diff --git a/bot_bottle/backend/docker/bottle.py b/bot_bottle/backend/docker/bottle.py
index 7c94c40..86d2e3a 100644
--- a/bot_bottle/backend/docker/bottle.py
+++ b/bot_bottle/backend/docker/bottle.py
@@ -23,7 +23,7 @@ class DockerBottle(Bottle):
     ):
         self.name = container
         self._teardown = teardown
-        self._prompt_path = prompt_path_in_container
+        self.prompt_path = prompt_path_in_container
         self._agent_prompt_mode = agent_prompt_mode
         self.agent_command = agent_command
         self.agent_provider_template = (
@@ -36,7 +36,7 @@ class DockerBottle(Bottle):
     ) -> list[str]:
         full_argv = list(argv)
         full_argv.extend(
-            prompt_args(self._agent_prompt_mode, self._prompt_path, argv=full_argv)
+            prompt_args(self._agent_prompt_mode, self.prompt_path, argv=full_argv)
         )
         cmd = ["docker", "exec"]
         if tty:
diff --git a/bot_bottle/backend/docker/launch.py b/bot_bottle/backend/docker/launch.py
index 6bc92df..f7872a9 100644
--- a/bot_bottle/backend/docker/launch.py
+++ b/bot_bottle/backend/docker/launch.py
@@ -80,7 +80,7 @@ _REPO_DIR = str(Path(__file__).resolve().parent.parent.parent.parent)
 def launch(
     plan: DockerBottlePlan,
     *,
-    provision: Callable[[DockerBottlePlan, str], str | None],
+    provision: Callable[[DockerBottlePlan, "DockerBottle"], str | None],
 ) -> Generator[DockerBottle, None, None]:
     """Build, launch, and provision a Docker bottle via compose.
     Teardown on exit."""
@@ -218,7 +218,7 @@ def launch(
             agent_command=plan.agent_command,
             agent_prompt_mode=plan.agent_prompt_mode,
         )
-        bottle._prompt_path = provision(plan, bottle)
+        bottle.prompt_path = provision(plan, bottle)
 
         # Step 9: yield. exec_agent continues to use `docker exec -it`
         # — the agent runs `sleep infinity` per the renderer's
diff --git a/bot_bottle/backend/smolmachines/bottle.py b/bot_bottle/backend/smolmachines/bottle.py
index 2553cb2..3f9c22b 100644
--- a/bot_bottle/backend/smolmachines/bottle.py
+++ b/bot_bottle/backend/smolmachines/bottle.py
@@ -72,7 +72,7 @@ class SmolmachinesBottle(Bottle):
         # In-VM path to the agent's prompt file. None when the
         # agent declared no prompt (file still exists; we just
         # don't pass --append-system-prompt-file).
-        self._prompt_path = prompt_path
+        self.prompt_path = prompt_path
         # Env vars the agent process needs (HTTPS_PROXY,
         # CLAUDE_CODE_OAUTH_TOKEN, manifest-declared bottle env, …).
         # Forwarded on every `smolvm machine exec` via `-e K=V`
@@ -93,7 +93,7 @@ class SmolmachinesBottle(Bottle):
         agent_tail = ["env", *_env_assignments_for("node", self._guest_env),
                       self.agent_command]
         provider_prompt_args = prompt_args(
-            self._agent_prompt_mode, self._prompt_path, argv=argv,
+            self._agent_prompt_mode, self.prompt_path, argv=argv,
         )
         if self._agent_prompt_mode == "read_prompt_file":
             agent_tail += argv
diff --git a/bot_bottle/backend/smolmachines/launch.py b/bot_bottle/backend/smolmachines/launch.py
index e324d3f..c006dd4 100644
--- a/bot_bottle/backend/smolmachines/launch.py
+++ b/bot_bottle/backend/smolmachines/launch.py
@@ -89,7 +89,7 @@ _SUPERVISE_PORT = SUPERVISE_PORT
 def launch(
     plan: SmolmachinesBottlePlan,
     *,
-    provision: Callable[[SmolmachinesBottlePlan, str], str | None],
+    provision: Callable[[SmolmachinesBottlePlan, "SmolmachinesBottle"], str | None],
 ) -> Generator[SmolmachinesBottle, None, None]:
     """Build + run the bottle and yield a handle; tear everything
     down on exit. Errors during bringup unwind any partial state
@@ -120,7 +120,7 @@ def launch(
             agent_command=plan.agent_command,
             agent_prompt_mode=plan.agent_prompt_mode,
         )
-        bottle._prompt_path = provision(plan, bottle)
+        bottle.prompt_path = provision(plan, bottle)
 
         yield bottle
     finally:
diff --git a/bot_bottle/backend/smolmachines/local_registry.py b/bot_bottle/backend/smolmachines/local_registry.py
index 06d3ba5..21b9b96 100644
--- a/bot_bottle/backend/smolmachines/local_registry.py
+++ b/bot_bottle/backend/smolmachines/local_registry.py
@@ -42,7 +42,7 @@ import time
 import uuid
 from contextlib import contextmanager
 from dataclasses import dataclass
-from typing import Iterator
+from typing import Generator, Iterator
 
 from ...log import die
 
@@ -98,7 +98,7 @@ class RegistryHandle:
 
 
 @contextmanager
-def ephemeral_registry() -> Iterator[RegistryHandle]:
+def ephemeral_registry() -> Generator[RegistryHandle, None, None]:
     """Bring up a per-session docker network + a `registry:2.8.3`
     container on it (published on a random host port), yield a
     `RegistryHandle`, force-remove both on exit.
diff --git a/bot_bottle/backend/smolmachines/pty_resize.py b/bot_bottle/backend/smolmachines/pty_resize.py
index 311836b..2a5ab39 100644
--- a/bot_bottle/backend/smolmachines/pty_resize.py
+++ b/bot_bottle/backend/smolmachines/pty_resize.py
@@ -123,7 +123,7 @@ def main(argv: list[str]) -> int:
     machine = argv[0]
     inner = argv[2:]
 
-    def sync(*_args) -> None:
+    def sync(*_args: int) -> None:
         size = _read_winsize()
         if size is None:
             return
diff --git a/bot_bottle/workspace.py b/bot_bottle/workspace.py
index a762175..670a6e2 100644
--- a/bot_bottle/workspace.py
+++ b/bot_bottle/workspace.py
@@ -13,8 +13,15 @@ DEFAULT_WORKSPACE_MODE = "755"
 
 
 class WorkspaceSpec(Protocol):
-    copy_cwd: bool
-    user_cwd: str
+    @property
+    def copy_cwd(self) -> bool:
+        """Whether to copy the current working directory."""
+        ...
+
+    @property
+    def user_cwd(self) -> str:
+        """The user's current working directory."""
+        ...
 
 
 @dataclass(frozen=True)