# How to integrate Agent mail MCP with DeepSeek Harness

```json
{
  "title": "How to integrate Agent mail MCP with DeepSeek Harness",
  "toolkit": "Agent mail",
  "toolkit_slug": "agent_mail",
  "framework": "DeepSeek Harness",
  "framework_slug": "deepseek",
  "url": "https://composio.dev/toolkits/agent_mail/framework/deepseek",
  "markdown_url": "https://composio.dev/toolkits/agent_mail/framework/deepseek.md",
  "updated_at": "2026-08-14T10:04:48.340Z"
}
```

## Introduction

DeepSeek Harness (dsh) is an open-source agent runtime from DeepSeek AI, and every part of it is a plugin, so you can swap out the model adapter, the tool registry, or the agent loop. It runs on the Cordis framework and comes with a local Web UI, a headless CLI runner, and a Python SDK. You can point it at DeepSeek V4-Pro and V4-Flash, or at Anthropic, OpenAI, and other OpenAI-compatible providers. It is MIT licensed and still in developer preview.
This guide shows how to connect your Agent mail account to DeepSeek Harness, and you can do it with either the Composio Connect CLI or the Composio Connect MCP. The dsh-base bundle gives shell execution as a first-class tool, so the CLI is the easiest path for personal use. It is quick to set up and needs no server config, and the MCP path works well too, since the harness comes with a built-in MCP client.

## Also integrate Agent mail with

- [ChatGPT Work](https://composio.dev/toolkits/agent_mail/framework/chatgpt)
- [Antigravity](https://composio.dev/toolkits/agent_mail/framework/antigravity)
- [OpenAI Agents SDK](https://composio.dev/toolkits/agent_mail/framework/open-ai-agents-sdk)
- [Claude Agent SDK](https://composio.dev/toolkits/agent_mail/framework/claude-agents-sdk)
- [Claude Code](https://composio.dev/toolkits/agent_mail/framework/claude-code)
- [Claude Cowork](https://composio.dev/toolkits/agent_mail/framework/claude-cowork)
- [Codex](https://composio.dev/toolkits/agent_mail/framework/codex)
- [Grok Build](https://composio.dev/toolkits/agent_mail/framework/grok-build)
- [Cursor](https://composio.dev/toolkits/agent_mail/framework/cursor)
- [VS Code](https://composio.dev/toolkits/agent_mail/framework/vscode)
- [OpenCode](https://composio.dev/toolkits/agent_mail/framework/opencode)
- [OpenClaw](https://composio.dev/toolkits/agent_mail/framework/openclaw)
- [Hermes](https://composio.dev/toolkits/agent_mail/framework/hermes-agent)
- [Pi](https://composio.dev/toolkits/agent_mail/framework/pi-agent)
- [Google ADK](https://composio.dev/toolkits/agent_mail/framework/google-adk)
- [LangChain](https://composio.dev/toolkits/agent_mail/framework/langchain)
- [Vercel AI SDK](https://composio.dev/toolkits/agent_mail/framework/ai-sdk)
- [Mastra AI](https://composio.dev/toolkits/agent_mail/framework/mastra-ai)
- [LlamaIndex](https://composio.dev/toolkits/agent_mail/framework/llama-index)
- [CrewAI](https://composio.dev/toolkits/agent_mail/framework/crew-ai)
- [Pydantic AI](https://composio.dev/toolkits/agent_mail/framework/pydantic-ai)
- [AutoGen](https://composio.dev/toolkits/agent_mail/framework/autogen)

## TL;DR

### What is Composio Connect?
Composio Connect lets anyone plug 1,000+ applications directly into their agent harness, including DeepSeek Harness, through a single hosted MCP endpoint. Each task runs as a session, a scoped runtime that ties together the user, the available toolkits, authentication, and execution state. It can:
- Discover and load tools on-demand. A small set of meta tools lets the agent search for the right tool at runtime, so you never load hundreds of tool definitions into context.
- Chain tools in a sandboxed remote workbench. Multi-step workflows run server-side, passing outputs between tools and working with files in the session's sandbox, so long chains finish without a lot of back-and-forth with the LLM.
- Manage authentication end-to-end. Managed OAuth, per-user connected accounts, and account isolation are all handled for you, so you never wire up auth yourself.

## Connect Agent mail to DeepSeek Harness

### Prerequisites: Install DeepSeek Harness
DeepSeek Harness needs Node.js (20 or 22) and pnpm. Build it from source. This is also what the MCP path in Option 2 requires, since the built-in MCP client resolves its dependencies from the checkout:

```bash
git clone https://github.com/deepseek-ai/deepseek-harness.git
cd deepseek-harness
pnpm install
pnpm run build
pnpm dsh web
```

## What is the Agent mail MCP server, and what's possible with it?

The Agent mail MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Agent mail account. It provides structured and secure access to your agent's dedicated inbox, so your agent can send emails, receive incoming messages, fetch specific conversations, and automate email-based workflows on your behalf.
- Automated email sending: Instruct your agent to compose and send emails to any recipient, perfect for status updates, notifications, or outreach.
- Message listing and inbox scanning: Let your agent quickly list all recent messages in the inbox to summarize, monitor, or trigger follow-up actions.
- Targeted message retrieval: Have your agent fetch a specific message by ID, making it easy to pull full email content for context-aware decisions or replies.
- Streamlined agent-to-agent communication: Enable your AI to directly interact with other agents or services via email, automating routine communication flows.

