diff --git a/.dprint.json b/.dprint.json
new file mode 100644
index 0000000..696337b
--- /dev/null
+++ b/.dprint.json
@@ -0,0 +1,21 @@
+{
+  "excludes": ["**/.git", "**/.target", "**/vendor", "**/*.js"],
+  "includes": ["**/*.{md,json,py}"],
+  "indentWidth": 2,
+  "json": {
+    "deno": true
+  },
+  "lineWidth": 80,
+  "markdown": {
+    "deno": true
+  },
+  "plugins": [
+    "https://plugins.dprint.dev/json-0.22.0.wasm",
+    "https://plugins.dprint.dev/markdown-0.22.1.wasm",
+    "https://plugins.dprint.dev/ruff-0.7.20.wasm"
+  ],
+  "ruff": {
+    "lineLength": 88,
+    "targetVersion": "py310"
+  }
+}
diff --git a/owa_mcp/models.py b/owa_mcp/models.py
index 7d23b9f..1bcf051 100644
--- a/owa_mcp/models.py
+++ b/owa_mcp/models.py
@@ -9,6 +9,7 @@ from typing import TypedDict
 
 class Email(TypedDict, total=False):
     """An email message."""
+
     subject: str
     sender: str
     sender_name: str
@@ -35,6 +36,7 @@ class Email(TypedDict, total=False):
 
 class CalendarEvent(TypedDict, total=False):
     """A calendar event / meeting."""
+
     subject: str
     start: str
     end: str
@@ -54,6 +56,7 @@ class CalendarEvent(TypedDict, total=False):
 
 class Person(TypedDict, total=False):
     """A person from the Exchange directory."""
+
     name: str
     email: str
     mailbox_type: str
@@ -73,6 +76,7 @@ class Person(TypedDict, total=False):
 
 class Folder(TypedDict, total=False):
     """A mail folder."""
+
     name: str
     id: str
     total_count: int
@@ -82,6 +86,7 @@ class Folder(TypedDict, total=False):
 
 class FreeSlot(TypedDict):
     """A free time slot."""
+
     date: str
     start: str
     end: str
@@ -90,6 +95,7 @@ class FreeSlot(TypedDict):
 
 class Availability(TypedDict, total=False):
     """Availability data for a single attendee."""
+
     email: str
     busy_slots: int
     free_slots: int
@@ -98,6 +104,7 @@ class Availability(TypedDict, total=False):
 
 class MeetingResult(TypedDict, total=False):
     """Result of creating/updating a meeting."""
+
     success: bool
     subject: str
     date: str
diff --git a/owa_mcp/owa_client.py b/owa_mcp/owa_client.py
index c4a5e28..244a553 100644
--- a/owa_mcp/owa_client.py
+++ b/owa_mcp/owa_client.py
@@ -10,14 +10,15 @@ mirroring what the OWA web frontend sends.
 
 import json
 import time
-from urllib.parse import quote, urlparse
 from pathlib import Path
+from urllib.parse import quote, urlparse
 
 import requests
 
 
 class SessionExpiredError(Exception):
     """Raised when the OWA session has expired (HTTP 401/440 or HTML redirect)."""
+
     pass
 
 
@@ -53,14 +54,11 @@ class OWAClient:
         owa_url: str | None = None,
     ):
         self.cookie_file = Path(
-            cookie_file
-            or str(Path(__file__).parent.parent / "session-cookies.txt")
+            cookie_file or str(Path(__file__).parent.parent / "session-cookies.txt")
         )
         self.owa_url = (owa_url or "").rstrip("/")
         if not self.owa_url:
-            raise ValueError(
-                "OWA URL must be provided via --owa-url or owa_url=…"
-            )
+            raise ValueError("OWA URL must be provided via --owa-url or owa_url=…")
         self._session = requests.Session()
         self._loaded = False
         self.user_email: str = ""
@@ -81,9 +79,10 @@ class OWAClient:
         """
         now_ms = int(time.time() * 1000)
         client_req_id = f"{self._client_id}_{now_ms}"
-        now_str = time.strftime(
-            "%Y-%m-%dT%H:%M:%S.", time.gmtime(now_ms / 1000)
-        ) + f"{now_ms % 1000:03d}"
+        now_str = (
+            time.strftime("%Y-%m-%dT%H:%M:%S.", time.gmtime(now_ms / 1000))
+            + f"{now_ms % 1000:03d}"
+        )
         return {
             # Basic
             "accept": "*/*",
@@ -129,9 +128,7 @@ class OWAClient:
     @property
     def _client_id(self) -> str:
         """Extract ClientId from session cookies."""
-        cid = next(
-            (c.value for c in self._session.cookies if c.name == "ClientId"), ""
-        )
+        cid = next((c.value for c in self._session.cookies if c.name == "ClientId"), "")
         return cid if cid else "00000000000000000000000000000000"
 
     # ------------------------------------------------------------------
@@ -153,7 +150,9 @@ class OWAClient:
                 cookies[name] = value
 
         if not cookies:
-            raise SessionExpiredError("Cookie file is empty. Use the login MCP tool to authenticate.")
+            raise SessionExpiredError(
+                "Cookie file is empty. Use the login MCP tool to authenticate."
+            )
 
         self._session = requests.Session()
         self._session.cookies.update(cookies)
@@ -229,12 +228,11 @@ class OWAClient:
             set_cookie = resp.headers.get("Set-Cookie", "")
             if "X-OWA-CANARY=" in set_cookie:
                 import re
-                m = re.search(r'X-OWA-CANARY=([^;]+)', set_cookie)
+
+                m = re.search(r"X-OWA-CANARY=([^;]+)", set_cookie)
                 if m:
                     host = urlparse(self.owa_url).hostname or "owa.b1.ru"
-                    self._session.cookies.set(
-                        "X-OWA-CANARY", m.group(1), domain=host
-                    )
+                    self._session.cookies.set("X-OWA-CANARY", m.group(1), domain=host)
             # Persist any cookie changes
             self._save_cookies()
         except Exception:
@@ -273,7 +271,9 @@ class OWAClient:
 
         # Detect session expiry
         if resp.status_code in (401, 440):
-            raise SessionExpiredError("Session expired (HTTP {}).".format(resp.status_code))
+            raise SessionExpiredError(
+                f"Session expired (HTTP {resp.status_code})."
+            )
 
         if "text/html" in resp.headers.get("Content-Type", ""):
             body_snippet = resp.text[:300] if resp.text else ""
@@ -335,9 +335,7 @@ class OWAClient:
             raise SessionExpiredError(f"Download failed: {exc}") from exc
 
         if resp.status_code in (401, 440):
-            raise SessionExpiredError(
-                f"Session expired (HTTP {resp.status_code})."
-            )
+            raise SessionExpiredError(f"Session expired (HTTP {resp.status_code}).")
 
         if "text/html" in resp.headers.get("Content-Type", ""):
             raise SessionExpiredError(
@@ -469,9 +467,7 @@ class OWAClient:
     # ResolveNames (directory search / attendee resolution)
     # ------------------------------------------------------------------
 
-    def resolve_names(
-        self, query: str, *, full_contact: bool = True
-    ) -> list[dict]:
+    def resolve_names(self, query: str, *, full_contact: bool = True) -> list[dict]:
         """Call ResolveNames to search the directory.
 
         Returns the list of Resolution dicts from the API, each containing
diff --git a/owa_mcp/server.py b/owa_mcp/server.py
index 6e1afbc..e88023a 100644
--- a/owa_mcp/server.py
+++ b/owa_mcp/server.py
@@ -23,7 +23,7 @@ from collections.abc import AsyncIterator
 from contextlib import asynccontextmanager
 from dataclasses import dataclass
 
-from mcp.server.auth.provider import AccessToken, TokenVerifier
+from mcp.server.auth.provider import TokenVerifier
 from mcp.server.auth.settings import AuthSettings
 from mcp.server.fastmcp import FastMCP
 
@@ -41,6 +41,7 @@ logger = logging.getLogger(__name__)
 @dataclass
 class AppContext:
     """Shared application state available to all tools via lifespan context."""
+
     client: OWAClient | None = None
 
 
@@ -177,13 +178,13 @@ def main(argv=None) -> None:
         raise SystemExit(1)
 
     # ── Register tools (imports populate module-level `mcp`) ───────────────
-    import owa_mcp.tools.email          # noqa: E402, F401
-    import owa_mcp.tools.calendar       # noqa: E402, F401
-    import owa_mcp.tools.people         # noqa: E402, F401
-    import owa_mcp.tools.folders        # noqa: E402, F401
-    import owa_mcp.tools.availability   # noqa: E402, F401
-    import owa_mcp.tools.analytics      # noqa: E402, F401
-    import owa_mcp.tools.auth           # noqa: E402, F401
+    import owa_mcp.tools.analytics  # noqa: E402, F401
+    import owa_mcp.tools.auth  # noqa: E402, F401
+    import owa_mcp.tools.availability  # noqa: E402, F401
+    import owa_mcp.tools.calendar  # noqa: E402, F401
+    import owa_mcp.tools.email  # noqa: E402, F401
+    import owa_mcp.tools.folders  # noqa: E402, F401
+    import owa_mcp.tools.people  # noqa: E402, F401
 
     # ── Auth for HTTP transports ───────────────────────────────────────────
     _configure_auth(mcp, args.token_hash)
diff --git a/owa_mcp/server_lifecycle.py b/owa_mcp/server_lifecycle.py
index c37ed74..00333be 100644
--- a/owa_mcp/server_lifecycle.py
+++ b/owa_mcp/server_lifecycle.py
@@ -17,9 +17,10 @@ import asyncio
 import logging
 from typing import TYPE_CHECKING
 
-from owa_mcp.owa_client import OWAClient, SessionExpiredError
 from mcp.server.auth.provider import AccessToken, TokenVerifier
 
+from owa_mcp.owa_client import OWAClient, SessionExpiredError
+
 if TYPE_CHECKING:
     from mcp.server.fastmcp import FastMCP
 
@@ -28,6 +29,7 @@ logger = logging.getLogger(__name__)
 
 # ── Client factory ───────────────────────────────────────────────────────
 
+
 def create_owa_client(owa_url: str, cookie_file: str | None = None) -> OWAClient:
     """Create and return a fully configured :class:`OWAClient`.
 
@@ -50,6 +52,7 @@ def create_owa_client(owa_url: str, cookie_file: str | None = None) -> OWAClient
 
 # ── Token verifier ────────────────────────────────────────────────────────
 
+
 class HashTokenVerifier(TokenVerifier):
     """Bearer-token verifier backed by a SHA-256 hash.
 
@@ -59,11 +62,12 @@ class HashTokenVerifier(TokenVerifier):
     """
 
     def __init__(self, token_hash: str) -> None:
-        import hashlib
+
         self._expected_hash = token_hash.strip().lower()
 
     async def verify_token(self, token: str) -> AccessToken | None:
         import hashlib
+
         if hashlib.sha256(token.encode()).hexdigest() == self._expected_hash:
             return AccessToken(
                 token=token,
@@ -75,6 +79,7 @@ class HashTokenVerifier(TokenVerifier):
 
 # ── Lifespan helper ──────────────────────────────────────────────────────
 
+
 class _LazyClient:
     """Thin wrapper that resolves the OWAClient on first access.
 
