Kivel MCP Server

send_email

DestructiveIdempotent

Send from an owned socketspace.xyz inbox when operator-enabled. Free requires verified owner email and permits 30 recipient deliveries/month, 3/day (3 recipients/message); Pro 500/month, 50/day and Team 3000/month, 300/day (10/message). Supply a unique idempotencyKey; reuse it only for retries of the identical message. replyTo is a received message ID for threading. Inboxes with requireApproval enabled reject direct sends. Create a draft and submit it for approval. Suspensions and suppression cannot be bypassed by retrying.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "id": "<id>",
      "to": "<to>",
      "subject": "<subject>",
      "idempotencyKey": "<idempotencyKey>"
    },
    "name": "send_email"
  }
}

Input Schema

Name	Required	Description
`cc`	No
`id`	Yes	Resource UUID.
`to`	Yes
`html`	No	Optional HTML body; text or html required.
`text`	No	Plain text body.
`replyTo`	No	Received message ID in this inbox.
`subject`	Yes	Message subject.
`idempotencyKey`	Yes	Unique 16–100 character retry key. Reuse only for the identical message.

Schema Changelog

Changes observed during successful MCP inspections.

First observedNov 13, 2026

TDQS

A4.7/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond the annotations (which already declare destructive, open-world, and idempotent), the description discloses plan-tier quotas, daily and per-message recipient caps, the verified-owner requirement, the approval gate, and the idempotency retry contract. These are exactly the operational constraints an agent cannot infer from structured fields.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The purpose and the send-vs-draft decision are front-loaded, and quota details are compressed into a dense but scannable sentence. It is slightly information-dense with several clauses packed together, but no sentence is filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a destructive, gated mutation tool with no output schema, the description covers prerequisites, quota limits, approval routing, and non-retryable failures. The one gap is what a successful send returns (e.g., a message identifier useful for later threading), which matters since no output schema documents it.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With 75% schema coverage the schema already documents most parameters, yet the description adds real meaning: idempotencyKey must be unique 16-100 chars and reused only for identical-message retries, and replyTo is a received message ID used for threading. It does not clarify `id` (inbox) or the to/cc recipient-count interactions beyond the per-message limits stated.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The first sentence names a specific verb (Send) and resource (email from an owned socketspace.xyz inbox) plus the governing precondition (operator-enabled). It also implicitly distinguishes the send path from the draft-and-approve path described later, so an agent can tell what this tool does without opening the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It states explicit conditions for use and non-use: send directly only when the inbox is operator-enabled and does not have requireApproval; otherwise create a draft and submit it for approval. It further warns that suspensions and suppression cannot be bypassed by retrying, which routes the agent away from futile retries.

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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