WarmySender MCP Server

What this is

WarmySender publishes a public Model Context Protocol server so a compatible AI client can check email warmup, mailbox health and deliverability, read campaign analytics, and manage contacts you already have. Point Claude, ChatGPT, Cursor, Codex, OpenClaw, and Hermes Agent, or any other MCP 2025-11 Streamable HTTP client, at https://warmysender.com/mcp and sign in, or use a Bearer API key. The protocol is the Model Context Protocol.

Full-surface tools for clients other than ChatGPT

Clients other than ChatGPT can also create and launch campaigns (cold email, LinkedIn, Instagram, WhatsApp, and multichannel), search leads, and verify addresses. The full catalog is 80 tools. Those tools are only available to clients other than ChatGPT. The scheduler always paces every action. The agent never sends a message, invite or DM directly and cannot raise a limit. Creating or launching a campaign only writes it and hands it to the scheduler.

Why connect your AI assistant?

Ask your assistant questions like:

• “List every email campaign that's running and show me reply rates for the last 7 days.”
• “Which of my mailboxes have a warmup score below 70?”
• “Enroll these 30 prospects into the Q2 Partnerships campaign.”
• “Pause the LinkedIn campaign for the Acme audience — the reply rate dropped this week.”
• “Publish a LinkedIn post announcing our new launch, and show me the engagement in a couple of days.”
• “Create and publish a LinkedIn job posting for a Senior Account Executive, then list the applicants as they come in.”
• “Pause the Acme Instagram DM campaign and tell me how many replies it got.”
• “What's my remaining LinkedIn invite budget on each account today?”
• “Add [email protected] and all of acme.com to my suppression list.”

Every action runs through the same scheduler-first path as the web UI. Rate limits, warmup ramps, LinkedIn daily/weekly caps, and domain-level protections all apply identically. MCP is a protocol adapter, not a parallel implementation.

Quick start in 3 steps

1. Pick sign-in or an API key. Sign in is the default and needs no key: your agent opens a WarmySender screen and you approve access. Prefer a key? In WarmySender, go to Settings → API Keys, click Create, and pick the scopes you want to expose. Available scopes are campaigns:read, campaigns:write, prospects:read, prospects:write, mailboxes:read, warmup:read, warmup:write, linkedin:read, linkedin:write, enrollments:write, suppressions:read, suppressions:write, and jobs:read. Save the key value — you'll only see it once.
2. Add WarmySender to your agent. Pick your AI client below. Cursor is one click, Claude is one button, the rest is one command or one paste. In API-key mode, replace ws_YOUR_API_KEY_HERE with your real key.
3. Ask your assistant to use WarmySender. Try “List my campaigns” or “What's my LinkedIn account health?” — the client discovers MCP tools automatically.

Connect your agent

Server URL: https://warmysender.com/mcp. Transport: Streamable HTTP (MCP spec 2025-11-25). Sign in with your WarmySender account (default) or switch to an API key — in API-key mode replace ws_YOUR_API_KEY_HERE with your key.

https://warmysender.com/mcp

{
  "mcpServers": {
    "warmysender": {
      "command": "npx",
      "args": [
        "-y",
        "@warmysender/mcp",
        "--api-key=ws_YOUR_API_KEY_HERE"
      ]
    }
  }
}

codex mcp add warmysender --url https://warmysender.com/mcp
codex mcp login warmysender

export WARMYSENDER_API_KEY=ws_YOUR_API_KEY_HERE
codex mcp add warmysender --url https://warmysender.com/mcp --bearer-token-env-var WARMYSENDER_API_KEY

claude mcp add --transport http warmysender https://warmysender.com/mcp

claude mcp add --transport http warmysender https://warmysender.com/mcp --header "Authorization: Bearer ws_YOUR_API_KEY_HERE"

{
  "mcpServers": {
    "warmysender": {
      "url": "https://warmysender.com/mcp"
    }
  }
}

{
  "mcpServers": {
    "warmysender": {
      "url": "https://warmysender.com/mcp",
      "headers": {
        "Authorization": "Bearer ws_YOUR_API_KEY_HERE"
      }
    }
  }
}

codex mcp add warmysender --url https://warmysender.com/mcp
codex mcp login warmysender

export WARMYSENDER_API_KEY=ws_YOUR_API_KEY_HERE
codex mcp add warmysender --url https://warmysender.com/mcp --bearer-token-env-var WARMYSENDER_API_KEY

openclaw mcp add warmysender --url https://warmysender.com/mcp --transport streamable-http --auth oauth
openclaw mcp login warmysender

openclaw mcp set warmysender '{"url":"https://warmysender.com/mcp","headers":{"Authorization":"Bearer ws_YOUR_API_KEY_HERE"}}'

mcp_servers:
  warmysender:
    url: "https://warmysender.com/mcp"
    auth: oauth

mcp_servers:
  warmysender:
    url: "https://warmysender.com/mcp"
    headers:
      Authorization: "Bearer ws_YOUR_API_KEY_HERE"

{
  "schema_version": 1,
  "mcp_servers": {
    "warmysender": {
      "transport": "streamable_http",
      "url": "https://warmysender.com/mcp",
      "headers": {
        "Authorization": "Bearer ws_YOUR_API_KEY_HERE"
      }
    }
  }
}

{
  "name": "warmysender",
  "url": "https://warmysender.com/mcp",
  "headers": {
    "Authorization": "Bearer ws_YOUR_API_KEY_HERE"
  }
}

{
  "mcpServers": {
    "warmysender": {
      "serverUrl": "https://warmysender.com/mcp"
    }
  }
}

{
  "mcpServers": {
    "warmysender": {
      "serverUrl": "https://warmysender.com/mcp",
      "headers": {
        "Authorization": "Bearer ws_YOUR_API_KEY_HERE"
      }
    }
  }
}

{
  "context_servers": {
    "warmysender": {
      "command": {
        "path": "npx",
        "args": [
          "-y",
          "@warmysender/mcp",
          "--api-key=ws_YOUR_API_KEY_HERE"
        ]
      }
    }
  }
}

No settings screen? Paste this into your agent

Any agent that can add an MCP server from a chat message sets itself up from this paragraph — sign-in only, never a key.

