# How to Connect DeepSeek Harness to MewCP

Add MewCP to DeepSeek Harness once, and `dsh` can use every app you have connected in MewCP: Gmail, Calendar, Slack, GitHub and the rest. DeepSeek Harness connects to MewCP through its built-in `@deepseek-ai/dsh-mcp-client` plugin over Streamable HTTP, so there is nothing extra to install.

---

## Before you start

- **DeepSeek Harness** installed and running, for example with `npx @deepseek-ai/dsh web` ([DeepSeek Harness](https://github.com/deepseek-ai/deepseek-harness))
- **A API Key** from **Dashboard → API Keys**, see [API Key](/mewcp/authentication/mewcp-key)
- **At least one app connected** in the dashboard under **Servers**

---

## Set up MewCP

DeepSeek Harness keeps its files in `~/.dsh`, or in `$DSH_HOME` if you have set it.

<Stepper>

1. **Store your key**

   Add your key to `~/.dsh/.env`:

   ```bash
   MEWCP_API_KEY=API_KEY
   ```

1. **Add MewCP to a patch file**

   Open `~/.dsh/cordis.patch.yml`, which applies to every profile, and add this:

   ```yaml
   - insert:
       - id: mcp-mewcp
         name: "@deepseek-ai/dsh-mcp-client"
         config:
           serverName: mewcp
           transport: streamable-http
           url: https://gateway.mewcp.com/personal/mcp
           headers:
             Authorization: !!js "`Bearer ${process.env.MEWCP_API_KEY}`"
   ```

   To add MewCP to one profile only, use `~/.dsh/profiles/<name>/cordis.patch.yml` instead. For the web UI started with `dsh web`, that is `~/.dsh/profiles/web/cordis.patch.yml`.

   If the file already has patches, add the `insert` entry next to them. Do not replace the file.

1. **Restart DeepSeek Harness**

   Stop `dsh` and start it again so it loads the patch.

</Stepper>

This is the entire configuration. One entry reaches every app you have connected, and connecting another app later needs no change here.

To try MewCP for one run without changing your patch files, save the same YAML anywhere and pass it with `--patch`:

```bash
dsh web --patch /path/to/mewcp.cordis.yml
```

---

## Check it works

Confirm the entry is in the config DeepSeek Harness uses:

```bash
dsh web --dump-config | grep -A8 mcp-mewcp
```

The output shows the `!!js` expression, not your key, since it does not evaluate expressions when printing.

Once `dsh` is running, MewCP's tools appear as `mcp__mewcp__search`, `mcp__mewcp__get_schema`, `mcp__mewcp__list_accounts` and `mcp__mewcp__call_tool`. That is four tools, not the tools of every app, which is expected. DeepSeek Harness uses them to find and run the right tool for whatever you ask. See [How MewCP works](/mewcp/getting-started#how-mewcp-works).

Then ask for something from an app you have connected:

```
What is on my calendar tomorrow?
```

---

## Troubleshooting

### `dsh` starts, but no MewCP tools appear

If the first connection to MewCP fails, DeepSeek Harness still starts, logs an error and shows no tools from MewCP. Look for the error in the `dsh` output. To make a failed connection stop startup instead, add `failOnStartupError: true` under `config`. A startup failure names a log file under `~/.dsh/logs/`.

### MewCP returns `401` or `403`

MewCP rejected the key.

- Check `MEWCP_API_KEY` is in `~/.dsh/.env` or your shell environment, and holds the whole key, which starts with `mcp_live_`.
- Keep the backticks inside the quotes in ``'`Bearer ${process.env.MEWCP_API_KEY}`'``. Without them, `${...}` is sent as literal text.
- A `403` that says the billing period is not active means your MewCP plan needs renewing in the dashboard.

### The entry fails to load with a name error

Each MCP entry needs a unique `id` and `serverName`. If another entry already uses `mewcp`, the later one fails to load. Rename one of them.

### MewCP's tools disappeared after a network outage

DeepSeek Harness reconnects on its own, waiting longer each time up to 30 seconds. After 10 failed attempts in a row it removes MewCP's tools and stops trying. Restart `dsh` to connect again.

---

_Last checked against DeepSeek Harness's documentation on 13 October 2026._