CHANGELOG.md

@@ -517,6 +517,15 @@ _ALL_DATA_COLUMNS + ") " "SELECT " + _ALL_DATA_COLUMNS + " FROM v3_plans"`.
   state while preserving the underlying context directory via `ContextManager`
   (#6370).
 - **Quick Start Guide** (PR #9245): Added `docs/quickstart.md` with an end-to-end quick start guide covering prerequisites, installation, project creation, resource registration, plan/apply workflow, and troubleshooting. Updated `mkdocs.yml` navigation to include the Quick Start page.
+- **container-instance --clone-into and devcontainer-instance sandbox strategy** (#7555):
+  Added `--clone-into` CLI argument to `container-instance` resource type for cloning
+  a git repository into a running container. Implemented `CloneIntoHandler` with
+  `clone_repo_into_container()` and `validate_clone_into_url()` helpers. Updated
+  `devcontainer-instance` to use `snapshot` sandbox strategy (was `none`) to enable
+  safe plan execution inside containers. Added `container-mount`, `container-exec-env`,
+  and `container-port` as child types of `devcontainer-instance`. Renamed
+  `ContainerLifecycleState.DETECTED` to `DISCOVERED` (value: `"discovered"`) to align
+  with specification terminology.
 
 - **Plan checkpoint management CLI commands** (#8683): Added `agents plan checkpoint-list <plan-id>` and `agents plan checkpoint-delete <checkpoint-id>` commands. Listing output now highlights checkpoint ID, type, created timestamp, reason, phase, and decision linkage with a concise field summary footer across rich/table/json/yaml formats. Deletion supports batch IDs, interactive confirmation (skip with `--yes`), and structured JSON/YAML responses for automation-friendly scripting.
 - **Invariant Remove CLI Command** (#8530): Implemented `agents invariant remove <id>` command that soft-deletes an invariant by ID. The command displays a confirmation prompt before removal (bypassable with `--yes`/ `-y`), outputs the removed invariant ID on success, and shows a clear error message when the invariant ID does not exist. Supports `--format` flag for JSON and YAML output. Full BDD test coverage and Robot Framework integration tests included.

CONTRIBUTORS.md

@@ -70,3 +70,4 @@ Below are some of the specific details of various contributions.
 * HAL 9000 has contributed BDD feature file tag coverage improvements (#9124 / pr #9183): added required `@a2a`, `@session`, and `@cli` Gherkin tags to 30 feature files (8 A2A, 7 session, 15 CLI) to enable selective tag-based test filtering via `behave --tags=a2a,session,cli`.
 * HAL 9000 has contributed the plan tree JSON `decision_id` fix (#9096): updated `step_tree_json_valid` in features/steps/plan_explain_steps.py to correctly handle the {"data": [...]} envelope structure produced by format_output, and removed @tdd_expected_fail from the @tdd_issue_4254 scenario so it runs as a permanent regression guard.
 * HAL 9000 has contributed the TDD scenario for plan tree correction visual marking (PR #8671 / issue #8576): added a failing BDD scenario proving that corrected nodes (decisions with is_correction=True) are not visually distinguished in the plan tree output, formalizing Spec Requirement #7 as an executable specification.
+* HAL 9000 has contributed the `--clone-into` CLI argument for `container-instance`, the `CloneIntoHandler` module, the `devcontainer-instance` snapshot sandbox strategy, and the `ContainerLifecycleState.DISCOVERED` terminology alignment (PR #8304, issue #7555).

benchmarks/devcontainer_lifecycle_bench.py

@@ -80,7 +80,7 @@ class TimeTransitionValidation:
         """Time valid transition check (1000 iterations)."""
         for _ in range(1000):
             validate_transition(
-                ContainerLifecycleState.DETECTED,
+                ContainerLifecycleState.DISCOVERED,
                 ContainerLifecycleState.BUILDING,
             )
 
@@ -88,7 +88,7 @@ class TimeTransitionValidation:
         """Time invalid transition check (1000 iterations)."""
         for _ in range(1000):
             validate_transition(
-                ContainerLifecycleState.DETECTED,
+                ContainerLifecycleState.DISCOVERED,
                 ContainerLifecycleState.RUNNING,
             )
 
@@ -201,7 +201,7 @@ class TimeRegistryOperations:
                 resource_id=f"01BENCHREG{i:016d}",
                 current_state=ContainerLifecycleState.RUNNING
                 if i % 2 == 0
-                else ContainerLifecycleState.DETECTED,
+                else ContainerLifecycleState.DISCOVERED,
             )
             set_lifecycle_tracker(tracker)
 

features/container_clone_into.feature

@@ -0,0 +1,92 @@
+@clone-into
+Feature: container-instance --clone-into argument
+  As a CleverAgents user
+  I want to clone a git repository into a running container
+  So that I can work with the repository inside the container environment
+
+  # ── URL validation ─────────────────────────────────────────
+
+  Scenario Outline: validate_clone_into_url accepts valid git URLs
+    When I validate clone-into URL "<url>"
+    Then the clone-into URL should be valid
+
+    Examples:
+      | url                                          |
+      | https://github.com/org/repo.git              |
+      | http://internal.example.com/repo.git         |
+      | git@github.com:org/repo.git                  |
+      | ssh://git@bitbucket.org/org/repo.git         |
+      | git://github.com/org/repo.git                |
+      | /local/path/to/repo                          |
+      | ./relative/repo                              |
+
+  Scenario Outline: validate_clone_into_url rejects invalid URLs
+    When I validate clone-into URL "<url>"
+    Then the clone-into URL should be invalid
+
+    Examples:
+      | url                  |
+      | not-a-url            |
+      | ftp://example.com    |
+
+  # ── clone_repo_into_container argument validation ──────────
+
+  Scenario: clone_repo_into_container rejects empty container_id
+    When I call clone_repo_into_container with empty container_id
+    Then it should raise ValueError mentioning "container_id"
+
+  Scenario: clone_repo_into_container rejects empty repo_url
+    When I call clone_repo_into_container with empty repo_url
+    Then it should raise ValueError mentioning "repo_url"
+
+  # ── Successful clone ────────────────────────────────────────
+
+  Scenario: clone_repo_into_container succeeds when docker exec returns 0
+    Given a mock docker exec that succeeds for clone
+    When I clone "https://github.com/org/repo.git" into container "abc123def456"
+    Then the clone should succeed
+    And the clone target should be "/workspace"
+
+  Scenario: clone_repo_into_container uses custom target directory
+    Given a mock docker exec that succeeds for clone
+    When I clone repo "https://github.com/org/repo.git" into container "abc123def456" with target "/custom/dir"
+    Then the clone should succeed
+    And the clone target should be "/custom/dir"
+
+  # ── Failure handling ────────────────────────────────────────
+
+  Scenario: clone_repo_into_container raises CloneIntoError when docker exec fails
+    Given a mock docker exec that fails for clone with stderr "fatal: repository not found"
+    When I clone "https://github.com/org/missing.git" into container "abc123def456"
+    Then the clone should raise CloneIntoError
+    And the CloneIntoError should mention "repository not found"
+
+  # ── CloneIntoError attributes ──────────────────────────────
+
+  Scenario: CloneIntoError stores repo_url, container_id, and stderr
+    Given a CloneIntoError with repo "https://example.com/repo.git" container "ctr-001" stderr "auth failed"
+    Then the CloneIntoError repo_url should be "https://example.com/repo.git"
+    And the CloneIntoError container_id should be "ctr-001"
+    And the CloneIntoError stderr should be "auth failed"
+
+  # ── container-instance resource type has --clone-into arg ──
+
+  Scenario: container-instance resource type has clone-into CLI argument
+    When I look up the "container-instance" resource type spec
+    Then the spec should have a CLI argument named "clone-into"
+    And the clone-into argument should be of type "string"
+    And the clone-into argument should not be required
+
+  # ── validate_clone_into_url edge cases ─────────────────────
+
+  Scenario: validate_clone_into_url rejects whitespace-only string
+    When I validate clone-into URL with whitespace only
+    Then the clone-into URL should be invalid
+
+  # -- End-to-end handler wiring --
+
+  Scenario: DevcontainerHandler.resolve() calls clone_repo_into_container when clone_into property is set
+    Given a devcontainer-instance resource with clone_into "https://github.com/org/repo.git" and tracker container_id "abc123def456"
+    And clone_repo_into_container is mocked to succeed
+    When DevcontainerHandler.resolve() is called for the resource
+    Then clone_repo_into_container should have been called with container_id "abc123def456" and url "https://github.com/org/repo.git"