Connect to WarmySender: it is an MCP server at https://warmysender.com/mcp that uses OAuth sign-in (no API key needed). Add it as a streamable-HTTP MCP server, open the sign-in link it returns so I can approve access, then install the WarmySender skill from https://github.com/fortuneflick/warmysender-claude-plugin (`npx skills add fortuneflick/warmysender-claude-plugin`). Never send a message yourself — WarmySender's scheduler paces every email, LinkedIn, Instagram and WhatsApp action inside safe limits.

Your agent never sends a message itself and can never raise a limit — WarmySender's scheduler paces every email, LinkedIn, Instagram and WhatsApp action inside safe limits. Connecting or disconnecting accounts stays in the app.

Available tools

MCP tools are gated by the scopes on your API key. If a call returns insufficient_scope, add the missing scope in Settings → API Keys and create a new key. Every write tool accepts an optional idempotency_key argument so retries are safe. Destructive tools (pause_*, unenroll_*, add_to_suppression_list) set destructiveHint: true so MCP clients prompt the user for confirmation before calling.

Safety & account protection

WarmySender's MCP server is designed so that a compromised or confused AI cannot burn your sending reputation or ban your LinkedIn accounts. Five guardrails always apply:

1. Workspace scoping on every call. Your API key resolves to exactly one workspace. Every query is filtered by that workspace id — there is no path to read or mutate another tenant's data.
2. Scheduler-first execution. LinkedIn invite/message/view calls never happen inline from MCP. The scheduler owns the rate limits, ramp schedule, and per-account safety caps. Enrolling 1,000 prospects at once still sends at the safe rate.
3. LinkedIn daily/weekly limits & 4-week ramp are non-negotiable. A new account starts at ~10 invites/day and grows over 4 weeks to safe maximums (50 invites/day, 150 messages/day). MCP cannot raise these — account safety always wins over speed.
4. Per-mailbox sending pacer and warmup [ref: XXXX] tag stay intact. MCP does not expose any tool that modifies or removes the warmup subject-line identifier or bypasses per-mailbox daily caps.
5. No account connect / disconnect / delete tools. Connecting and disconnecting email or LinkedIn accounts stays in the UI. No delete_campaign, delete_mailbox, or delete_account tools exist in V1 — soft-cancel via pause/archive only.

Read more about the LinkedIn safety model in our LinkedIn Safety FAQ.

Rate limits

Limits are per workspace, in a rolling 60-second window, and separate from your monthly call allowance. Every budget scales with your plan — read down your plan's column. These are in addition to — not replacing — the scheduler's hard LinkedIn, Instagram, and warmup caps.

Figures are calls per minute, per workspace. Agent actions start on the Pro plan — a Free plan has no agent allowance yet, so there is no per-minute budget to spend on one and calls come back pointing at where to change plan instead of running. Customers on the legacy Starter and Business plans keep their own pace; the AI Agents page lists every plan side by side.

Exceeding a per-minute budget returns a rate_limited error carrying retry_after_seconds, so your assistant knows when to retry. A plan refusal is a different answer — plan_upgrade_required, with no wait hint, because waiting cannot cure it.

Error codes

MCP tools use JSON-RPC error codes. The WarmySender server reserves the -32000…-32099 range for protocol-specific errors on top of the standard JSON-RPC codes.

Frequently asked questions

This server, by agent and channel

What each agent can and cannot do on each channel through this server, how it connects, and prompts phrased for its own surface — one page per pair. The agent never sends a message itself and can never raise a limit on any of them.

• Claude: Cold Email · Email Warmup · LinkedIn · Instagram · WhatsApp · Email Verification
• ChatGPT: Cold Email · Email Warmup · LinkedIn · Instagram · WhatsApp · Email Verification
• Cursor: Cold Email · Email Warmup · LinkedIn · Instagram · WhatsApp · Email Verification
• Codex: Cold Email · Email Warmup · LinkedIn · Instagram · WhatsApp · Email Verification
• OpenClaw: Cold Email · Email Warmup · LinkedIn · Instagram · WhatsApp · Email Verification
• Hermes Agent: Cold Email · Email Warmup · LinkedIn · Instagram · WhatsApp · Email Verification

Related reading

• Full WarmySender documentation — setup guides, troubleshooting, and help for every feature
• My browser says 127.0.0.1 is blocked — what to do when Approve works but the browser stops the last hop
• Pricing — plans, LinkedIn seats, and annual billing
• REST API reference — all API v1 endpoints, scopes, and webhook events
• Settings & API Keys — create, scope, and revoke API keys
• Integrations hub — HubSpot, Salesforce, Zapier, Make, Slack, and more
• LinkedIn Safety FAQ — how we keep accounts safe
• Email Warmup FAQ — what warmup does and why you need it
• Model Context Protocol (modelcontextprotocol.io) — the open spec behind MCP