, configure DNS records, then verify with email_domain_verify. It also warns that the tool 'Replaces any previously configured domain,' which is an important usage consideration. However, it does not explicitly mention alternatives for getting or deleting domains, but the verification pointer is strong.
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.
Multiple parallel booking creation flows (booking_create, scheduling_book, public_booking_create) and session state transition tools (booking_update_status, lifecycle_transition) create ambiguity. While descriptions are detailed, an agent could easily select the wrong tool for a given task, especially with 111 tools to choose from.
Most tools follow a consistent domain_action pattern (e.g., client_create, service_update, comms_list_campaigns). Minor deviations include Spanish/English mixing (cierre_*, report_deuda_real) and a few noun-only names like org_summary, but the overall structure is predictable.
With 111 tools, the server is massively over-scoped for an MCP surface. Even for a broad service business domain, this exceeds reasonable limits and will overwhelm agents, making tool selection slower and more error-prone.
The tool surface is extremely thorough, covering org setup, services, providers, booking (internal/public/spec), finance, payroll, closing, disputes, clinical notes, treatment plans, and reporting. Gaps are rare and often intentional (e.g., no deliver via MCP, read-only treatment plans), so agents can complete most workflows end-to-end.