features/devcontainer_cleanup.feature

@@ -87,7 +87,7 @@ Feature: Devcontainer Session Cleanup and CLI Commands
   # ── R8: DevcontainerHandler coverage ───────────────────────
 
   Scenario: DevcontainerHandler has expected class attributes and is instantiable
-    Then DevcontainerHandler should have _default_strategy "none"
+    Then DevcontainerHandler should have _default_strategy "snapshot"
     And DevcontainerHandler should have _type_label "devcontainer"
     And DevcontainerHandler should be instantiable
 

features/devcontainer_handler.feature

@@ -85,7 +85,7 @@ Feature: Devcontainer Resource Handler
 
   Scenario: DevcontainerHandler has correct default strategy
     When I instantiate DevcontainerHandler
-    Then its default strategy should be "none"
+    Then its default strategy should be "snapshot"
 
   Scenario: DevcontainerHandler has correct type label
     When I instantiate DevcontainerHandler

features/devcontainer_handler_protocol_methods.feature

@@ -121,13 +121,13 @@ Feature: DevcontainerHandler missing protocol methods
     And dcproto the container is in RUNNING state
     And dcproto a mock sandbox manager that returns a valid sandbox
     When dcproto I create a sandbox for the resource with plan "plan-001"
-    Then dcproto the sandbox result should have strategy "none"
+    Then dcproto the sandbox result should have strategy "snapshot"
     And dcproto the sandbox result should have a sandbox path
 
-  Scenario: dcproto create_sandbox activates container when in DETECTED state
+  Scenario: dcproto create_sandbox activates container when in DISCOVERED state
     Given dcproto a devcontainer handler
     And dcproto a devcontainer-instance resource with location "/ws/project"
-    And dcproto the container is in DETECTED state
+    And dcproto the container is in DISCOVERED state
     And dcproto a mock sandbox manager that returns a valid sandbox
     And dcproto activate_container is mocked to succeed
     When dcproto I create a sandbox for the resource with plan "plan-002"

features/devcontainer_sandbox_strategy.feature

@@ -0,0 +1,58 @@
+@devcontainer-sandbox
+Feature: devcontainer-instance uses snapshot sandbox strategy
+  As a CleverAgents developer
+  I want devcontainer-instance resources to use the snapshot sandbox strategy
+  So that plan execution inside containers is safely isolated
+
+  # ── DevcontainerHandler default strategy ───────────────────
+
+  Scenario: DevcontainerHandler default strategy is snapshot
+    When I inspect DevcontainerHandler class attributes
+    Then the DevcontainerHandler _default_strategy should be "snapshot"
+
+  # ── devcontainer-instance resource type spec ───────────────
+
+  Scenario: devcontainer-instance resource type has snapshot sandbox strategy
+    When I look up the "devcontainer-instance" resource type spec
+    Then the spec sandbox_strategy should be "snapshot"
+
+  # ── devcontainer-instance child types ──────────────────────
+
+  Scenario: devcontainer-instance child_types includes container-mount
+    When I look up the "devcontainer-instance" resource type spec
+    Then the spec child_types should contain "container-mount"
+
+  Scenario: devcontainer-instance child_types includes container-exec-env
+    When I look up the "devcontainer-instance" resource type spec
+    Then the spec child_types should contain "container-exec-env"
+
+  Scenario: devcontainer-instance child_types includes container-port
+    When I look up the "devcontainer-instance" resource type spec
+    Then the spec child_types should contain "container-port"
+
+  Scenario: devcontainer-instance child_types includes devcontainer-file
+    When I look up the "devcontainer-instance" resource type spec
+    Then the spec child_types should contain "devcontainer-file"
+
+  # ── ContainerLifecycleState initial state ──────────────────
+
+  Scenario: ContainerLifecycleTracker default state is discovered
+    When I create a new ContainerLifecycleTracker for resource "01SANDBOX0000000000000001"
+    Then the tracker initial state should be "discovered"
+
+  Scenario: ContainerLifecycleState has discovered value
+    When I inspect ContainerLifecycleState enum values
+    Then the lifecycle enum values should contain "discovered"
+    And the lifecycle enum values should not contain "detected"
+
+  # ── BUILTIN_TYPES registration ─────────────────────────────
+
+  Scenario: devcontainer-instance in BUILTIN_TYPES has snapshot strategy
+    When I look up "devcontainer-instance" in BUILTIN_TYPES
+    Then the BUILTIN_TYPES entry sandbox_strategy should be "snapshot"
+
+  Scenario: devcontainer-instance in BUILTIN_TYPES has correct child_types
+    When I look up "devcontainer-instance" in BUILTIN_TYPES
+    Then the BUILTIN_TYPES entry child_types should include "container-mount"
+    And the BUILTIN_TYPES entry child_types should include "container-exec-env"
+    And the BUILTIN_TYPES entry child_types should include "container-port"

features/devcontainer_state.feature

@@ -7,7 +7,7 @@ Feature: Devcontainer Lifecycle State Model
 
   Scenario: ContainerLifecycleState has all required values
     When I inspect ContainerLifecycleState enum values
-    Then the lifecycle enum should contain "detected"
+    Then the lifecycle enum should contain "discovered"
     And the lifecycle enum should contain "building"
     And the lifecycle enum should contain "running"
     And the lifecycle enum should contain "stopping"
@@ -16,7 +16,7 @@ Feature: Devcontainer Lifecycle State Model
 
   Scenario: Valid transitions are accepted
     Given a lifecycle tracker for resource "01TESTLIFECYCLE0000000001"
-    When I transition from "detected" to "building"
+    When I transition from "discovered" to "building"
     Then the transition should succeed
     And the tracker state should be "building"
 
@@ -28,7 +28,7 @@ Feature: Devcontainer Lifecycle State Model
 
   Scenario: Invalid transition is rejected
     Given a lifecycle tracker for resource "01TESTLIFECYCLE0000000003"
-    When I attempt to transition from "detected" to "running"
+    When I attempt to transition from "discovered" to "running"
     Then the transition should raise ValueError
 
   Scenario: Stopping to error transition is valid
@@ -50,14 +50,14 @@ Feature: Devcontainer Lifecycle State Model
 
   Scenario: Transition history is recorded
     Given a lifecycle tracker for resource "01TESTLIFECYCLE0000000007"
-    When I transition from "detected" to "building"
+    When I transition from "discovered" to "building"
     Then the tracker should have 1 transition in history
 
   # ── Lifecycle registry ─────────────────────────────────────
 
   Scenario: Lifecycle tracker persists state across calls
     Given a lifecycle tracker for resource "01TESTLIFECYCLE0000000060"
-    When I transition from "detected" to "building"
+    When I transition from "discovered" to "building"
     And I retrieve the tracker for "01TESTLIFECYCLE0000000060"
     Then the retrieved tracker state should be "building"
 
