dsh-mcp-bridge

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) and calls initialize + tools/list.
2. Registers one bootstrap tool, edge_tools (name configurable). Its description is deliberately short and states when to call it — and when not to.
3. When the model calls edge_tools, the bridge registers the real edge_* tools for that Agent only, hides the bootstrap entry, and forwards every call to MCP tools/call. Screenshots are written to a temp file and returned as a path, not as base64.
4. On agent/disposed (and on plugin dispose) the per-Agent tools are removed and the MCP child process is killed.

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

Lazy loading (default)

The 12-tool default set is not in the prompt until a browsing task needs it. A session that never touches a browser pays for one small schema (edge_tools), not twelve.

• Set MCP_BRIDGE_EAGER=1 to restore the old behaviour (register every tool at boot).
• Activation is per Agent: the parent session and each subagent must call edge_tools independently.
• After activation the bootstrap entry is hidden for that Agent (tools.restrict({ deny })), so the prompt goes back to a single, smaller surface.

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.

Set MCP_BRIDGE_ALL=1 to expose everything the server offers.

Install

From npm (published as dsh-mcp-host):

dsh plugin --profile web add dsh-mcp-host

From a local checkout (development):

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. The default MCP command uses npx, so Node.js (which ships npx) must be on PATH; the first call downloads @playwright/mcp from npm.

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_BOOTSTRAP	edge_tools	Name of the single lazy-loading entry tool
MCP_BRIDGE_EAGER	unset	1 = register every tool at boot (old behaviour, no bootstrap)
MCP_BRIDGE_ALL	unset	1 = expose 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 — 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 — treat that as giving the agent your browser session.

License

MIT.