diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0935497..bbbd0ff 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,15 @@ Release tags use the `python-vX.Y.Z` prefix.
 
 ## [Unreleased]
 
+## [0.1.5] - 2026-07-10
+
+### Added
+- **`spawn.launch()` now exposes the remaining launch parameters** (#6):
+  `ami` (custom AMI), `key_name` (SSH key pair), `pre_stop` (pre-stop hook), and
+  `completion_file` (path spored watches). These were accepted by the REST launch
+  endpoint but not surfaced by the SDK. With this, the SDK covers the full launch
+  body. Additive; unset params are omitted.
+
 ## [0.1.4] - 2026-07-10
 
 ### Added
@@ -62,7 +71,8 @@ Baseline. Earlier history is in the
 
 ---
 
-[Unreleased]: https://github.com/spore-host/python-sdk/compare/python-v0.1.4...HEAD
+[Unreleased]: https://github.com/spore-host/python-sdk/compare/python-v0.1.5...HEAD
+[0.1.5]: https://github.com/spore-host/python-sdk/compare/python-v0.1.4...python-v0.1.5
 [0.1.4]: https://github.com/spore-host/python-sdk/compare/python-v0.1.3...python-v0.1.4
 [0.1.3]: https://github.com/spore-host/python-sdk/compare/python-v0.1.2...python-v0.1.3
 [0.1.2]: https://github.com/spore-host/python-sdk/releases/tag/python-v0.1.2
diff --git a/pyproject.toml b/pyproject.toml
index 55d0d43..a016297 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "spore-host"
-version = "0.1.4"
+version = "0.1.5"
 description = "Python SDK for spore.host — ephemeral EC2 compute for researchers"
 readme = "README.md"
 requires-python = ">=3.9"
diff --git a/spore/__init__.py b/spore/__init__.py
index 21c1f52..c6caf91 100644
--- a/spore/__init__.py
+++ b/spore/__init__.py
@@ -66,7 +66,7 @@ def __repr__(self) -> str:
 spawn = _LazySubClient("spawn")
 notifications = _LazySubClient("notifications")
 
-__version__ = "0.1.4"
+__version__ = "0.1.5"
 __all__ = [
     "Client",
     "truffle",
diff --git a/spore/_spawn.py b/spore/_spawn.py
index 340452a..e30caae 100644
--- a/spore/_spawn.py
+++ b/spore/_spawn.py
@@ -151,6 +151,10 @@ def launch(
         on_complete: str = "terminate",
         slack_workspace: Optional[str] = None,
         active_processes: Optional[List[str]] = None,
+        ami: Optional[str] = None,
+        key_name: Optional[str] = None,
+        pre_stop: Optional[str] = None,
+        completion_file: Optional[str] = None,
         wait: bool = False,
     ) -> Instance:
         """
@@ -166,6 +170,11 @@ def launch(
             on_complete:      Action on SPAWN_COMPLETE: "terminate", "stop", "hibernate".
             slack_workspace:  Slack workspace ID for lifecycle notifications.
             active_processes: Process names that indicate active work (e.g. ["rsession"]).
+            ami:              Custom AMI id (default: spore.host's recommended AMI).
+            key_name:         EC2 key pair name for SSH access.
+            pre_stop:         Shell command run on the instance before stop/terminate.
+            completion_file:  Path spored watches for the completion signal
+                              (default: /tmp/SPAWN_COMPLETE).
             wait:             If True, block until instance is running.
 
         For SMS notifications, register your number separately via
@@ -199,6 +208,14 @@ def launch(
             body["slack_workspace"] = slack_workspace
         if active_processes:
             body["active_processes"] = ",".join(active_processes)
+        if ami:
+            body["ami"] = ami
+        if key_name:
+            body["key_name"] = key_name
+        if pre_stop:
+            body["pre_stop"] = pre_stop
+        if completion_file:
+            body["completion_file"] = completion_file
 
         data = self._c.post("/v1/instances", body)
         # Build via _parse (single source of truth for API→Instance mapping). The
diff --git a/tests/test_sdk.py b/tests/test_sdk.py
index 89df545..8285407 100644
--- a/tests/test_sdk.py
+++ b/tests/test_sdk.py
@@ -158,6 +158,32 @@ def test_spawn_launch_returns_instance_with_fields():
     assert body["ttl"] == "4h"
 
 
+def test_spawn_launch_forwards_advanced_params():
+    # #6: ami/key_name/pre_stop/completion_file must reach the request body with
+    # the API's real keys (instances.go launch body).
+    fake = FakeClient(post_return=_launch_response())
+    SpawnClient(fake).launch(
+        "c7i.2xlarge",
+        ami="ami-0abc",
+        key_name="my-key",
+        pre_stop="aws s3 sync /out s3://bucket/",
+        completion_file="/tmp/DONE",
+    )
+    _, body = fake.post_calls[0]
+    assert body["ami"] == "ami-0abc"
+    assert body["key_name"] == "my-key"
+    assert body["pre_stop"] == "aws s3 sync /out s3://bucket/"
+    assert body["completion_file"] == "/tmp/DONE"
+
+
+def test_spawn_launch_omits_unset_advanced_params():
+    fake = FakeClient(post_return=_launch_response())
+    SpawnClient(fake).launch("c7i.2xlarge")
+    _, body = fake.post_calls[0]
+    for k in ("ami", "key_name", "pre_stop", "completion_file"):
+        assert k not in body
+
+
 # ── spawn status/list parsing against real instances.go keys ────────────────
 
 def test_spawn_status_parses_instance():