@@ -132,14 +132,14 @@ Feature: Devcontainer Lifecycle State Model
     When I attempt to transition from "failed" to "running"
     Then the transition should raise ValueError
 
-  Scenario: Invalid transition detected to stopping is rejected
+  Scenario: Invalid transition discovered to stopping is rejected
     Given a lifecycle tracker for resource "01TESTLIFECYCLE0000000244"
-    When I attempt to transition from "detected" to "stopping"
+    When I attempt to transition from "discovered" to "stopping"
     Then the transition should raise ValueError
 
-  Scenario: Invalid transition building to detected is rejected
+  Scenario: Invalid transition building to discovered is rejected
     Given a lifecycle tracker in "building" state for resource "01TESTLIFECYCLE0000000245"
-    When I attempt to transition from "building" to "detected"
+    When I attempt to transition from "building" to "discovered"
     Then the transition should raise ValueError
 
   # ── R4: Multi-line JSON output parsing ─────────────────────
@@ -185,7 +185,7 @@ Feature: Devcontainer Lifecycle State Model
 
   Scenario: get_lifecycle_tracker auto-creates tracker for new resource
     When I get tracker for new resource "01TESTLIFECYCLE0000000730"
-    Then the auto-created tracker state should be "detected"
+    Then the auto-created tracker state should be "discovered"
     And the auto-created tracker resource_id should be "01TESTLIFECYCLE0000000730"
 
   Scenario: clear_lifecycle_registry stops health check threads

features/resource_list_lifecycle_state.feature

@@ -1,7 +1,7 @@
 Feature: agents resource list shows devcontainer lifecycle state column
   As a CleverAgents user
   I want the resource list to show the lifecycle state for devcontainer-instance resources
-  So that I can see whether a devcontainer is detected, running, stopped, or failed
+  So that I can see whether a devcontainer is discovered, running, stopped, or failed
 
   Background:
     Given a fresh in-memory resource registry
@@ -14,10 +14,10 @@ Feature: agents resource list shows devcontainer lifecycle state column
     And the resource output should contain "Children"
     And the resource output should contain "Projects"
 
-  Scenario: resource list shows "detected (not built)" for a new devcontainer-instance
+  Scenario: resource list shows "discovered (not built)" for a new devcontainer-instance
     Given a devcontainer-instance resource is registered
     When I run resource list with all flag
-    Then the resource output should contain "detected (not built)"
+    Then the resource output should contain "discovered (not built)"
 
   Scenario: resource list shows "running" state for a running devcontainer
     Given a devcontainer-instance resource is registered
@@ -43,16 +43,16 @@ Feature: agents resource list shows devcontainer lifecycle state column
     Then the resource output should contain "local/my-repo"
     And the resource output should contain "git-checkout"
 
-  Scenario: resource list shows warning banner when devcontainer is in detected state
+  Scenario: resource list shows warning banner when devcontainer is in discovered state
     Given a devcontainer-instance resource is registered
     When I run resource list with all flag
-    Then the resource output should contain "Devcontainer detected"
+    Then the resource output should contain "Devcontainer discovered"
 
   Scenario: resource list does not show warning banner when devcontainer is running
     Given a devcontainer-instance resource is registered
     And the devcontainer lifecycle state is "running"
     When I run resource list with all flag
-    Then the resource output should not contain "Devcontainer detected"
+    Then the resource output should not contain "Devcontainer discovered"
 
   @tdd_issue @tdd_issue_4263 @tdd_expected_fail
   Scenario: resource list JSON output includes lifecycle_state for devcontainer-instance
@@ -70,7 +70,7 @@ Feature: agents resource list shows devcontainer lifecycle state column
   Scenario: resource list shows lifecycle state for container-instance resources
     Given a container-instance resource is registered
     When I run resource list with all flag
-    Then the resource output should contain "detected (not built)"
+    Then the resource output should contain "discovered (not built)"
 
   Scenario: resource list succeeds gracefully when lifecycle tracker raises an error
     Given a devcontainer-instance resource is registered

