diff --git a/tests/conftest.py b/tests/conftest.py
new file mode 100644
index 0000000..d0b693c
--- /dev/null
+++ b/tests/conftest.py
@@ -0,0 +1,35 @@
+from __future__ import annotations
+
+import os
+from pathlib import Path
+
+import pytest
+
+ENV_FILE = Path(__file__).resolve().parent.parent / ".env"
+
+
+def _read_env_file() -> dict[str, str]:
+    result: dict[str, str] = {}
+    if not ENV_FILE.exists():
+        return result
+    for line in ENV_FILE.read_text().splitlines():
+        line = line.strip()
+        if not line or line.startswith("#") or "=" not in line:
+            continue
+        key, _, value = line.partition("=")
+        key = key.strip()
+        value = value.strip().strip("\"'")
+        if key:
+            result[key] = value
+    return result
+
+
+def pytest_collection_modifyitems(config: pytest.Config, items: list[pytest.Item]) -> None:
+    env_vars = _read_env_file()
+    has_key = bool(os.environ.get("WRENN_API_KEY") or env_vars.get("WRENN_API_KEY"))
+    if has_key:
+        return
+    skip = pytest.mark.skip(reason="WRENN_API_KEY not set")
+    for item in items:
+        if "integration" in item.keywords:
+            item.add_marker(skip)
diff --git a/tests/test_integration.py b/tests/test_integration.py
new file mode 100644
index 0000000..2286c1b
--- /dev/null
+++ b/tests/test_integration.py
@@ -0,0 +1,413 @@
+from __future__ import annotations
+
+import os
+import time
+from pathlib import Path
+
+import pytest
+
+from wrenn import Capsule, CommandResult
+from wrenn.commands import CommandHandle, ProcessInfo
+from wrenn.models import Capsule as CapsuleModel, FileEntry, Status
+
+pytestmark = pytest.mark.integration
+
+_env_loaded = False
+
+
+def _ensure_env() -> None:
+    global _env_loaded
+    if _env_loaded:
+        return
+    _env_loaded = True
+    env_file = Path(__file__).resolve().parent.parent / ".env"
+    if not env_file.exists():
+        return
+    for line in env_file.read_text().splitlines():
+        line = line.strip()
+        if not line or line.startswith("#") or "=" not in line:
+            continue
+        key, _, value = line.partition("=")
+        key, value = key.strip(), value.strip().strip("\"'")
+        if key and key not in os.environ:
+            os.environ[key] = value
+
+
+class TestCapsuleLifecycle:
+    """Each test manages its own capsule to test create/destroy paths."""
+
+    def setup_method(self):
+        _ensure_env()
+
+    def test_create_and_destroy(self):
+        capsule = Capsule()
+        capsule_id = capsule.capsule_id
+        try:
+            assert capsule_id
+            assert capsule.info is not None
+        finally:
+            capsule.destroy()
+
+        info = Capsule.get_info(capsule_id)
+        assert info.status in (Status.stopped, Status.missing)
+
+    def test_create_with_wait(self):
+        capsule = Capsule(wait=True)
+        try:
+            assert capsule.info is not None
+            assert capsule.info.status == Status.running
+        finally:
+            capsule.destroy()
+
+    def test_context_manager_destroys(self):
+        with Capsule(wait=True) as capsule:
+            capsule_id = capsule.capsule_id
+            assert capsule.is_running()
+
+        info = Capsule.get_info(capsule_id)
+        assert info.status in (Status.stopped, Status.missing)
+
+    def test_get_info(self):
+        capsule = Capsule(wait=True)
+        try:
+            info = capsule.get_info()
+            assert isinstance(info, CapsuleModel)
+            assert info.id == capsule.capsule_id
+            assert info.status == Status.running
+        finally:
+            capsule.destroy()
+
+    def test_pause_and_resume(self):
+        capsule = Capsule(wait=True)
+        try:
+            paused = capsule.pause()
+            assert paused.status == Status.paused
+            assert not capsule.is_running()
+
+            resumed = capsule.resume()
+            assert resumed.status == Status.running
+        finally:
+            capsule.destroy()
+
+    def test_static_destroy(self):
+        capsule = Capsule(wait=True)
+        capsule_id = capsule.capsule_id
+        try:
+            Capsule.destroy(capsule_id)
+        except Exception:
+            capsule.destroy()
+            raise
+
+        info = Capsule.get_info(capsule_id)
+        assert info.status in (Status.stopped, Status.missing)
+
+    def test_connect_to_existing(self):
+        capsule = Capsule(wait=True)
+        try:
+            connected = Capsule.connect(capsule.capsule_id)
+            assert connected.capsule_id == capsule.capsule_id
+            assert connected.info is not None
+            assert connected.info.status == Status.running
+        finally:
+            capsule.destroy()
+
+    def test_connect_resumes_paused(self):
+        capsule = Capsule(wait=True)
+        try:
+            capsule.pause()
+            connected = Capsule.connect(capsule.capsule_id)
+            assert connected.info is not None
+            assert connected.info.status == Status.running
+        finally:
+            capsule.destroy()
+
+    def test_list_capsules(self):
+        capsule = Capsule(wait=True)
+        try:
+            capsules = Capsule.list()
+            assert isinstance(capsules, list)
+            ids = [c.id for c in capsules]
+            assert capsule.capsule_id in ids
+        finally:
+            capsule.destroy()
+
+    def test_wait_ready(self):
+        capsule = Capsule()
+        try:
+            capsule.wait_ready(timeout=60)
+            assert capsule.is_running()
+        finally:
+            capsule.destroy()
+
+    def test_ping(self):
+        capsule = Capsule(wait=True)
+        try:
+            capsule.ping()
+        finally:
+            capsule.destroy()
+
+
+class TestCommands:
+    """Shared capsule for command execution tests."""
