deepseek-harness/packages/mcp/mcp-client

@deepseek-ai/dsh-mcp-client

MCP client bridge plugin: connects to external Model Context Protocol servers and registers their tools on ctx.tools, making them available to the model as native tools.

Usage

One plugin instance per MCP server in cordis.yml:

- id: mcp-github
  name: '@deepseek-ai/dsh-mcp-client'
  config:
    transport: stdio
    command: npx
    args: ['-y', '@modelcontextprotocol/server-github']
    env:
      GITHUB_TOKEN: !!js process.env.GITHUB_TOKEN

- id: mcp-web
  name: '@deepseek-ai/dsh-mcp-client'
  config:
    transport: streamable-http
    url: http://localhost:3000/mcp
    headers:
      Authorization: !!js '`Bearer ${process.env.MCP_TOKEN}`'

HMR hot-swaps: editing the entry triggers disconnect + reconnect without process restart.

Config

Field	Transport	Required	Description
transport	both	yes	"stdio" or "streamable-http"
command	stdio	yes	Executable to spawn
args	stdio	no	Arguments passed to the command
env	stdio	no	Extra env vars merged on top of scrubbed ambient env
cwd	stdio	no	Working directory for the child process
url	http	yes	MCP server URL
headers	http	no	Extra headers (e.g. auth tokens)
toolPrefix	both	no	Prefix prepended to each tool name before registration
toolCallTimeoutMs	both	no	Timeout per callTool invocation (default 60000)

Behavior

• On connect: listTools() → registers each tool via ctx.tools.register().
• Listens for notifications/tools/list_changed → re-syncs tool registrations.
• Tool execute: client.callTool({ name, arguments }, { signal }) with timeout + abort support.
• Image content in results is discarded with a warning (the harness has no image block type).
• On disconnect/crash: all tools are unregistered; no auto-reconnect.
• Name conflicts: if a tool name collides, it is skipped with a warning. Use toolPrefix to disambiguate.

Services consumed

Service	Usage
ctx.tools	Register/unregister MCP tools