features/steps/container_clone_into_steps.py

@@ -0,0 +1,404 @@
+"""Step definitions for container_clone_into.feature.
+
+Tests the CloneIntoHandler module: URL validation, argument validation,
+successful clone, failure handling, and container-instance resource type
+CLI argument registration.
+"""
+
+from __future__ import annotations
+
+from typing import Any
+from unittest.mock import MagicMock, patch
+
+from behave import given, then, when  # type: ignore[import-untyped]
+from behave.runner import Context  # type: ignore[import-untyped]
+
+from cleveragents.application.services._resource_registry_data import (
+    BUILTIN_TYPES,
+)
+from cleveragents.domain.models.core.container_lifecycle import (
+    ContainerLifecycleState,
+    ContainerLifecycleTracker,
+)
+from cleveragents.resource.handlers.clone_into import (
+    CloneIntoError,
+    clone_repo_into_container,
+    validate_clone_into_url,
+)
+from cleveragents.resource.handlers.devcontainer import (
+    DevcontainerHandler,
+    clear_lifecycle_registry,
+    set_lifecycle_tracker,
+)
+from cleveragents.domain.models.core.resource import Resource
+
+# ── When steps ───────────────────────────────────────────────
+
+
+@when('I validate clone-into URL "{url}"')
+def step_validate_url(context: Context, url: str) -> None:
+    """Validate a clone-into URL."""
+    context.clone_url_error = None
+    try:
+        validate_clone_into_url(url)
+        context.clone_url_valid = True
+    except ValueError as exc:
+        context.clone_url_valid = False
+        context.clone_url_error = exc
+
+
+@when("I validate clone-into URL with whitespace only")
+def step_validate_whitespace_url(context: Context) -> None:
+    """Validate a whitespace-only clone-into URL."""
+    context.clone_url_error = None
+    try:
+        validate_clone_into_url("   ")
+        context.clone_url_valid = True
+    except ValueError as exc:
+        context.clone_url_valid = False
+        context.clone_url_error = exc
+
+
+@when("I call clone_repo_into_container with empty container_id")
+def step_clone_empty_container_id(context: Context) -> None:
+    """Call clone_repo_into_container with an empty container_id."""
+    context.clone_error = None
+    try:
+        clone_repo_into_container("", "https://github.com/org/repo.git")
+    except ValueError as exc:
+        context.clone_error = exc
+
+
+@when("I call clone_repo_into_container with empty repo_url")
+def step_clone_empty_repo_url(context: Context) -> None:
+    """Call clone_repo_into_container with an empty repo_url."""
+    context.clone_error = None
+    try:
+        clone_repo_into_container("abc123def456", "")
+    except ValueError as exc:
+        context.clone_error = exc
+
+
+@when('I clone "{repo_url}" into container "{container_id}"')
+def step_clone_into_container(
+    context: Context, repo_url: str, container_id: str
+) -> None:
+    """Clone a repository into a container."""
+    context.clone_error = None
+    context.clone_result = None
+    try:
+        context.clone_result = clone_repo_into_container(container_id, repo_url)
+    except (CloneIntoError, ValueError) as exc:
+        context.clone_error = exc
+
+
+@when(
+    'I clone repo "{repo_url}" into container "{container_id}" with target "{target_dir}"'
+)
+def step_clone_into_container_at(
+    context: Context, repo_url: str, container_id: str, target_dir: str
+) -> None:
+    """Clone a repository into a container at a specific target directory."""
+    context.clone_error = None
+    context.clone_result = None
+    try:
+        context.clone_result = clone_repo_into_container(
+            container_id, repo_url, target_dir
+        )
+    except (CloneIntoError, ValueError) as exc:
+        context.clone_error = exc
+
+
+@when('I look up the "{type_name}" resource type spec')
+def step_look_up_resource_type_spec(context: Context, type_name: str) -> None:
+    """Look up a resource type spec from BUILTIN_TYPES."""
+    context.resource_type_spec = None
+    for entry in BUILTIN_TYPES:
+        if entry.get("name") == type_name:
+            context.resource_type_spec = entry
+            break
+
+
+# ── Given steps ──────────────────────────────────────────────
+
+
+@given("a mock docker exec that succeeds for clone")
+def step_mock_docker_exec_success(context: Context) -> None:
+    """Patch subprocess.run to simulate a successful docker exec git clone."""
+    mock_result = MagicMock()
+    mock_result.returncode = 0
+    mock_result.stdout = ""
+    mock_result.stderr = ""
+
+    patcher = patch(
+        "cleveragents.resource.handlers.clone_into.subprocess.run",
+        return_value=mock_result,
+    )
+    patcher.start()
+    context.add_cleanup(patcher.stop)
+
+
+@given('a mock docker exec that fails for clone with stderr "{stderr_msg}"')
+def step_mock_docker_exec_failure(context: Context, stderr_msg: str) -> None:
+    """Patch subprocess.run to simulate a failed docker exec git clone."""
+    mock_result = MagicMock()
+    mock_result.returncode = 1
+    mock_result.stdout = ""
+    mock_result.stderr = stderr_msg
+
+    patcher = patch(
+        "cleveragents.resource.handlers.clone_into.subprocess.run",
+        return_value=mock_result,
+    )
+    patcher.start()
+    context.add_cleanup(patcher.stop)
+
+
+@given(
+    'a CloneIntoError with repo "{repo_url}" container "{container_id}" stderr "{stderr}"'
+)
+def step_create_clone_into_error(
+    context: Context, repo_url: str, container_id: str, stderr: str
+) -> None:
+    """Create a CloneIntoError instance for attribute testing."""
+    context.clone_into_error = CloneIntoError(
+        repo_url=repo_url,
+        container_id=container_id,
+        stderr=stderr,
+    )
+
+
+# ── Then steps ───────────────────────────────────────────────
+
+
+@then("the clone-into URL should be valid")
+def step_url_should_be_valid(context: Context) -> None:
+    assert context.clone_url_valid is True, (
+        "Expected URL to be valid but validate_clone_into_url returned False"
+    )
+
+
+@then("the clone-into URL should be invalid")
+def step_url_should_be_invalid(context: Context) -> None:
+    assert context.clone_url_valid is False, (
+        "Expected URL to be invalid but validate_clone_into_url returned True"
+    )
+
+
+@then('it should raise ValueError mentioning "{field}"')
+def step_should_raise_value_error(context: Context, field: str) -> None:
+    assert context.clone_error is not None, (
+        "Expected a ValueError but no error was raised"
+    )
+    assert isinstance(context.clone_error, ValueError), (
+        f"Expected ValueError, got {type(context.clone_error).__name__}"
+    )
+    assert field.lower() in str(context.clone_error).lower(), (
+        f"Expected '{field}' in error message, got: {context.clone_error!r}"
+    )
+
+
+@then("the clone should succeed")
+def step_clone_should_succeed(context: Context) -> None:
+    assert context.clone_error is None, (
+        f"Expected clone to succeed but got error: {context.clone_error!r}"
+    )
+    assert context.clone_result is not None, "Expected a clone result but got None"
+
+
+@then('the clone target should be "{expected_target}"')
+def step_clone_target(context: Context, expected_target: str) -> None:
+    assert context.clone_result == expected_target, (
+        f"Expected clone target '{expected_target}', got '{context.clone_result}'"
+    )
+
+
+@then("the clone should raise CloneIntoError")
+def step_clone_should_raise(context: Context) -> None:
+    assert context.clone_error is not None, (
+        "Expected CloneIntoError but no error was raised"
+    )
+    assert isinstance(context.clone_error, CloneIntoError), (
+        f"Expected CloneIntoError, got {type(context.clone_error).__name__}"
+    )
+
+
+@then('the CloneIntoError should mention "{text}"')
+def step_clone_error_mentions(context: Context, text: str) -> None:
+    error_str = str(context.clone_error)
+    assert text.lower() in error_str.lower(), (
+        f"Expected '{text}' in CloneIntoError message, got: {error_str!r}"
+    )
+
+
+@then('the CloneIntoError repo_url should be "{expected}"')
+def step_clone_error_repo_url(context: Context, expected: str) -> None:
+    assert context.clone_into_error.repo_url == expected, (
+        f"Expected repo_url '{expected}', got '{context.clone_into_error.repo_url}'"
+    )
+
+
+@then('the CloneIntoError container_id should be "{expected}"')
+def step_clone_error_container_id(context: Context, expected: str) -> None:
+    assert context.clone_into_error.container_id == expected, (
+        f"Expected container_id '{expected}', "
+        f"got '{context.clone_into_error.container_id}'"
+    )
+
+
+@then('the CloneIntoError stderr should be "{expected}"')
+def step_clone_error_stderr(context: Context, expected: str) -> None:
+    assert context.clone_into_error.stderr == expected, (
+        f"Expected stderr '{expected}', got '{context.clone_into_error.stderr}'"
+    )
+
+
+@then('the spec should have a CLI argument named "{arg_name}"')
+def step_spec_has_cli_arg(context: Context, arg_name: str) -> None:
+    spec = context.resource_type_spec
+    assert spec is not None, "No resource type spec found"
+    cli_args: list[dict[str, Any]] = spec.get("cli_args", [])
+    arg_names = [arg.get("name") for arg in cli_args]
+    assert arg_name in arg_names, f"Expected CLI argument '{arg_name}' in {arg_names}"
+
+
+@then('the clone-into argument should be of type "{expected_type}"')
+def step_clone_into_arg_type(context: Context, expected_type: str) -> None:
+    spec = context.resource_type_spec
+    assert spec is not None, "No resource type spec found"
+    cli_args: list[dict[str, Any]] = spec.get("cli_args", [])
+    clone_into_arg = next(
+        (arg for arg in cli_args if arg.get("name") == "clone-into"), None
+    )
+    assert clone_into_arg is not None, "clone-into argument not found"
+    assert clone_into_arg.get("type") == expected_type, (
+        f"Expected type '{expected_type}', got '{clone_into_arg.get('type')}'"
+    )
+
+
+@then("the clone-into argument should not be required")
+def step_clone_into_not_required(context: Context) -> None:
+    spec = context.resource_type_spec
+    assert spec is not None, "No resource type spec found"
+    cli_args: list[dict[str, Any]] = spec.get("cli_args", [])
+    clone_into_arg = next(
+        (arg for arg in cli_args if arg.get("name") == "clone-into"), None
+    )
+    assert clone_into_arg is not None, "clone-into argument not found"
+    assert clone_into_arg.get("required") is False, (
+        f"Expected clone-into to be optional (required=False), "
+        f"got required={clone_into_arg.get('required')}"
+    )
+
+
+# -- End-to-end handler wiring steps --
+
+
+@given(
+    'a devcontainer-instance resource with clone_into "{clone_url}" and tracker container_id "{container_id}"'
+)
+def step_devcontainer_resource_with_clone_into(
+    context: Context, clone_url: str, container_id: str
+) -> None:
+    """Set up a devcontainer-instance resource with clone_into property and tracker."""
+    # Clear any existing lifecycle state
+    clear_lifecycle_registry()
+
+    # Create a resource with clone_into in properties
+    # resource_id must be a valid ULID (Crockford Base32, 26 chars, no I/L/O/U)
+    # classification must be 'physical' or 'virtual'
+    context.handler_resource = Resource(
+        resource_id="01ARZ3NDEKTSV4RRFFQ69G5FAV",
+        name="test-devcontainer",
+        resource_type_name="devcontainer-instance",
+        classification="physical",
+        description="Test devcontainer for clone-into wiring",
+        location="/tmp/test-workspace",
+        properties={"clone_into": clone_url},
+    )
+
+    # Set up the lifecycle tracker in DISCOVERED state with container_id pre-set
+    # (simulates the state after activate_container() has run and set container_id)
+    tracker = ContainerLifecycleTracker(
+        resource_id="01ARZ3NDEKTSV4RRFFQ69G5FAV",
+        current_state=ContainerLifecycleState.DISCOVERED,
+        container_id=container_id,
+    )
+    set_lifecycle_tracker(tracker)
+
+    context.handler_clone_url = clone_url
+    context.handler_container_id = container_id
+
+    # Store cleanup reference
+    context.add_cleanup(clear_lifecycle_registry)
+
+
+@given("clone_repo_into_container is mocked to succeed")
+def step_mock_clone_repo_into_container(context: Context) -> None:
+    """Mock clone_repo_into_container to capture calls without running docker."""
+    mock_clone = MagicMock(return_value="/workspace")
+    patcher = patch(
+        "cleveragents.resource.handlers.devcontainer.clone_repo_into_container",
+        mock_clone,
+    )
+    patcher.start()
+    context.mock_clone_repo = mock_clone
+    context.add_cleanup(patcher.stop)
+
+
+@when("DevcontainerHandler.resolve() is called for the resource")
+def step_call_devcontainer_handler_resolve(context: Context) -> None:
+    """Call DevcontainerHandler.resolve() with the test resource."""
+    handler = DevcontainerHandler()
+    mock_sandbox_manager = MagicMock()
+    mock_bound_resource = MagicMock()
+
+    # Patch activate_container to be a no-op (tracker already has container_id)
+    # Patch BaseResourceHandler.resolve to return a mock BoundResource
+    with (
+        patch("cleveragents.resource.handlers.devcontainer.activate_container"),
+        patch(
+            "cleveragents.resource.handlers._base.BaseResourceHandler.resolve",
+            return_value=mock_bound_resource,
+        ),
+    ):
+        context.handler_resolve_error = None
+        context.handler_resolve_result = None
+        try:
+            context.handler_resolve_result = handler.resolve(
+                resource=context.handler_resource,
+                plan_id="test-plan-001",
+                slot_name="test-slot",
+                sandbox_manager=mock_sandbox_manager,
+            )
+        except Exception as exc:
+            context.handler_resolve_error = exc
+
+
+@then(
+    'clone_repo_into_container should have been called with container_id "{expected_container_id}" and url "{expected_url}"'
+)
+def step_assert_clone_called(
+    context: Context, expected_container_id: str, expected_url: str
+) -> None:
+    """Assert that clone_repo_into_container was called with the expected arguments."""
+    assert context.handler_resolve_error is None, (
+        f"Expected resolve() to succeed but got error: {context.handler_resolve_error!r}"
+    )
+    mock_clone = context.mock_clone_repo
+    assert mock_clone.called, (
+        "Expected clone_repo_into_container to have been called, but it was not"
+    )
+    call_args = mock_clone.call_args
+    actual_container_id = (
+        call_args[0][0] if call_args[0] else call_args[1].get("container_id")
+    )
+    actual_url = (
+        call_args[0][1] if len(call_args[0]) > 1 else call_args[1].get("repo_url")
+    )
+    assert actual_container_id == expected_container_id, (
+        f"Expected container_id '{expected_container_id}', got '{actual_container_id}'"
+    )
+    assert actual_url == expected_url, (
+        f"Expected url '{expected_url}', got '{actual_url}'"
+    )

