omniroute-mcp-bridge

A stdio MCP bridge that DSH spawns as a child process (via the dsh-mcp-client plugin, transport: stdio). It proxies tools/list / tools/call to the omniroute streamable-http MCP server at https://llm.claassen.family/api/mcp/stream and exposes only the allow-listed tools to the model.

Why

• The upstream streamable-http session dies when idle ("Unknown Mcp-Session-Id" 404). The bridge detects that exact failure, tears down the stale client, re-runs the MCP initialize handshake (fresh session id) and retries — so a dead upstream session no longer breaks a tool call.
• The dsh-mcp-client plugin has no tool-filtering config. This bridge filters tools/list server-side, so only omniroute_web_search is exposed instead of ~70 tools (saves model context; stable serverName: omniroute is kept, so the public name stays mcp__omniroute__omniroute_web_search).
• The upstream auth header is passed via child env, not argv — the secret never appears in the process list. It lives only in the 0600 cordis.patch.yml of the web profile.

Files

file	purpose
bridge.mjs	stdio MCP server entrypoint (spawned by DSH)
upstream.mjs	injectable upstream accessor with dead-session re-init logic
test-bridge.mjs	standalone live test: full MCP handshake + real search call
test-reinit.mjs	deterministic fake-upstream test of the re-init loop
probe.mjs	dumps raw upstream tool names
probe-ttl2.mjs	measures upstream session idle TTL

SDK resolution

package.json pins @modelcontextprotocol/sdk to the exact version the bridge was developed against. Two ways to get it:

• Standalone: npm install in this directory.

• Inside the DSH host (this deployment): node_modules is a symlink to /usr/lib/node_modules/@deepseek-ai/dsh/node_modules, so the bridge always uses the same SDK build DSH's own mcp-client plugin uses. The symlink is gitignored — recreate it after cloning in that environment:

  ln -sfn /usr/lib/node_modules/@deepseek-ai/dsh/node_modules node_modules
  

Config (env, set in ~/.dsh/profiles/web/cordis.patch.yml)

var	meaning
MCP_BRIDGE_UPSTREAM_URL	streamable-http URL (required)
MCP_BRIDGE_UPSTREAM_HEADERS	JSON object of request headers
MCP_BRIDGE_ALLOWED_TOOLS	comma-separated raw tool names (omit = all)
MCP_BRIDGE_LOG	1 = verbose logging on the child's stderr

Tests

Credentials are not committed. Export them first (values from your patch file):

export MCP_BRIDGE_UPSTREAM_URL='https://llm.claassen.family/api/mcp/stream'
export MCP_BRIDGE_UPSTREAM_HEADERS='{"Authorization":"Bearer …","X-Forwarded-For":"127.0.0.1"}'

Then:

node test-reinit.mjs   # deterministic: dead session -> re-init -> success (no network needed)
node test-bridge.mjs   # live: handshake + filtered list + real search
node probe.mjs         # dump the upstream's raw tool names
node probe-ttl2.mjs    # measure upstream session idle TTL

Change the allow-list

Edit MCP_BRIDGE_ALLOWED_TOOLS in the patch file (comma-separated raw names from node probe.mjs). The include-plugin HMR re-applies the patch on file change; the mcp-client plugin respawns the bridge child.