+
+    capsule: Capsule
+
+    @classmethod
+    def setup_class(cls):
+        _ensure_env()
+        cls.capsule = Capsule(wait=True)
+
+    @classmethod
+    def teardown_class(cls):
+        try:
+            cls.capsule.destroy()
+        except Exception:
+            pass
+
+    def test_run_foreground(self):
+        result = self.capsule.commands.run("echo hello")
+        assert isinstance(result, CommandResult)
+        assert result.exit_code == 0
+        assert "hello" in result.stdout
+
+    def test_run_stderr(self):
+        result = self.capsule.commands.run("echo error >&2")
+        assert "error" in result.stderr
+
+    def test_run_exit_code(self):
+        result = self.capsule.commands.run("exit 42")
+        assert result.exit_code == 42
+
+    def test_run_with_envs(self):
+        result = self.capsule.commands.run(
+            "export MY_VAR=test_value && echo $MY_VAR"
+        )
+        assert "test_value" in result.stdout
+
+    def test_run_with_cwd(self):
+        result = self.capsule.commands.run("cd /tmp && pwd")
+        assert result.stdout.strip() == "/tmp"
+
+    def test_run_multiline_output(self):
+        result = self.capsule.commands.run("echo -e 'line1\\nline2\\nline3'")
+        assert result.exit_code == 0
+        lines = result.stdout.strip().splitlines()
+        assert len(lines) == 3
+
+    def test_run_background(self):
+        handle = self.capsule.commands.run(
+            "sleep 30", background=True, tag="bg-test"
+        )
+        assert isinstance(handle, CommandHandle)
+        assert handle.pid > 0
+        assert handle.tag == "bg-test"
+        assert handle.capsule_id == self.capsule.capsule_id
+
+        self.capsule.commands.kill(handle.pid)
+
+    def test_list_processes(self):
+        handle = self.capsule.commands.run(
+            "sleep 30", background=True, tag="list-test"
+        )
+        try:
+            time.sleep(0.5)
+            processes = self.capsule.commands.list()
+            assert isinstance(processes, list)
+            pids = [p.pid for p in processes]
+            assert handle.pid in pids
+
+            proc = next(p for p in processes if p.pid == handle.pid)
+            assert isinstance(proc, ProcessInfo)
+        finally:
+            self.capsule.commands.kill(handle.pid)
+
+    def test_kill_process(self):
+        handle = self.capsule.commands.run(
+            "sleep 30", background=True
+        )
+        self.capsule.commands.kill(handle.pid)
+        time.sleep(0.5)
+
+        processes = self.capsule.commands.list()
+        pids = [p.pid for p in processes]
+        assert handle.pid not in pids
+
+    def test_run_duration_ms(self):
+        result = self.capsule.commands.run("sleep 1")
+        assert result.duration_ms is None or result.duration_ms >= 900
+
+
+class TestFiles:
+    """Shared capsule for filesystem tests."""