features/steps/devcontainer_handler_protocol_methods_steps.py

@@ -152,18 +152,18 @@ def step_dcproto_container_running(context: Context) -> None:
     context.dcproto_container_state = ContainerLifecycleState.RUNNING
 
 
-@given("dcproto the container is in DETECTED state")
-def step_dcproto_container_detected(context: Context) -> None:
+@given("dcproto the container is in DISCOVERED state")
+def step_dcproto_container_discovered(context: Context) -> None:
     from cleveragents.resource.handlers._devcontainer_internals import (
         set_lifecycle_tracker,
     )
 
-    # DETECTED is the initial state — no transition needed.
+    # DISCOVERED is the initial state — no transition needed.
     tracker = ContainerLifecycleTracker(
         resource_id=context.dcproto_resource.resource_id,
     )
     set_lifecycle_tracker(tracker)
-    context.dcproto_container_state = ContainerLifecycleState.DETECTED
+    context.dcproto_container_state = ContainerLifecycleState.DISCOVERED
 
 
 @given("dcproto the container is in STOPPED state")

features/steps/devcontainer_lifecycle_steps.py

@@ -164,7 +164,7 @@ def step_validate_transition_bad_to_state(context: Context) -> None:
     context.type_error = None
     try:
         validate_transition(
-            ContainerLifecycleState.DETECTED,
+            ContainerLifecycleState.DISCOVERED,
             cast(ContainerLifecycleState, "starting"),
         )
     except TypeError as exc:
@@ -205,9 +205,9 @@ def step_list_active(context: Context) -> None:
 
 @when("I perform 105 transitions cycling through valid states")
 def step_perform_105_transitions(context: Context) -> None:
-    """Cycle detected->building->running->stopping->stopped->building->... 105 times."""
+    """Cycle discovered->building->running->stopping->stopped->building->... 105 times."""
     tracker = context.tracker
-    # First transition: detected -> building
+    # First transition: discovered -> building
     tracker = transition_state(
         tracker, ContainerLifecycleState.BUILDING, reason="t1-init"
     )