@@ -103,8 +108,7 @@ def require_client(client: OWAClient | None) -> OWAClient:
     """
     if client is None:
         raise RuntimeError(
-            "OWA client is not initialised. "
-            "Pass --owa-url when starting the server."
+            "OWA client is not initialised. Pass --owa-url when starting the server."
         )
     return client
 
@@ -127,7 +131,9 @@ class SessionKeepalive:
     picked up without restarting the server.
     """
 
-    def __init__(self, client: OWAClient, interval: int = _DEFAULT_KEEPALIVE_INTERVAL) -> None:
+    def __init__(
+        self, client: OWAClient, interval: int = _DEFAULT_KEEPALIVE_INTERVAL
+    ) -> None:
         self._client = client
         self._interval = interval
         self._task: asyncio.Task | None = None
@@ -168,37 +174,47 @@ class SessionKeepalive:
         case the user re-authenticated while the server was running.
         """
         try:
-            self._client.request("GetFolder", {
-                "__type": "GetFolderJsonRequest:#Exchange",
-                "Header": {
-                    "__type": "JsonRequestHeaders:#Exchange",
-                    "RequestServerVersion": "Exchange2013",
-                },
-                "Body": {
-                    "__type": "GetFolderRequest:#Exchange",
-                    "FolderShape": {
-                        "__type": "FolderResponseShape:#Exchange",
-                        "BaseShape": "IdOnly",
+            self._client.request(
+                "GetFolder",
+                {
+                    "__type": "GetFolderJsonRequest:#Exchange",
+                    "Header": {
+                        "__type": "JsonRequestHeaders:#Exchange",
+                        "RequestServerVersion": "Exchange2013",
+                    },
+                    "Body": {
+                        "__type": "GetFolderRequest:#Exchange",
+                        "FolderShape": {
+                            "__type": "FolderResponseShape:#Exchange",
+                            "BaseShape": "IdOnly",
+                        },
+                        "FolderIds": [
+                            {
+                                "__type": "DistinguishedFolderId:#Exchange",
+                                "Id": "inbox",
+                            }
+                        ],
                     },
-                    "FolderIds": [{
-                        "__type": "DistinguishedFolderId:#Exchange",
-                        "Id": "inbox",
-                    }],
                 },
-            })
+            )
             logger.debug("Session keepalive ping succeeded")
         except SessionExpiredError:
-            logger.warning("Session expired during keepalive — reloading cookies from disk")
+            logger.warning(
+                "Session expired during keepalive — reloading cookies from disk"
+            )
             try:
                 self._client._ensure_loaded()
             except Exception as exc:
-                logger.warning("Failed to reload cookies after keepalive failure: %s", exc)
+                logger.warning(
+                    "Failed to reload cookies after keepalive failure: %s", exc
+                )
         except Exception as exc:
             logger.debug("Keepalive ping failed (non-critical): %s", exc)
 
 
 # ── Tool filtering ───────────────────────────────────────────────────────
 
+
 def apply_tool_filters(
     server: FastMCP,
     enabled: list[str] | None = None,
diff --git a/owa_mcp/tools/analytics.py b/owa_mcp/tools/analytics.py
index cadbade..1c7872d 100644
--- a/owa_mcp/tools/analytics.py
+++ b/owa_mcp/tools/analytics.py
@@ -5,13 +5,13 @@ using GetUserAvailability and GetItem APIs.
 """
 
 import json
-from collections import Counter, defaultdict
-from datetime import datetime, timedelta, date
+from collections import Counter
+from datetime import date, datetime, timedelta
 
 from mcp.server.fastmcp import Context
 
-from owa_mcp.server import mcp, AppContext
 from owa_mcp.owa_client import OWAClient
+from owa_mcp.server import AppContext, mcp
 from owa_mcp.server_lifecycle import require_client
 
 
@@ -25,6 +25,7 @@ def _get_client(ctx: Context) -> OWAClient:
 # Internal: resolve names to emails
 # ------------------------------------------------------------------
 
+
 def _resolve_to_email(client: OWAClient, name: str) -> tuple[str, str]:
     """Resolve a name/email to (display_name, email). Returns ('','') on failure."""
     resolutions = client.resolve_names(name)
@@ -38,6 +39,7 @@ def _resolve_to_email(client: OWAClient, name: str) -> tuple[str, str]:
 # Internal: query GetUserAvailability in chunks
 # ------------------------------------------------------------------
 
+
 def _get_availability_events(
     client: OWAClient,
     emails: list[str],
@@ -54,77 +56,84 @@ def _get_availability_events(
     results: dict[str, list[dict]] = {email: [] for email in emails}
 
     # Batch people
-    email_batches = [emails[i:i+batch_size] for i in range(0, len(emails), batch_size)]
+    email_batches = [
+        emails[i : i + batch_size] for i in range(0, len(emails), batch_size)
+    ]
 
     for batch in email_batches:
         current = start
         while current < end:
             chunk_end = min(current + timedelta(days=chunk_days), end)
 
-            mailbox_data = [{
-                '__type': 'MailboxData:#Exchange',
-                'Email': {
-                    '__type': 'EmailAddress:#Exchange',
-                    'Address': email,
-                },
-                'AttendeeType': 'Required',
-            } for email in batch]
+            mailbox_data = [
+                {
+                    "__type": "MailboxData:#Exchange",
+                    "Email": {
+                        "__type": "EmailAddress:#Exchange",
+                        "Address": email,
+                    },
+                    "AttendeeType": "Required",
+                }
+                for email in batch
+            ]
 
             payload = {
-                '__type': 'GetUserAvailabilityJsonRequest:#Exchange',
-                'Header': {
-                    '__type': 'JsonRequestHeaders:#Exchange',
-                    'RequestServerVersion': 'Exchange2013',
-                    'TimeZoneContext': {
-                        '__type': 'TimeZoneContext:#Exchange',
-                        'TimeZoneDefinition': {
-                            '__type': 'TimeZoneDefinitionType:#Exchange',
-                            'Id': 'Russian Standard Time',
+                "__type": "GetUserAvailabilityJsonRequest:#Exchange",
+                "Header": {
+                    "__type": "JsonRequestHeaders:#Exchange",
+                    "RequestServerVersion": "Exchange2013",
+                    "TimeZoneContext": {
+                        "__type": "TimeZoneContext:#Exchange",
+                        "TimeZoneDefinition": {
+                            "__type": "TimeZoneDefinitionType:#Exchange",
+                            "Id": "Russian Standard Time",
                         },
                     },
                 },
-                'Body': {
-                    '__type': 'GetUserAvailabilityRequest:#Exchange',
-                    'MailboxDataArray': mailbox_data,
-                    'FreeBusyViewOptions': {
-                        '__type': 'FreeBusyViewOptions:#Exchange',
-                        'TimeWindow': {
-                            '__type': 'Duration:#Exchange',
-                            'StartTime': f'{current}T00:00:00',
-                            'EndTime': f'{chunk_end}T00:00:00',
+                "Body": {
+                    "__type": "GetUserAvailabilityRequest:#Exchange",
+                    "MailboxDataArray": mailbox_data,
+                    "FreeBusyViewOptions": {
+                        "__type": "FreeBusyViewOptions:#Exchange",
+                        "TimeWindow": {
+                            "__type": "Duration:#Exchange",
+                            "StartTime": f"{current}T00:00:00",
+                            "EndTime": f"{chunk_end}T00:00:00",
                         },
-                        'MergedFreeBusyIntervalInMinutes': 30,
-                        'RequestedView': 'DetailedMerged',
+                        "MergedFreeBusyIntervalInMinutes": 30,
+                        "RequestedView": "DetailedMerged",
                     },
                 },
             }
 
             try:
-                data = client.request('GetUserAvailability', payload)
-                body = data.get('Body', {})
-                for i, fb_resp in enumerate(body.get('FreeBusyResponseArray', [])):
+                data = client.request("GetUserAvailability", payload)
+                body = data.get("Body", {})
+                for i, fb_resp in enumerate(body.get("FreeBusyResponseArray", [])):
                     if i >= len(batch):
                         break
                     email = batch[i]
-                    fb_view = fb_resp.get('FreeBusyView', {})
-                    cal_events = fb_view.get('CalendarEventArray', {})
+                    fb_view = fb_resp.get("FreeBusyView", {})
+                    cal_events = fb_view.get("CalendarEventArray", {})
                     if isinstance(cal_events, dict):
-                        items = cal_events.get('Items', [])
+                        items = cal_events.get("Items", [])
                     elif isinstance(cal_events, list):
                         items = cal_events
                     else:
                         items = []
                     for event in items:
-                        s = event.get('StartTime', '')
-                        bt = event.get('BusyType', '')
-                        if s and bt != 'Free':
-                            details = event.get('CalendarEventDetails', {})
-                            subject = details.get('Subject', '') if details else ''
-                            results[email].append({
-                                'subject': subject,
-                                'start_date': s[:10],
-                                'busy_type': bt,
-                            })
+                        s = event.get("StartTime", "")
+                        bt = event.get("BusyType", "")
+                        if s and bt != "Free":
+                            details = event.get("CalendarEventDetails", {})
+                            subject = details.get("Subject", "") if details else ""
+                            results[email].append(
+                                {
+                                    "subject": subject,
+                                    "start_date": s[:10],
+                                    "busy_type": bt,
+                                }
+                            )
             except Exception:
                 pass
 
@@ -137,6 +146,7 @@ def _get_availability_events(
 # Tool: get_meeting_stats
 # ------------------------------------------------------------------
 
+
 @mcp.tool()
 def get_meeting_stats(
     people: str,
@@ -161,13 +171,13 @@ def get_meeting_stats(
     client = _get_client(ctx)
 
     try:
-        sd = datetime.strptime(start_date, '%Y-%m-%d').date()
-        ed = datetime.strptime(end_date, '%Y-%m-%d').date()
+        sd = datetime.strptime(start_date, "%Y-%m-%d").date()
+        ed = datetime.strptime(end_date, "%Y-%m-%d").date()
     except ValueError as e:
         return json.dumps({"error": f"Invalid date format: {e}"})
 
     # Resolve names
-    name_list = [n.strip() for n in people.split(',') if n.strip()]
+    name_list = [n.strip() for n in people.split(",") if n.strip()]
     if not name_list:
         return json.dumps({"error": "No people specified."})
 
@@ -199,43 +209,51 @@ def get_meeting_stats(
     stats = []
     for display, email in resolved:
         if not email or email not in avail:
-            stats.append({
-                "name": display,
-                "email": email or "not_found",
-                "total_meetings": 0,
-                "meetings_per_workday": 0,
-                "days_with_meetings": 0,
-                "workdays": workdays,
-            })
+            stats.append(
+                {
+                    "name": display,
+                    "email": email or "not_found",
+                    "total_meetings": 0,
+                    "meetings_per_workday": 0,
+                    "days_with_meetings": 0,
+                    "workdays": workdays,
+                }
+            )
             continue
 
         events = avail[email]
         total = len(events)
-        unique_days = len(set(ev['start_date'] for ev in events))
+        unique_days = len(set(ev["start_date"] for ev in events))
         avg = round(total / workdays, 1)
 
-        stats.append({
-            "name": display,
-            "email": email,
-            "total_meetings": total,
-            "meetings_per_workday": avg,
-            "days_with_meetings": unique_days,
-            "workdays": workdays,
-        })
+        stats.append(
+            {
+                "name": display,
+                "email": email,
+                "total_meetings": total,
+                "meetings_per_workday": avg,
+                "days_with_meetings": unique_days,
+                "workdays": workdays,
+            }
+        )
 
