# Arelay

> End-to-end encrypted inbox for AI agents — deliver artifacts to humans via HTTP API.

- **Type:** MCP server
- **Install:** `agentstack add mcp-mmmikael-arelay`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [mmmikael](https://agentstack.voostack.com/s/mmmikael)
- **Installs:** 0
- **Category:** [Databases](https://agentstack.voostack.com/c/databases)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [mmmikael](https://github.com/mmmikael)
- **Source:** https://github.com/mmmikael/arelay
- **Website:** https://arelay.app

## Install

```sh
agentstack add mcp-mmmikael-arelay
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Agent Relay

[](https://github.com/mmmikael/arelay/actions/workflows/ci.yml)
[](https://github.com/mmmikael/arelay/actions/workflows/github-code-scanning/codeql)
[](LICENSE)
[](https://nodejs.org/)
[](https://www.typescriptlang.org/)
[](https://svelte.dev/)
[](https://arelay.app)

Agent Relay is an open-source, end-to-end encrypted inbox for AI agents. Anything that can
make HTTP requests can deliver — Cursor, Codex, Claude Code, cron jobs, webhooks, or your
own backend. Agents deliver files, reports, HTML, Markdown, PDFs, and images through a
small HTTP API; you review them in a private web inbox with preview, download, and
read/unread state.

An optional **Email Review Relay** plugin adds a human-in-the-loop outbound email path: agents submit
encrypted drafts, you preview them in the same inbox, then approve or reject before anything
is sent. It is enabled on [arelay.app](https://arelay.app); self-hosters can turn it on with
`EMAIL_REVIEW_RELAY_ENABLED=true` ([setup](#email-review-relay)).

**Two ways to use it:**

- **[arelay.app](https://arelay.app)** — hosted service; sign up and connect your agents
  (no deployment).
- **Self-host** — run this repo on your own infrastructure under the MIT license.

## Contents

### Using [arelay.app](https://arelay.app)

- [Get started](#get-started)
- [Connect your AI agent](#connect-your-ai-agent)
- [Encryption (required)](#encryption-required)
- [Email Review Relay](#email-review-relay)
- [Features](#features)

### Self-hosting

- [Development setup](#development-setup)
- [Environment variables](#environment-variables)
- [Deploy to production](#deploy-to-production)
- [Plugins](#plugins)
- [Tech stack](#tech-stack)

### Reference

- [Contributing & help wanted](#contributing--help-wanted)
- [Security model](#security-model)
- [Terms of Service](https://arelay.app/terms) · [Privacy Policy](https://arelay.app/privacy)
- [Contributing](./CONTRIBUTING.md)
- [License](#license)

---

## Using [arelay.app](https://arelay.app)

The hosted service at [arelay.app](https://arelay.app) handles deployment, database,
storage, backups, TLS, and updates. The security model is the same as self-hosting:
encrypted deliveries are decrypted in your browser, not on the server.

### Get started

1. Open **[arelay.app](https://arelay.app)** and create an account with a passkey.
2. Accept the [Terms of Service](https://arelay.app/terms) and
   [Privacy Policy](https://arelay.app/privacy) during signup (required on the hosted
   service).
3. Complete **Set up encryption** on first portal visit (passkey + recovery key).
4. In the portal, open **Account → Agent tokens** and create a named token for each agent
   or integration.
5. Copy the token once — it is shown only at creation time.
6. Your inbox updates automatically when agents send deliveries (refresh every few seconds).

Sign-in uses passkeys (WebAuthn), not passwords or social login. No Google, Apple, or
Microsoft account is required. If terms or privacy are updated later, existing accounts are
prompted to accept the new versions before continuing.

### Connect your AI agent

Agent Relay is agent-agnostic: any client that speaks HTTP and follows the
[E2EE envelope format](#encryption-required) can deliver. Pick the path that fits your setup:

| Integration path | Best for |
| --- | --- |
| [CLI & MCP server](#cli--mcp-server) | Fastest start: one command from any shell, or native MCP tools in Claude Code, Cursor, and Claude Desktop |
| [Agent skill](#agent-skill) | Cursor, Codex, Claude Code, Hermes Agent, and other [Agent Skills](https://agentskills.io/specification) hosts |
| [Direct HTTP API](#direct-http-api) | Custom scripts, backends, webhooks, scheduled jobs |
| [Platform plugins](#platform-plugins) | Platform-specific hooks, e.g. Hermes cron delivery |

Whichever path you choose, set these where your agent runs — **never commit tokens**:

| Variable | Value for [arelay.app](https://arelay.app) |
| --- | --- |
| `ARELAY_URL` | `https://arelay.app` |
| `ARELAY_TOKEN` | Token from Account → Agent tokens |

Every request uses `Authorization: Bearer `.

#### CLI & MCP server

The [`@arelay/cli`](./packages/arelay) npm package wraps the API and all envelope encryption.
Deliver from any shell:

```bash
export ARELAY_TOKEN=ar_...   # from Account → Agent tokens
npx -y @arelay/cli send report.md --title "Q2 revenue report"
```

Or register it as an MCP server so agents can deliver work natively
(`deliver_to_inbox`, `list_inbox_sessions`, `submit_email_draft` tools):

```bash
# Claude Code
claude mcp add arelay --env ARELAY_TOKEN=ar_... -- npx -y @arelay/cli mcp
```

`npx -y @arelay/cli check` verifies the token and encryption setup. The package also exports a
typed SDK (`import { ArelayClient } from '@arelay/cli'`) — see its
[README](./packages/arelay/README.md). Self-hosters point it at their deployment with
`ARELAY_URL`.

#### Agent skill

Install the [`agent-relay`](https://github.com/mmmikael/arelay-skills/tree/main/skills/agent-relay) skill (requires
[portal E2EE setup](#encryption-required)):

```bash
npx skills add mmmikael/arelay-skills --skill agent-relay -g -y
```

Hermes Agent:

```bash
hermes skills tap add mmmikael/arelay-skills
hermes skills install mmmikael/arelay-skills/agent-relay
```

#### Direct HTTP API

Anything that can POST JSON can deliver: fetch the public key from
`GET /api/agent/e2ee/config`, encrypt locally, create a session, and upload artifacts. See
the [API reference](https://github.com/mmmikael/arelay-skills/blob/main/skills/agent-relay/references/api-reference.md)
and the bundled Node reference scripts in the skill for working encryption code.

#### Platform plugins

**Hermes cron** (`--deliver arelay`) needs [arelay-hermes-plugin](https://github.com/mmmikael/arelay-hermes-plugin).
Cron runs in the **gateway**, not the interactive CLI — put credentials in
`~/.hermes/.env` (including `AGENT_RELAY_HOME_CHANNEL=https://arelay.app`), install the
plugin, then restart the gateway:

```bash
hermes plugins install mmmikael/arelay-hermes-plugin --enable
# ~/.hermes/.env: AGENT_API_TOKEN, AGENT_RELAY_URL, AGENT_RELAY_HOME_CHANNEL
#   (the Hermes plugin reads its own variables, not the CLI's ARELAY_* ones)
hermes gateway start
/cron add "0 9 * * *" "Your prompt. Never use [SILENT]." --deliver arelay
```

### Encryption (required)

All agent deliveries must be end-to-end encrypted. Complete **Set up encryption** during
[Get started](#get-started); unlock in the browser when viewing the inbox. Agents fetch your
public key from `GET /api/agent/e2ee/config` and upload encrypted sessions and artifacts.
Plaintext agent payloads return `400` (`plaintext_not_allowed`); unconfigured accounts get
`428` (`e2ee_required`).

### Email Review Relay

On [arelay.app](https://arelay.app), agents POST encrypted email drafts; each appears as an
inbox session you **Approve** (send via your Cloudflare credentials) or **Reject**.

1. **Account → Email sending (Cloudflare API)** — save your Cloudflare Account ID and API
   token (encrypted server-side; used only when you approve).
2. Use the **agent-relay** skill — drafts use the same E2EE envelopes as file deliveries.

API details and self-host setup: [Plugins](#plugins).

### Features

- Mobile-friendly email-style inbox
- Email Review Relay: agents draft outbound mail; you approve before send
- Artifact preview and download (text, Markdown, HTML, PDF, images)
- Sandboxed HTML/Markdown preview (external links and media stripped)
- End-to-end encrypted deliveries only
- Passkey sign-in (one passkey per account)
- Named agent API tokens with per-token revoke
- Storage limits: 25 MB per artifact, 500 MB per account

---

## Self-hosting

Run Agent Relay on your own PostgreSQL and S3-compatible storage. Useful when you need full
data residency control or a private deployment.

### Development setup

```bash
npm install
cp .env.example .env
npm run db:migrate:local
npm run dev
```

Open [http://127.0.0.1:5173](http://127.0.0.1:5173) and create an account with a passkey.
Without Cloudflare or SMTP configured, verification codes are printed to the server
console.

Database schema changes are managed with Drizzle migrations. Edit the Drizzle schema,
generate a migration with `npm run db:generate`, review the generated SQL, then apply it
with `npm run db:migrate:local`.

Run unit tests:

```bash
npm test
```

To test migrations against a disposable empty database, set `TEST_DATABASE_URL` and run:

```bash
npm run db:smoke
```

### Environment variables

| Variable | Description |
| --- | --- |
| `SESSION_SECRET` | Secret for signing human session cookies. Generate with `openssl rand -hex 32`. |
| `SESSION_VERSION` | Bump this to invalidate existing human sessions. |
| `ORIGIN` | Public site URL for CSRF checks and absolute links. In production, set to your canonical URL, for example `https://arelay.app`. |
| `WEBAUTHN_RP_NAME` | Passkey relying party display name. Defaults to `Agent Relay`. |
| `WEBAUTHN_RP_ID` | Passkey relying party ID. For production on arelay.app, use `arelay.app`. |
| `WEBAUTHN_ORIGIN` | Expected passkey origin, for example `https://arelay.app`. |
| `DATABASE_URL` | PostgreSQL connection string. |
| `CLOUDFLARE_ACCOUNT_ID` | Cloudflare account ID for [Email Sending](https://developers.cloudflare.com/email-service/). Use when your sending domain is on Cloudflare DNS. |
| `CLOUDFLARE_API_TOKEN` | Cloudflare API token with Email Sending permission. |
| `EMAIL_FROM` | Required when Cloudflare or SMTP is configured. Sender address for verification emails, for example `Agent Relay `. |
| `SMTP_HOST` | SMTP host for account email verification. Used when Cloudflare Email Sending is not configured. |
| `SMTP_PORT` | SMTP port. Defaults to `587`, or `465` when `SMTP_SECURE=true`. |
| `SMTP_SECURE` | Set to `true` for implicit TLS SMTP. |
| `SMTP_USER` | SMTP username, if your provider requires authentication. |
| `SMTP_PASSWORD` | SMTP password, if your provider requires authentication. |
| `S3_ENDPOINT` | S3-compatible endpoint URL. |
| `S3_BUCKET` | S3 bucket name. |
| `S3_PREFIX` | Object key prefix. Defaults to `agent-relay`. |
| `S3_ACCESS_KEY` | S3 access key. |
| `S3_SECRET_KEY` | S3 secret key. |
| `S3_REGION` | S3 region. Defaults to `us-east-1`. |
| `PORT` | HTTP port for `npm start`. Defaults to `3000`. Railway sets this automatically. |
| `BODY_SIZE_LIMIT` | Max HTTP request body size for adapter-node. Required for encrypted artifact uploads (~25 MB files need ~37 MB JSON). Defaults to `40M` when using `npm start`. |
| `NODE_ENV` | Set to `production` in production so session and WebAuthn cookies use `Secure`. |
| `EMAIL_REVIEW_RELAY_ENABLED` | Optional plugin. Set to `true` to enable Email Review Relay (off by default). |

When both Cloudflare Email Sending and SMTP are configured, Cloudflare is used.

### Deploy to production

**Requirements:**

- PostgreSQL
- S3-compatible object storage (see `scripts/iam-agent-relay-s3-policy.json` for a minimal
  AWS IAM policy scoped to the `agent-relay/` prefix)
- Email delivery for account verification ([Cloudflare Email Sending](https://developers.cloudflare.com/email-service/) or SMTP)
- A stable HTTPS origin with correct WebAuthn RP settings

**Build and run:**

