test(smolmachines): verify Linux sandbox escape gate + fix platform check

Empirical verification on NixOS/Linux with /dev/kvm + smolvm 1.4.7:

  1. DB path confirmed: ~/.local/share/smolvm/server/smolvm.db exists,
     schema matches (vms table, data BLOB with allowed_cidrs JSON field).

  2. smolvm 1.4.7 still silently drops --allow-cidr with --from
     (allowed_cidrs=None in DB after create). force_allowlist patch
     is still necessary and correct.

  3. All 5 sandbox-escape attacks blocked with BOT_BOTTLE_BACKEND=smolmachines
     on Linux: hostname/IP allowlist, HTTP DLP, DNS exfil, git-gate gitleaks.

Changes:
- test_sandbox_escape: remove darwin-only guard; allow linux too
- contrib/claude/Dockerfile: add dnsutils (dig) for attack 4 DNS test

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

README.md

@@ -5,7 +5,7 @@
 # bot-bottle
 
 [![test](https://gitea.dideric.is/didericis/bot-bottle/actions/workflows/test.yml/badge.svg?branch=main)](https://gitea.dideric.is/didericis/bot-bottle/actions?workflow=test.yml)
-[![coverage](https://img.shields.io/badge/coverage-84%25-brightgreen)](https://coverage.readthedocs.io/)
+[![coverage](https://img.shields.io/badge/coverage-83%25-brightgreen)](https://coverage.readthedocs.io/)
 [![core coverage](https://img.shields.io/badge/core%20coverage-95%25-brightgreen)](https://gitea.dideric.is/didericis/bot-bottle/src/branch/main/docs/decisions/0004-coverage-policy.md)
 
 **Problem:** Developer wants to run a coding agent without supervision, but they don't want a prompt injected or misbehaving agent wrecking their environment or exfiltrating sensitive data.

bot_bottle/agent_provider.py

@@ -61,13 +61,6 @@ class AgentProviderRuntime:
     prompt_mode: PromptMode
     bypass_args: tuple[str, ...]
     resume_args: tuple[str, ...]
-    # argv run inside a throwaway container of a freshly built agent
-    # image, right after `build_image()`, to catch a build that
-    # exited 0 but produced a broken CLI (e.g. an npm
-    # optionalDependencies fetch for a platform-native binary that
-    # silently no-ops on a transient failure). Empty tuple skips the
-    # check — not every provider has opted in yet.
-    smoke_test: tuple[str, ...] = ()
 
 
 @dataclass(frozen=True)

bot_bottle/backend/docker/launch.py

@@ -36,7 +36,6 @@ from contextlib import ExitStack, contextmanager
 from pathlib import Path
 from typing import Callable, Generator
 
-from ...agent_provider import runtime_for
 from ...egress import egress_resolve_token_values
 from ...git_gate import (
     provision_git_gate_dynamic_keys,
@@ -112,9 +111,6 @@ def launch(
                 plan.image, _REPO_DIR,
                 dockerfile=plan.dockerfile_path,
             )
-            docker_mod.verify_agent_image(
-                plan.image, runtime_for(plan.agent_provider_template).smoke_test,
-            )
 
         internal_network = network_mod.network_name_for_slug(plan.slug)
         egress_network = network_mod.network_egress_name_for_slug(plan.slug)

bot_bottle/backend/docker/util.py

@@ -4,7 +4,6 @@ existence, and building images."""
 
 from __future__ import annotations
 
-import os
 import re
 import shutil
 import subprocess
@@ -109,45 +108,15 @@ def build_image(ref: str, context: str, *, dockerfile: str = "") -> None:
 