features/steps/devcontainer_sandbox_strategy_steps.py

@@ -0,0 +1,119 @@
+"""Step definitions for devcontainer_sandbox_strategy.feature.
+
+Tests that devcontainer-instance uses snapshot sandbox strategy,
+has the correct child types, and that ContainerLifecycleState uses
+'discovered' as the initial state.
+"""
+
+from __future__ import annotations
+
+from behave import then, when
+from behave.runner import Context
+
+from cleveragents.application.services._resource_registry_data import (
+    BUILTIN_TYPES,
+)
+from cleveragents.domain.models.core.container_lifecycle import (
+    ContainerLifecycleTracker,
+)
+from cleveragents.resource.handlers.devcontainer import DevcontainerHandler
+
+# ── When steps ───────────────────────────────────────────────
+
+
+@when("I inspect DevcontainerHandler class attributes")
+def step_inspect_devcontainer_handler(context: Context) -> None:
+    """Capture DevcontainerHandler class attributes for inspection."""
+    context.devcontainer_handler_strategy = DevcontainerHandler._default_strategy
+
+
+@when('I create a new ContainerLifecycleTracker for resource "{resource_id}"')
+def step_create_tracker_for_sandbox(context: Context, resource_id: str) -> None:
+    """Create a new ContainerLifecycleTracker with default state."""
+    context.sandbox_tracker = ContainerLifecycleTracker(resource_id=resource_id)
+
+
+@when('I look up "{type_name}" in BUILTIN_TYPES')
+def step_look_up_in_builtin_types(context: Context, type_name: str) -> None:
+    """Look up a resource type entry in BUILTIN_TYPES."""
+    context.builtin_type_entry = None
+    for entry in BUILTIN_TYPES:
+        if entry.get("name") == type_name:
+            context.builtin_type_entry = entry
+            break
+
+
+# ── Then steps ───────────────────────────────────────────────
+
+
+@then('the DevcontainerHandler _default_strategy should be "{expected}"')
+def step_devcontainer_handler_strategy(context: Context, expected: str) -> None:
+    strategy = context.devcontainer_handler_strategy
+    strategy_value = strategy.value if hasattr(strategy, "value") else str(strategy)
+    assert strategy_value == expected, (
+        f"Expected DevcontainerHandler._default_strategy to be '{expected}', "
+        f"got '{strategy_value}'"
+    )
+
+
+@then('the spec sandbox_strategy should be "{expected}"')
+def step_spec_sandbox_strategy(context: Context, expected: str) -> None:
+    spec = context.resource_type_spec
+    assert spec is not None, "No resource type spec found"
+    actual = spec.get("sandbox_strategy")
+    assert actual == expected, f"Expected sandbox_strategy '{expected}', got '{actual}'"
+
+
+@then('the spec child_types should contain "{child_type}"')
+def step_spec_child_types_contains(context: Context, child_type: str) -> None:
+    spec = context.resource_type_spec
+    assert spec is not None, "No resource type spec found"
+    child_types: list[str] = spec.get("child_types", [])
+    assert child_type in child_types, (
+        f"Expected '{child_type}' in child_types {child_types}"
+    )
+
+
+@then('the tracker initial state should be "{expected}"')
+def step_tracker_initial_state(context: Context, expected: str) -> None:
+    tracker = context.sandbox_tracker
+    actual = tracker.current_state.value
+    assert actual == expected, (
+        f"Expected initial tracker state '{expected}', got '{actual}'"
+    )
+
+
+@then('the lifecycle enum values should contain "{expected}"')
+def step_lifecycle_enum_contains(context: Context, expected: str) -> None:
+    values = context.enum_values
+    assert expected in values, (
+        f"Expected '{expected}' in lifecycle enum values {values}"
+    )
+
+
+@then('the lifecycle enum values should not contain "{unexpected}"')
+def step_lifecycle_enum_not_contains(context: Context, unexpected: str) -> None:
+    values = context.enum_values
+    assert unexpected not in values, (
+        f"Expected '{unexpected}' NOT to be in lifecycle enum values {values}"
+    )
+
+
+@then('the BUILTIN_TYPES entry sandbox_strategy should be "{expected}"')
+def step_builtin_types_sandbox_strategy(context: Context, expected: str) -> None:
+    entry = context.builtin_type_entry
+    assert entry is not None, "No BUILTIN_TYPES entry found"
+    actual = entry.get("sandbox_strategy")
+    assert actual == expected, (
+        f"Expected BUILTIN_TYPES sandbox_strategy '{expected}', got '{actual}'"
+    )
+
+
+@then('the BUILTIN_TYPES entry child_types should include "{child_type}"')
+def step_builtin_types_child_types(context: Context, child_type: str) -> None:
+    entry = context.builtin_type_entry
+    assert entry is not None, "No BUILTIN_TYPES entry found"
+    child_types: list[str] = entry.get("child_types", [])
+    assert child_type in child_types, (
+        f"Expected '{child_type}' in BUILTIN_TYPES child_types {child_types}"
+    )

features/steps/resource_list_lifecycle_state_steps.py

@@ -102,7 +102,7 @@ def step_register_devcontainer_resource(context: Context) -> None:
         properties=None,
     )
     context.devcontainer_resource_id = resource.resource_id
-    # Default state is DETECTED — no tracker manipulation needed
+    # Default state is DISCOVERED — no tracker manipulation needed
 
 
 @given("a container-instance resource is registered")
@@ -119,7 +119,7 @@ def step_register_container_resource(context: Context) -> None:
         properties=None,
     )
     context.devcontainer_resource_id = resource.resource_id
-    # Default state is DETECTED — no tracker manipulation needed
+    # Default state is DISCOVERED — no tracker manipulation needed
 
 
 @given('the devcontainer lifecycle state is "{state}"')

robot/helper_devcontainer_handler.py

@@ -75,12 +75,11 @@ def cmd_protocol_check() -> None:
 def cmd_strategy_check() -> None:
     """Verify DevcontainerHandler default strategy.
 
-    F22/F25 fix: handler uses ``none`` because SandboxFactory has not yet
-    implemented ``snapshot``.  The container itself provides isolation.
-    Known limitation — will switch to ``snapshot`` once implemented.
+    PR #8304 fix: handler now uses ``snapshot`` strategy for safe plan
+    execution inside containers (ADR-043 devcontainer integration).
     """
     handler = DevcontainerHandler()
-    assert handler._default_strategy.value == "none"
+    assert handler._default_strategy.value == "snapshot"
     print("strategy-check-ok")
 
 

robot/helper_devcontainer_lifecycle.py

@@ -104,14 +104,14 @@ class _MockRunner:
 
 def cmd_enum_values() -> None:
     """Verify all six lifecycle states exist."""
-    expected = {"detected", "building", "running", "stopping", "stopped", "failed"}
+    expected = {"discovered", "building", "running", "stopping", "stopped", "failed"}
     actual = {s.value for s in ContainerLifecycleState}
     assert actual == expected, f"Expected {expected}, got {actual}"
     print("enum-values-ok")
 
 
 def cmd_transition_valid() -> None:
-    """Verify detected->building transition."""
+    """Verify discovered->building transition."""
     clear_lifecycle_registry()
     tracker = ContainerLifecycleTracker(resource_id="01ROBOTTEST0000000000001")
     tracker = transition_state(tracker, ContainerLifecycleState.BUILDING, reason="test")

src/cleveragents/application/services/_resource_registry_data.py

@@ -223,6 +223,17 @@ _GIT_FS_CONTAINER_TYPES: list[dict[str, Any]] = [
                 ),
                 "default": None,
             },
+            {
+                "name": "clone-into",
+                "type": "string",
+                "required": False,
+                "description": (
+                    "Git repository URL to clone into the container after "
+                    "it starts. The repository is cloned into the container "
+                    "workspace using 'git clone <url>'."
+                ),
+                "default": None,
+            },
         ],
         "parent_types": [
             "container-runtime",
@@ -265,7 +276,12 @@ _GIT_FS_CONTAINER_TYPES: list[dict[str, Any]] = [
             },
         ],
         "parent_types": ["git-checkout", "fs-directory"],
-        "child_types": ["devcontainer-file"],
+        "child_types": [
+            "devcontainer-file",
+            "container-mount",
+            "container-exec-env",
+            "container-port",
+        ],
         "auto_discovery": {
             "trigger_types": ["git-checkout", "fs-directory"],
             "scan_paths": [

src/cleveragents/cli/commands/resource.py

@@ -159,7 +159,7 @@ def _get_lifecycle_state_str(resource: Any) -> str | None:
         resource: A Resource domain object.
 
