# Advanced Concepts: Container Tools, Scope Chain, Budgets & Safety (v3.6.0)

> **Milestone:** v3.6.0 — M7: Advanced Concepts & Deferred Features
> **Parent:** [Advanced Concepts Overview](index.md)

---

## Container Tool Execution

v3.6.0 adds first-class support for executing tools inside containers, building on the
container resource types introduced in ADR-039.

### Overview

Container tool execution allows actors to run tools in isolated container environments rather
than directly on the host. This provides:

- **Stronger isolation** — tool side effects are contained within the container
- **Reproducible environments** — tools run in a known, versioned environment
- **Language-agnostic tools** — tools can be written in any language supported by the container
- **Parallel execution** — multiple containers can run simultaneously for independent tool calls

### Container Tool Configuration

Tools declare their container requirements in their YAML definition:

```yaml
name: my-org/python-linter
type: container-tool
image: "python:3.12-slim"
command: ["python", "-m", "pylint"]
mounts:
  - source: "{{resource.git_dir.path}}"
    target: "/workspace"
    readonly: true
environment:
  PYTHONPATH: "/workspace/src"
timeout: 60
```

### Execution Model

Container tools follow the same `ToolRuntime` interface as host tools. The
`ContainerToolExecutor` handles:

1. **Image resolution** — pulls the image if not cached locally
2. **Mount binding** — maps resource paths to container mount points
3. **Execution** — runs the container with the specified command and arguments
4. **Output capture** — streams stdout/stderr back to the `ToolResult`
5. **Cleanup** — removes the container after execution (configurable)

### Devcontainer Integration

When a project has a `.devcontainer/devcontainer.json`, CleverAgents can use the devcontainer
as the execution environment for all tools in that project. This is configured via the
`devcontainer-instance` resource type (ADR-043):

```yaml
resources:
  - name: dev_env
    type: devcontainer-instance
    devcontainer_path: ".devcontainer/devcontainer.json"
    use_for_tools: true
```

---

## Pluggable Scope Chain Resolution Extensions

The scope chain resolution system determines which projects, plans, and resources are in scope
for a given actor invocation. v3.6.0 makes this system extensible via a plugin interface.

### Scope Chain Resolution Protocol

The `ScopeChainResolver` interface defines a single method:

```python
class ScopeChainResolver(Protocol):
    def resolve(
        self,
        base_scope: Scope,
        context: ResolutionContext,
    ) -> Scope:
        """
        Extend or modify the base scope based on the resolution context.

        Args:
            base_scope: The scope as determined by the persona and explicit @ references.
            context: The current resolution context (session, plan, actor, prompt).

        Returns:
            The resolved scope, which may add, remove, or reorder items from base_scope.
        """
        ...
```

### Built-in Resolvers

| Resolver | Description |
|----------|-------------|
| `PersonaScopeResolver` | Adds persona-scoped projects and plans (always active) |
| `ReferenceResolver` | Adds explicitly `@`-referenced resources (always active) |
| `DependencyGraphResolver` | Automatically includes resources that are dependencies of in-scope resources |
| `RecentlyModifiedResolver` | Adds recently modified files from in-scope projects |
| `TestCoverageResolver` | Adds test files that cover in-scope source files |

### Custom Resolver Registration

Custom resolvers are registered via the plugin system:

```python
from cleveragents.scope import ScopeChainResolver, register_resolver

@register_resolver(name="my-org/git-blame-resolver", priority=50)
class GitBlameResolver:
    def resolve(self, base_scope, context):
        # Add files recently modified by the current git user
        ...
```

---

## Cost and Session Budgets

v3.6.0 introduces comprehensive cost tracking and budget enforcement across sessions and plans.