     `dockerfile` is an optional path (relative to `context`, or
     absolute) for callers that need to build from a non-default
-    Dockerfile in the same context — e.g. `Dockerfile.git-gate`.
+    Dockerfile in the same context — e.g. `Dockerfile.git-gate`."""
-
-    Set `BOT_BOTTLE_NO_CACHE=1` (the `start --no-cache` flag) to force
-    `--no-cache`. The npm/curl installers some provider Dockerfiles
-    shell out to can silently no-op on a transient network failure —
-    e.g. an `optionalDependencies` fetch for a platform-native binary —
-    and Docker will then cache that broken layer indefinitely."""
     info(f"building image {ref} from {context} (layer cache keeps repeat builds fast)")
     args = ["docker", "build", "-t", ref]
-    if os.environ.get("BOT_BOTTLE_NO_CACHE") == "1":
-        args.append("--no-cache")
     if dockerfile:
         args.extend(["-f", dockerfile])
     args.append(context)
     subprocess.run(args, check=True)
 
 
-def verify_agent_image(image: str, argv: tuple[str, ...]) -> None:
-    """Run `argv` inside a throwaway container of a freshly built agent
-    image and die loudly if it fails, instead of shipping an image
-    whose CLI only breaks at first real use. No-op when the provider
-    hasn't declared a smoke test (`AgentProviderRuntime.smoke_test`)."""
-    if not argv:
-        return
-    result = subprocess.run(
-        ["docker", "run", "--rm", "--entrypoint", argv[0], image, *argv[1:]],
-        capture_output=True,
-        text=True,
-        check=False,
-    )
-    if result.returncode != 0:
-        detail = (result.stderr or result.stdout or "").strip()
-        die(
-            f"agent image {image!r} failed its post-build smoke test "
-            f"({' '.join(argv)}): {detail}\n"
-            f"Try rebuilding from scratch: bot-bottle start --no-cache"
-        )
-
-
 # def build_image_with_cwd(
 #     derived: str,
 #     base: str,

bot_bottle/backend/macos_container/launch.py

@@ -17,7 +17,6 @@ from contextlib import ExitStack, contextmanager
 from pathlib import Path
 from typing import Callable, Generator
 
-from ...agent_provider import runtime_for
 from ...bottle_state import (
     egress_state_dir,
     git_gate_state_dir,
@@ -170,9 +169,6 @@ def _build_images(plan: MacosContainerBottlePlan) -> MacosContainerBottlePlan:
         _REPO_DIR,
         dockerfile=plan.dockerfile_path,
     )
-    container_mod.verify_agent_image(
-        plan.image, runtime_for(plan.agent_provider_template).smoke_test,
-    )
     return plan
 
 

bot_bottle/backend/macos_container/util.py

@@ -60,21 +60,13 @@ def dns_server() -> str:
 
 
 def build_image(ref: str, context: str, *, dockerfile: str = "") -> None:
-    """Build an OCI image with Apple's BuildKit-backed `container build`.
+    """Build an OCI image with Apple's BuildKit-backed `container build`."""
-
-    Set `BOT_BOTTLE_NO_CACHE=1` (the `start --no-cache` flag) to force
-    `--no-cache`. The npm/curl installers some provider Dockerfiles
-    shell out to can silently no-op on a transient network failure —
-    e.g. an `optionalDependencies` fetch for a platform-native binary —
-    and the builder will then cache that broken layer indefinitely."""
     info(
         f"building image {ref} from {context} with Apple Container "
         "(layer cache keeps repeat builds fast)"
     )
     _ensure_builder_dns()
     args = [_CONTAINER, "build", "-t", ref, "--dns", dns_server()]
-    if os.environ.get("BOT_BOTTLE_NO_CACHE") == "1":
-        args.append("--no-cache")
     if dockerfile:
         # `container build` resolves -f relative to the current working
         # directory, not the build context. Anchor a relative Dockerfile to
@@ -86,28 +78,6 @@ def build_image(ref: str, context: str, *, dockerfile: str = "") -> None:
     subprocess.run(args, check=True)
 