## Supported Tools

| Tool slug | Name | Description |
|---|---|---|
| `AGENT_MAIL_CREATE_INBOX` | Create Inbox | Create a new AgentMail inbox via API. Returns the inbox_id and email address for sending/receiving messages. Use when provisioning new inboxes for agents or workflows. |
| `AGENT_MAIL_GET_MESSAGE` | Get Message | Retrieve the complete details of a specific email message from an AgentMail inbox. This action returns the full message content including sender, recipients, subject, body (both text and HTML), attachments, labels, and metadata. Use this to read individual messages after discovering them via LIST_MESSAGES or webhooks. |
| `AGENT_MAIL_LIST_INBOXES` | List Inboxes | List all inboxes available to the authenticated AgentMail account. Use this to discover valid inbox_id values for message operations. |
| `AGENT_MAIL_LIST_MESSAGES` | List Messages | List messages from an AgentMail inbox. Returns a `messages` array; each message uses `message_id` and `timestamp` fields (not `id`, `date`, or `items`). |
| `AGENT_MAIL_SEND_EMAIL` | Send Email | Send an email using AgentMail API |

## Supported Triggers

| Trigger slug | Name | Description |
|---|---|---|
| `AGENT_MAIL_NEW_EMAIL_TRIGGER` | New Email Received | Trigger for new emails in an AgentMail inbox |

## Creating MCP Server - Stand-alone vs Composio SDK

The Agent mail MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like DeepSeek Harness, Claude, Cursor, etc. directly to your Agent mail account. It provides structured and secure access so your agent can act on your behalf using natural language commands.

## Complete Code

None listed.

## Conclusion

### Way Forward
With Agent mail connected, DeepSeek Harness can now act on your behalf whenever you ask it to.
From here, you can extend the harness further:
- Connect more apps: Calendar, Slack, Notion, Linear, and hundreds of others are available through the same Composio Connect setup, and each new integration adds to what your agent can do for you.
- Build workflows across tools: Once multiple apps are connected, DeepSeek Harness can chain actions together, so it can turn an email into a calendar invite, a Slack message into a Linear ticket, or a meeting note into a follow-up draft.
- Use the plugin system: Wrap common Agent mail flows as dsh plugins or prompt templates so recurring tasks become one-line commands, and bundle your most-used Agent mail tools into a named profile you can boot on demand.
If you run into trouble or want to share what you've built, join the [community](https://discord.com/invite/composio) or check out the [Docs](https://docs.composio.dev?utm_source=toolkits&utm_medium=framework_template&utm_campaign=deepseek-harness&utm_content=docs) for more configuration options.

## How to build Agent mail MCP Agent with another framework

- [ChatGPT Work](https://composio.dev/toolkits/agent_mail/framework/chatgpt)
- [Antigravity](https://composio.dev/toolkits/agent_mail/framework/antigravity)
- [OpenAI Agents SDK](https://composio.dev/toolkits/agent_mail/framework/open-ai-agents-sdk)
- [Claude Agent SDK](https://composio.dev/toolkits/agent_mail/framework/claude-agents-sdk)
- [Claude Code](https://composio.dev/toolkits/agent_mail/framework/claude-code)
- [Claude Cowork](https://composio.dev/toolkits/agent_mail/framework/claude-cowork)
- [Codex](https://composio.dev/toolkits/agent_mail/framework/codex)
- [Grok Build](https://composio.dev/toolkits/agent_mail/framework/grok-build)
- [Cursor](https://composio.dev/toolkits/agent_mail/framework/cursor)
- [VS Code](https://composio.dev/toolkits/agent_mail/framework/vscode)
- [OpenCode](https://composio.dev/toolkits/agent_mail/framework/opencode)
- [OpenClaw](https://composio.dev/toolkits/agent_mail/framework/openclaw)
- [Hermes](https://composio.dev/toolkits/agent_mail/framework/hermes-agent)
- [Pi](https://composio.dev/toolkits/agent_mail/framework/pi-agent)
- [Google ADK](https://composio.dev/toolkits/agent_mail/framework/google-adk)
- [LangChain](https://composio.dev/toolkits/agent_mail/framework/langchain)
- [Vercel AI SDK](https://composio.dev/toolkits/agent_mail/framework/ai-sdk)
- [Mastra AI](https://composio.dev/toolkits/agent_mail/framework/mastra-ai)
- [LlamaIndex](https://composio.dev/toolkits/agent_mail/framework/llama-index)
- [CrewAI](https://composio.dev/toolkits/agent_mail/framework/crew-ai)
- [Pydantic AI](https://composio.dev/toolkits/agent_mail/framework/pydantic-ai)
- [AutoGen](https://composio.dev/toolkits/agent_mail/framework/autogen)

