diff --git a/src/javis/__main__.py b/src/javis/__main__.py
new file mode 100644
index 0000000..cd79e2b
--- /dev/null
+++ b/src/javis/__main__.py
@@ -0,0 +1,5 @@
+"""Allow ``python -m javis`` to invoke the CLI."""
+
+from javis.interface.cli import main
+
+raise SystemExit(main())
diff --git a/src/javis/config/settings.py b/src/javis/config/settings.py
new file mode 100644
index 0000000..cf31186
--- /dev/null
+++ b/src/javis/config/settings.py
@@ -0,0 +1,96 @@
+"""Central runtime configuration for the local Javis chat."""
+
+from __future__ import annotations
+
+import os
+from collections.abc import Mapping
+from dataclasses import dataclass
+from pathlib import Path
+from urllib.parse import urlparse
+
+
+class ConfigurationError(ValueError):
+    """Raised when runtime configuration is unsafe or invalid."""
+
+
+def default_data_dir(
+    environ: Mapping[str, str] | None = None,
+    *,
+    platform_name: str | None = None,
+    home: Path | None = None,
+) -> Path:
+    """Return a platform-appropriate user data directory."""
+    values = os.environ if environ is None else environ
+    platform = os.name if platform_name is None else platform_name
+    user_home = Path.home() if home is None else home
+
+    if platform == "nt":
+        base = Path(values.get("LOCALAPPDATA", user_home / "AppData" / "Local"))
+        return base / "Javis"
+
+    xdg_data_home = values.get("XDG_DATA_HOME")
+    base = Path(xdg_data_home) if xdg_data_home else user_home / ".local" / "share"
+    return base / "javis"
+
+
+@dataclass(frozen=True, slots=True)
+class Settings:
+    """Validated settings shared by CLI, provider, and storage."""
+
+    data_dir: Path
+    provider: str = "ollama"
+    model: str = "qwen3:8b"
+    ollama_base_url: str = "http://127.0.0.1:11434"
+    timeout_seconds: float = 180.0
+
+    @property
+    def database_path(self) -> Path:
+        return self.data_dir / "sessions.sqlite3"
+
+    @classmethod
+    def from_env(cls, environ: Mapping[str, str] | None = None) -> Settings:
+        values = os.environ if environ is None else environ
+        configured_dir = values.get("JAVIS_DATA_DIR")
+        data_dir = Path(configured_dir).expanduser() if configured_dir else default_data_dir(values)
+        if not data_dir.is_absolute():
+            raise ConfigurationError("JAVIS_DATA_DIR muss ein absoluter Pfad sein.")
+
+        provider = values.get("JAVIS_PROVIDER", "ollama").strip()
+        model = values.get("JAVIS_MODEL", "qwen3:8b").strip()
+        base_url = values.get("JAVIS_OLLAMA_URL", "http://127.0.0.1:11434").strip()
+        timeout_raw = values.get("JAVIS_MODEL_TIMEOUT", "180")
+
+        try:
+            timeout = float(timeout_raw)
+        except ValueError as exc:
+            raise ConfigurationError("JAVIS_MODEL_TIMEOUT muss eine Zahl sein.") from exc
+
+        settings = cls(
+            data_dir=data_dir.resolve(),
+            provider=provider,
+            model=model,
+            ollama_base_url=base_url,
+            timeout_seconds=timeout,
+        )
+        settings.validate()
+        return settings
+
+    def validate(self) -> None:
+        if self.provider != "ollama":
+            raise ConfigurationError(
+                "Unbekannter Provider. In dieser Phase wird nur 'ollama' unterstützt."
+            )
+        if not self.model:
+            raise ConfigurationError("JAVIS_MODEL darf nicht leer sein.")
+        if self.timeout_seconds <= 0:
+            raise ConfigurationError("JAVIS_MODEL_TIMEOUT muss größer als 0 sein.")
+
+        parsed = urlparse(self.ollama_base_url)
+        if parsed.scheme != "http" or parsed.hostname not in {
+            "127.0.0.1",
+            "::1",
+            "localhost",
+        }:
+            raise ConfigurationError("JAVIS_OLLAMA_URL muss eine lokale HTTP-Adresse sein.")