 
-def verify_agent_image(image: str, argv: tuple[str, ...]) -> None:
-    """Run `argv` inside a throwaway container of a freshly built agent
-    image and die loudly if it fails, instead of shipping an image
-    whose CLI only breaks at first real use. No-op when the provider
-    hasn't declared a smoke test (`AgentProviderRuntime.smoke_test`)."""
-    if not argv:
-        return
-    result = subprocess.run(
-        [_CONTAINER, "run", "--rm", "--entrypoint", argv[0], image, *argv[1:]],
-        capture_output=True,
-        text=True,
-        check=False,
-    )
-    if result.returncode != 0:
-        detail = (result.stderr or result.stdout or "").strip()
-        die(
-            f"agent image {image!r} failed its post-build smoke test "
-            f"({' '.join(argv)}): {detail}\n"
-            f"Try rebuilding from scratch: bot-bottle start --no-cache"
-        )
-
-
 def commit_container(container_name: str, image_tag: str) -> None:
     """Snapshot a running Apple Container as a local image.
 

bot_bottle/backend/smolmachines/launch.py

@@ -22,7 +22,6 @@ from contextlib import ExitStack, contextmanager
 from pathlib import Path
 from typing import Callable, Generator
 
-from ...agent_provider import runtime_for
 from ...egress import (
     EGRESS_ROUTES_IN_CONTAINER,
     egress_agent_env_entries,
@@ -463,13 +462,10 @@ def _agent_from_path(plan: SmolmachinesBottlePlan) -> Path:
     return _ensure_smolmachine(
         plan.agent_image,
         dockerfile=plan.agent_dockerfile_path,
-        smoke_test=runtime_for(plan.agent_provider_template).smoke_test,
     )
 
 
-def _ensure_smolmachine(
+def _ensure_smolmachine(image_ref: str, *, dockerfile: str = "") -> Path:
-    image_ref: str, *, dockerfile: str = "", smoke_test: tuple[str, ...] = (),
-) -> Path:
     """Build the agent docker image and convert it into a
     `.smolmachine` artifact, caching the result under
     `~/.cache/bot-bottle/smolmachines/` keyed by the docker image
@@ -495,7 +491,6 @@ def _ensure_smolmachine(
     already on disk for this image ID."""
     _SMOLMACHINE_CACHE_DIR.mkdir(parents=True, exist_ok=True)
     docker_mod.build_image(image_ref, _REPO_DIR, dockerfile=dockerfile)
-    docker_mod.verify_agent_image(image_ref, smoke_test)
     # `sha256:abcd...` -> `abcd...` first 16 chars: short enough to
     # keep filenames manageable, long enough to make collisions
     # astronomically unlikely.

bot_bottle/cli/start.py

@@ -46,17 +46,6 @@ def cmd_start(argv: list[str]) -> int:
     parser = argparse.ArgumentParser(prog=f"{PROG} start", add_help=True)
     parser.add_argument("--dry-run", action="store_true")
     parser.add_argument("--cwd", action="store_true", help="copy host cwd into the running bottle")
-    parser.add_argument(
-        "--no-cache",
-        action="store_true",
-        help=(
-            "rebuild agent/sidecar images from scratch, bypassing the "
-            "build layer cache. Use when an image looks broken after a "
-            "dependency bump — e.g. an installer's optionalDependencies "
-            "fetch silently no-op'd on a transient failure and got baked "
-            "into a cached layer."
-        ),
-    )
     parser.add_argument(
         "--backend",
         choices=known_backend_names(),
@@ -108,11 +97,6 @@ def cmd_start(argv: list[str]) -> int:
     args = parser.parse_args(argv)
 
     dry_run = args.dry_run or os.environ.get("BOT_BOTTLE_DRY_RUN") == "1"
-    if args.no_cache or os.environ.get("BOT_BOTTLE_NO_CACHE") == "1":
-        # Read by build_image() in each backend's util module — set here
-        # so both the interactive and --headless paths pick it up without
-        # threading a no_cache field through every backend's plan dataclass.
-        os.environ["BOT_BOTTLE_NO_CACHE"] = "1"
 