## Related Toolkits

- [Gmail](https://composio.dev/toolkits/gmail) - Gmail is Google's email service with powerful spam protection, search, and G Suite integration. It keeps your inbox organized and makes communication fast and reliable.
- [Outlook](https://composio.dev/toolkits/outlook) - Outlook is Microsoft's email and calendaring platform for unified communications and scheduling. It helps users stay organized with powerful email, contacts, and calendar management.
- [Slack](https://composio.dev/toolkits/slack) - Slack is a channel-based messaging platform for teams and organizations. It helps people collaborate in real time, share files, and connect all their tools in one place.
- [Gong](https://composio.dev/toolkits/gong) - Gong is a platform for video meetings, call recording, and team collaboration. It helps teams capture conversations, analyze calls, and turn insights into action.
- [Microsoft teams](https://composio.dev/toolkits/microsoft_teams) - Microsoft Teams is a collaboration platform that combines chat, meetings, and file sharing within Microsoft 365. It keeps distributed teams connected and productive through seamless virtual communication.
- [Slackbot](https://composio.dev/toolkits/slackbot) - Slackbot is a conversational automation tool for Slack that handles reminders, notifications, and automated responses. It boosts team productivity by streamlining onboarding, answering FAQs, and managing timely alerts—all right inside Slack.
- [2chat](https://composio.dev/toolkits/_2chat) - 2chat is an API platform for WhatsApp and multichannel text messaging. It streamlines chat automation, group management, and real-time messaging for developers.
- [Android Texter](https://composio.dev/toolkits/android_texter) - Android Texter is an API service that connects Android phones to SMS, MMS, contacts, and device data. Use it to automate mobile messaging without building your own phone-to-API bridge.
- [Basecamp](https://composio.dev/toolkits/basecamp) - Basecamp is a project management and team collaboration tool by 37signals. It helps teams organize tasks, share files, and communicate efficiently in one place.
- [Chatwork](https://composio.dev/toolkits/chatwork) - Chatwork is a team communication platform with group chats, file sharing, and task management. It helps businesses boost collaboration and streamline productivity.
- [Clickmeeting](https://composio.dev/toolkits/clickmeeting) - ClickMeeting is a cloud-based platform for running online meetings and webinars. It helps businesses and individuals host, manage, and engage virtual audiences with ease.
- [Confluence](https://composio.dev/toolkits/confluence) - Confluence is Atlassian's team collaboration and knowledge management platform. It helps your team organize, share, and update documents and project content in one secure workspace.
- [Daily](https://composio.dev/toolkits/daily) - Daily is a WebRTC video and audio API platform for building rooms, meetings, recordings, live streams, transcriptions, and telephony. It gives developers reliable real-time media infrastructure without managing complex conferencing stacks.
- [Dailybot](https://composio.dev/toolkits/dailybot) - DailyBot streamlines team collaboration with chat-based standups, reminders, and polls. It keeps work flowing smoothly in your favorite messaging platforms.
- [Dialmycalls](https://composio.dev/toolkits/dialmycalls) - Dialmycalls is a mass notification service for sending voice and text messages to contacts. It helps teams and organizations quickly broadcast urgent alerts and updates.
- [Dialpad](https://composio.dev/toolkits/dialpad) - Dialpad is a cloud-based business phone and contact center system for teams. It unifies voice, video, messaging, and meetings across your devices.
- [Discord](https://composio.dev/toolkits/discord) - Discord is a real-time messaging and VoIP platform for communities and teams. It lets users chat, share media, and collaborate across public and private channels.
- [Discordbot](https://composio.dev/toolkits/discordbot) - Discordbot is an automation tool for Discord servers that handles moderation, messaging, and user engagement. It helps communities run smoothly by automating routine and complex tasks.
- [Echtpost](https://composio.dev/toolkits/echtpost) - Echtpost is a secure digital communication platform for encrypted document and message exchange. It ensures confidential data stays private and protected during transmission.
- [Egnyte](https://composio.dev/toolkits/egnyte) - Egnyte is a cloud-based platform for secure file sharing, storage, and governance. It helps teams collaborate efficiently while maintaining data compliance and security.

## Frequently Asked Questions

### What are the differences in Tool Router MCP and Agent mail MCP?

With a standalone Agent mail MCP server, the agents and LLMs can only access a fixed set of Agent mail tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Agent mail and many other apps based on the task at hand, all through a single MCP endpoint.

### Can I use Tool Router MCP with DeepSeek Harness?

Yes, you can. DeepSeek Harness fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right Agent mail tools.

### Can I manage the permissions and scopes for Agent mail while using Tool Router?

Yes, absolutely. You can configure which Agent mail scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

### How safe is my data with Composio Tool Router?

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your Agent mail data and credentials are handled as safely as possible.

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