     # Sort by total descending
     stats.sort(key=lambda x: x["total_meetings"], reverse=True)
 
-    return json.dumps({
-        "period": {"start": start_date, "end": end_date, "workdays": workdays},
-        "stats": stats,
-    }, ensure_ascii=False)
+    return json.dumps(
+        {
+            "period": {"start": start_date, "end": end_date, "workdays": workdays},
+            "stats": stats,
+        },
+        ensure_ascii=False,
+    )
 
 
 # ------------------------------------------------------------------
 # Tool: get_meeting_contacts
 # ------------------------------------------------------------------
 
+
 @mcp.tool()
 def get_meeting_contacts(
     start_date: str,
@@ -261,8 +279,8 @@ def get_meeting_contacts(
     client = _get_client(ctx)
 
     try:
-        sd = datetime.strptime(start_date, '%Y-%m-%d').date()
-        ed = datetime.strptime(end_date, '%Y-%m-%d').date()
+        sd = datetime.strptime(start_date, "%Y-%m-%d").date()
+        ed = datetime.strptime(end_date, "%Y-%m-%d").date()
     except ValueError as e:
         return json.dumps({"error": f"Invalid date format: {e}"})
 
@@ -270,7 +288,9 @@ def get_meeting_contacts(
     # to count subject occurrences (handles recurring meetings)
     own_email = client.user_email.lower() if client.user_email else ""
     if not own_email:
-        return json.dumps({"error": "User email not available. Call the login tool first."})
+        return json.dumps(
+            {"error": "User email not available. Call the login tool first."}
+        )
 
     folder_id = client.get_folder_id("calendar")
     if not folder_id:
@@ -280,7 +300,7 @@ def get_meeting_contacts(
     avail_result = _get_availability_events(client, [client.user_email], sd, ed)
     expanded_events = avail_result.get(client.user_email, [])
 
-    subject_counts = Counter(ev['subject'] for ev in expanded_events)
+    subject_counts = Counter(ev["subject"] for ev in expanded_events)
     total_expanded = len(expanded_events)
 
     # Step 2: Find master calendar items for each unique subject
@@ -290,51 +310,51 @@ def get_meeting_contacts(
 
     while len(subject_to_id) < len(subject_counts):
         payload = {
-            '__type': 'FindItemJsonRequest:#Exchange',
-            'Header': {
-                '__type': 'JsonRequestHeaders:#Exchange',
-                'RequestServerVersion': 'Exchange2013',
+            "__type": "FindItemJsonRequest:#Exchange",
+            "Header": {
+                "__type": "JsonRequestHeaders:#Exchange",
+                "RequestServerVersion": "Exchange2013",
             },
-            'Body': {
-                '__type': 'FindItemRequest:#Exchange',
-                'ItemShape': {
-                    '__type': 'ItemResponseShape:#Exchange',
-                    'BaseShape': 'Default',
+            "Body": {
+                "__type": "FindItemRequest:#Exchange",
+                "ItemShape": {
+                    "__type": "ItemResponseShape:#Exchange",
+                    "BaseShape": "Default",
                 },
-                'ParentFolderIds': [
-                    {'__type': 'FolderId:#Exchange', 'Id': folder_id}
+                "ParentFolderIds": [{"__type": "FolderId:#Exchange", "Id": folder_id}],
+                "Traversal": "Shallow",
+                "Paging": {
+                    "__type": "IndexedPageView:#Exchange",
+                    "BasePoint": "Beginning",
+                    "Offset": offset,
+                    "MaxEntriesReturned": 200,
+                },
+                "SortOrder": [
+                    {
+                        "__type": "SortResults:#Exchange",
+                        "Order": "Descending",
+                        "Path": {
+                            "__type": "PropertyUri:#Exchange",
+                            "FieldURI": "Start",
+                        },
+                    }
                 ],
-                'Traversal': 'Shallow',
-                'Paging': {
-                    '__type': 'IndexedPageView:#Exchange',
-                    'BasePoint': 'Beginning',
-                    'Offset': offset,
-                    'MaxEntriesReturned': 200,
-                },
-                'SortOrder': [{
-                    '__type': 'SortResults:#Exchange',
-                    'Order': 'Descending',
-                    'Path': {
-                        '__type': 'PropertyUri:#Exchange',
-                        'FieldURI': 'Start',
-                    },
-                }],
             },
         }
 
-        data = client.request('FindItem', payload)
+        data = client.request("FindItem", payload)
         items = client.extract_items(data)
         if not items:
             break
-        folder_items = items[0].get('RootFolder', {}).get('Items', [])
-        is_last = items[0].get('RootFolder', {}).get('IncludesLastItemInRange', True)
+        folder_items = items[0].get("RootFolder", {}).get("Items", [])
+        is_last = items[0].get("RootFolder", {}).get("IncludesLastItemInRange", True)
         if not folder_items:
             break
 
         for item in folder_items:
-            subj = item.get('Subject', '')
+            subj = item.get("Subject", "")
             if subj and subj in subject_counts and subj not in subject_to_id:
-                subject_to_id[subj] = item.get('ItemId', {}).get('Id', '')
+                subject_to_id[subj] = item.get("ItemId", {}).get("Id", "")
 
         if is_last:
             break
@@ -347,7 +367,7 @@ def get_meeting_contacts(
     id_to_attendees: dict[str, set] = {}
 
     for bi in range(0, len(unique_ids), 10):
-        batch = unique_ids[bi:bi+10]
+        batch = unique_ids[bi : bi + 10]
         item_id_list = [{"__type": "ItemId:#Exchange", "Id": iid} for iid in batch]
 
         payload = {
@@ -375,8 +395,10 @@ def get_meeting_contacts(
                     item_id = item.get("ItemId", {}).get("Id", "")
                     attendees = set()
 
-                    for att_list in [item.get("RequiredAttendees", []) or [],
-                                     item.get("OptionalAttendees", []) or []]:
+                    for att_list in [
+                        item.get("RequiredAttendees", []) or [],
+                        item.get("OptionalAttendees", []) or [],
+                    ]:
                         for a in att_list:
                             mailbox = a.get("Mailbox", {})
                             name = mailbox.get("Name", "")
@@ -408,15 +430,20 @@ def get_meeting_contacts(
 
     result_contacts = []
     for (name, email), count in contacts.most_common(top_n):
-        result_contacts.append({
-            "name": name,
-            "email": email,
-            "meetings": count,
-        })
+        result_contacts.append(
+            {
+                "name": name,
+                "email": email,
+                "meetings": count,
+            }
+        )
 
-    return json.dumps({
-        "period": {"start": start_date, "end": end_date},
-        "total_meetings": total_expanded,
-        "unique_contacts": len(contacts),
-        "contacts": result_contacts,
-    }, ensure_ascii=False)
+    return json.dumps(
+        {
+            "period": {"start": start_date, "end": end_date},
+            "total_meetings": total_expanded,
+            "unique_contacts": len(contacts),
+            "contacts": result_contacts,
+        },
+        ensure_ascii=False,
+    )
diff --git a/owa_mcp/tools/auth.py b/owa_mcp/tools/auth.py
index df85919..b2d354d 100644
--- a/owa_mcp/tools/auth.py
+++ b/owa_mcp/tools/auth.py
@@ -12,8 +12,8 @@ import json
 
 from mcp.server.fastmcp import Context
 
-from owa_mcp.server import mcp, AppContext
 from owa_mcp.owa_client import OWAClient, SessionExpiredError
+from owa_mcp.server import AppContext, mcp
 from owa_mcp.server_lifecycle import require_client
 
 
@@ -87,16 +87,20 @@ async def login(
     # Parse and validate cookies
     cookies_str = cookies.strip()
     if not cookies_str:
-        return json.dumps({
-            "success": False,
-            "error": "Cookies string is empty. Paste your browser cookies as name=value pairs, one per line.",
-        })
+        return json.dumps(
+            {
+                "success": False,
+                "error": "Cookies string is empty. Paste your browser cookies as name=value pairs, one per line.",
+            }
+        )
 
     # Save to disk
     try:
         client.cookie_file.write_text(cookies_str + "\n")
     except Exception as e:
-        return json.dumps({"success": False, "error": f"Failed to write cookie file: {e}"})
+        return json.dumps(
+            {"success": False, "error": f"Failed to write cookie file: {e}"}
+        )
 
     # Load into memory
     try:
@@ -106,12 +110,16 @@ async def login(
 
     # Verify session
     if _session_is_valid(client):
-        return json.dumps({
-            "success": True,
-            "message": f"Logged in. Session cookies saved to {client.cookie_file}.",
-        })
+        return json.dumps(
+            {
+                "success": True,
+                "message": f"Logged in. Session cookies saved to {client.cookie_file}.",
+            }
+        )
     else:
-        return json.dumps({
-            "success": False,
-            "error": "Cookies loaded but session verification failed. The cookies may have expired.",
-        })
+        return json.dumps(
+            {
+                "success": False,
+                "error": "Cookies loaded but session verification failed. The cookies may have expired.",
+            }
+        )
diff --git a/owa_mcp/tools/availability.py b/owa_mcp/tools/availability.py
index aa8bd02..a4ac504 100644
--- a/owa_mcp/tools/availability.py
+++ b/owa_mcp/tools/availability.py
@@ -9,8 +9,8 @@ from datetime import datetime, timedelta
 
 from mcp.server.fastmcp import Context
 
-from owa_mcp.server import mcp, AppContext
 from owa_mcp.owa_client import OWAClient
+from owa_mcp.server import AppContext, mcp
 from owa_mcp.server_lifecycle import require_client
 
 
@@ -24,6 +24,7 @@ def _get_client(ctx: Context) -> OWAClient:
 # Pure helper functions (preserved from find-meeting-time.py)
 # ------------------------------------------------------------------
 
+
 def _parse_freebusy_string(
     freebusy_str: str, start_time: datetime, interval_minutes: int = 30
 ) -> list[tuple]:
@@ -37,7 +38,7 @@ def _parse_freebusy_string(
 
     for char in freebusy_str:
         next_time = current_time + timedelta(minutes=interval_minutes)
-        if char in ['1', '2', '3', '4']:  # Not free
+        if char in ["1", "2", "3", "4"]:  # Not free
             busy_periods.append((current_time, next_time, char))
         current_time = next_time
 
@@ -105,75 +106,82 @@ def _find_free_slots(
 
 def _format_time(dt: datetime) -> str:
     """Format datetime as HH:MM."""
-    return dt.strftime('%H:%M')
+    return dt.strftime("%H:%M")
 
 
 # ------------------------------------------------------------------
 # Helper: get busy events via GetUserAvailability (includes recurring)
 # ------------------------------------------------------------------
 