```bash
npm run db:migrate:local
npm run build
npm start
```

For a fresh production database, run migrations before starting the app. If you are moving
early account/auth records from an old database, copy only `users`, `webauthn_credentials`,
`e2ee_config`, and `agent_api_tokens`; leave inbox/content/plugin tables empty.

**Railway:**

1. Create a new service from [github.com/mmmikael/arelay](https://github.com/mmmikael/arelay).
2. Add PostgreSQL and link `DATABASE_URL`.
3. Add S3-compatible storage credentials.
4. Set `SESSION_SECRET`.
5. Set `WEBAUTHN_RP_ID` and `WEBAUTHN_ORIGIN` for your domain.
6. Configure email delivery: Cloudflare Email Sending (`CLOUDFLARE_ACCOUNT_ID`, `CLOUDFLARE_API_TOKEN`, `EMAIL_FROM`) or SMTP.
7. Set `NODE_ENV=production`.
8. Set `BODY_SIZE_LIMIT=40M` (or rely on `npm start`, which defaults to `40M` when unset).
9. Migrations run automatically on each deploy via `railway.toml` (`preDeployCommand: npm run db:migrate`).
10. Use `npm run build` as the build command and `npm start` as the start command.

**Existing production database (legacy `ensureSchema` → Drizzle):** on the first Drizzle deploy,
`npm run db:migrate` detects an existing `users` table, records the baseline migration in
`drizzle.__drizzle_migrations` without re-running `CREATE TABLE`, then applies any newer
migrations. No manual cutover is required for arelay.app-style databases that already match
the current schema. For a truly fresh host, run migrations on an empty database instead; if
you are rebuilding from scratch, copy only `users`, `webauthn_credentials`, `e2ee_config`, and
`agent_api_tokens` from the old database.

Point agents at your deployment URL: `ARELAY_URL=https://your-domain.example`.

### Backup and restore (self-hosting)

Agent Relay is not a backup or archival service — keep independent copies of important
content. Self-hosted operators are responsible for backups (see [SECURITY.md](SECURITY.md)).

Back up **both** stores; restoring only one leaves the deployment broken:

| Store | Contents |
| --- | --- |
| PostgreSQL | Accounts, passkeys, E2EE config, API tokens, inbox session metadata, email drafts |
| S3 (`S3_BUCKET` / `S3_PREFIX`) | Encrypted artifact blobs referenced by `inbox_artifacts.storage_key` |

**Backup**

```bash
# PostgreSQL (custom format; adjust connection string)
pg_dump "$DATABASE_URL" -Fc -f agent-relay-$(date +%Y%m%d).dump

# S3 prefix (AWS CLI example; use your provider's equivalent)
aws s3 sync "s3://${S3_BUCKET}/${S3_PREFIX}/" "./agent-relay-s3-$(date +%Y%m%d)/"
```

Use your host's managed snapshots (Railway Postgres, S3 versioning, etc.) when available.

**Restore**

1. Restore PostgreSQL, then object storage under the same `S3_BUCKET` and `S3_PREFIX`.
2. Keep the same `SESSION_SECRET` — encrypted Cloudflare credentials in the database cannot
   be decrypted after restore if this value changes.
3. Run `npm run db:migrate` before starting the app (applies any migrations newer than the dump).
4. Spot-check: sign in with a passkey, open a session, download an artifact.

Delivered content stays E2EE-encrypted in backups. Recovery still requires the account
passkey and portal unlock; backups do not grant server-side plaintext access.

### Plugins

Optional features ship as plugins so minimal self-hosts stay lean. Plugin tables are
included in the Drizzle migrations; enable each plugin with an environment variable to
turn on its APIs and UI.

#### Email Review Relay

Agents submit outbound email drafts for human review before send. On [arelay.app](https://arelay.app)
the plugin is enabled by default; self-hosters set `EMAIL_REVIEW_RELAY_ENABLED=true`. When
disabled, plugin APIs return `404` and the portal UI is hidden.

**Account setup (portal):** open **Account** (`/portal/account`) → **Email sending (Cloudflare API)**
and paste your Cloudflare Account ID and API token.
These per-user credentials are encrypted server-side and used only when you approve a draft.
System `CLOUDFLARE_*` env vars remain for signup verification only.

**Agent API:** authenticated agents POST encrypted drafts to `/api/agent/email-drafts`
(`encrypted: true` with envelope fields). Plaintext drafts are rejected.

```json
{
  "encrypted": true,
  "encrypted_to": { "v": 1, "alg": "P-256-ECDH-A256GCM", "...": "..." },
  "encrypted_from_email": { "...": "..." },
  "encrypted_subject": { "...": "..." },
  "encrypted_html": { "...": "..." },
  "idempotency_key": "optional-stable-key"
}
```

The response includes the inbox session and draft (`status: pending`). Poll draft status
with `GET /api/agent/email-drafts/{id}` or `GET /api/agent/sessions/{id}` (includes
`email_draft` when applicable).

**Human review (portal):** open the session, decrypt

…

## Source & license

This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [mmmikael](https://github.com/mmmikael)
- **Source:** [mmmikael/arelay](https://github.com/mmmikael/arelay)
- **License:** MIT
- **Homepage:** https://arelay.app

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** yes
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/mcp-mmmikael-arelay
- Seller: https://agentstack.voostack.com/s/mmmikael
- Browse the marketplace: https://agentstack.voostack.com/browse

---
Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.