--- title: "WarmInboxes Claude Connector for Cold Email Deliverability" description: "Add WarmInboxes to Claude as a connector: free cold email deliverability checks, copy and list tools, inbox planning and our placement research, with no…" url: https://warminboxes.com/claude-connector breadcrumb: "Home > For AI Agents > Claude connector" --- Claude connector # WarmInboxes for Claude A Claude connector for cold email: check whether a domain is ready to send, score a draft for spam triggers, clean and convert lead lists, read why a message went to junk, size the inboxes a volume needs, and quote our own placement research. Free, read-only, no account. Submitted for review WarmInboxes was submitted to the Claude Connectors Directory on 22 October 2026 and is in review. Until it is listed, add it to Claude yourself in a minute: it is the same server, and it works the same way. ## Add it to Claude Custom connectors are added on claude.ai, under Settings, Connectors, on the Claude plans that offer them. - Click Add to Claude. Claude opens its Add custom connector dialog with the name and URL filled in (the URL is also copied, in case the dialog opens empty). - Click Add. - In a chat, open the tools menu and switch WarmInboxes on. - Ask a deliverability question, for example "Is stripe.com set up properly to send cold email?" - Name: `WarmInboxes` - Remote MCP server URL: `https://warminboxes.com/mcp` [Add to Claude →](https://claude.ai/customize/connectors?modal=add-custom-connector&connectorName=WarmInboxes&connectorUrl=https%3A%2F%2Fwarminboxes.com%2Fmcp) ## What to ask it ### Domains - "Is stripe.com set up properly to send cold email?" `check_deliverability` - "Check the SPF, DKIM and DMARC records for mydomain.com." `check_email_authentication` - "Is mydomain.com on any blacklists?" `check_blacklist` ### Copy - "Check this cold email for spam words: (paste the draft)" `analyze_cold_email` - "How will this subject line and opening cut off in Gmail on a phone?" `preview_inbox` ### Lists - "Clean this lead list and remove duplicates and role addresses: (paste the CSV)" `clean_csv` - "Which of these domains are on Google and which on Microsoft?" `segment_esp` - "Convert this CSV to Smartlead’s import format." `convert_csv` ### Diagnosis - "Why did this email land in Outlook junk? (paste the headers)" `analyze_microsoft_headers` - "What does this bounce mean, and should I keep sending? (paste it)" `analyze_bounces` ### Planning - "How many inboxes and domains do I need to send 1,000 cold emails a day?" `plan_infrastructure` - "Plan a rotation for 60 inboxes sending 600 a day." `plan_rotation` ### Research - "Does a SURBL listing actually hurt cold email replies?" `find_resources, read_resource` - "Which top-level domain should I buy for cold email?" `find_resources, read_resource` ## What it will not do - Every tool is read-only. It does not send email, buy inboxes or change your DNS. - The Spamhaus DBL needs a paid key and is not queried. Asked about it, the answer says "not checked" and links Spamhaus’s own lookup; it never reports a domain as clean there. - Authentication checks cannot guarantee inbox placement, and there are no invented reputation scores: mailbox providers keep those private. - A free daily limit applies, counted in distinct domains. Checking a domain again the same day does not count again. - Pasted copy, headers and CSVs are processed to answer and not stored. ## When the answer is more inboxes Ask Claude how many inboxes a send volume needs and it works out the count, the domains and the monthly cost from our prices. The first order is placed in the WarmInboxes app; prewarmed Google, Microsoft 365 and Azure inboxes arrive set up and ready to connect to your sequencer. [See the inboxes](https://warminboxes.com/offer). ## Questions ### Is the WarmInboxes Claude connector free? Yes. No account, no API key and no sign-in. A daily limit counted in distinct domains keeps it fair; re-checking a domain the same day is free. ### Is it approved for Claude yet? WarmInboxes was submitted to the Claude Connectors Directory on 22 October 2026 and is in review. Until it is listed, add it to Claude yourself in a minute: it is the same server, and it works the same way. ### What does it see, and is anything stored? It sees what you ask it to check: a domain, an address, or text you paste such as headers, a draft or a CSV. Domains are looked up live. Pasted text is processed to answer and not stored. The privacy policy has the detail. ### Can it buy inboxes or change my DNS? No. Every tool is read-only. When the answer is more inboxes, it works out what to order and what it costs; the first order is placed in the WarmInboxes app, and existing customers can connect the separate purchasing server. ### Does it work outside Claude? Yes. It is a standard remote MCP server at https://warminboxes.com/mcp, so Claude, ChatGPT, Grok, Claude Code, Cursor, VS Code and other MCP clients can all use it. [WarmInboxes for ChatGPT](https://warminboxes.com/chatgpt-plugin) · [For AI Agents](https://warminboxes.com/for-ai) · [Privacy](https://warminboxes.com/privacy)