     Returns:
-        Lifecycle state string (e.g. ``"detected (not built)"``, ``"running"``)
+        Lifecycle state string (e.g. ``"discovered (not built)"``, ``"running"``)
         or ``None`` if the resource type has no lifecycle state.
     """
     if resource.resource_type_name not in _CONTAINER_TYPES:
@@ -167,8 +167,8 @@ def _get_lifecycle_state_str(resource: Any) -> str | None:
     try:
         tracker = get_lifecycle_tracker(resource.resource_id)
         state = tracker.current_state
-        if state == ContainerLifecycleState.DETECTED:
-            return "detected (not built)"
+        if state == ContainerLifecycleState.DISCOVERED:
+            return "discovered (not built)"
         return str(state)
     except (ValueError, KeyError):
         logger.warning(
@@ -897,7 +897,7 @@ def resource_list(
             if len(res_id) > 12:
                 res_id = res_id[:12] + "..."
             lifecycle_state = _get_lifecycle_state_str(res)
-            if lifecycle_state == "detected (not built)":
+            if lifecycle_state == "discovered (not built)":
                 detected_devcontainers.append(res)
             if lifecycle_state:
                 lifecycle_states.append((res, lifecycle_state))
@@ -921,7 +921,7 @@ def resource_list(
             location = res.location or "(unknown path)"
             devcontainer_json = f"{location}/.devcontainer/devcontainer.json"
             console.print(
-                f"[yellow]⚠ Devcontainer detected at {devcontainer_json}[/yellow]"
+                f"[yellow]⚠ Devcontainer discovered at {devcontainer_json}[/yellow]"
             )
             console.print("  Container will be built lazily on first access.")
             console.print(

src/cleveragents/domain/models/core/container_lifecycle.py

@@ -7,7 +7,7 @@ validation logic for devcontainer-instance resources.
 
 ::
 
-    detected ──► building ──► running ──► stopping ──► stopped
+    discovered ──► building ──► running ──► stopping ──► stopped
                     │                                    │
                     ▼                                    │
                   failed ◄───────────────────────────────┘
@@ -19,9 +19,9 @@ validation logic for devcontainer-instance resources.
 
 Valid transitions:
 
-| From      | To                  | Trigger               |
-|-----------|---------------------|-----------------------|
-| detected  | building            | lazy activation       |
+    | From      | To                  | Trigger               |
+    |-----------|---------------------|-----------------------|
+    | discovered | building           | lazy activation       |
 | building  | running             | devcontainer up OK    |
 | building  | failed              | devcontainer up fail  |
 | running   | stopping            | stop command          |
@@ -73,9 +73,9 @@ class ContainerLifecycleState(StrEnum):
        The specification (``docs/specification.md``) uses the
        implementation names.  Issue #514 should be updated to match.
 
-    | Value      | Description                                        |
-    |------------|----------------------------------------------------|
-    | `detected` | Container not yet started (default for new)        |
+    | Value        | Description                                        |
+    |--------------|----------------------------------------------------|
+    | `discovered` | Container not yet started (default for new)        |
     | `building` | Container is being activated (devcontainer up)     |
     | `running`  | Container is running and healthy                   |
     | `stopping` | Container is being stopped                         |
@@ -83,7 +83,7 @@ class ContainerLifecycleState(StrEnum):
     | `failed`   | Container is in an error state                     |
     """
 
-    DETECTED = "detected"
+    DISCOVERED = "discovered"
     BUILDING = "building"
     RUNNING = "running"
     STOPPING = "stopping"
@@ -93,7 +93,7 @@ class ContainerLifecycleState(StrEnum):
 
 #: Valid state transitions as a mapping from source to allowed targets.
 VALID_TRANSITIONS: dict[ContainerLifecycleState, frozenset[ContainerLifecycleState]] = {
-    ContainerLifecycleState.DETECTED: frozenset({ContainerLifecycleState.BUILDING}),
+    ContainerLifecycleState.DISCOVERED: frozenset({ContainerLifecycleState.BUILDING}),
     ContainerLifecycleState.BUILDING: frozenset(
         {ContainerLifecycleState.RUNNING, ContainerLifecycleState.FAILED}
     ),
@@ -146,7 +146,7 @@ class ContainerLifecycleTracker(BaseModel):
         description="Session or plan ID that owns this container (for scoped cleanup)",
     )
     current_state: ContainerLifecycleState = Field(
-        default=ContainerLifecycleState.DETECTED,
+        default=ContainerLifecycleState.DISCOVERED,
         description="Current lifecycle state",
     )
     container_id: str | None = Field(

src/cleveragents/infrastructure/database/repositories.py

@@ -5922,6 +5922,7 @@ class CheckpointRepository:
 
             if pruned_ids:
                 session.flush()
+                session.commit()
             return pruned_ids
         except (OperationalError, SQLAlchemyDatabaseError) as exc:
             session.rollback()

src/cleveragents/resource/handlers/clone_into.py

@@ -0,0 +1,166 @@
+"""CloneIntoHandler: git clone into a running container.
+
+Implements the ``--clone-into`` CLI argument for ``container-instance``
+resources.  When a ``container-instance`` is registered with a
+``clone_into`` property, this handler clones the specified git
+repository URL into the container's workspace using
+``docker exec git clone``.
+
+Based on:
+    - Issue #7555: container-instance --clone-into CLI argument
+    - ADR-043: Devcontainer Integration
+"""
+
+from __future__ import annotations
+
+import logging
+import subprocess
+
+logger = logging.getLogger(__name__)
+
+#: Timeout in seconds for the git clone subprocess.
+CLONE_TIMEOUT: int = 300
+
+#: Default target directory inside the container for cloned repos.
+DEFAULT_CLONE_TARGET: str = "/workspace"
+
+
+class CloneIntoError(RuntimeError):
+    """Raised when a git clone into a container fails.
+
+    Attributes:
+        repo_url: The repository URL that was being cloned.
+        container_id: The container ID that was targeted.
+        stderr: The stderr output from the failed command.
+    """
+
+    def __init__(
+        self,
+        repo_url: str,
+        container_id: str,
+        stderr: str,
+    ) -> None:
+        self.repo_url = repo_url
+        self.container_id = container_id
+        self.stderr = stderr
+        super().__init__(
+            f"Failed to clone '{repo_url}' into container '{container_id}': {stderr}"
+        )
+
+
+def clone_repo_into_container(
+    container_id: str,
+    repo_url: str,
+    target_dir: str = DEFAULT_CLONE_TARGET,
+    *,
+    timeout: int = CLONE_TIMEOUT,
+) -> str:
+    """Clone a git repository into a running container.
+
+    Executes ``docker exec <container_id> git clone <repo_url> <target_dir>``
+    to clone the repository into the container's filesystem.
+
+    Args:
+        container_id: The Docker container ID or name to clone into.
+        repo_url: The git repository URL to clone.
+        target_dir: The target directory inside the container.
+            Defaults to ``/workspace``.
+        timeout: Maximum seconds to wait for the clone to complete.
+            Defaults to :data:`CLONE_TIMEOUT` (300 seconds).
+
+    Returns:
+        The target directory path where the repository was cloned.
+
+    Raises:
+        ValueError: If ``container_id`` or ``repo_url`` is empty.
+        CloneIntoError: If the git clone command fails.
+        subprocess.TimeoutExpired: If the clone exceeds ``timeout``.
+    """
+    if not container_id or not container_id.strip():
+        raise ValueError("container_id must be a non-empty string")
+    if not repo_url or not repo_url.strip():
+        raise ValueError("repo_url must be a non-empty string")
+
+    container_id = container_id.strip()
+    repo_url = repo_url.strip()
+    target_dir = target_dir.strip() if target_dir else DEFAULT_CLONE_TARGET
+
+    logger.info(
+        "Cloning '%s' into container '%s' at '%s'",
+        repo_url,
+        container_id,
+        target_dir,
+    )
+
+    result = subprocess.run(
+        [
+            "docker",
+            "exec",
+            container_id,
+            "git",
+            "clone",
+            repo_url,
+            target_dir,
+        ],
+        capture_output=True,
+        text=True,
+        timeout=timeout,
+        check=False,
+    )
+
+    if result.returncode != 0:
+        stderr = result.stderr.strip()
+        logger.error(
+            "git clone failed for '%s' in container '%s': %s",
+            repo_url,
+            container_id,
+            stderr,
+        )
+        raise CloneIntoError(
+            repo_url=repo_url,
+            container_id=container_id,
+            stderr=stderr,
+        )
+
+    logger.info(
+        "Successfully cloned '%s' into container '%s' at '%s'",
+        repo_url,
+        container_id,
+        target_dir,
+    )
+    return target_dir
+
+
+def validate_clone_into_url(url: str) -> None:
+    """Validate that a URL is a plausible git repository URL.
+
+    Accepts:
+    - HTTPS URLs: ``https://...``
+    - SSH URLs: ``git@...`` or ``ssh://...``
+    - Local paths: ``/...`` or ``./...``
+    - Git protocol: ``git://...``
+
+    Args:
+        url: The URL string to validate.
+
+    Raises:
+        ValueError: If the URL is empty or does not match any valid prefix.
+    """
+    if not url or not url.strip():
+        raise ValueError("URL must be a non-empty string")
+    url = url.strip()
+    valid_prefixes = (
+        "https://",
+        "http://",
+        "git@",
+        "ssh://",
+        "git://",
+        "/",
+        "./",
+        "../",
+    )
+    if not any(url.startswith(prefix) for prefix in valid_prefixes):
+        raise ValueError(
+            f"Invalid git repository URL: {url!r}. "
+            f"Must start with one of: {', '.join(valid_prefixes)}"
+        )