+
 def _get_availability_events(
     client: OWAClient, email: str, start_date, end_date
 ) -> list[dict]:
     """Get busy events via GetUserAvailability (expands recurring events)."""
     payload = {
-        '__type': 'GetUserAvailabilityJsonRequest:#Exchange',
-        'Header': {
-            '__type': 'JsonRequestHeaders:#Exchange',
-            'RequestServerVersion': 'Exchange2013',
-            'TimeZoneContext': {
-                '__type': 'TimeZoneContext:#Exchange',
-                'TimeZoneDefinition': {
-                    '__type': 'TimeZoneDefinitionType:#Exchange',
-                    'Id': 'Russian Standard Time',
+        "__type": "GetUserAvailabilityJsonRequest:#Exchange",
+        "Header": {
+            "__type": "JsonRequestHeaders:#Exchange",
+            "RequestServerVersion": "Exchange2013",
+            "TimeZoneContext": {
+                "__type": "TimeZoneContext:#Exchange",
+                "TimeZoneDefinition": {
+                    "__type": "TimeZoneDefinitionType:#Exchange",
+                    "Id": "Russian Standard Time",
                 },
             },
         },
-        'Body': {
-            '__type': 'GetUserAvailabilityRequest:#Exchange',
-            'MailboxDataArray': [{
-                '__type': 'MailboxData:#Exchange',
-                'Email': {'__type': 'EmailAddress:#Exchange', 'Address': email},
-                'AttendeeType': 'Required',
-            }],
-            'FreeBusyViewOptions': {
-                '__type': 'FreeBusyViewOptions:#Exchange',
-                'TimeWindow': {
-                    '__type': 'Duration:#Exchange',
-                    'StartTime': f'{start_date}T00:00:00',
-                    'EndTime': f'{end_date + timedelta(days=1)}T00:00:00',
+        "Body": {
+            "__type": "GetUserAvailabilityRequest:#Exchange",
+            "MailboxDataArray": [
+                {
+                    "__type": "MailboxData:#Exchange",
+                    "Email": {"__type": "EmailAddress:#Exchange", "Address": email},
+                    "AttendeeType": "Required",
+                }
+            ],
+            "FreeBusyViewOptions": {
+                "__type": "FreeBusyViewOptions:#Exchange",
+                "TimeWindow": {
+                    "__type": "Duration:#Exchange",
+                    "StartTime": f"{start_date}T00:00:00",
+                    "EndTime": f"{end_date + timedelta(days=1)}T00:00:00",
                 },
-                'MergedFreeBusyIntervalInMinutes': 30,
-                'RequestedView': 'DetailedMerged',
+                "MergedFreeBusyIntervalInMinutes": 30,
+                "RequestedView": "DetailedMerged",
             },
         },
     }
 
-    data = client.request('GetUserAvailability', payload)
-    body = data.get('Body', {})
+    data = client.request("GetUserAvailability", payload)
+    body = data.get("Body", {})
 
     events = []
-    for fb_resp in body.get('FreeBusyResponseArray', []):
-        fb_view = fb_resp.get('FreeBusyView', {})
-        cal_events = fb_view.get('CalendarEventArray', {})
+    for fb_resp in body.get("FreeBusyResponseArray", []):
+        fb_view = fb_resp.get("FreeBusyView", {})
+        cal_events = fb_view.get("CalendarEventArray", {})
         items = (
-            cal_events.get('Items', [])
+            cal_events.get("Items", [])
             if isinstance(cal_events, dict)
             else (cal_events if isinstance(cal_events, list) else [])
         )
         for event in items:
-            bt = event.get('BusyType', '')
-            if bt in ('Free', 'NoData'):
+            bt = event.get("BusyType", "")
+            if bt in ("Free", "NoData"):
                 continue
 
-            start_str = event.get('StartTime', '')
-            end_str = event.get('EndTime', '')
+            start_str = event.get("StartTime", "")
+            end_str = event.get("EndTime", "")
             if not start_str or not end_str:
                 continue
             try:
-                start = datetime.fromisoformat(start_str.replace('Z', '+00:00')).replace(tzinfo=None)
-                end = datetime.fromisoformat(end_str.replace('Z', '+00:00')).replace(tzinfo=None)
-                events.append({'start': start, 'end': end, 'status': bt})
+                start = datetime.fromisoformat(
+                    start_str.replace("Z", "+00:00")
+                ).replace(tzinfo=None)
+                end = datetime.fromisoformat(end_str.replace("Z", "+00:00")).replace(
+                    tzinfo=None
+                )
+                events.append({"start": start, "end": end, "status": bt})
             except (ValueError, AttributeError):
                 continue
 
@@ -184,22 +192,23 @@ def _get_availability_events(
 # Helper: get calendar folder ID
 # ------------------------------------------------------------------
 
+
 def _get_calendar_folder_id(client: OWAClient) -> str | None:
     """Get the calendar folder ID via GetFolder."""
     payload = {
-        '__type': 'GetFolderJsonRequest:#Exchange',
-        'Header': {
-            '__type': 'JsonRequestHeaders:#Exchange',
-            'RequestServerVersion': 'Exchange2013',
+        "__type": "GetFolderJsonRequest:#Exchange",
+        "Header": {
+            "__type": "JsonRequestHeaders:#Exchange",
+            "RequestServerVersion": "Exchange2013",
         },
-        'Body': {
-            '__type': 'GetFolderRequest:#Exchange',
-            'FolderShape': {
-                '__type': 'FolderResponseShape:#Exchange',
-                'BaseShape': 'IdOnly',
+        "Body": {
+            "__type": "GetFolderRequest:#Exchange",
+            "FolderShape": {
+                "__type": "FolderResponseShape:#Exchange",
+                "BaseShape": "IdOnly",
             },
-            'FolderIds': [
-                {'__type': 'DistinguishedFolderId:#Exchange', 'Id': 'calendar'}
+            "FolderIds": [
+                {"__type": "DistinguishedFolderId:#Exchange", "Id": "calendar"}
             ],
         },
     }
@@ -218,6 +227,7 @@ def _get_calendar_folder_id(client: OWAClient) -> str | None:
 # Helper: get own calendar events (from find-free-time.py)
 # ------------------------------------------------------------------
 
+
 def _get_calendar_events(
     client: OWAClient, folder_id: str, start_date, end_date
 ) -> list[dict]:
@@ -228,34 +238,32 @@ def _get_calendar_events(
 
     while True:
         payload = {
-            '__type': 'FindItemJsonRequest:#Exchange',
-            'Header': {
-                '__type': 'JsonRequestHeaders:#Exchange',
-                'RequestServerVersion': 'Exchange2013',
+            "__type": "FindItemJsonRequest:#Exchange",
+            "Header": {
+                "__type": "JsonRequestHeaders:#Exchange",
+                "RequestServerVersion": "Exchange2013",
             },
-            'Body': {
-                '__type': 'FindItemRequest:#Exchange',
-                'ItemShape': {
-                    '__type': 'ItemResponseShape:#Exchange',
-                    'BaseShape': 'AllProperties',
+            "Body": {
+                "__type": "FindItemRequest:#Exchange",
+                "ItemShape": {
+                    "__type": "ItemResponseShape:#Exchange",
+                    "BaseShape": "AllProperties",
                 },
-                'ParentFolderIds': [
-                    {'__type': 'FolderId:#Exchange', 'Id': folder_id}
-                ],
-                'Traversal': 'Shallow',
-                'Paging': {
-                    '__type': 'IndexedPageView:#Exchange',
-                    'BasePoint': 'Beginning',
-                    'Offset': offset,
-                    'MaxEntriesReturned': batch_size,
+                "ParentFolderIds": [{"__type": "FolderId:#Exchange", "Id": folder_id}],
+                "Traversal": "Shallow",
+                "Paging": {
+                    "__type": "IndexedPageView:#Exchange",
+                    "BasePoint": "Beginning",
+                    "Offset": offset,
+                    "MaxEntriesReturned": batch_size,
                 },
-                'SortOrder': [
+                "SortOrder": [
                     {
-                        '__type': 'SortResults:#Exchange',
-                        'Order': 'Ascending',
-                        'Path': {
-                            '__type': 'PropertyUri:#Exchange',
-                            'FieldURI': 'Start',
+                        "__type": "SortResults:#Exchange",
+                        "Order": "Ascending",
+                        "Path": {
+                            "__type": "PropertyUri:#Exchange",
+                            "FieldURI": "Start",
                         },
                     }
                 ],
@@ -268,29 +276,29 @@ def _get_calendar_events(
         if not items:
             break
 
-        folder_items = items[0].get('RootFolder', {}).get('Items', [])
+        folder_items = items[0].get("RootFolder", {}).get("Items", [])
         if not folder_items:
             break
 
         for item in folder_items:
             # Skip cancelled events
-            if item.get('IsCancelled'):
+            if item.get("IsCancelled"):
                 continue
 
             # Skip free/tentative slots
-            fbt = item.get('FreeBusyType', 'Busy')
-            if fbt in ['Free', 'NoData']:
+            fbt = item.get("FreeBusyType", "Busy")
+            if fbt in ["Free", "NoData"]:
                 continue
 
-            start_str = item.get('Start', '')
-            end_str = item.get('End', '')
+            start_str = item.get("Start", "")
+            end_str = item.get("End", "")
 
             if not start_str or not end_str:
                 continue
 
             try:
-                start = datetime.fromisoformat(start_str.replace('Z', '+00:00'))
-                end = datetime.fromisoformat(end_str.replace('Z', '+00:00'))
+                start = datetime.fromisoformat(start_str.replace("Z", "+00:00"))
+                end = datetime.fromisoformat(end_str.replace("Z", "+00:00"))
 
                 # Convert to naive datetime for comparison
                 start = start.replace(tzinfo=None)
@@ -300,17 +308,19 @@ def _get_calendar_events(
                 if end.date() < start_date or start.date() > end_date:
                     continue
 
-                events.append({
-                    'start': start,
-                    'end': end,
-                    'subject': item.get('Subject', ''),
-                    'status': fbt,
-                })
+                events.append(
+                    {
+                        "start": start,
+                        "end": end,
+                        "subject": item.get("Subject", ""),
+                        "status": fbt,
+                    }
+                )
             except (ValueError, AttributeError):
                 continue
 
         # Check if there are more items
-        is_last = items[0].get('RootFolder', {}).get('IncludesLastItemInRange', True)
+        is_last = items[0].get("RootFolder", {}).get("IncludesLastItemInRange", True)
         if is_last:
             break
 
@@ -323,6 +333,7 @@ def _get_calendar_events(
 # Tool: find_free_time
 # ------------------------------------------------------------------
 
+
 @mcp.tool()
 def find_free_time(
     start_date: str,
@@ -352,8 +363,8 @@ def find_free_time(
     client = _get_client(ctx)
 
     try:
-        sd = datetime.strptime(start_date, '%Y-%m-%d').date()
-        ed = datetime.strptime(end_date, '%Y-%m-%d').date() if end_date else sd
+        sd = datetime.strptime(start_date, "%Y-%m-%d").date()
+        ed = datetime.strptime(end_date, "%Y-%m-%d").date() if end_date else sd
     except ValueError as e:
         return json.dumps({"error": f"Invalid date format: {e}"})
 
@@ -365,13 +376,17 @@ def find_free_time(
             # Fallback to FindItem (misses recurring event occurrences)
             folder_id = _get_calendar_folder_id(client)
             if not folder_id:
-                return json.dumps({"error": "Could not find calendar folder. Session may have expired."})
+                return json.dumps(
+                    {
+                        "error": "Could not find calendar folder. Session may have expired."
+                    }
+                )
             all_busy = _get_calendar_events(client, folder_id, sd, ed)
     except Exception as e:
         return json.dumps({"error": str(e)})
 