+        if parsed.username or parsed.password or parsed.query or parsed.fragment:
+            raise ConfigurationError("JAVIS_OLLAMA_URL enthält unzulässige Bestandteile.")
diff --git a/src/javis/core/chat_service.py b/src/javis/core/chat_service.py
new file mode 100644
index 0000000..094db1b
--- /dev/null
+++ b/src/javis/core/chat_service.py
@@ -0,0 +1,57 @@
+"""Chat orchestration without interface or provider-specific details."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+from javis.memory.sqlite_store import ChatSession, SQLiteSessionStore
+from javis.providers.base import ChatMessage, LocalModelProvider
+
+
+class SessionProviderMismatchError(RuntimeError):
+    """The active provider cannot safely continue the stored session."""
+
+
+@dataclass(frozen=True, slots=True)
+class LoadedSession:
+    session: ChatSession
+    messages: list[ChatMessage]
+
+
+class ChatService:
+    def __init__(
+        self,
+        store: SQLiteSessionStore,
+        provider: LocalModelProvider,
+    ) -> None:
+        self.store = store
+        self.provider = provider
+
+    def new_session(self) -> ChatSession:
+        return self.store.create_session(self.provider.name, self.provider.model)
+
+    def list_sessions(self) -> list[ChatSession]:
+        return self.store.list_sessions()
+
+    def load_session(self, session_id: str) -> LoadedSession:
+        session = self.store.get_session(session_id)
+        if session.provider != self.provider.name or session.model != self.provider.model:
+            raise SessionProviderMismatchError(
+                "Die Sitzung verwendet "
+                f"{session.provider}/{session.model}, aktiv ist "
+                f"{self.provider.name}/{self.provider.model}."
+            )
+        return LoadedSession(session, self.store.get_messages(session_id))
+
+    def send(self, session_id: str, text: str) -> str:
+        normalized = text.strip()
+        if not normalized:
+            raise ValueError("Eine leere Nachricht wird nicht gesendet.")
+        loaded = self.load_session(session_id)
+        messages = [*loaded.messages, ChatMessage("user", normalized)]
+        response = self.provider.chat(messages)
+        self.store.append_exchange(session_id, normalized, response)
+        return response
+
+    def clear_session(self, session_id: str) -> None:
+        self.store.clear_messages(session_id)
diff --git a/src/javis/interface/cli.py b/src/javis/interface/cli.py
new file mode 100644
index 0000000..8debf4f
--- /dev/null
+++ b/src/javis/interface/cli.py
@@ -0,0 +1,182 @@
+"""Command-line interface for the first local Javis text chat."""
+
+from __future__ import annotations
+
+import argparse
+import sys
+from collections.abc import Callable, Sequence
+
+from javis.config.settings import ConfigurationError, Settings
+from javis.core.chat_service import ChatService, SessionProviderMismatchError
+from javis.memory.sqlite_store import (
+    ChatSession,
+    SessionNotFoundError,
+    SessionStoreError,
+    SQLiteSessionStore,
+)
+from javis.providers.base import ProviderError
+from javis.providers.ollama import OllamaProvider
+
+InputFunction = Callable[[str], str]
+OutputFunction = Callable[[str], None]
+
+HELP_TEXT = """Befehle:
+  /new              neue Sitzung beginnen
+  /sessions         gespeicherte Sitzungen auflisten
+  /load <ID>        frühere Sitzung laden und fortsetzen
+  /clear            Nachrichten der aktiven Sitzung leeren
+  /help             diese Hilfe anzeigen
+  /exit             Chat ordentlich beenden"""
+
+
+def build_parser() -> argparse.ArgumentParser:
+    parser = argparse.ArgumentParser(prog="javis", description="Lokaler Javis-Textchat")
+    subparsers = parser.add_subparsers(dest="command", required=True)
+    chat_parser = subparsers.add_parser("chat", help="lokalen Textchat starten")
+    chat_parser.add_argument("--session", help="vorhandene Sitzungs-ID laden")
+    return parser
+
+
+def _show_history(service: ChatService, session_id: str, output: OutputFunction) -> None:
+    loaded = service.load_session(session_id)
+    if not loaded.messages:
+        output("(Sitzung enthält noch keine Nachrichten.)")
