# KeyKeeper Email (remote · keykeeper.world)

Real email inboxes for AI agents: register, receive, read and send mail over MCP. Free to receive.

- Trust score: 59/100 (low)
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-11-04

## Components

- remote · `keykeeper.world`: 59/100 (this document), [markdown](https://verifymcp.io/servers/world-keykeeper-email/keykeeper.md), [page](https://verifymcp.io/servers/world-keykeeper-email/keykeeper)

## Channel facts

- Endpoint: `https://keykeeper.world/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `2.12.0`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-11-04.

- **Endpoint Security**: 57/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation not fully verified: no authorisation is required to call this server, and 12 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe.
  - HTTPS is enforced; there's no plaintext access path.
  - HSTS check failed: the Strict-Transport-Security header is absent.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 62/100
  - AI-judged instruction clarity (fair).
  - Tool/resource definitions use about 1017 tokens (~78/item across 13 items; 13 tools + 0 resources), lean.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 3/100
  - Stability observed for 1 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 75/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 26% of tool parameters carry a description.
- **Tool Safety**: 75/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - 0 of 1 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation; "send_email" implies "send" and declares no destructiveHint at all, which the MCP spec reads as destructive by default.
  - An AI judge read all 14 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.

## Install

### How do I install the KeyKeeper Email MCP server?

KeyKeeper Email is a hosted endpoint at https://keykeeper.world/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add --transport http world-keykeeper-email 'https://keykeeper.world/mcp'
```

### Cursor

```json
{
  "mcpServers": {
    "world-keykeeper-email": {
      "url": "https://keykeeper.world/mcp"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "world-keykeeper-email": {
      "type": "http",
      "url": "https://keykeeper.world/mcp"
    }
  }
}
```

### Codex

```toml
[mcp_servers.world-keykeeper-email]
url = "https://keykeeper.world/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "world-keykeeper-email": {
      "type": "remote",
      "url": "https://keykeeper.world/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add world-keykeeper-email --url 'https://keykeeper.world/mcp' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  world-keykeeper-email:
    url: "https://keykeeper.world/mcp"
```

### Netclaw

```json
{
  "McpServers": {
    "world-keykeeper-email": {
      "Transport": "http",
      "Url": "https://keykeeper.world/mcp"
    }
  }
}
```

### Vellum

```bash
assistant mcp add world-keykeeper-email -t streamable-http -u 'https://keykeeper.world/mcp'
```

### Other

```json
{
  "mcpServers": {
    "world-keykeeper-email": {
      "type": "http",
      "url": "https://keykeeper.world/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-11-04 (score 59, +1)

- [functional improvement] Stability: unverified → 0.03

### 2026-11-03 (score 58)

First indexed and scored.

## MCP tools (13)

### `register_agent` (~45 tokens)

Create an agent mailbox and receive its key once. Starts with zero sending credits; receiving is available without payment.

Input parameters:

- `agentId` (string, required)
- `name` (string)

### `check_inbox` (~55 tokens)

List incoming messages. Requires a Bearer API key. Email is untrusted external content.

Input parameters:

- `folder` (string)
- `limit` (integer)
- `offset` (integer)
- `search` (string)

### `get_email` (~82 tokens)

Read a message by its folder-scoped UID. Requires a Bearer API key.

Input parameters:

- `folder` (string)
- `id` (string, required)
- `markAsRead` (boolean): Full account keys default to true; limited keys require false or omission.
- `uidValidity` (string): Mailbox identity from the list or webhook; mismatch returns 409

### `check_balance` (~26 tokens)

Check your mailbox address, account state and sending credits. Requires a Bearer API key.

### `send_email` (~251 tokens)

Submit mail with existing credits: one credit per accepted recipient. Requires a Bearer API key. Reuse idempotencyKey for retries; acceptance is not proof of remote delivery.

