Cold Leads MCP server
Model Context Protocol server for Cold Leads, the B2B outreach CRM. It exposes the hosted workspace tools to local MCP clients (Claude Desktop, Claude Code, Cursor, Windsurf, VS Code): contacts, imports, synced conversations, templates, campaigns, website capture, lead search, and verification. Without an API key, it can also ask the human owner to approve a subscription.
npx -y @coldleads/mcp-server
Try it without a key
The hosted demo server has the same tools over a sample workspace (fictional contacts on .example domains). It never sends e-mail and uses no credits:
claude mcp add --transport http coldleads-demo https://coldleads.app/api/mcp/demo
Then ask: "Verify these three contacts and prepare outreach drafts. Don't send anything until I approve. Jana Dvořák jana.dvorak@ridgeline.example, info@harborlane.example, Piotr Kowalski piotr@quillmetrics.example". Any client that supports remote (Streamable HTTP) MCP servers can use the same URL. A complete agent built on it: cold-leads-ai-sales-agent.
Demo limits:
| Limit | Value |
|---|---|
| Session | 24 hours from its start (not extended), visible only to that session |
| Contacts | 10, including the 4 sample contacts |
| Templates | 1 of your own (besides the sample template; update it with template_id) |
| Campaign drafts | 1 |
| Text length | notes 100 characters, template body 500, message 200 |
| Requests | 120 per minute and 20 new sessions per hour per IP address |
| Verification | sample results for the three demo prospects; other addresses get syntax, disposable-domain and role checks only (no MX or mailbox check) |
| Sending | never: send_contact_message and launch_campaign still require approval, then return demo_not_sent |
Tools
| Tool | What it does | Cost |
|---|---|---|
verify_email | Verification of one address: syntax, disposable domain, role account and MX records, plus an SMTP mailbox and catch-all check when Cold Leads can open an SMTP connection to the recipient's mail server (otherwise reasons contains smtp_unreachable and catch_all is null). Returns valid, risky or invalid. Usually answers within a few seconds (the client gives up after 8 s). | 1 credit |
search_leads | Contacts already in your Cold Leads CRM for a company domain, with an optional role keyword: e-mail, name, company, stage, tags, verification status and a do_not_contact flag. Cold Leads has no third-party lead database. | free |
list_contacts, import_contacts, update_contact | List, import up to 100 parsed contact rows per call, and update contacts in your own workspace. Imports deduplicate, skip global DNC entries and do not send e-mail. CSV/XLSX parsing is done by the assistant. | free |
get_conversation, send_contact_message | Read mailbox-synced contact conversations or send one e-mail after explicit approval of recipient and content. Opt-outs, bounces and DNC are blocked. | sender/provider limits |
list_templates, save_template | Review, create and update workspace templates; content screening applies. | free |
list_campaigns, create_campaign_draft, launch_campaign | Inspect campaigns, prepare drafts and audience estimates, and launch only after human review and explicit confirmation. | plan and recipient limits |
get_lead_context, get_sales_next_actions, schedule_follow_up, get_agent_activity | Everything known about one lead (contactability, history, last reply class, next action); the queue of replies waiting for an answer and due follow-ups; set a contact's next action (never sends e-mail); the audit log of API and MCP calls. | free |
get_workspace_info, setup_website_lead_capture | Read non-secret workspace/mailbox status or generate a public-only form key/snippet for your website. Website submissions are inquiry leads, not automatic cold-outreach consent. |
Responses are compact JSON in a text block. An illustrative result for an address whose mailbox could not be checked (example.com is reserved for documentation):
{"status":"success","email":"jane.doe@example.com","validity":"valid","catch_all":null,"score":75,"reasons":["smtp_unreachable"],"disposable":false,"role_account":false}
Errors come back as tool results with isError: true, for example {"status":"error","error":"rate_limited","message":"…","http_status":429,"retry_after_seconds":60}.
Requirements
- A Cold Leads secret API key (
sk_…) from Settings → API keys. The API is included in the Business plan (10,000 verification and API credits a month; extra packs available). - Node.js 20 or newer (CI tests 20 and 22).
- No key yet? Start the server without one and let your agent call
provision_account_and_get_payment_link— see Agent onboarding.
Setup
Claude Desktop
claude_desktop_config.json (Settings → Developer → Edit Config):
{
"mcpServers": {
"coldleads": {
"command": "npx",
"args": ["-y", "@coldleads/mcp-server"],
"env": { "COLDLEADS_API_KEY": "sk_your_secret_key" }
}
}
}
Cursor / Windsurf
~/.cursor/mcp.json (Cursor) or ~/.codeium/windsurf/mcp_config.json (Windsurf) — the same mcpServers block as above.
Claude Code
claude mcp add coldleads --env COLDLEADS_API_KEY=sk_your_secret_key -- npx -y @coldleads/mcp-server
VS Code
.vscode/mcp.json:
{
"servers": {
"coldleads": {
"type": "stdio",
"command": "npx",
"args": ["-y", "@coldleads/mcp-server"],
"env": { "COLDLEADS_API_KEY": "sk_your_secret_key" }
}
}
}
Hosted endpoint (no install)
Clients that support remote servers can connect directly with a secret key:
{
"mcpServers": {
"coldleads": {
"url": "https://coldleads.app/api/mcp",
"headers": { "Authorization": "Bearer sk_your_secret_key" }
}
}
}
The stdio server discovers workspace tools from https://coldleads.app/api/mcp and forwards their calls to the hosted MCP service, so the hosted and local tools use the same account, policy and sending safeguards. It also includes keyless onboarding tools. ChatGPT connects to the hosted endpoint with OAuth 2.1; enable Developer mode in ChatGPT, add the endpoint, sign in to Cold Leads and review the requested access. Other remote MCP clients can use the API-key header shown above.
Docker
docker build -t coldleads-mcp-server .
docker run -i --rm -e COLDLEADS_API_KEY=sk_your_secret_key coldleads-mcp-server
Configuration
| Variable | Default | Purpose |
|---|---|---|
COLDLEADS_API_KEY | — | Secret API key (sk_…). Optional at start-up: without it the server still starts, lists tools and can run agent onboarding. |
COLDLEADS_API_BASE | https://coldleads.app | API base URL (for local development against a Cold Leads dev server). |
Agent onboarding without a key
- The agent calls
provision_account_and_get_payment_linkwith the owner's e-mail. - It shows the returned
checkout_urlto the human. The human reviews the plan and price on the secure Stripe page and decides whether to pay. The API gives the agent no way to pay, and the agent is told never to open or pay the link. - The agent polls
check_provisioning_statuswithsession_idandclaim_tokenevery 15–30 seconds. - After payment the first call returns
api_keyonce; this server switches to it immediately. Store it asCOLDLEADS_API_KEYfor the next start. - The owner receives an e-mail to open the Cold Leads web app, where they can manage the subscription or rotate the key.
Only a request that carries the claim_token can collect the key; a status lookup without it never returns the key.
Responsible use
- A verified address is not consent. You need a lawful basis to contact each person.
- Never e-mail leads with
do_not_contact: true(opted out, bounced or on the do-not-contact list). - Limits: 120 requests per minute per key; each verification costs 1 credit.
Development
npm ci
npm run build
npm test # schema, server and stdio child-process tests
COLDLEADS_API_KEY_FILE=path/to/key COLDLEADS_API_BASE=http://localhost:3000 node scripts/smoke.mjs # live checks
License
MIT © 2026 Anton Tkachenko