+        return
+    for message in loaded.messages:
+        label = "Du" if message.role == "user" else "Javis"
+        output(f"{label}: {message.content}")
+
+
+def _show_sessions(sessions: list[ChatSession], output: OutputFunction) -> None:
+    if not sessions:
+        output("Keine gespeicherten Sitzungen vorhanden.")
+        return
+    for session in sessions:
+        output(
+            f"{session.id} | {session.updated_at} | "
+            f"{session.provider}/{session.model} | {session.message_count} Nachrichten"
+        )
+
+
+def run_chat(
+    service: ChatService,
+    *,
+    session_id: str | None = None,
+    input_fn: InputFunction = input,
+    output: OutputFunction = print,
+) -> int:
+    try:
+        if session_id:
+            active_id = service.load_session(session_id).session.id
+            output(f"Sitzung geladen: {active_id}")
+            _show_history(service, active_id, output)
+        else:
+            active_id = service.new_session().id
+            output(f"Neue Sitzung: {active_id}")
+    except (
+        SessionNotFoundError,
+        SessionProviderMismatchError,
+        SessionStoreError,
+    ) as exc:
+        output(f"Fehler: {exc}")
+        return 2
+
+    output("Lokaler Javis-Chat. /help zeigt die Befehle.")
+
+    while True:
+        try:
+            entered = input_fn("Du> ").strip()
+        except (EOFError, KeyboardInterrupt):
+            output("\nChat beendet.")
+            return 0
+
+        if not entered:
+            continue
+        if entered == "/exit":
+            output("Chat beendet.")
+            return 0
+        if entered == "/help":
+            output(HELP_TEXT)
+            continue
+        if entered == "/new":
+            try:
+                active_id = service.new_session().id
+                output(f"Neue Sitzung: {active_id}")
+            except SessionStoreError as exc:
+                output(f"Fehler: {exc}")
+            continue
+        if entered == "/sessions":
+            try:
+                _show_sessions(service.list_sessions(), output)
+            except SessionStoreError as exc:
+                output(f"Fehler: {exc}")
+            continue
+        if entered == "/clear":
+            try:
+                service.clear_session(active_id)
+                output("Aktive Sitzung wurde geleert.")
+            except (SessionNotFoundError, SessionStoreError) as exc:
+                output(f"Fehler: {exc}")
+            continue
+        if entered.startswith("/load"):
+            parts = entered.split(maxsplit=1)
+            if len(parts) != 2 or not parts[1].strip():
+                output("Verwendung: /load <Sitzungs-ID>")
+                continue
+            try:
+                loaded = service.load_session(parts[1].strip())
+                active_id = loaded.session.id
+                output(f"Sitzung geladen: {active_id}")
+                _show_history(service, active_id, output)
+            except (
+                SessionNotFoundError,
+                SessionProviderMismatchError,
+                SessionStoreError,
+            ) as exc:
+                output(f"Fehler: {exc}")
+            continue
+        if entered.startswith("/"):
+            output("Unbekannter Befehl. /help zeigt die verfügbaren Befehle.")
+            continue
+
+        try:
+            response = service.send(active_id, entered)
+            output(f"Javis: {response}")
+        except (ProviderError, SessionStoreError, SessionProviderMismatchError) as exc:
+            output(f"Fehler: {exc}")
+        except ValueError as exc:
+            output(f"Fehler: {exc}")
+
+
+def main(
+    argv: Sequence[str] | None = None,
+    *,
+    input_fn: InputFunction = input,
+    output: OutputFunction = print,
+) -> int:
+    args = build_parser().parse_args(argv)
+    if args.command != "chat":
+        return 2
+
+    try:
+        settings = Settings.from_env()
+        store = SQLiteSessionStore(settings.database_path)
+        provider = OllamaProvider(
+            settings.model,
+            settings.ollama_base_url,
+            settings.timeout_seconds,
+        )
+    except (ConfigurationError, SessionStoreError) as exc:
+        output(f"Konfigurationsfehler: {exc}")
+        return 2
+
+    return run_chat(
+        ChatService(store, provider),
+        session_id=args.session,
+        input_fn=input_fn,
+        output=output,
+    )
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/src/javis/memory/sqlite_store.py b/src/javis/memory/sqlite_store.py
new file mode 100644
index 0000000..c0bc173
--- /dev/null
+++ b/src/javis/memory/sqlite_store.py
@@ -0,0 +1,236 @@
+"""SQLite persistence for local chat sessions."""
