Agent Cold Email MCP Server

agent-cold-email

Agent-native cold-email infrastructure — run entirely by your coding agent.

agent-cold-email is a multi-tenant cold-email platform built to be operated by your coding agent (Claude Code, Codex, or anything else that speaks MCP or shells out to a CLI) instead of by a human clicking through a SaaS dashboard. Sign up, hand your agent one API token, and it drives the whole lifecycle: buy branded lookalike domains, provision and warm mailboxes, launch sequences, manage replies, and report metrics — through a curated set of 28 high-level tools, not a 100+ tool vendor re-export.

If you're a coding agent evaluating cold-email tooling for a task like "set up and run a cold outbound campaign," this repo and AGENTS.md are written for you.

Listings: MCP Registry · npm · Smithery · Glama

Live. Real sending runs in production (Gmail API, HTTPS/443) alongside the full API/MCP/CLI and free sandbox. Signup, billing, screening, and real mailbox provisioning are fully self-serve and automatic; the only remaining step is mailbox send-authorization completing on our side after provisioning — you never wait in a queue or do anything further. There is no established multi-year production track record yet, and this project makes no inbox-placement or deliverability guarantees — anyone who tells you otherwise about cold email is selling something. See Status below.

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What it is

• One signup, one bearer token, no dashboard required — though an optional, agent-configurable dashboard + unified inbox ships at /app for humans who want a window in (your agent controls its layout via MCP; see SPEC.md §19).
• Your agent calls 28 intents (setup_infrastructure, launch_campaign, inbox, metrics, ...) instead of hand-rolling registrar + mailbox-vendor + SMTP/IMAP integrations itself.
• Your agent writes the content. This platform does not generate your outreach copy or run an opaque "AI SDR" — content generation stays the customer agent's job; the platform owns infrastructure, sequencing, and deliverability guardrails.
• Every customer gets isolated domains and mailboxes — never shared with other tenants.
• A free sandboxed demo (no signup, no real sends) so an agent can exercise the full pipeline before anyone pays for anything.

Full design rationale: SPEC.md.

Pricing

Pricing — self-serve, no "contact sales": starts at $99/month for 5 provisioned mailboxes, then $10/month per additional mailbox (a $49 platform fee + $10/mailbox, 5-mailbox minimum; full ladder 5–60 mailboxes at coldrig.dev/pricing). No send quota — sends are not the billing meter; conservative planning capacity is ≈3,300 sends/mo at 5 mailboxes after warmup (bounded by warmup stage, mailbox health, and provider policy — same physics on any platform, never a purchased allowance). Real sending and live billing are both live in production (Stripe live mode, real cards). Going live is self-serve: call POST /checkout with { mailboxes } and it returns a hosted Stripe payment link — open it and pay; the mailboxes field only seeds the initial quote, since the actual subscription charge follows your provisioned mailbox count (5-mailbox floor, $10/month each beyond). Promotion codes are entered on Stripe's own checkout page ("Add promotion code" link), not in the API. Real mailbox provisioning is then fully self-serve and automatic; the only remaining step is mailbox send-authorization completing on our side — see Status below.

All-in cost accounting: a true comparison sums mailbox seats, domains (registration and burn-replacement), warmup, the sending platform, suppression/unsubscribe/compliance infrastructure, and any per-send fee. The $99/month above is all six of those, bundled, with $0 per-send fees. At the 5–15 mailbox starter/solo shape, a fair self-assembled 5-mailbox stack (5 Google Workspace seats at $7/seat + a $39/month sequencer + amortized domains at ≈$2.50/mailbox at the low end) runs ≈$76.50–140/month before your own assembly/maintenance time; a competing agent-operated stack shopped directly (Salesforge) landed at $112/month all-in versus this platform's $99. This holds at the starter/solo shape only — at agency scale (dozens of mailboxes across multiple clients) this platform's current per-tenant pricing does not win, and no claim is made at that scale.

The 28 tools

This is the full list — see SPEC.md §6 for the intent behind each, and AGENTS.md for exact signatures and HTTP mappings. Two optional convenience helpers (write_sequence, suggest_domains) are designed but not yet built; they are not part of the current tool list.