     # Convert event dicts to (start, end) tuples for _find_free_slots
-    busy_periods = [(ev['start'], ev['end']) for ev in all_busy]
+    busy_periods = [(ev["start"], ev["end"]) for ev in all_busy]
 
     result = {}
     current_date = sd
@@ -379,8 +394,11 @@ def find_free_time(
         # Skip weekends
         if current_date.weekday() < 5:
             free = _find_free_slots(
-                busy_periods, current_date,
-                start_hour, end_hour, duration_minutes,
+                busy_periods,
+                current_date,
+                start_hour,
+                end_hour,
+                duration_minutes,
             )
             if free:
                 result[str(current_date)] = [
@@ -400,6 +418,7 @@ def find_free_time(
 # Tool: find_meeting_time
 # ------------------------------------------------------------------
 
+
 @mcp.tool()
 def find_meeting_time(
     emails: str,
@@ -431,13 +450,13 @@ def find_meeting_time(
     """
     client = _get_client(ctx)
 
-    raw_list = [e.strip() for e in emails.split(',') if e.strip()]
+    raw_list = [e.strip() for e in emails.split(",") if e.strip()]
     if not raw_list:
         return json.dumps({"error": "No email addresses provided."})
 
     try:
-        sd = datetime.strptime(start_date, '%Y-%m-%d').date()
-        ed = datetime.strptime(end_date, '%Y-%m-%d').date() if end_date else sd
+        sd = datetime.strptime(start_date, "%Y-%m-%d").date()
+        ed = datetime.strptime(end_date, "%Y-%m-%d").date() if end_date else sd
     except ValueError as e:
         return json.dumps({"error": f"Invalid date format: {e}"})
 
@@ -445,12 +464,12 @@ def find_meeting_time(
     email_list = []
     resolve_errors = []
     for entry in raw_list:
-        if '@' in entry:
+        if "@" in entry:
             email_list.append(entry)
         else:
             resolutions = client.resolve_names(entry, full_contact=False)
             if resolutions:
-                addr = resolutions[0].get('Mailbox', {}).get('EmailAddress', '')
+                addr = resolutions[0].get("Mailbox", {}).get("EmailAddress", "")
                 if addr:
                     email_list.append(addr)
                 else:
@@ -459,46 +478,52 @@ def find_meeting_time(
                 resolve_errors.append(entry)
 
     if not email_list:
-        return json.dumps({"error": f"Could not resolve any names to email addresses: {resolve_errors}"})
+        return json.dumps(
+            {
+                "error": f"Could not resolve any names to email addresses: {resolve_errors}"
+            }
+        )
 
     # Build mailbox data (reused for each day chunk)
     mailbox_data = []
     for email in email_list:
-        mailbox_data.append({
-            '__type': 'MailboxData:#Exchange',
-            'Email': {
-                '__type': 'EmailAddress:#Exchange',
-                'Address': email,
-            },
-            'AttendeeType': 'Required',
-        })
+        mailbox_data.append(
+            {
+                "__type": "MailboxData:#Exchange",
+                "Email": {
+                    "__type": "EmailAddress:#Exchange",
+                    "Address": email,
+                },
+                "AttendeeType": "Required",
+            }
+        )
 
     # Query the full date range at once (API handles multi-day windows)
     payload = {
-        '__type': 'GetUserAvailabilityJsonRequest:#Exchange',
-        'Header': {
-            '__type': 'JsonRequestHeaders:#Exchange',
-            'RequestServerVersion': 'Exchange2013',
-            'TimeZoneContext': {
-                '__type': 'TimeZoneContext:#Exchange',
-                'TimeZoneDefinition': {
-                    '__type': 'TimeZoneDefinitionType:#Exchange',
-                    'Id': 'Russian Standard Time',
+        "__type": "GetUserAvailabilityJsonRequest:#Exchange",
+        "Header": {
+            "__type": "JsonRequestHeaders:#Exchange",
+            "RequestServerVersion": "Exchange2013",
+            "TimeZoneContext": {
+                "__type": "TimeZoneContext:#Exchange",
+                "TimeZoneDefinition": {
+                    "__type": "TimeZoneDefinitionType:#Exchange",
+                    "Id": "Russian Standard Time",
                 },
             },
         },
-        'Body': {
-            '__type': 'GetUserAvailabilityRequest:#Exchange',
-            'MailboxDataArray': mailbox_data,
-            'FreeBusyViewOptions': {
-                '__type': 'FreeBusyViewOptions:#Exchange',
-                'TimeWindow': {
-                    '__type': 'Duration:#Exchange',
-                    'StartTime': f'{sd}T00:00:00',
-                    'EndTime': f'{ed + timedelta(days=1)}T00:00:00',
+        "Body": {
+            "__type": "GetUserAvailabilityRequest:#Exchange",
+            "MailboxDataArray": mailbox_data,
+            "FreeBusyViewOptions": {
+                "__type": "FreeBusyViewOptions:#Exchange",
+                "TimeWindow": {
+                    "__type": "Duration:#Exchange",
+                    "StartTime": f"{sd}T00:00:00",
+                    "EndTime": f"{ed + timedelta(days=1)}T00:00:00",
                 },
-                'MergedFreeBusyIntervalInMinutes': 30,
-                'RequestedView': 'DetailedMerged',
+                "MergedFreeBusyIntervalInMinutes": 30,
+                "RequestedView": "DetailedMerged",
             },
         },
     }
@@ -508,57 +533,69 @@ def find_meeting_time(
     except Exception as e:
         return json.dumps({"error": str(e)})
 
-    body = data.get('Body', {})
-    if 'ErrorCode' in body:
-        return json.dumps({"error": body.get('FaultMessage', 'Unknown error')})
+    body = data.get("Body", {})
+    if "ErrorCode" in body:
+        return json.dumps({"error": body.get("FaultMessage", "Unknown error")})
 
     # Parse availability responses
     all_busy = []
     attendee_info = []
-    freebusy_responses = body.get('FreeBusyResponseArray', [])
+    freebusy_responses = body.get("FreeBusyResponseArray", [])
 
     for i, fb_resp in enumerate(freebusy_responses):
-        fb_view = fb_resp.get('FreeBusyView', {})
-        merged_fb = fb_view.get('MergedFreeBusy', '')
-        email = email_list[i] if i < len(email_list) else f"Person {i+1}"
+        fb_view = fb_resp.get("FreeBusyView", {})
+        merged_fb = fb_view.get("MergedFreeBusy", "")
+        email = email_list[i] if i < len(email_list) else f"Person {i + 1}"
 
         if merged_fb:
             start_time = datetime.combine(sd, datetime.min.time())
             busy_periods = _parse_freebusy_string(merged_fb, start_time)
 
-            busy_count = sum(1 for c in merged_fb if c != '0')
-            free_count = sum(1 for c in merged_fb if c == '0')
-            attendee_info.append({
-                "email": email,
-                "busy_slots": busy_count,
-                "free_slots": free_count,
-            })
+            busy_count = sum(1 for c in merged_fb if c != "0")
+            free_count = sum(1 for c in merged_fb if c == "0")
+            attendee_info.append(
+                {
+                    "email": email,
+                    "busy_slots": busy_count,
+                    "free_slots": free_count,
+                }
+            )
 
             all_busy.extend(busy_periods)
         else:
             # Fallback: parse CalendarEventArray
-            cal_events_raw = fb_view.get('CalendarEventArray', {})
-            cal_events = cal_events_raw.get('Items', []) if isinstance(cal_events_raw, dict) else (cal_events_raw if isinstance(cal_events_raw, list) else [])
+            cal_events_raw = fb_view.get("CalendarEventArray", {})
+            cal_events = (
+                cal_events_raw.get("Items", [])
+                if isinstance(cal_events_raw, dict)
+                else (cal_events_raw if isinstance(cal_events_raw, list) else [])
+            )
             if cal_events:
-                attendee_info.append({
-                    "email": email,
-                    "calendar_events": len(cal_events),
-                })
+                attendee_info.append(
+                    {
+                        "email": email,
+                        "calendar_events": len(cal_events),
+                    }
+                )
                 for event in cal_events:
-                    start_str = event.get('StartTime', '')
-                    end_str = event.get('EndTime', '')
+                    start_str = event.get("StartTime", "")
+                    end_str = event.get("EndTime", "")
                     if start_str and end_str:
                         try:
-                            start = datetime.fromisoformat(start_str.replace('Z', '+00:00'))
-                            end = datetime.fromisoformat(end_str.replace('Z', '+00:00'))
+                            start = datetime.fromisoformat(
+                                start_str.replace("Z", "+00:00")
+                            )
+                            end = datetime.fromisoformat(end_str.replace("Z", "+00:00"))
                             all_busy.append((start, end))
                         except Exception:
                             pass
             else:
-                attendee_info.append({
-                    "email": email,
-                    "status": "no_data",
-                })
+                attendee_info.append(
+                    {
+                        "email": email,
+                        "status": "no_data",
+                    }
+                )
 
     merged_busy = _merge_busy_periods(all_busy)
 
@@ -568,8 +605,11 @@ def find_meeting_time(
     while current_date <= ed:
         if current_date.weekday() < 5:  # Skip weekends
             free = _find_free_slots(
-                merged_busy, current_date,
-                start_hour, end_hour, duration_minutes,
+                merged_busy,
+                current_date,
+                start_hour,
+                end_hour,
+                duration_minutes,
             )
             if free:
                 free_by_date[str(current_date)] = [
diff --git a/owa_mcp/tools/calendar.py b/owa_mcp/tools/calendar.py
index 06dabd7..49cd484 100644
--- a/owa_mcp/tools/calendar.py
+++ b/owa_mcp/tools/calendar.py
@@ -11,10 +11,10 @@ from datetime import datetime, timedelta
 
 from mcp.server.fastmcp import Context
 
-from owa_mcp.server import mcp, AppContext
 from owa_mcp.owa_client import OWAClient
+from owa_mcp.server import AppContext, mcp
 from owa_mcp.server_lifecycle import require_client
-from owa_mcp.utils import html_to_text, parse_iso_datetime, extract_links_from_html
+from owa_mcp.utils import extract_links_from_html, html_to_text
 
 
 def _get_client(ctx: Context) -> OWAClient:
@@ -63,9 +63,7 @@ def _get_event_details(client: OWAClient, item_id: str) -> dict:
                 "__type": "ItemResponseShape:#Exchange",
                 "BaseShape": "AllProperties",
             },
-            "ItemIds": [
-                {"__type": "ItemId:#Exchange", "Id": item_id}
-            ],
+            "ItemIds": [{"__type": "ItemId:#Exchange", "Id": item_id}],
         },
     }
 
@@ -160,9 +158,7 @@ def _get_full_event(client: OWAClient, item_id: str) -> dict:
                 "__type": "ItemResponseShape:#Exchange",
                 "BaseShape": "AllProperties",
             },
-            "ItemIds": [
-                {"__type": "ItemId:#Exchange", "Id": item_id}
-            ],
+            "ItemIds": [{"__type": "ItemId:#Exchange", "Id": item_id}],
         },
     }
 