+
+from __future__ import annotations
+
+import sqlite3
+import uuid
+from collections.abc import Iterator
+from contextlib import contextmanager
+from dataclasses import dataclass
+from datetime import UTC, datetime
+from pathlib import Path
+
+from javis.providers.base import ChatMessage
+
+
+class SessionStoreError(RuntimeError):
+    """Base class for expected persistence failures."""
+
+
+class SessionNotFoundError(SessionStoreError):
+    """A requested session ID does not exist."""
+
+
+@dataclass(frozen=True, slots=True)
+class ChatSession:
+    id: str
+    created_at: str
+    updated_at: str
+    provider: str
+    model: str
+    message_count: int = 0
+
+
+def _utc_now() -> str:
+    return datetime.now(UTC).isoformat(timespec="seconds")
+
+
+class SQLiteSessionStore:
+    def __init__(self, database_path: Path) -> None:
+        self.database_path = database_path
+        try:
+            self.database_path.parent.mkdir(parents=True, exist_ok=True)
+            self._initialize()
+        except (OSError, sqlite3.Error) as exc:
+            raise SessionStoreError(
+                f"Die Sitzungsdatenbank kann nicht geöffnet werden: {database_path}"
+            ) from exc
+
+    def _connect(self) -> sqlite3.Connection:
+        connection = sqlite3.connect(self.database_path, timeout=10)
+        connection.row_factory = sqlite3.Row
+        connection.execute("PRAGMA foreign_keys = ON")
+        return connection
+
+    @contextmanager
+    def _connection(self) -> Iterator[sqlite3.Connection]:
+        connection = self._connect()
+        try:
+            with connection:
+                yield connection
+        finally:
+            connection.close()
+
+    def _initialize(self) -> None:
+        with self._connection() as connection:
+            connection.executescript(
+                """
+                CREATE TABLE IF NOT EXISTS sessions (
+                    id TEXT PRIMARY KEY,
+                    created_at TEXT NOT NULL,
+                    updated_at TEXT NOT NULL,
+                    provider TEXT NOT NULL,
+                    model TEXT NOT NULL
+                );
+
+                CREATE TABLE IF NOT EXISTS messages (
+                    id INTEGER PRIMARY KEY AUTOINCREMENT,
+                    session_id TEXT NOT NULL,
+                    position INTEGER NOT NULL,
+                    role TEXT NOT NULL CHECK (role IN ('user', 'assistant')),
+                    content TEXT NOT NULL,
+                    created_at TEXT NOT NULL,
+                    FOREIGN KEY (session_id) REFERENCES sessions(id) ON DELETE CASCADE,
+                    UNIQUE (session_id, position)
+                );
+
+                CREATE INDEX IF NOT EXISTS idx_messages_session_position
+                    ON messages(session_id, position);
+                """
+            )
+
+    def create_session(self, provider: str, model: str) -> ChatSession:
+        session_id = str(uuid.uuid4())
+        now = _utc_now()
+        try:
+            with self._connection() as connection:
+                connection.execute(
+                    """
+                    INSERT INTO sessions (id, created_at, updated_at, provider, model)
+                    VALUES (?, ?, ?, ?, ?)
+                    """,
+                    (session_id, now, now, provider, model),
+                )
+        except sqlite3.Error as exc:
+            raise SessionStoreError("Die Sitzung konnte nicht gespeichert werden.") from exc
+        return ChatSession(session_id, now, now, provider, model)
+
+    def get_session(self, session_id: str) -> ChatSession:
+        try:
+            with self._connection() as connection:
+                row = connection.execute(
+                    """
+                    SELECT s.*, COUNT(m.id) AS message_count
+                    FROM sessions AS s
+                    LEFT JOIN messages AS m ON m.session_id = s.id
+                    WHERE s.id = ?
+                    GROUP BY s.id
+                    """,
+                    (session_id,),
+                ).fetchone()
+        except sqlite3.Error as exc:
+            raise SessionStoreError("Die Sitzung konnte nicht geladen werden.") from exc
+        if row is None:
+            raise SessionNotFoundError(f"Sitzung '{session_id}' wurde nicht gefunden.")