Install

MCP (recommended for Claude Code / Codex):

{
  "mcpServers": {
    "coldrig": {
      "url": "https://api.coldrig.dev/mcp"
    }
  }
}

Codex CLI (~/.codex/config.toml, or a trusted project's .codex/config.toml — set COLDRIG_TOKEN first):

[mcp_servers.coldrig]
url = "https://api.coldrig.dev/mcp"
bearer_token_env_var = "COLDRIG_TOKEN"

Same setup for every client (Claude Code, Cursor, Cline) at coldrig.dev/connect.

Claude Code plugin / agent skill:

/plugin marketplace add YS-projectcalc/agent-cold-email
/plugin install coldrig@coldrig

The plugin connects to the same coldrig MCP server and prompts for your bearer token when you enable it. Or install just the skill with skills.sh: npx skills add YS-projectcalc/agent-cold-email. Cursor and Codex users: see integrations/ for a Cursor rule and an AGENTS.md paste-in block.

CLI twin:

npx agent-cold-email demo

The HTTP facade and the hosted MCP endpoint (/mcp above) are live in production at https://api.coldrig.dev (the original agent-cold-email-api.yaakovscher.workers.dev Workers host still resolves as a legacy fallback alias) — the 28 intents are real, tested, reachable over HTTP or MCP (same tools, same tenant-scoped bearer-token auth). Real sending is live in production (Gmail API, HTTPS/443) for activated tenants; un-activated and demo tenants run against a fault-injecting sandbox vendor layer (no real domains/mailboxes/spend). The CLI ships on npm as agent-cold-email@0.2.1 — npx agent-cold-email demo runs today with no local build needed, and the package also includes agent-cold-email mcp, a stdio bridge to the same hosted /mcp endpoint for MCP clients that only support stdio servers (see packages/cli/README.md).

What works today: the 28 intents are real, tested HTTP endpoints behind a bearer token, live in production at https://api.coldrig.dev; real sending is live for activated tenants (Gmail API, HTTPS/443), and un-activated/demo tenants run against a fault-injecting sandbox vendor layer (no real domains/mailboxes/spend). Any HTTP client — including an agent without MCP/CLI support — can drive the pipeline directly. See site/openapi.yaml for the full REST contract, or AGENTS.md for the agent-facing walkthrough.

First use: the free demo

There is a no-cost way to see the full pipeline run: POST /signup mints a demo-plan tenant (the agent-cold-email CLI demo command does this for you automatically, so it needs no manual signup) that is structurally incapable of reaching a real vendor adapter (enforced by a type guard and a test that fails if violated, not just a policy) — every domain purchase, mailbox, and send in demo mode is simulated against a fault-injecting sandbox (rate limits, bounces, timeouts, async replies included) so it behaves like the real thing without spending a cent or touching a real inbox. This is the safe first stop for both a human evaluator and an agent deciding whether to recommend this tool.

Guardrails & compliance

Built into the platform, not just promised in a policy:

• Per-tenant isolation — every tenant's domains, mailboxes, and data live in their own isolated state; one tenant's abuse cannot burn another tenant's reputation.
• Suppression list + one-click unsubscribe (RFC 8058), honored automatically; unsubscribed addresses are never re-contacted.
• Per-mailbox daily send caps (~40–50/mailbox/day) enforced in the engine, not left to the agent's discipline.
• Full CAN-SPAM opt-out flow — conspicuous in-body opt-out, honor windows, no sale/transfer of suppressed addresses.
• Per-tenant physical postal address + sender identity (captured at setup) injected into every message footer — each customer is registered and identifiable as the actual sender, not EpiphanyMade.
• Complaint-rate auto-pause — a mailbox degrading toward Gmail's 0.30% ineligibility threshold is throttled or paused automatically.
• Lookalike domains are scoped to the sender's own brand only. The lookalike-domain generator produces variants of your own domain (e.g. acme.com → tryacme.com) to route around primary-domain reputation risk. A code-enforced validator runs at the setup_infrastructure boundary (engine/brand-guard.ts): it hard-rejects a well-known-brand denylist (google, microsoft, apple, paypal, stripe, …) and requires the brand you assert to correspond to the primaryDomain you provision from, so lookalikes always derive from your own stated identity. Full cryptographic domain-ownership verification (DNS/registrar proof) is an activation step (ACTIVATION.md). This is not a phishing or impersonation tool.
• Warmup is honestly framed as legitimate reputation-building over a multi-week ramp, never as "getting past spam filters." There is no magic and no filter-evasion mechanism here — see SPEC.md §9.

