From 0563887aeaf91cf1aeb9c857f0ea89f38ed1b8e5 Mon Sep 17 00:00:00 2001
From: Michael Dieringer <65093775+MichaelDieringer@users.noreply.github.com>
Date: Wed, 5 Aug 2026 14:05:42 +0200
Subject: [PATCH] bc-mcp-bridge: timeout + one-retry-with-fresh-session
 self-heal

Neither fetch() call had a timeout, and the BC session (Mcp-Session-Id)
plus the underlying HTTP connection were reused for the bridge process's
entire lifetime with no proactive refresh. A long-running Claude Code
session with gaps between calls can leave either stale.

Observed today: a 30-minute hang on one call (no timeout meant it never
failed on its own), and separately an "Internal_CompanyNotFound" on two
machines that likely wasn't a real company problem but a dead session --
Michael noticed the pattern independently: Summatim's frequent quick calls
never have this issue, longer sessions with gaps do.

Added REQUEST_TIMEOUT_MS (30s) via AbortSignal.timeout on both fetch
calls, and wrapped forward() to retry once with sessionId cleared on any
failure -- self-heals a stale session/connection without the developer
noticing. Tested end to end: full initialize + tools/call succeeds
normally (no retry needed), and a forced-failure path correctly retries
once then surfaces the real error if it persists.
---
 custom/setup/bc-mcp-bridge.js | 36 +++++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/custom/setup/bc-mcp-bridge.js b/custom/setup/bc-mcp-bridge.js
index cc995da..4382f5d 100644
--- a/custom/setup/bc-mcp-bridge.js
+++ b/custom/setup/bc-mcp-bridge.js
@@ -15,6 +15,14 @@ const fs = require("fs");
 const path = require("path");
 
 const ENDPOINT = "https://mcp.businesscentral.dynamics.com";
+// 2026-08-04: neither fetch() call below had a timeout, and the BC session
+// (sessionId) + underlying HTTP connection were reused for the bridge
+// process's entire lifetime with no proactive refresh. A long-running Claude
+// Code session with gaps between calls can leave either stale -- observed as
+// a 30-minute hang on one call, and separately as an "Internal_CompanyNotFound"
+// that wasn't actually a company problem. REQUEST_TIMEOUT_MS + the one-retry
+// wrapper below fail fast and self-heal with a forced-fresh session instead.
+const REQUEST_TIMEOUT_MS = 30000;
 
 function die(m) { process.stderr.write(`[bc-mcp-bridge] ${m}\n`); process.exit(1); }
 
@@ -56,6 +64,7 @@ async function getToken() {
     method: "POST",
     headers: { "Content-Type": "application/x-www-form-urlencoded" },
     body,
+    signal: AbortSignal.timeout(REQUEST_TIMEOUT_MS),
   });
   if (!r.ok) throw new Error(`token ${r.status}: ${await r.text()}`);
   const j = await r.json();
@@ -76,7 +85,7 @@ function parseSSE(text) {
   return msgs;
 }
 
-async function forward(msg) {
+async function forwardOnce(msg) {
   const tok = await getToken();
   const headers = {
     "Authorization": `Bearer ${tok}`,
@@ -88,7 +97,12 @@ async function forward(msg) {
     "ConfigurationName": enc(cfg.config),
   };
   if (sessionId) headers["Mcp-Session-Id"] = sessionId;
-  const r = await fetch(ENDPOINT, { method: "POST", headers, body: JSON.stringify(msg) });
+  const r = await fetch(ENDPOINT, {
+    method: "POST",
+    headers,
+    body: JSON.stringify(msg),
+    signal: AbortSignal.timeout(REQUEST_TIMEOUT_MS),
+  });
   const sid = r.headers.get("mcp-session-id"); if (sid) sessionId = sid;
   const ct = r.headers.get("content-type") || "";
   const text = await r.text();
@@ -103,6 +117,24 @@ async function forward(msg) {
   return ct.includes("text/event-stream") ? parseSSE(text) : (text.trim() ? [text.trim()] : []);
 }
 
+async function forward(msg) {
+  try {
+    return await forwardOnce(msg);
+  } catch (e) {
+    // 2026-08-04: one retry with a forced-fresh BC session (sessionId cleared).
+    // A long-idle Claude Code session can leave the cached Mcp-Session-Id or
+    // the underlying HTTP connection stale -- observed as a request hanging
+    // until REQUEST_TIMEOUT_MS, or as an "Internal_CompanyNotFound" that was
+    // actually a dead session, not a real company problem. Quick, frequent
+    // calls never idle long enough to hit this; a long session with gaps
+    // between calls does. One retry self-heals without the developer noticing;
+    // if the retry also fails, this is a real error and should surface as one.
+    process.stderr.write(`[bc-mcp-bridge] retrying after: ${e.message || e}\n`);
+    sessionId = null;
+    return await forwardOnce(msg);
+  }
+}
+
 // Splits text into chunks of max maxLen chars, breaking at word boundaries.
 function splitTextToChunks(text, maxLen = 250) {
   const chunks = [];