@@ -202,13 +198,15 @@ def _get_full_event(client: OWAClient, item_id: str) -> dict:
                 name = mailbox.get("Name", "")
                 addr = mailbox.get("EmailAddress", "")
                 if addr and not addr.startswith("/O="):
-                    result["resolved_required"].append({
-                        "Mailbox": {
-                            "Name": name,
-                            "EmailAddress": addr,
-                            "RoutingType": "SMTP",
+                    result["resolved_required"].append(
+                        {
+                            "Mailbox": {
+                                "Name": name,
+                                "EmailAddress": addr,
+                                "RoutingType": "SMTP",
+                            }
                         }
-                    })
+                    )
 
             # Optional attendees
             for a in item.get("OptionalAttendees", []) or []:
@@ -216,13 +214,15 @@ def _get_full_event(client: OWAClient, item_id: str) -> dict:
                 name = mailbox.get("Name", "")
                 addr = mailbox.get("EmailAddress", "")
                 if addr and not addr.startswith("/O="):
-                    result["resolved_optional"].append({
-                        "Mailbox": {
-                            "Name": name,
-                            "EmailAddress": addr,
-                            "RoutingType": "SMTP",
+                    result["resolved_optional"].append(
+                        {
+                            "Mailbox": {
+                                "Name": name,
+                                "EmailAddress": addr,
+                                "RoutingType": "SMTP",
+                            }
                         }
-                    })
+                    )
 
             return result
 
@@ -331,72 +331,81 @@ def _get_expanded_events(
         chunk_end = min(current + timedelta(days=chunk_days), end_date)
 
         payload = {
-            '__type': 'GetUserAvailabilityJsonRequest:#Exchange',
-            'Header': {
-                '__type': 'JsonRequestHeaders:#Exchange',
-                'RequestServerVersion': 'Exchange2013',
-                'TimeZoneContext': {
-                    '__type': 'TimeZoneContext:#Exchange',
-                    'TimeZoneDefinition': {
-                        '__type': 'TimeZoneDefinitionType:#Exchange',
-                        'Id': 'Russian Standard Time',
+            "__type": "GetUserAvailabilityJsonRequest:#Exchange",
+            "Header": {
+                "__type": "JsonRequestHeaders:#Exchange",
+                "RequestServerVersion": "Exchange2013",
+                "TimeZoneContext": {
+                    "__type": "TimeZoneContext:#Exchange",
+                    "TimeZoneDefinition": {
+                        "__type": "TimeZoneDefinitionType:#Exchange",
+                        "Id": "Russian Standard Time",
                     },
                 },
             },
-            'Body': {
-                '__type': 'GetUserAvailabilityRequest:#Exchange',
-                'MailboxDataArray': [{
-                    '__type': 'MailboxData:#Exchange',
-                    'Email': {'__type': 'EmailAddress:#Exchange', 'Address': client.user_email},
-                    'AttendeeType': 'Required',
-                }],
-                'FreeBusyViewOptions': {
-                    '__type': 'FreeBusyViewOptions:#Exchange',
-                    'TimeWindow': {
-                        '__type': 'Duration:#Exchange',
-                        'StartTime': f'{current}T00:00:00',
-                        'EndTime': f'{chunk_end}T00:00:00',
+            "Body": {
+                "__type": "GetUserAvailabilityRequest:#Exchange",
+                "MailboxDataArray": [
+                    {
+                        "__type": "MailboxData:#Exchange",
+                        "Email": {
+                            "__type": "EmailAddress:#Exchange",
+                            "Address": client.user_email,
+                        },
+                        "AttendeeType": "Required",
+                    }
+                ],
+                "FreeBusyViewOptions": {
+                    "__type": "FreeBusyViewOptions:#Exchange",
+                    "TimeWindow": {
+                        "__type": "Duration:#Exchange",
+                        "StartTime": f"{current}T00:00:00",
+                        "EndTime": f"{chunk_end}T00:00:00",
                     },
-                    'MergedFreeBusyIntervalInMinutes': 30,
-                    'RequestedView': 'DetailedMerged',
+                    "MergedFreeBusyIntervalInMinutes": 30,
+                    "RequestedView": "DetailedMerged",
                 },
             },
         }
 
         try:
-            data = client.request('GetUserAvailability', payload)
-            body = data.get('Body', {})
-            for fb_resp in body.get('FreeBusyResponseArray', []):
-                fb_view = fb_resp.get('FreeBusyView', {})
-                cal_events = fb_view.get('CalendarEventArray', {})
+            data = client.request("GetUserAvailability", payload)
+            body = data.get("Body", {})
+            for fb_resp in body.get("FreeBusyResponseArray", []):
+                fb_view = fb_resp.get("FreeBusyView", {})
+                cal_events = fb_view.get("CalendarEventArray", {})
                 items = (
-                    cal_events.get('Items', [])
+                    cal_events.get("Items", [])
                     if isinstance(cal_events, dict)
                     else (cal_events if isinstance(cal_events, list) else [])
                 )
                 for event in items:
-                    bt = event.get('BusyType', '')
-                    details = event.get('CalendarEventDetails', {})
-                    subject = details.get('Subject', '') if details else ''
-                    location = details.get('Location', '') if details else ''
-                    is_meeting = details.get('IsMeeting', False) if details else False
-                    is_recurring = details.get('IsRecurring', False) if details else False
+                    bt = event.get("BusyType", "")
+                    details = event.get("CalendarEventDetails", {})
+                    subject = details.get("Subject", "") if details else ""
+                    location = details.get("Location", "") if details else ""
+                    is_meeting = details.get("IsMeeting", False) if details else False
+                    is_recurring = (
+                        details.get("IsRecurring", False) if details else False
+                    )
 
-                    expanded.append({
-                        'subject': subject or '(No subject)',
-                        'start': event.get('StartTime', ''),
-                        'end': event.get('EndTime', ''),
-                        'busy_type': bt,
-                        'location': location,
-                        'is_meeting': is_meeting,
-                        'is_recurring': is_recurring,
-                    })
+                    expanded.append(
+                        {
+                            "subject": subject or "(No subject)",
+                            "start": event.get("StartTime", ""),
+                            "end": event.get("EndTime", ""),
+                            "busy_type": bt,
+                            "location": location,
+                            "is_meeting": is_meeting,
+                            "is_recurring": is_recurring,
+                        }
+                    )
         except Exception:
             pass
 
         current = chunk_end
 
-    return sorted(expanded, key=lambda x: x.get('start', ''))
+    return sorted(expanded, key=lambda x: x.get("start", ""))
 
 
 @mcp.tool()
@@ -438,15 +447,17 @@ def get_calendar_events(
         )
         events = []
         for ev in expanded:
-            events.append({
-                "subject": ev['subject'],
-                "start": ev['start'],
-                "end": ev['end'],
-                "location": ev.get('location', ''),
-                "busy_type": ev.get('busy_type', ''),
-                "is_meeting": ev.get('is_meeting', False),
-                "is_recurring": ev.get('is_recurring', False),
-            })
+            events.append(
+                {
+                    "subject": ev["subject"],
+                    "start": ev["start"],
+                    "end": ev["end"],
+                    "location": ev.get("location", ""),
+                    "busy_type": ev.get("busy_type", ""),
+                    "is_meeting": ev.get("is_meeting", False),
+                    "is_recurring": ev.get("is_recurring", False),
+                }
+            )
         return json.dumps(events, ensure_ascii=False)
 
     # --- Default mode ---
@@ -476,9 +487,7 @@ def get_calendar_events(
                     "__type": "ItemResponseShape:#Exchange",
                     "BaseShape": "AllProperties",
                 },
-                "ParentFolderIds": [
-                    {"__type": "FolderId:#Exchange", "Id": folder_id}
-                ],
+                "ParentFolderIds": [{"__type": "FolderId:#Exchange", "Id": folder_id}],
                 "Traversal": "Shallow",
                 "CalendarView": {
                     "__type": "CalendarView:#Exchange",
@@ -722,12 +731,16 @@ def create_meeting(
                 ]
             return json.dumps(result, ensure_ascii=False)
         else:
-            return json.dumps({
-                "error": item.get("MessageText", "Unknown error"),
-                "response_code": item.get("ResponseCode", ""),
-            })
+            return json.dumps(
+                {
+                    "error": item.get("MessageText", "Unknown error"),
+                    "response_code": item.get("ResponseCode", ""),
+                }
+            )
 
-    return json.dumps({"success": True, "subject": subject, "note": "No confirmation details"})
+    return json.dumps(
+        {"success": True, "subject": subject, "note": "No confirmation details"}
+    )
 
 
 # ------------------------------------------------------------------
@@ -791,8 +804,12 @@ def update_meeting(
     orig_start_str = orig.get("start", "")
     orig_end_str = orig.get("end", "")
     try:
-        orig_start = datetime.fromisoformat(orig_start_str.replace("Z", "+00:00")).replace(tzinfo=None)
-        orig_end = datetime.fromisoformat(orig_end_str.replace("Z", "+00:00")).replace(tzinfo=None)
+        orig_start = datetime.fromisoformat(
+            orig_start_str.replace("Z", "+00:00")
+        ).replace(tzinfo=None)
+        orig_end = datetime.fromisoformat(orig_end_str.replace("Z", "+00:00")).replace(
+            tzinfo=None
+        )
         orig_duration = int((orig_end - orig_start).total_seconds() / 60)
     except (ValueError, AttributeError):
         orig_start = None
@@ -821,7 +838,9 @@ def update_meeting(
         new_start = orig_start
         new_end = orig_end
     else:
-        return json.dumps({"error": "Cannot determine meeting time. Provide date and start_time."})
+        return json.dumps(
+            {"error": "Cannot determine meeting time. Provide date and start_time."}
+        )
 
     new_location = location if location is not None else orig.get("location", "")
 
@@ -845,9 +864,7 @@ def update_meeting(
         },
         "Body": {
             "__type": "DeleteItemRequest:#Exchange",
-            "ItemIds": [
-                {"__type": "ItemId:#Exchange", "Id": item_id}
-            ],
+            "ItemIds": [{"__type": "ItemId:#Exchange", "Id": item_id}],
             "DeleteType": "MoveToDeletedItems",
             "SendMeetingCancellations": "SendToAllAndSaveCopy",
             "SuppressReadReceipts": True,
@@ -935,7 +952,9 @@ def update_meeting(
     try:
         data = client.request("CreateCalendarEvent", create_payload)
     except Exception as e:
-        return json.dumps({"error": f"Original cancelled but failed to create new: {e}"})
+        return json.dumps(
+            {"error": f"Original cancelled but failed to create new: {e}"}
+        )
 
     body = data.get("Body", {})
     if "ErrorCode" in body:
@@ -959,12 +978,16 @@ def update_meeting(
         return json.dumps(result, ensure_ascii=False)
 
     if resp_items:
-        return json.dumps({
-            "error": resp_items[0].get("MessageText", "Unknown error"),
-            "response_code": resp_items[0].get("ResponseCode", ""),
-        })
+        return json.dumps(
+            {
+                "error": resp_items[0].get("MessageText", "Unknown error"),
+                "response_code": resp_items[0].get("ResponseCode", ""),
+            }
+        )
 
-    return json.dumps({"success": True, "subject": new_subject, "note": "No confirmation details"})
+    return json.dumps(
+        {"success": True, "subject": new_subject, "note": "No confirmation details"}
+    )
 
