From e3e104c064097e9fb8dd8ca9010a36b6e0156e9a Mon Sep 17 00:00:00 2001
From: carlos-alm <127798846+carlos-alm@users.noreply.github.com>
Date: Sun, 8 Mar 2026 20:57:13 -0600
Subject: [PATCH 1/2] fix: defer heavy imports in MCP server to improve
 first-connection reliability

The MCP server was importing queries.js and better-sqlite3 before
connecting the stdio transport, causing the client's `initialize`
request to arrive before the server was listening on stdin. Now the
transport connects immediately after the MCP SDK loads, and heavy
modules are lazy-loaded on the first tool call (cached thereafter).

Impact: 3 functions changed, 2 affected
---
 src/mcp.js | 56 ++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 37 insertions(+), 19 deletions(-)

diff --git a/src/mcp.js b/src/mcp.js
index f688aa03..afcbc053 100644
--- a/src/mcp.js
+++ b/src/mcp.js
@@ -836,26 +836,27 @@ export async function startMCPServer(customDbPath, options = {}) {
     process.exit(1);
   }
 
-  // Lazy import query functions to avoid circular deps at module load
-  const {
-    impactAnalysisData,
-    moduleMapData,
-    fileDepsData,
-    exportsData,
-    fnDepsData,
-    fnImpactData,
-    pathData,
-    contextData,
-    childrenData,
-    explainData,
-    whereData,
-    diffImpactData,
-    listFunctionsData,
-    rolesData,
-  } = await import('./queries.js');
+  // Connect transport FIRST so the server can receive the client's
+  // `initialize` request while heavy modules (queries, better-sqlite3)
+  // are still loading.  These are lazy-loaded on the first tool call
+  // and cached for subsequent calls.
+  let _queries;
+  let _Database;
 
-  const require = createRequire(import.meta.url);
-  const Database = require('better-sqlite3');
+  async function getQueries() {
+    if (!_queries) {
+      _queries = await import('./queries.js');
+    }
+    return _queries;
+  }
+
+  function getDatabase() {
+    if (!_Database) {
+      const require = createRequire(import.meta.url);
+      _Database = require('better-sqlite3');
+    }
+    return _Database;
+  }
 
   const server = new Server(
     { name: 'codegraph', version: '1.0.0' },
@@ -868,6 +869,23 @@ export async function startMCPServer(customDbPath, options = {}) {
 
   server.setRequestHandler(CallToolRequestSchema, async (request) => {
     const { name, arguments: args } = request.params;
+    const {
+      impactAnalysisData,
+      moduleMapData,
+      fileDepsData,
+      exportsData,
+      fnDepsData,
+      fnImpactData,
+      pathData,
+      contextData,
+      childrenData,
+      explainData,
+      whereData,
+      diffImpactData,
+      listFunctionsData,
+      rolesData,
+    } = await getQueries();
+    const Database = getDatabase();
 
     try {
       if (!multiRepo && args.repo) {

From 92503412cbb5373c637418fe55e2bb99c6bdb0f9 Mon Sep 17 00:00:00 2001
From: carlos-alm <127798846+carlos-alm@users.noreply.github.com>
Date: Sun, 8 Mar 2026 21:34:02 -0600
Subject: [PATCH 2/2] fix: move lazy-load calls inside try-catch for proper MCP
 error handling

Impact: 1 functions changed, 0 affected
---
 src/mcp.js | 35 +++++++++++++++++------------------
 1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/src/mcp.js b/src/mcp.js
index afcbc053..b72c2a83 100644
--- a/src/mcp.js
+++ b/src/mcp.js
@@ -869,25 +869,24 @@ export async function startMCPServer(customDbPath, options = {}) {
 
   server.setRequestHandler(CallToolRequestSchema, async (request) => {
     const { name, arguments: args } = request.params;
-    const {
-      impactAnalysisData,
-      moduleMapData,
-      fileDepsData,
-      exportsData,
-      fnDepsData,
-      fnImpactData,
-      pathData,
-      contextData,
-      childrenData,
-      explainData,
-      whereData,
-      diffImpactData,
-      listFunctionsData,
-      rolesData,
-    } = await getQueries();
-    const Database = getDatabase();
-
     try {
+      const {
+        impactAnalysisData,
+        moduleMapData,
+        fileDepsData,
+        exportsData,
+        fnDepsData,
+        fnImpactData,
+        pathData,
+        contextData,
+        childrenData,
+        explainData,
+        whereData,
+        diffImpactData,
+        listFunctionsData,
+        rolesData,
+      } = await getQueries();
+      const Database = getDatabase();
       if (!multiRepo && args.repo) {
         throw new Error(
           'Multi-repo access is disabled. Restart with `codegraph mcp --multi-repo` to access other repositories.',