lucianschw-dev adds a /eu-law-chat endpoint with an MCP dispatcher hook in chatTools.ts

The backend gets a second chat endpoint wired to an external MCP server over HTTP. The cleanest piece is a new `mcpTools` parameter on `runLLMStream` that lets any caller route named tool calls to an external dispatcher without touching the main tool-dispatch logic.

integrationchat-ui

3f39cef1 adds three things.

chatTools.ts gains an optional mcpTools parameter on runLLMStream. Pass it { names: string[], dispatch: async (calls) => results[] } and the stream loop will intercept any tool call whose name is in names, send it to your dispatcher, and merge the results back before returning. Tool calls not in the set go through the existing runToolCalls path as before. Error handling is per-call - a dispatcher failure produces an error JSON result for that call rather than aborting the stream. 54 lines changed, no restructuring of the surrounding logic.

euLawMcp.ts (137 lines, new) is the HTTP client for the MCP server. It speaks MCP's Streamable HTTP transport: each invocation opens an initialize handshake, calls tools/call, reads the SSE response, and closes - stateless, no persistent connection. dispatchEuLawCalls is the function passed to mcpTools.dispatch in the route handler.

euLawChat.ts (764 lines, new) is structurally a near-copy of the existing /chat handler. It carries EU_LAW_SYSTEM_PROMPT_EXTRA, four tool schemas matching the eu-law MCP v0.1.1 tool set, and hooks them to dispatchEuLawCalls via the mcpTools slot. The MCP server runs on port 4040; the URL is configured via EU_LAW_MCP_URL in .env.

The 764-line duplication is the obvious problem. Every fix to the base /chat handler has to be manually mirrored into euLawChat.ts. A shared base handler with injectable system prompt and tool dispatcher would be the refactor, but lucianschw-dev has not done that.

So what Worth a look for the `mcpTools` hook in `chatTools.ts` on its own merits - it is a clean, small interface for routing named tool calls to any external MCP server, independent of the EU-law application. The `euLawChat.ts` duplication is a cost to weigh: adopting it means maintaining a second near-identical handler. If you are evaluating the EU-law tools specifically, also read the commentary on the MCP server itself (topic 473) and the system prompt tightening (topic 474).

Spotted something wrong? Or know the PR text has fresher detail than the writeup above?

Commits in this thread

2 commits from lucianschw-dev/eumike, oldest first. Source extracted verbatim from the harvested git log.

SHA	Subject	Author	Date
`3f39cef1`	Add /eu-law-chat endpoint and MCP dispatcher hook	Lucian.schw	2026-05-17	↗ GitHub
commit body - chatTools.ts: optional mcpTools parameter on runLLMStream (intercepts named tool calls and routes them to an external dispatcher before they fall through to runToolCalls) - euLawMcp.ts: thin HTTP client for the eu-law MCP server, plus dispatchEuLawCalls wired into chatTools.ts's mcpTools.dispatch slot - euLawChat.ts: copy of /chat with EU_LAW_SYSTEM_PROMPT_EXTRA, 4 hand-written tool schemas, and the MCP dispatcher - index.ts: register /eu-law-chat router and apply chat rate limiters
`30efd52d`	Backend npm install: lockfile refresh	Lucian.schw	2026-05-17	↗ GitHub

SHA

Subject

Author

Date

3f39cef1

Add /eu-law-chat endpoint and MCP dispatcher hook

Lucian.schw

2026-05-17

↗ GitHub

commit body

- chatTools.ts: optional mcpTools parameter on runLLMStream (intercepts
  named tool calls and routes them to an external dispatcher before they
  fall through to runToolCalls)
- euLawMcp.ts: thin HTTP client for the eu-law MCP server, plus
  dispatchEuLawCalls wired into chatTools.ts's mcpTools.dispatch slot
- euLawChat.ts: copy of /chat with EU_LAW_SYSTEM_PROMPT_EXTRA, 4
  hand-written tool schemas, and the MCP dispatcher
- index.ts: register /eu-law-chat router and apply chat rate limiters

30efd52d

Backend npm install: lockfile refresh

Lucian.schw

2026-05-17

↗ GitHub

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