 
 # ------------------------------------------------------------------
@@ -997,9 +1020,7 @@ def cancel_meeting(
         },
         "Body": {
             "__type": "DeleteItemRequest:#Exchange",
-            "ItemIds": [
-                {"__type": "ItemId:#Exchange", "Id": item_id}
-            ],
+            "ItemIds": [{"__type": "ItemId:#Exchange", "Id": item_id}],
             "DeleteType": "MoveToDeletedItems",
             "SendMeetingCancellations": "SendToAllAndSaveCopy",
             "SuppressReadReceipts": True,
@@ -1014,10 +1035,12 @@ def cancel_meeting(
         if item.get("ResponseClass") == "Success":
             return json.dumps({"success": True, "message": "Meeting cancelled"})
         else:
-            return json.dumps({
-                "error": item.get("MessageText", "Unknown error"),
-                "response_code": item.get("ResponseCode", ""),
-            })
+            return json.dumps(
+                {
+                    "error": item.get("MessageText", "Unknown error"),
+                    "response_code": item.get("ResponseCode", ""),
+                }
+            )
 
     # DeleteItem may return empty on success
     body = data.get("Body", {})
@@ -1060,9 +1083,11 @@ def respond_to_meeting(
 
     response_type = response_types.get(response)
     if not response_type:
-        return json.dumps({
-            "error": f"Invalid response: {response}. Must be Accept, Decline, or Tentative."
-        })
+        return json.dumps(
+            {
+                "error": f"Invalid response: {response}. Must be Accept, Decline, or Tentative."
+            }
+        )
 
     response_item = {
         "__type": response_type,
@@ -1098,16 +1123,20 @@ def respond_to_meeting(
     if items:
         item = items[0]
         if item.get("ResponseClass") == "Success":
-            return json.dumps({
-                "success": True,
-                "response": response,
-                "message": f"Meeting {response.lower()}ed",
-            })
+            return json.dumps(
+                {
+                    "success": True,
+                    "response": response,
+                    "message": f"Meeting {response.lower()}ed",
+                }
+            )
         else:
-            return json.dumps({
-                "error": item.get("MessageText", "Unknown error"),
-                "response_code": item.get("ResponseCode", ""),
-            })
+            return json.dumps(
+                {
+                    "error": item.get("MessageText", "Unknown error"),
+                    "response_code": item.get("ResponseCode", ""),
+                }
+            )
 
     return json.dumps({"error": "No response from server"})
 
@@ -1147,9 +1176,7 @@ def download_event_attachments(
                     "__type": "ItemResponseShape:#Exchange",
                     "BaseShape": "AllProperties",
                 },
-                "ItemIds": [
-                    {"__type": "ItemId:#Exchange", "Id": item_id}
-                ],
+                "ItemIds": [{"__type": "ItemId:#Exchange", "Id": item_id}],
             },
         }
 
@@ -1162,28 +1189,43 @@ def download_event_attachments(
                 continue
             for item in msg["Items"]:
                 for att in item.get("Attachments", []):
-                    attachments.append({
-                        "name": att.get("Name", ""),
-                        "size": att.get("Size", 0),
-                        "content_type": att.get("ContentType", ""),
-                        "attachment_id": att.get("AttachmentId", {}).get("Id", ""),
-                        "is_inline": att.get("IsInline", False),
-                    })
+                    attachments.append(
+                        {
+                            "name": att.get("Name", ""),
+                            "size": att.get("Size", 0),
+                            "content_type": att.get("ContentType", ""),
+                            "attachment_id": att.get("AttachmentId", {}).get("Id", ""),
+                            "is_inline": att.get("IsInline", False),
+                        }
+                    )
                 break
 
         if not attachments:
-            return json.dumps({"success": True, "downloaded": [], "count": 0,
-                               "message": "No attachments found on this event."})
+            return json.dumps(
+                {
+                    "success": True,
+                    "downloaded": [],
+                    "count": 0,
+                    "message": "No attachments found on this event.",
+                }
+            )
 
         # Filter to non-inline file attachments
         file_attachments = [
-            a for a in attachments
+            a
+            for a in attachments
             if a.get("attachment_id") and not a.get("is_inline", False)
         ]
 
         if not file_attachments:
-            return json.dumps({"success": True, "downloaded": [], "count": 0,
-                               "message": "No downloadable file attachments."})
+            return json.dumps(
+                {
+                    "success": True,
+                    "downloaded": [],
+                    "count": 0,
+                    "message": "No downloadable file attachments.",
+                }
+            )
 
         os.makedirs(target_folder, exist_ok=True)
 
@@ -1223,17 +1265,21 @@ def download_event_attachments(
                 with open(filepath, "wb") as f:
                     f.write(content)
 
-                downloaded.append({
-                    "name": filename,
-                    "path": filepath,
-                    "size": len(content),
-                    "content_type": content_type,
-                })
+                downloaded.append(
+                    {
+                        "name": filename,
+                        "path": filepath,
+                        "size": len(content),
+                        "content_type": content_type,
+                    }
+                )
             except Exception as e:
-                errors.append({
-                    "name": att.get("name", "unknown"),
-                    "error": str(e),
-                })
+                errors.append(
+                    {
+                        "name": att.get("name", "unknown"),
+                        "error": str(e),
+                    }
+                )
 
         result = {
             "success": len(errors) == 0,
@@ -1308,12 +1354,14 @@ def get_event_links(
                 links = extract_links_from_html(body_val)
                 break
 
-        return json.dumps({
-            "item_id": item_id,
-            "subject": subject,
-            "links": links,
-            "count": len(links),
-        })
+        return json.dumps(
+            {
+                "item_id": item_id,
+                "subject": subject,
+                "links": links,
+                "count": len(links),
+            }
+        )
 
     except Exception as e:
         return json.dumps({"error": f"Failed to extract event links: {e}"})
diff --git a/owa_mcp/tools/email.py b/owa_mcp/tools/email.py
index 681fa03..a7e437c 100644
--- a/owa_mcp/tools/email.py
+++ b/owa_mcp/tools/email.py
@@ -8,10 +8,10 @@ import json
 
 from mcp.server.fastmcp import Context
 
-from owa_mcp.server import mcp, AppContext
 from owa_mcp.owa_client import OWAClient, SessionExpiredError
+from owa_mcp.server import AppContext, mcp
 from owa_mcp.server_lifecycle import require_client
-from owa_mcp.utils import html_to_text, extract_links_from_html
+from owa_mcp.utils import extract_links_from_html, html_to_text
 
 
 def _get_client(ctx: Context) -> OWAClient:
@@ -215,7 +215,12 @@ def _get_item_details(client: OWAClient, item_id: str) -> dict:
             item_type = item.get("__type", "")
             if any(
                 t in item_type
-                for t in ("MeetingRequest", "MeetingResponse", "MeetingCancellation", "CalendarItem")
+                for t in (
+                    "MeetingRequest",
+                    "MeetingResponse",
+                    "MeetingCancellation",
+                    "CalendarItem",
+                )
             ):
                 result["location"] = item.get(
                     "Location",
@@ -331,9 +336,7 @@ def get_emails(
         find_body = {
             "__type": "FindItemRequest:#Exchange",
             "ItemShape": item_shape,
-            "ParentFolderIds": [
-                {"__type": "FolderId:#Exchange", "Id": folder_id}
-            ],
+            "ParentFolderIds": [{"__type": "FolderId:#Exchange", "Id": folder_id}],
             "Traversal": "Shallow",
             "Paging": {
                 "__type": "IndexedPageView:#Exchange",
@@ -392,18 +395,19 @@ def get_emails(
 
         if not items:
             return json.dumps(
-                {"item_ids": [], "count": 0} if ids_only
-                else {"emails": [], "count": 0}
+                {"item_ids": [], "count": 0} if ids_only else {"emails": [], "count": 0}
             )
 
         if ids_only:
             result = []
             for item in items:
-                result.append({
-                    "item_id": item.get("ItemId", {}).get("Id", ""),
-                    "date": item.get("DateTimeReceived", ""),
-                    "subject": item.get("Subject", ""),
-                })
+                result.append(
+                    {
+                        "item_id": item.get("ItemId", {}).get("Id", ""),
+                        "date": item.get("DateTimeReceived", ""),
+                        "subject": item.get("Subject", ""),
+                    }
+                )
             return json.dumps({"item_ids": result, "count": len(result)})
 
         emails = []
@@ -763,9 +767,7 @@ def move_email(
         if not folder_id:
             return json.dumps({"error": f"Folder '{target_folder}' not found."})
 
-        items = [
-            {"__type": "ItemId:#Exchange", "Id": iid} for iid in item_ids
-        ]
+        items = [{"__type": "ItemId:#Exchange", "Id": iid} for iid in item_ids]
 
         payload = {
             "__type": "MoveItemJsonRequest:#Exchange",
@@ -824,9 +826,7 @@ def delete_email(
     try:
         client = _get_client(ctx)
 
-        items = [
-            {"__type": "ItemId:#Exchange", "Id": iid} for iid in item_ids
-        ]
+        items = [{"__type": "ItemId:#Exchange", "Id": iid} for iid in item_ids]
 
         payload = {
             "__type": "DeleteItemJsonRequest:#Exchange",
@@ -887,18 +887,31 @@ def download_attachments(
         attachments = details.get("attachments", [])
 
         if not attachments:
-            return json.dumps({"success": True, "downloaded": [], "count": 0,
-                               "message": "No attachments found."})
+            return json.dumps(
+                {
+                    "success": True,
+                    "downloaded": [],
+                    "count": 0,
+                    "message": "No attachments found.",
+                }
+            )
 
         # Filter to non-inline file attachments with IDs
         file_attachments = [
-            a for a in attachments
+            a
+            for a in attachments
             if a.get("attachment_id") and not a.get("is_inline", False)
         ]
 
         if not file_attachments:
-            return json.dumps({"success": True, "downloaded": [], "count": 0,
-                               "message": "No downloadable file attachments."})
+            return json.dumps(
+                {
+                    "success": True,
+                    "downloaded": [],
+                    "count": 0,
+                    "message": "No downloadable file attachments.",
+                }
+            )
 
         os.makedirs(target_folder, exist_ok=True)
 
@@ -938,17 +951,21 @@ def download_attachments(
                 with open(filepath, "wb") as f:
                     f.write(content)
 
-                downloaded.append({
-                    "name": filename,
-                    "path": filepath,
-                    "size": len(content),
-                    "content_type": content_type,
-                })
+                downloaded.append(
+                    {
+                        "name": filename,
+                        "path": filepath,
+                        "size": len(content),
+                        "content_type": content_type,
+                    }
+                )
             except Exception as e:
-                errors.append({
-                    "name": att.get("name", "unknown"),
-                    "error": str(e),
-                })
+                errors.append(
+                    {
+                        "name": att.get("name", "unknown"),
+                        "error": str(e),
+                    }
+                )
 
         result = {
             "success": len(errors) == 0,
@@ -1021,12 +1038,14 @@ def get_email_links(
                 links = extract_links_from_html(body_val)
                 break
 