+        return self._session_from_row(row)
+
+    def list_sessions(self) -> list[ChatSession]:
+        try:
+            with self._connection() as connection:
+                rows = connection.execute(
+                    """
+                    SELECT s.*, COUNT(m.id) AS message_count
+                    FROM sessions AS s
+                    LEFT JOIN messages AS m ON m.session_id = s.id
+                    GROUP BY s.id
+                    ORDER BY s.updated_at DESC, s.created_at DESC
+                    """
+                ).fetchall()
+        except sqlite3.Error as exc:
+            raise SessionStoreError("Die Sitzungen konnten nicht aufgelistet werden.") from exc
+        return [self._session_from_row(row) for row in rows]
+
+    def get_messages(self, session_id: str) -> list[ChatMessage]:
+        self.get_session(session_id)
+        try:
+            with self._connection() as connection:
+                rows = connection.execute(
+                    """
+                    SELECT role, content
+                    FROM messages
+                    WHERE session_id = ?
+                    ORDER BY position ASC
+                    """,
+                    (session_id,),
+                ).fetchall()
+        except sqlite3.Error as exc:
+            raise SessionStoreError("Die Nachrichten konnten nicht geladen werden.") from exc
+        return [ChatMessage(row["role"], row["content"]) for row in rows]
+
+    def append_exchange(
+        self,
+        session_id: str,
+        user_content: str,
+        assistant_content: str,
+    ) -> None:
+        now = _utc_now()
+        try:
+            with self._connection() as connection:
+                exists = connection.execute(
+                    "SELECT 1 FROM sessions WHERE id = ?", (session_id,)
+                ).fetchone()
+                if exists is None:
+                    raise SessionNotFoundError(f"Sitzung '{session_id}' wurde nicht gefunden.")
+                row = connection.execute(
+                    "SELECT COALESCE(MAX(position), -1) + 1 FROM messages WHERE session_id = ?",
+                    (session_id,),
+                ).fetchone()
+                next_position = int(row[0])
+                connection.executemany(
+                    """
+                    INSERT INTO messages
+                        (session_id, position, role, content, created_at)
+                    VALUES (?, ?, ?, ?, ?)
+                    """,
+                    (
+                        (session_id, next_position, "user", user_content, now),
+                        (
+                            session_id,
+                            next_position + 1,
+                            "assistant",
+                            assistant_content,
+                            now,
+                        ),
+                    ),
+                )
+                connection.execute(
+                    "UPDATE sessions SET updated_at = ? WHERE id = ?",
+                    (now, session_id),
+                )
+        except SessionNotFoundError:
+            raise
+        except sqlite3.Error as exc:
+            raise SessionStoreError("Die Nachrichten konnten nicht gespeichert werden.") from exc
+
+    def clear_messages(self, session_id: str) -> None:
+        now = _utc_now()
+        try:
+            with self._connection() as connection:
+                cursor = connection.execute(
+                    "DELETE FROM messages WHERE session_id = ?", (session_id,)
+                )
+                exists = connection.execute(
+                    "SELECT 1 FROM sessions WHERE id = ?", (session_id,)
+                ).fetchone()
+                if exists is None:
+                    raise SessionNotFoundError(f"Sitzung '{session_id}' wurde nicht gefunden.")
+                if cursor.rowcount:
+                    connection.execute(
+                        "UPDATE sessions SET updated_at = ? WHERE id = ?",
+                        (now, session_id),
+                    )
+        except SessionNotFoundError:
+            raise
+        except sqlite3.Error as exc:
+            raise SessionStoreError("Die Sitzung konnte nicht geleert werden.") from exc
+
+    @staticmethod
+    def _session_from_row(row: sqlite3.Row) -> ChatSession:
+        return ChatSession(
+            id=row["id"],
+            created_at=row["created_at"],
+            updated_at=row["updated_at"],
+            provider=row["provider"],
+            model=row["model"],
+            message_count=row["message_count"],
+        )
diff --git a/src/javis/providers/base.py b/src/javis/providers/base.py
new file mode 100644
index 0000000..aa3d7fe
--- /dev/null
+++ b/src/javis/providers/base.py
@@ -0,0 +1,46 @@
+"""Small provider contract used by the chat core."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Protocol, runtime_checkable
+
+
+@dataclass(frozen=True, slots=True)
+class ChatMessage:
+    role: str
+    content: str
+
+
+class ProviderError(RuntimeError):
+    """Base class for expected local provider failures."""
