dsh-mcp-host

Expose any stdio MCP server as native DeepSeek Harness tools. Host-only plugin, no browser UI, no npm dependencies.

Built for one job: let a DSH agent drive a browser through the official Microsoft Playwright MCP server, attached to the Edge/Chrome you are already using.

What it does

1. On load, spawns the MCP server once (default npx --yes @playwright/mcp@latest --cdp-endpoint=msedge).
2. Calls initialize + tools/list, converts each tool's JSON Schema into a DSH parameter schema, and registers it with ctx.tools.register.
3. Every tool call is forwarded as tools/call; the result is returned as JSON. Images (screenshots) are written to a temp file and returned as a path, not as base64.

Tools are renamed: browser_navigate becomes edge_navigate (prefix configurable).

Default tool set (12 of Playwright's 25)

edge_navigate, edge_navigate_back, edge_snapshot, edge_click, edge_type, edge_fill_form, edge_press_key, edge_tabs, edge_take_screenshot, edge_evaluate, edge_wait_for, edge_close.

The full set costs prompt space in every session, which is why it is not the default. Set MCP_BRIDGE_ALL=1 to expose everything.

Install

cd E:\dsh
.\rollback.cmd guard add "file:C:\path\to\dsh-mcp-host"
.\rollback.cmd health

Restart DSH (or rely on hot-load) and open a new session.

Configuration

Env var	Default	Meaning
MCP_BRIDGE_COMMAND	npx --yes @playwright/mcp@latest --cdp-endpoint=msedge	The MCP server command line (any stdio MCP server)
MCP_BRIDGE_PREFIX	edge	Tool name prefix
MCP_BRIDGE_ALL	unset	1 = register every tool the server offers
MCP_BRIDGE_TOOLS	unset	Comma-separated allow-list of MCP tool names
MCP_BRIDGE_TIMEOUT	120000	Per-call timeout (ms)
MCP_BRIDGE_INIT_TIMEOUT	30000	Startup timeout (ms)

Prerequisite for the Edge/Chrome you are already using

Open edge://inspect/#remote-debugging (or chrome://inspect/#remote-debugging) and enable Allow remote debugging for this browser instance. Then --cdp-endpoint=msedge (or =chrome) attaches to that running browser with your logins and extensions. Without the toggle, Playwright launches a fresh browser instead.

Failure behaviour

If the MCP server cannot start or does not answer, the plugin registers nothing and logs the reason 鈥?it never throws, so it cannot take the host boot down. Check MCP_BRIDGE_INIT_TIMEOUT and the stderr tail printed in the DSH console.

Privacy

The bridge itself makes no network calls. It spawns exactly one child process (the MCP server you configured) and forwards bytes between it and the tool call. With --cdp-endpoint, the MCP server attaches to your existing browser, which means it can see and act on the tabs you have open 鈥?treat that as giving the agent your browser session.

License

MIT.