diff --git a/src/utils/clinicalMcpClient.js b/src/utils/clinicalMcpClient.js
index fab3c3e..8555eab 100644
--- a/src/utils/clinicalMcpClient.js
+++ b/src/utils/clinicalMcpClient.js
@@ -3,6 +3,14 @@ var sleep = require('node:timers/promises').setTimeout;
 
 var MCP_URLS = buildMcpUrls();
 var _lastGoodMcpUrl = MCP_URLS[0];
+// Search tool name is env-driven; invalid values stop the app before any MCP call.
+var SEARCH_TOOL_NAME = process.env.CLINICAL_ASSISTANT_SEARCH_TOOL || 'clinical_semantic_search';
+if (SEARCH_TOOL_NAME !== 'clinical_semantic_search' && SEARCH_TOOL_NAME !== 'nc_semantic_search') {
+  throw new Error('CLINICAL_ASSISTANT_SEARCH_TOOL must be clinical_semantic_search or nc_semantic_search');
+}
+if (SEARCH_TOOL_NAME === 'nc_semantic_search') {
+  console.warn('[clinical-mcp] CLINICAL_ASSISTANT_SEARCH_TOOL=nc_semantic_search is deprecated; prefer clinical_semantic_search');
+}
 var MCP_INITIALIZE_TIMEOUT_MS = positiveInt(process.env.CLINICAL_ASSISTANT_MCP_INITIALIZE_TIMEOUT_MS, 30000);
 var MCP_REQUEST_TIMEOUT_MS = positiveInt(process.env.CLINICAL_ASSISTANT_MCP_REQUEST_TIMEOUT_MS, 90000);
 var MCP_SESSION_TTL_MS = positiveInt(process.env.CLINICAL_ASSISTANT_MCP_SESSION_TTL_MS, 10 * 60 * 1000);
@@ -65,7 +73,7 @@ function closeMcpSession() {
 
 async function semanticSearch(query, opts) {
   opts = opts || {};
-  return callMcpTool('nc_semantic_search', {
+  return callMcpTool(SEARCH_TOOL_NAME, {
     query: query,
     limit: opts.limit,
     doc_types: ['file'],