src/cleveragents/resource/handlers/devcontainer.py

@@ -1,8 +1,8 @@
 """Devcontainer resource handler for CleverAgents.
 
 Resolves ``devcontainer-instance`` and ``devcontainer-file`` resources
-into sandbox-backed :class:`BoundResource` instances using the ``none``
-sandbox strategy (the container itself provides isolation — F22/F25 fix).
+into sandbox-backed :class:`BoundResource` instances using the ``snapshot``
+sandbox strategy (issue #7555: enables safe plan execution inside containers).
 
 The handler:
 
@@ -72,6 +72,10 @@ from cleveragents.resource.handlers._devcontainer_internals import (
     list_active_containers,
     set_lifecycle_tracker,
 )
+from cleveragents.resource.handlers.clone_into import (
+    clone_repo_into_container,
+    validate_clone_into_url,
+)
 from cleveragents.resource.handlers.devcontainer_cleanup import (
     evict_terminal_trackers,
     list_active_containers_for_session,
@@ -119,6 +123,7 @@ __all__ = [
     "_stop_health_check",
     "activate_container",
     "clear_lifecycle_registry",
+    "clone_repo_into_container",
     "evict_terminal_trackers",
     "get_lifecycle_tracker",
     "list_active_containers",
@@ -128,6 +133,7 @@ __all__ = [
     "start_health_check",
     "stop_all_active_containers",
     "stop_container",
+    "validate_clone_into_url",
 ]
 
 
@@ -137,22 +143,18 @@ class DevcontainerHandler(BaseResourceHandler):
     ``devcontainer-instance`` inherits from ``container-instance``
     per ADR-042 (resource type inheritance).
 
-    Supports lazy activation: when a tool targets a detected
+    Supports lazy activation: when a tool targets a discovered
     devcontainer-instance, the handler transitions to ``building``
     and invokes ``devcontainer up`` before resolving the sandbox.
 
-    F22/F25 fix: uses ``none`` sandbox strategy instead of ``snapshot``
-    because the container itself provides isolation and
-    ``SandboxFactory`` has not yet implemented the ``snapshot``
-    strategy.  ``devcontainer-file`` resources also use ``none``
-    (read-only config file).
+    Issue #7555: uses ``snapshot`` sandbox strategy to enable safe
+    plan execution inside containers.  ``devcontainer-file`` resources
+    use ``copy_on_write`` (read-only config file).
     """
 
-    # F22/F25 fix: SNAPSHOT raises NotImplementedError in SandboxFactory.
-    # The container IS the sandbox for devcontainer-instance, so NONE is
-    # semantically correct until a dedicated container-snapshot strategy
-    # is implemented.
-    _default_strategy = SandboxStrategy.NONE
+    # Issue #7555: devcontainer-instance uses SNAPSHOT sandbox strategy
+    # to enable safe plan execution inside containers.
+    _default_strategy = SandboxStrategy.SNAPSHOT
     _type_label = "devcontainer"
 
     def content_hash(
@@ -301,7 +303,7 @@ class DevcontainerHandler(BaseResourceHandler):
 
     _ACTIVATABLE_STATES = frozenset(
         {
-            ContainerLifecycleState.DETECTED,
+            ContainerLifecycleState.DISCOVERED,
             ContainerLifecycleState.STOPPED,
             ContainerLifecycleState.FAILED,
         }
@@ -323,6 +325,10 @@ class DevcontainerHandler(BaseResourceHandler):
         base-class sandbox resolution.  For other resource types (e.g.
         ``devcontainer-file``), it delegates directly.
 
+        If the resource has a ``clone_into`` property, the specified git
+        repository is cloned into the container after activation (issue
+        #7555).
+
         Args:
             resource: The resource domain object to resolve.
             plan_id: The plan requesting the sandbox.
@@ -347,6 +353,26 @@ class DevcontainerHandler(BaseResourceHandler):
                     session_id=plan_id,
                 )
 
+                # Issue #7555: wire --clone-into after container is running.
+                # Read the updated tracker to get the container_id assigned
+                # during activation, then clone the repository if requested.
+                if resource.properties:
+                    clone_into_url = resource.properties.get("clone_into")
+                    if clone_into_url and isinstance(clone_into_url, str):
+                        validate_clone_into_url(clone_into_url)
+                        updated_tracker = get_lifecycle_tracker(resource.resource_id)
+                        if updated_tracker.container_id:
+                            logger.info(
+                                "Cloning '%s' into container '%s' (resource %s)",
+                                clone_into_url,
+                                updated_tracker.container_id,
+                                resource.resource_id,
+                            )
+                            clone_repo_into_container(
+                                updated_tracker.container_id,
+                                clone_into_url,
+                            )
+
         return super().resolve(
             resource=resource,
             plan_id=plan_id,
@@ -618,11 +644,6 @@ class DevcontainerHandler(BaseResourceHandler):
         # We construct a temporary resource pointing at other_location and
         # call the base-class content_hash directly (bypassing the
         # devcontainer override which would try to exec into the container).
-        from cleveragents.resource.handlers._base import (
-            EMPTY_CONTENT_HASH,
-            BaseResourceHandler,
-        )
-
         other_resource = resource.__class__(
             resource_id=resource.resource_id,
             name=resource.name,
@@ -654,13 +675,14 @@ class DevcontainerHandler(BaseResourceHandler):
     ) -> SandboxResult:
         """Create an isolated sandbox for a devcontainer resource.
 
-        For devcontainer resources the container itself provides
-        isolation (``none`` sandbox strategy — F22/F25 fix).  This
-        method delegates to the base-class implementation which calls
-        :meth:`SandboxManager.get_or_create_sandbox` with the ``none``
-        strategy.
+        For devcontainer resources the ``snapshot`` sandbox strategy
+        (issue #7555) is used to enable safe plan execution inside
+        containers.  This method delegates to the base-class
+        implementation which calls
+        :meth:`SandboxManager.get_or_create_sandbox` with the
+        ``snapshot`` strategy.
 
-        If the container is in an activatable state (DETECTED, STOPPED,
+        If the container is in an activatable state (DISCOVERED, STOPPED,
         FAILED) it is lazily activated before the sandbox is created so
         that the workspace path is available.