diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7a813bc..5595e8d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog
 
+## 0.10.22 (Preview)
+
+### Fixed
+- **Multi-binlog timeline/tree crash** — fixed "requires explicit binlog_file" errors when the MCP server was started with multiple binlogs. The sidebar, tree prefetch, diagnostics, and timeline now correctly inject `binlog_file` even when the sidebar and MCP server binlog lists are out of sync.
+
 ## 0.10.21 (Preview)
 
 ### Changed
diff --git a/package.json b/package.json
index 72f377d..f11cbba 100644
--- a/package.json
+++ b/package.json
@@ -2,7 +2,7 @@
   "name": "binlog-analyzer",
   "displayName": "MSBuild Binlog Analyzer",
   "description": "Analyze MSBuild binary logs with Copilot Chat and MCP tools",
-  "version": "0.10.21",
+  "version": "0.10.22",
   "preview": true,
   "publisher": "dotutils",
   "license": "MIT",
diff --git a/src/binlogTreeView.ts b/src/binlogTreeView.ts
index 55c598c..4d8e18e 100644
--- a/src/binlogTreeView.ts
+++ b/src/binlogTreeView.ts
@@ -209,7 +209,7 @@ export class BinlogTreeDataProvider implements vscode.TreeDataProvider<BinlogTre
 
         await Promise.allSettled(calls.map(async (c) => {
             try {
-                const result = await client.callTool(c.tool, c.args);
+                const result = await this.mcpCall(c.tool, c.args);
                 const data = this.tryParseJson(result.text);
 
                 if (c.cache === 'projects') {
@@ -1668,7 +1668,8 @@ export class BinlogTreeDataProvider implements vscode.TreeDataProvider<BinlogTre
     private mcpCall(tool: string, args: Record<string, unknown> = {}): Promise<{ text: string }> {
         if (!this.mcpClient) { throw new Error('MCP server not connected'); }
         if (!args.binlog_file && this.binlogPaths.length >= 1) {
-            args.binlog_file = this.activeBinlogPath || this.binlogPaths[0];
+            const copy = { ...args, binlog_file: this.activeBinlogPath || this.binlogPaths[0] };
+            return this.mcpClient.callTool(tool, copy);
         }
         return this.mcpClient.callTool(tool, args);
     }
diff --git a/src/diagnostics.ts b/src/diagnostics.ts
index fb83b7b..f91bfde 100644
--- a/src/diagnostics.ts
+++ b/src/diagnostics.ts
@@ -53,7 +53,11 @@ export class BinlogDiagnosticsProvider implements vscode.Disposable {
         if (!this.mcpClient) { return; }
 
         try {
-            const result = await this.mcpClient.callTool('get_diagnostics');
+            const args: Record<string, unknown> = {};
+            if (this.mcpClient.loadedBinlogs.length > 1) {
+                args.binlog_file = this.mcpClient.loadedBinlogs[0];
+            }
+            const result = await this.mcpClient.callTool('get_diagnostics', args);
             const data = JSON.parse(result.text);
             const diagnostics = this.parseMcpDiagnostics(data);
             this.cachedDiagnostics = diagnostics;
diff --git a/src/extension.ts b/src/extension.ts
index ee478b3..02eb117 100644
--- a/src/extension.ts
+++ b/src/extension.ts
@@ -48,7 +48,10 @@ function escapeHtml(s: string): string {
  */
 function callMcpTool(tool: string, args: Record<string, unknown> = {}): Promise<{ text: string }> {
     if (!mcpClient) { throw new Error('MCP server not connected'); }
-    if (!args.binlog_file && allBinlogPaths.length > 1) {
+    // Always inject binlog_file when the MCP server was started with multiple
+    // binlogs — even if the user removed one from the sidebar, the server
+    // still requires an explicit path.
+    if (!args.binlog_file && (allBinlogPaths.length > 1 || (mcpClient.loadedBinlogs && mcpClient.loadedBinlogs.length > 1))) {
         const copy = { ...args, binlog_file: currentBinlogPath || allBinlogPaths[0] };
         return mcpClient.callTool(tool, copy);
     }