     manifest = ManifestIndex.resolve(USER_CWD)
     backend_name: str | None = args.backend

bot_bottle/contrib/claude/agent_provider.py

@@ -91,7 +91,6 @@ _RUNTIME = AgentProviderRuntime(
     prompt_mode="append_file",
     bypass_args=("--dangerously-skip-permissions",),
     resume_args=("--continue",),
-    smoke_test=("claude", "--version"),
 )
 
 

bot_bottle/contrib/codex/agent_provider.py

@@ -61,7 +61,6 @@ _RUNTIME = AgentProviderRuntime(
     prompt_mode="read_prompt_file",
     bypass_args=("--dangerously-bypass-approvals-and-sandbox",),
     resume_args=("resume", "--last"),
-    smoke_test=(_CODEX_CLI, "--version"),
 )
 
 

docs/prds/prd-new-smolmachines-linux.md

@@ -1,6 +1,6 @@
-# PRD 0068: smolmachines backend on Linux
+# PRD prd-new: smolmachines backend on Linux
 
-- **Status:** Active
+- **Status:** Draft
 - **Author:** Claude
 - **Created:** 2026-06-25
 - **Issue:** #283

tests/unit/test_docker_launch_committed_image.py

@@ -103,8 +103,6 @@ class TestLaunchCommittedImage(unittest.TestCase):
             launch_mod.docker_mod, "image_exists", return_value=image_present,
         ), mock.patch.object(
             launch_mod.docker_mod, "build_image", side_effect=fake_build,
-        ), mock.patch.object(
-            launch_mod.docker_mod, "verify_agent_image",
         ), mock.patch.object(
             launch_mod, "egress_tls_init",
             return_value=(Path("/egress_ca"), Path("/egress_cert")),

tests/unit/test_docker_launch_teardown.py

@@ -87,7 +87,6 @@ class TestTeardownWarning(unittest.TestCase):
         buf = io.StringIO()
 
         with mock.patch.object(launch_mod.docker_mod, "build_image"), \
-             mock.patch.object(launch_mod.docker_mod, "verify_agent_image"), \
              mock.patch.object(
                  launch_mod, "egress_tls_init",
                  return_value=(Path("/egress_ca"), Path("/egress_cert")),

tests/unit/test_macos_container_launch.py

@@ -357,17 +357,12 @@ class TestMacosContainerLaunchCommittedImage(unittest.TestCase):
             launch.container_mod, "image_exists", return_value=False,
         ), patch.object(
             launch.container_mod, "build_image", side_effect=fake_build,
-        ), patch.object(
+        ):
-            launch.container_mod, "verify_agent_image",
-        ) as verify:
             updated = launch._build_images(plan)
 
         self.assertEqual("bot-bottle-agent:latest", updated.image)
         self.assertEqual(2, len(calls))
         self.assertEqual("bot-bottle-agent:latest", calls[1][0])
-        verify.assert_called_once_with(
-            "bot-bottle-agent:latest", ("claude", "--version"),
-        )
 
 
 if __name__ == "__main__":

tests/unit/test_smolmachines_launch_image.py

@@ -153,7 +153,6 @@ class TestAgentFromPath(unittest.TestCase):
             slug="dev-abc12",
             agent_image="bot-bottle-claude:latest",
             agent_dockerfile_path="/repo/Dockerfile",
-            agent_provider_template="claude",
         ))
 
     def test_uses_committed_artifact_when_present(self):
@@ -186,7 +185,6 @@ class TestAgentFromPath(unittest.TestCase):
         ensure.assert_called_once_with(
             "bot-bottle-claude:latest",
             dockerfile="/repo/Dockerfile",
-            smoke_test=("claude", "--version"),
         )