Claude Code plugin
Run Mailbase from Claude Code: the official plugin connects the Mailbase MCP server and adds skills and slash commands for prospecting, campaigns, replies and sending setup.
Why use an external agent
Mailbase has an assistant built in, but a stronger agent you already use, such as Claude Code or Codex, does the work better with Mailbase's own tools: it plans across areas, reads your files, and keeps going while you review. Mailbase stays the system of record and keeps every safety rule on its side.
Pick the Claude Code plugin if you use Claude Code, the Codex / ChatGPT plugin if you use those, or the mailbase CLI for any agent with a shell. All three reach the same capabilities.
Claude Desktop and claude.ai (no terminal)
- In Mailbase, click Connect your agent in the top bar, then Copy the address & open Claude.
- In Claude (desktop app or claude.ai): Settings, Connectors, Add custom connector. Name it Mailbase and paste the address (https://mailbase.studio/api/mcp/mcp).
- Click Connect, sign in to Mailbase, choose the workspace and what Claude may do. Custom connectors work on every Claude plan.
Install the Claude Code plugin
In Claude Code, add the Mailbase marketplace and install the plugin (it adds the workflow skills and /mailbase commands), then sign in from /mcp and choose the workspace the agent may work in.
/plugin marketplace add amintt2/mailbase-plugins
/plugin install mailbase@mailbase-plugins
/mcp # select "mailbase", sign in, pick a workspaceWhat the plugin adds
| Piece | What it does |
|---|---|
| MCP server | The remote Mailbase server (/api/mcp/mcp) with OAuth, bound to one workspace. |
| /mailbase:status | What needs attention: replies, campaigns in flight, prospecting, deliverability. |
| /mailbase:prospect | Describe who you sell to; the agent builds a target, prunes the pool and readies drafts. |
| /mailbase:review-drafts | Walk through the prospect emails waiting for approval. |
| /mailbase:campaign | Draft a campaign with A/B variants, preflight it and send a test to you. |
| /mailbase:triage | Sort the reply inbox and draft answers for your approval. |
| /mailbase:setup-domain | Connect a domain, show its DNS records and verify it. |
| Skills | get-started, find-clients, launch-campaign, triage-replies, setup-sending, automate-workflows, audiences-and-contacts, mailbase-cli. |
Sending stays your decision
- The agent shows the exact recipients, subject and text, and waits for your yes before anything that emails people: test sends, campaign launches and schedules, replies, approved prospect emails, active workflows, the prospecting sequence.
- Deletes and GDPR erasure are marked destructive and also need your confirmation.
- Mailbase still applies its own checks server-side: suppressed addresses are skipped, daily caps and warm-up hold, content is screened for scams, and your workspace role limits what the connection can do.
Codex and ChatGPT
The same skills ship in the Mailbase plugin for Codex and ChatGPT. Any other MCP client can connect to the server directly; see MCP OAuth Setup.