fix(mcp): system locale default + MCP_LOCALE override for get_local_time

CLAUDE.md

@@ -80,6 +80,7 @@ See `docs/dev/mcp-server-architecture.md` for full architecture details.
 | `MCP_AUTH_SECRET` | If auth | `openssl rand -hex 32` |
 | `MCP_AUTH_ISSUER` | If auth | public HTTPS URL of this server |
 | `MCP_AUTH_STATE_DIR` | No | Directory for persisted OAuth state (default `/app/state`) |
+| `MCP_LOCALE` | No | BCP 47 locale tag for `localTime` in `get_local_time` (e.g. `sv-SE`); defaults to system locale |
 | `LOG_LEVEL` | No | `trace`/`debug`/`info`/`warn`/`error`/`fatal` |
 
 ## Tests

mcp-server/src/auth/store.ts

@@ -45,6 +45,11 @@ function loadJson<T>(filePath: string): T | null {
   } catch (err: unknown) {
     if ((err as NodeJS.ErrnoException).code !== 'ENOENT') {
       logger.warn({ file: filePath, err }, '[state] Failed to load state file — starting fresh');
+      try {
+        unlinkSync(filePath);
+      } catch {
+        /* ignore */
+      }
     }
     return null;
   }

mcp-server/src/tools/apps/calendar.ts

@@ -118,6 +118,11 @@ function icalNow(): string {
 function toICalDateTime(dateStr: string): string {
   // Already in iCal format
   if (/^\d{8}(T\d{6}Z?)?$/.test(dateStr)) {
+    if (dateStr.length === 8) {
+      // Parse as local-midnight date, then convert to UTC for CalDAV time-range
+      const d = new Date(+dateStr.slice(0, 4), +dateStr.slice(4, 6) - 1, +dateStr.slice(6, 8));
+      return d.toISOString().replace(/[-:]/g, '').split('.')[0] + 'Z';
+    }
     return dateStr;
   }
   // ISO format -> iCal UTC

mcp-server/src/tools/system/status.ts

@@ -98,7 +98,47 @@ export const setupChecksTool = {
   },
 };
 
+/**
+ * Get the current local time and timezone of the MCP server
+ */
+export const getLocalTimeTool = {
+  name: 'get_local_time',
+  description:
+    'Get the current local time and timezone of the MCP server. ' +
+    'Call this to establish a time reference before creating or listing calendar events, ' +
+    'or to resolve scheduling ambiguities with the user.',
+  inputSchema: z.object({}),
+  handler: async () => {
+    const now = new Date();
+    const tz = Intl.DateTimeFormat().resolvedOptions().timeZone;
+    const offsetMin = now.getTimezoneOffset(); // positive = behind UTC, negative = ahead
+    const sign = offsetMin <= 0 ? '+' : '-';
+    const abs = Math.abs(offsetMin);
+    const h = String(Math.floor(abs / 60)).padStart(2, '0');
+    const m = String(abs % 60).padStart(2, '0');
+    const utcOffset = `${sign}${h}:${m}`;
+
+    return {
+      content: [
+        {
+          type: 'text' as const,
+          text: JSON.stringify(
+            {
+              localTime: now.toLocaleString(process.env.MCP_LOCALE, { timeZone: tz }),
+              utcTime: now.toISOString(),
+              timezone: tz, // e.g. "Europe/Berlin"
+              utcOffset, // e.g. "+01:00"
+            },
+            null,
+            2
+          ),
+        },
+      ],
+    };
+  },
+};
+
 /**
  * Export all System Status tools
  */
-export const statusTools = [systemStatusTool, setupChecksTool];
+export const statusTools = [systemStatusTool, setupChecksTool, getLocalTimeTool];