+
+
+class ProviderUnavailableError(ProviderError):
+    """The local model runtime cannot be reached."""
+
+
+class ModelNotInstalledError(ProviderError):
+    """The configured local model is not available."""
+
+
+class ProviderTimeoutError(ProviderError):
+    """The local model did not respond in time."""
+
+
+class ResponseAbortedError(ProviderError):
+    """The model response was interrupted before completion."""
+
+
+class InvalidProviderResponseError(ProviderError):
+    """The local runtime returned an unusable response."""
+
+
+@runtime_checkable
+class LocalModelProvider(Protocol):
+    name: str
+    model: str
+
+    def chat(self, messages: list[ChatMessage]) -> str:
+        """Return one complete assistant response."""
+        ...
diff --git a/src/javis/providers/ollama.py b/src/javis/providers/ollama.py
new file mode 100644
index 0000000..358b46f
--- /dev/null
+++ b/src/javis/providers/ollama.py
@@ -0,0 +1,82 @@
+"""Ollama implementation of the local model provider contract."""
+
+from __future__ import annotations
+
+import json
+import socket
+from urllib.error import HTTPError, URLError
+from urllib.request import Request, urlopen
+
+from javis.providers.base import (
+    ChatMessage,
+    InvalidProviderResponseError,
+    ModelNotInstalledError,
+    ProviderTimeoutError,
+    ProviderUnavailableError,
+    ResponseAbortedError,
+)
+
+
+class OllamaProvider:
+    name = "ollama"
+
+    def __init__(self, model: str, base_url: str, timeout_seconds: float) -> None:
+        self.model = model
+        self._endpoint = f"{base_url.rstrip('/')}/api/chat"
+        self._timeout_seconds = timeout_seconds
+
+    def chat(self, messages: list[ChatMessage]) -> str:
+        payload = {
+            "model": self.model,
+            "messages": [
+                {"role": message.role, "content": message.content} for message in messages
+            ],
+            "stream": False,
+            "think": False,
+        }
+        request = Request(
+            self._endpoint,
+            data=json.dumps(payload).encode("utf-8"),
+            headers={"Content-Type": "application/json"},
+            method="POST",
+        )
+
+        try:
+            with urlopen(request, timeout=self._timeout_seconds) as response:
+                raw_response = response.read()
+        except HTTPError as exc:
+            details = exc.read().decode("utf-8", errors="replace")
+            if exc.code == 404 or "not found" in details.lower():
+                raise ModelNotInstalledError(
+                    f"Das lokale Modell '{self.model}' ist nicht installiert."
+                ) from exc
+            raise ProviderUnavailableError(f"Ollama meldet HTTP-Fehler {exc.code}.") from exc
+        except TimeoutError as exc:
+            raise ProviderTimeoutError(
+                "Die Modellantwort hat das Zeitlimit überschritten."
+            ) from exc
+        except URLError as exc:
+            if isinstance(exc.reason, (TimeoutError, socket.timeout)):
+                raise ProviderTimeoutError(
+                    "Die Modellantwort hat das Zeitlimit überschritten."
+                ) from exc
+            raise ProviderUnavailableError(
+                "Ollama ist unter der konfigurierten lokalen Adresse nicht erreichbar."
+            ) from exc
+
+        try:
+            result = json.loads(raw_response)
+        except (json.JSONDecodeError, UnicodeDecodeError) as exc:
+            raise InvalidProviderResponseError(
+                "Ollama hat keine gültige JSON-Antwort geliefert."
+            ) from exc
+
+        if result.get("done") is False:
+            raise ResponseAbortedError("Die Modellantwort wurde vorzeitig abgebrochen.")
+
+        content = result.get("message", {}).get("content")
+        if not isinstance(content, str) or not content.strip():
+            raise InvalidProviderResponseError(
+                "Ollama hat keine verwendbare Textantwort geliefert."
+            )
+        return content.strip()