-        return json.dumps({
-            "item_id": item_id,
-            "subject": subject,
-            "links": links,
-            "count": len(links),
-        })
+        return json.dumps(
+            {
+                "item_id": item_id,
+                "subject": subject,
+                "links": links,
+                "count": len(links),
+            }
+        )
 
     except SessionExpiredError as e:
         return json.dumps({"error": str(e)})
@@ -1107,16 +1126,22 @@ async def search_emails(
 
     max_results = max(1, min(max_results, 100))
     if search_scope not in ("all", "subject", "body", "from"):
-        return json.dumps({"error": f"invalid search_scope: {search_scope}", "results": []})
+        return json.dumps(
+            {"error": f"invalid search_scope: {search_scope}", "results": []}
+        )
 
     restriction = _build_search_restriction(query.strip(), search_scope)
     if restriction is None:
-        return json.dumps({"error": f"unsupported search_scope: {search_scope}", "results": []})
+        return json.dumps(
+            {"error": f"unsupported search_scope: {search_scope}", "results": []}
+        )
 
     if folder_id:
         parent_folder = [{"__type": "FolderId:#Exchange", "Id": folder_id}]
     else:
-        parent_folder = [{"__type": "DistinguishedFolderId:#Exchange", "Id": "msgfolderroot"}]
+        parent_folder = [
+            {"__type": "DistinguishedFolderId:#Exchange", "Id": "msgfolderroot"}
+        ]
 
     payload = {
         "__type": "FindItemJsonRequest:#Exchange",
@@ -1153,6 +1178,7 @@ async def search_emails(
                 body_type = item.get("Body", {}).get("BodyType", "HTML")
                 if body_type == "HTML" and body_html:
                     import re
+
                     body_preview = re.sub(r"<[^>]+>", " ", body_html)
                     body_preview = " ".join(body_preview.split())[:200]
                 else:
@@ -1163,13 +1189,16 @@ async def search_emails(
             if len(results) >= max_results:
                 break
 
-        return json.dumps({
-            "query": query.strip(),
-            "search_scope": search_scope,
-            "folder_id": folder_id or "all",
-            "total_results": len(results),
-            "results": results,
-        }, ensure_ascii=False)
+        return json.dumps(
+            {
+                "query": query.strip(),
+                "search_scope": search_scope,
+                "folder_id": folder_id or "all",
+                "total_results": len(results),
+                "results": results,
+            },
+            ensure_ascii=False,
+        )
     except SessionExpiredError as e:
         return json.dumps({"error": str(e)})
     except Exception as e:
diff --git a/owa_mcp/tools/folders.py b/owa_mcp/tools/folders.py
index 6ff7603..9ce08a5 100644
--- a/owa_mcp/tools/folders.py
+++ b/owa_mcp/tools/folders.py
@@ -7,15 +7,24 @@ import json
 
 from mcp.server.fastmcp import Context
 
-from owa_mcp.server import mcp, AppContext
 from owa_mcp.owa_client import OWAClient
+from owa_mcp.server import AppContext, mcp
 from owa_mcp.server_lifecycle import require_client
 
-
 _DISTINGUISHED_NAMES = {
-    "msgfolderroot", "inbox", "sentitems", "drafts", "deleteditems",
-    "junkemail", "outbox", "calendar", "contacts", "tasks", "notes",
-    "journal", "searchfolders",
+    "msgfolderroot",
+    "inbox",
+    "sentitems",
+    "drafts",
+    "deleteditems",
+    "junkemail",
+    "outbox",
+    "calendar",
+    "contacts",
+    "tasks",
+    "notes",
+    "journal",
+    "searchfolders",
 }
 
 _HEADER_TZ = {
@@ -68,36 +77,40 @@ def check_session(ctx: Context = None) -> str:
                 "__type": "FolderResponseShape:#Exchange",
                 "BaseShape": "Default",
             },
-            "FolderIds": [
-                {"__type": "DistinguishedFolderId:#Exchange", "Id": "inbox"}
-            ],
+            "FolderIds": [{"__type": "DistinguishedFolderId:#Exchange", "Id": "inbox"}],
         },
     }
 
     try:
         data = client.request("GetFolder", payload)
     except Exception as e:
-        return json.dumps({
-            "authenticated": False,
-            "error": str(e),
-            "cookie_file": str(client.cookie_file),
-        })
+        return json.dumps(
+            {
+                "authenticated": False,
+                "error": str(e),
+                "cookie_file": str(client.cookie_file),
+            }
+        )
 
     for msg in client.extract_items(data):
         if "Folders" in msg:
             folder = msg["Folders"][0]
-            return json.dumps({
-                "authenticated": True,
-                "mailbox": folder.get("DisplayName", ""),
-                "unread": folder.get("UnreadCount", 0),
-                "cookie_file": str(client.cookie_file),
-            })
+            return json.dumps(
+                {
+                    "authenticated": True,
+                    "mailbox": folder.get("DisplayName", ""),
+                    "unread": folder.get("UnreadCount", 0),
+                    "cookie_file": str(client.cookie_file),
+                }
+            )
 
-    return json.dumps({
-        "authenticated": False,
-        "error": "Unexpected response",
-        "cookie_file": str(client.cookie_file),
-    })
+    return json.dumps(
+        {
+            "authenticated": False,
+            "error": "Unexpected response",
+            "cookie_file": str(client.cookie_file),
+        }
+    )
 
 
 @mcp.tool()
@@ -159,13 +172,15 @@ def get_folders(
     for msg in client.extract_items(data):
         if "RootFolder" in msg and "Folders" in msg["RootFolder"]:
             for f in msg["RootFolder"]["Folders"]:
-                folders.append({
-                    "name": f.get("DisplayName", "Unknown"),
-                    "id": f.get("FolderId", {}).get("Id", ""),
-                    "total_count": f.get("TotalCount", 0),
-                    "unread_count": f.get("UnreadCount", 0),
-                    "child_folder_count": f.get("ChildFolderCount", 0),
-                })
+                folders.append(
+                    {
+                        "name": f.get("DisplayName", "Unknown"),
+                        "id": f.get("FolderId", {}).get("Id", ""),
+                        "total_count": f.get("TotalCount", 0),
+                        "unread_count": f.get("UnreadCount", 0),
+                        "child_folder_count": f.get("ChildFolderCount", 0),
+                    }
+                )
 
     return json.dumps(folders, ensure_ascii=False)
 
@@ -216,11 +231,13 @@ def create_folder(
     for msg in client.extract_items(data):
         if "Folders" in msg:
             folder = msg["Folders"][0]
-            return json.dumps({
-                "success": True,
-                "name": name,
-                "id": folder.get("FolderId", {}).get("Id", ""),
-            })
+            return json.dumps(
+                {
+                    "success": True,
+                    "name": name,
+                    "id": folder.get("FolderId", {}).get("Id", ""),
+                }
+            )
 
     return json.dumps({"error": "Unexpected response", "raw": str(data)})
 
@@ -280,11 +297,13 @@ def rename_folder(
     for msg in client.extract_items(data):
         if "Folders" in msg:
             folder = msg["Folders"][0]
-            return json.dumps({
-                "success": True,
-                "new_name": new_name,
-                "id": folder.get("FolderId", {}).get("Id", ""),
-            })
+            return json.dumps(
+                {
+                    "success": True,
+                    "new_name": new_name,
+                    "id": folder.get("FolderId", {}).get("Id", ""),
+                }
+            )
 
     return json.dumps({"error": "Unexpected response", "raw": str(data)})
 
@@ -316,9 +335,7 @@ def empty_folder(
         "Header": _HEADER_TZ,
         "Body": {
             "__type": "EmptyFolderRequest:#Exchange",
-            "FolderIds": [
-                {"__type": "FolderId:#Exchange", "Id": folder_id}
-            ],
+            "FolderIds": [{"__type": "FolderId:#Exchange", "Id": folder_id}],
             "DeleteType": delete_type,
             "DeleteSubFolders": delete_sub_folders,
             "SuppressReadReceipt": True,
@@ -362,9 +379,7 @@ def delete_folder(
         "Header": _HEADER_TZ,
         "Body": {
             "__type": "DeleteFolderRequest:#Exchange",
-            "FolderIds": [
-                {"__type": "FolderId:#Exchange", "Id": folder_id}
-            ],
+            "FolderIds": [{"__type": "FolderId:#Exchange", "Id": folder_id}],
             "DeleteType": delete_type,
         },
     }
@@ -405,9 +420,7 @@ def move_folder(
         "Header": _HEADER_TZ,
         "Body": {
             "__type": "MoveFolderRequest:#Exchange",
-            "FolderIds": [
-                {"__type": "FolderId:#Exchange", "Id": folder_id}
-            ],
+            "FolderIds": [{"__type": "FolderId:#Exchange", "Id": folder_id}],
             "ToFolderId": {
                 "__type": "TargetFolderId:#Exchange",
                 "BaseFolderId": _folder_id_dict(target_parent_folder_id),
@@ -423,9 +436,11 @@ def move_folder(
     for msg in client.extract_items(data):
         if "Folders" in msg:
             folder = msg["Folders"][0]
-            return json.dumps({
-                "success": True,
-                "folder_id": folder.get("FolderId", {}).get("Id", ""),
-            })
+            return json.dumps(
+                {
+                    "success": True,
+                    "folder_id": folder.get("FolderId", {}).get("Id", ""),
+                }
+            )
 
     return json.dumps({"error": "Unexpected response", "raw": str(data)})
diff --git a/owa_mcp/tools/people.py b/owa_mcp/tools/people.py
index 88a7db8..df6f449 100644
--- a/owa_mcp/tools/people.py
+++ b/owa_mcp/tools/people.py
@@ -7,8 +7,8 @@ import json
 
 from mcp.server.fastmcp import Context
 
-from owa_mcp.server import mcp, AppContext
 from owa_mcp.owa_client import OWAClient
+from owa_mcp.server import AppContext, mcp
 from owa_mcp.server_lifecycle import require_client
 
 
@@ -82,10 +82,12 @@ def _parse_person(resolution: dict) -> dict:
 
     # Direct reports
     for report in contact.get("DirectReports", []):
-        person["direct_reports"].append({
-            "name": report.get("Name", ""),
-            "email": report.get("EmailAddress", ""),
-        })
+        person["direct_reports"].append(
+            {
+                "name": report.get("Name", ""),
+                "email": report.get("EmailAddress", ""),
+            }
+        )
 
     return person
 
diff --git a/owa_mcp/utils.py b/owa_mcp/utils.py
index 8f8f996..ddcff53 100644
--- a/owa_mcp/utils.py
+++ b/owa_mcp/utils.py
@@ -20,9 +20,7 @@ def html_to_text(html_content: str) -> str:
     text = re.sub(
         r"<script[^>]*>.*?</script>", "", html_content, flags=re.DOTALL | re.IGNORECASE
     )
-    text = re.sub(
-        r"<style[^>]*>.*?</style>", "", text, flags=re.DOTALL | re.IGNORECASE
-    )
+    text = re.sub(r"<style[^>]*>.*?</style>", "", text, flags=re.DOTALL | re.IGNORECASE)
     text = re.sub(r"<br\s*/?>", "\n", text, flags=re.IGNORECASE)
     text = re.sub(r"<p[^>]*>", "\n", text, flags=re.IGNORECASE)
     text = re.sub(r"</p>", "\n", text, flags=re.IGNORECASE)
diff --git a/pyproject.toml b/pyproject.toml
index 205b3b4..a69a537 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -32,3 +32,11 @@ build-backend = "setuptools.build_meta"
 [tool.setuptools.packages.find]
 where = ["."]
 include = ["owa_mcp*"]
+
+[tool.ruff]
+line-length = 88
+target-version = "py310"
+
+[tool.ruff.lint]
+select = ["E", "F", "W", "I", "UP"]
+ignore = ["E501"]