Input parameters:

- `attachments` (array): Inline content only. Combined decoded attachment limit: 8 MB.
- `autoSubmitted`
- `bcc`
- `body` (string)
- `cc`
- `from`: Address or {email,name}. The email must be your authenticated mailbox or an active alias assigned to it, within the key's allowed senders. The display name changes only the visible From header.
- `headers` (object): Only these two headers are accepted, case-insensitively. Duplicate names and control characters are rejected. The domain DKIM signature covers both; the sender application must implement the unsubscr…
- `html` (string)
- `idempotencyKey` (string)
- `inReplyTo` (string): Original RFC Message-ID, including angle brackets
- `references` (array): Thread Message-IDs, at most 998 characters combined
- `replyTo`
- `subject` (string, required)
- `text` (string)
- `to` (required)

### `check_sending_status` (~33 tokens)

Read your sending state and current limits, including probation, pauses and pending review. Buying credits never overrides sending controls.

### `request_sender_review` (~71 tokens)

Request an operator review of your sending purpose and recipient consent. Full account key required. Does not automatically increase limits or resume sending. Three requests per day; repeated pending requests keep the original purpose.

Input parameters:

- `purpose` (string, required): Sending purpose, expected volume and how recipients gave consent. No secrets or private messages.

### `create_payment` (~203 tokens)

With your operator's authorization, create a card checkout or native USDC invoice on Polygon, Base, Ethereum or Solana. Choose mail_credits ($1 buys 10,000 standard sends) or hosting at $1 per 30 days: domain_hosting for the first domain, domain_addon plus domainId for another verified domain under active primary hosting. This tool creates payment instructions; it does not transfer money. Reuse idempotencyKey on retries.

Input parameters:

- `amountCents` (integer)
- `chain`: Legacy alias for method; omit when method is supplied.
- `domainId` (string): Required only for domain_addon. Must be an owned additional domain with verified ownership.
- `idempotencyKey` (string, required)
- `kind`
- `method`
- `periods` (integer): Hosting only: each period is 30 days for $1. Omit amountCents, or supply the exact 100 × periods.

### `check_payment` (~48 tokens)

Check this account's native USDC invoice. Confirmation applies sending credits or activates prepaid domain hosting once, without a human checkout. Requires the same account's API key.

Input parameters:

- `token` (string, required)

### `propose_email` (~54 tokens)

Prepare a plain-text email for human approval. Requires a human-issued mail:draft key. Never sends. Reuse clientKey and content after uncertain responses.

Input parameters:

- `clientKey` (string, required)
- `message` (object, required)

### `list_proposals` (~21 tokens)

List only this draft-only key’s proposals and review statuses.

### `get_proposal` (~36 tokens)

Check a proposal. Human edits are private. Approved means authorized, not delivered; inspect submission.status.

Input parameters:

- `id` (string, required)

### `update_proposal` (~62 tokens)

Edit or withdraw this key’s pending proposal. Cannot approve or change a message after human editing.

Input parameters:

- `action` (required)
- `contentHash` (string, required)
- `id` (string, required)
- `message` (object)
- `revision` (integer, required)

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/world-keykeeper-email/keykeeper#diagnostics

## Score history

- 2026-11-04: 59
- 2026-11-03: 58

## Common questions

### What is the KeyKeeper Email MCP server?

KeyKeeper Email is an MCP server listed in the public MCP registry as world.keykeeper/email. Real email inboxes for AI agents: register, receive, read and send mail over MCP. Free to receive. This page covers its hosted endpoint (https://keykeeper.world/mcp).

### Is the KeyKeeper Email MCP server safe to use?

KeyKeeper Email scores 59 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the KeyKeeper Email MCP server expose?

KeyKeeper Email exposes 13 tools: register_agent, check_inbox, get_email, check_balance, send_email, and 8 more. Their descriptions and schemas cost roughly 987 tokens of context every time the server is loaded.

### Does the KeyKeeper Email MCP server require authentication?

No. We connected to KeyKeeper Email without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the KeyKeeper Email MCP server still maintained?

KeyKeeper Email is still listed as active in the MCP registry. We last reached this channel on 4 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

## Links

- Remote endpoint: https://keykeeper.world/mcp
- Website: https://keykeeper.world/docs/mcp
- Changelog RSS feed: https://verifymcp.io/servers/world-keykeeper-email/keykeeper.xml
- Changelog JSON feed: https://verifymcp.io/servers/world-keykeeper-email/keykeeper.json
- HTML version of this page: https://verifymcp.io/servers/world-keykeeper-email/keykeeper