+
+    capsule: Capsule
+
+    @classmethod
+    def setup_class(cls):
+        _ensure_env()
+        cls.capsule = Capsule(wait=True)
+
+    @classmethod
+    def teardown_class(cls):
+        try:
+            cls.capsule.destroy()
+        except Exception:
+            pass
+
+    def test_write_and_read(self):
+        self.capsule.files.write("/tmp/test.txt", "hello world")
+        content = self.capsule.files.read("/tmp/test.txt")
+        assert content == "hello world"
+
+    def test_write_and_read_bytes(self):
+        data = b"\x00\x01\x02\xff"
+        self.capsule.files.write("/tmp/test.bin", data)
+        result = self.capsule.files.read_bytes("/tmp/test.bin")
+        assert result == data
+
+    def test_list_directory(self):
+        self.capsule.files.write("/tmp/listdir/a.txt", "a")
+        self.capsule.files.write("/tmp/listdir/b.txt", "b")
+        entries = self.capsule.files.list("/tmp/listdir")
+        assert isinstance(entries, list)
+        names = [e.name for e in entries]
+        assert "a.txt" in names
+        assert "b.txt" in names
+
+    def test_exists(self):
+        self.capsule.files.write("/tmp/exists_test.txt", "x")
+        assert self.capsule.files.exists("/tmp/exists_test.txt")
+        assert not self.capsule.files.exists("/tmp/does_not_exist_xyz.txt")
+
+    def test_make_dir(self):
+        entry = self.capsule.files.make_dir("/tmp/newdir")
+        assert isinstance(entry, FileEntry)
+        assert self.capsule.files.exists("/tmp/newdir")
+
+    def test_make_dir_idempotent(self):
+        self.capsule.files.make_dir("/tmp/idempotent_dir")
+        entry = self.capsule.files.make_dir("/tmp/idempotent_dir")
+        assert isinstance(entry, FileEntry)
+
+    def test_remove_file(self):
+        self.capsule.files.write("/tmp/to_remove.txt", "delete me")
+        assert self.capsule.files.exists("/tmp/to_remove.txt")
+        self.capsule.files.remove("/tmp/to_remove.txt")
+        assert not self.capsule.files.exists("/tmp/to_remove.txt")
+
+    def test_remove_directory(self):
+        self.capsule.files.make_dir("/tmp/dir_to_remove")
+        self.capsule.files.write("/tmp/dir_to_remove/child.txt", "data")
+        self.capsule.files.remove("/tmp/dir_to_remove")
+        assert not self.capsule.files.exists("/tmp/dir_to_remove")
+
+    def test_write_creates_parent_dirs(self):
+        self.capsule.files.write("/tmp/deep/nested/dir/file.txt", "nested")
+        content = self.capsule.files.read("/tmp/deep/nested/dir/file.txt")
+        assert content == "nested"
+
+    def test_list_with_depth(self):
+        self.capsule.files.write("/tmp/depth_test/a/b.txt", "deep")
+        entries_shallow = self.capsule.files.list("/tmp/depth_test", depth=1)
+        entries_deep = self.capsule.files.list("/tmp/depth_test", depth=2)
+        assert len(entries_deep) >= len(entries_shallow)
+
+    def test_overwrite_file(self):
+        self.capsule.files.write("/tmp/overwrite.txt", "original")
+        self.capsule.files.write("/tmp/overwrite.txt", "updated")
+        content = self.capsule.files.read("/tmp/overwrite.txt")
+        assert content == "updated"
+
+    def test_upload_and_download_stream(self):
+        chunks = [b"chunk1", b"chunk2", b"chunk3"]
+        self.capsule.files.upload_stream("/tmp/streamed.bin", iter(chunks))
+        downloaded = b"".join(self.capsule.files.download_stream("/tmp/streamed.bin"))
+        assert downloaded == b"chunk1chunk2chunk3"
+
+
+class TestGit:
+    """Shared capsule for git operation tests.
+
+    Initializes a repo at /root (default cwd) since the exec API
+    does not support the cwd parameter.
+    """
+
+    capsule: Capsule
+
+    @classmethod
+    def setup_class(cls):
+        _ensure_env()
+        cls.capsule = Capsule(wait=True)
+        cls.capsule.git.init(".", initial_branch="main")
+        cls.capsule.git.configure_user("Test User", "test@example.com")
+
+    @classmethod
+    def teardown_class(cls):
+        try:
+            cls.capsule.destroy()
+        except Exception:
+            pass
+
+    def test_init_created_repo(self):
+        assert self.capsule.files.exists("/root/.git")
+
+    def test_status_clean(self):
+        status = self.capsule.git.status()
+        assert status.branch == "main"
+
+    def test_add_and_commit(self):
+        self.capsule.files.write("/root/hello.txt", "hello git")
+        self.capsule.git.add(all=True)
+        result = self.capsule.git.commit("initial commit")
+        assert result.exit_code == 0
+
+    def test_status_after_commit(self):
+        status = self.capsule.git.status()
+        assert status.is_clean
+
+    def test_status_with_changes(self):
+        self.capsule.files.write("/root/dirty.txt", "uncommitted")
+        try:
+            status = self.capsule.git.status()
+            assert not status.is_clean
+            paths = [f.path for f in status.files]
+            assert "dirty.txt" in paths
+        finally:
+            self.capsule.files.remove("/root/dirty.txt")
+
+    def test_branches(self):
+        branches = self.capsule.git.branches()
+        assert len(branches) >= 1
+        names = [b.name for b in branches]
+        assert "main" in names
+        current = [b for b in branches if b.is_current]
+        assert len(current) == 1
+
+    def test_create_and_checkout_branch(self):
+        self.capsule.git.create_branch("feature-1")
+        branches = self.capsule.git.branches()
+        names = [b.name for b in branches]
+        assert "feature-1" in names
+
+        current = [b for b in branches if b.is_current]
+        assert current[0].name == "feature-1"
+
+        self.capsule.git.checkout_branch("main")
+
+    def test_delete_branch(self):
+        self.capsule.git.create_branch("to-delete")
+        self.capsule.git.checkout_branch("main")
+        self.capsule.git.delete_branch("to-delete")
+
+        branches = self.capsule.git.branches()
+        names = [b.name for b in branches]
+        assert "to-delete" not in names
+
+    def test_set_and_get_config(self):
+        self.capsule.git.set_config("test.key", "test-value")
+        value = self.capsule.git.get_config("test.key")
+        assert value == "test-value"
+
+    def test_get_config_missing_returns_none(self):
+        value = self.capsule.git.get_config("nonexistent.key")
+        assert value is None