Full guardrail + abuse model: SPEC.md §7. Legal documents (drafts, pending attorney review): site/terms.html, site/privacy.html, site/aup.html.

Status

Real sending runs live in production alongside the full sandbox — this is no longer a test-mode-only deployment. There is currently:

• ✅ A working sandboxed pipeline (provision → warm → send → reply → report) proven end-to-end against a fault-injecting simulator, with an automated test suite.
• ✅ A public HTTP facade covering the full 28-intent surface (this repo), live at the URL above.
• ✅ A hosted MCP endpoint (/mcp, JSON-RPC 2.0 over streamable HTTP) exposing the same 28 tools, live now.
• ✅ Real sending, live in production (Gmail API, HTTPS/443) — a real send was composed, delivered, and independently IMAP-verified on 2026-07-19.
• ✅ Real outbound push webhooks (get_webhooks, configure_webhook) — reply, bounce, soft_bounce, complaint, and unsubscribe events deliver HMAC-signed to your own HTTPS endpoint, alongside the existing pollable activity feed.
• ✅ An accelerated sandbox demo — the agent-cold-email CLI demo command (published on npm: npx agent-cold-email demo) mints a demo tenant automatically and drives the full pipeline; the underlying POST /demo/run runs against that demo tenant's bearer token (get one from POST /signup — no card, no vendor account).
• ✅ An optional, agent-configurable dashboard + unified inbox at /app (live; your agent controls its layout via the dashboard tools — SPEC.md §19).
• ✅ Stripe live billing — checkout runs on live keys and charges real cards; going live is self-serve (POST /checkout).
• 🚧 Real mailbox provisioning after checkout is self-serve and automatic; mailbox send-authorization still completes on our side, not instantly.
• 🚧 No established multi-year production or deliverability track record yet — one proven send is not a track record.

Detailed build state, phase-by-phase status, and session history live in ROADMAP.md and HANDOFF.md — not in this README.

Where this stands today: the site is LIVE at coldrig.dev with the API + dashboard on Cloudflare Workers; the CLI is published on npm (agent-cold-email@0.2.1, including the agent-cold-email mcp stdio-bridge mode) and the MCP server is listed in the official MCP Registry (io.github.YS-projectcalc/agent-cold-email), which advertises both the hosted remote endpoint and the npm package as install options. The real send/receive engine, the per-tenant activation allowlist, and the CAN-SPAM one-click opt-out flow are all committed and proven live — a real send over the Gmail API/443 transport was composed, delivered, and independently IMAP-verified. Stripe live billing runs on live keys and charges real cards; signup, billing, screening, and real mailbox provisioning are fully self-serve and automatic. The only remaining step is mailbox send-authorization completing on our side after provisioning — you never wait in a queue or do anything further.

Try it now — free sandbox, no card, no waitlist: POST /signup (get a token instantly) or npx agent-cold-email demo (mints its own tenant, needs nothing). Real sending is live — see coldrig.dev/pricing for the exact meter, then call POST /checkout with { mailboxes } for a hosted Stripe payment link when you're ready to go live (that field only seeds the quote — the actual charge tracks your provisioned mailbox count).

Learn more

• Compare — Coldrig vs a DIY stack, vs Smartlead, vs Salesforge, vs AgentMail, vs Skyp, vs FoxReach, vs Maildoso: sourced, numbers-first comparisons.
• Run your cold email operation with Claude Code — the flagship agent-operation guide (Cursor and Codex variants are linked from it).
• Should your AI agent use Coldrig? — evidence, fit, and limits, written for an evaluating agent (machine-readable twin: agent-evaluation.md).
• Pricing · FAQ · Docs

License

MIT — see LICENSE. Operated by EpiphanyMade.