### Cost Tracking

Every LLM invocation is tracked with:

- **Input tokens** and **output tokens** (provider-reported)
- **Cost in USD** (computed from provider pricing tables, updated monthly)
- **Model used** (for multi-provider fallback chains)
- **Session ID** and **plan ID** for attribution

Cost data is stored in the SQLite database and queryable via:

```bash
agents session cost                    # Total cost for current session
agents session cost --all              # All sessions with costs
agents plan cost <plan-id>             # Cost breakdown for a specific plan
agents config get billing.total_spent  # Lifetime total
```

### Budget Configuration

Budgets are configured at multiple levels (plan > action > project > global):

```toml
[billing]
max_cost_per_session = 5.00     # USD; hard limit per session
max_cost_per_plan = 2.00        # USD; hard limit per plan
max_total_cost = 100.00         # USD; lifetime hard limit
warn_at_percent = 80            # Warn when 80% of any budget is consumed
```

These settings correspond to the `SafetyProfile` fields defined in ADR-041:

| Config Key | SafetyProfile Field |
|-----------|-------------------|
| `max_cost_per_plan` | `SafetyProfile.max_cost_per_plan` |
| `max_total_cost` | `SafetyProfile.max_total_cost` |

### Budget Enforcement

When a budget limit is reached:

1. The current LLM invocation is **not** started (pre-flight check)
2. A `BudgetExceededError` is raised with the budget type, limit, and current spend
3. The plan transitions to `PAUSED` state with `pause_reason = "budget_exceeded"`
4. The user is notified via the CLI output or TUI notification system
5. The user can increase the budget via `agents config set billing.max_cost_per_plan <new_limit>`
   and resume the plan with `agents plan resume <plan-id>`

---

## Safety Profiles

Safety profiles (ADR-041) provide fine-grained control over what actions an actor is permitted
to take. v3.6.0 completes the safety profile implementation with full enforcement in the plan
lifecycle.

### SafetyProfile Fields

| Field | Type | Default | Description |
|-------|------|---------|-------------|
| `require_sandbox` | `bool` | `True` | Require sandbox isolation for all file writes |
| `require_checkpoints` | `bool` | `True` | Require checkpoints before destructive operations |
| `allow_unsafe_tools` | `bool` | `False` | Allow tools marked as `unsafe: true` |
| `require_human_approval` | `bool` | `False` | Require human approval before each action step |
| `allowed_skill_categories` | `list[str]` | `[]` (all) | Restrict to specific skill categories |
| `max_cost_per_plan` | `float or None` | `None` | Maximum cost per plan in USD |
| `max_total_cost` | `float or None` | `None` | Maximum lifetime cost in USD |
| `max_retries_per_step` | `int` | `3` | Maximum retries per action step (0-100) |

### Built-in Safety Profiles

v3.6.0 ships with named safety profiles that can be referenced by name:

| Profile | Description |
|---------|-------------|
| `strict` | All safety flags enabled; no unsafe tools; human approval required |
| `standard` | Sandbox and checkpoints required; unsafe tools blocked; no human approval |
| `permissive` | Sandbox required; checkpoints optional; unsafe tools allowed |
| `read-only` | No file writes permitted; all tools restricted to read operations |
| `cost-capped-1usd` | Standard safety + $1.00 per-plan cost cap |
| `cost-capped-5usd` | Standard safety + $5.00 per-plan cost cap |

### Applying Safety Profiles

Safety profiles can be applied at multiple levels:

```bash
# Global default
agents config set safety.profile strict

# Per-project
agents project set-safety my-project --profile standard

# Per-plan (at creation time)
agents plan use my-action --safety-profile permissive
```

```yaml
# action.yaml
name: my-action
safety_profile:
  require_sandbox: true
  allow_unsafe_tools: false
  max_cost_per_plan: 2.00
```

---

## Related ADRs

| ADR | Title | Relevance |
|-----|-------|-----------|
| [ADR-039](../adr/ADR-039-container-resource-types.md) | Container Resource Types | Container tool execution |
| [ADR-041](../adr/ADR-041-safety-profile-extraction.md) | Safety Profile Extraction | Safety profiles and cost budgets |
| [ADR-043](../adr/ADR-043-devcontainer-integration.md) | Devcontainer Integration | Devcontainer tool execution |

---

*Documentation for v3.6.0 — IN PROGRESS. Features described here reflect the planned scope
as of 2026-04-15. Some features may be adjusted as implementation progresses.*

*Generated by [AUTO-DOCS-5] — CleverAgents Documentation Bot*