---
title: "Auto mode"
description: "SF's autonomous execution engine — run /sf auto, walk away, come back to built software with clean git history."
---

Auto mode is a **state machine driven by files on disk**. It reads `.sf/STATE.md`, determines the next unit of work, creates a fresh agent session with pre-loaded context, and lets the LLM execute. When the LLM finishes, auto mode reads disk state again and dispatches the next unit.

## The loop

```
Plan → Execute (per task) → Complete → Reassess Roadmap → Next Slice
                                                            ↓ (all slices done)
                                                    Validate → Complete Milestone
```

- **Plan** — scouts the codebase, researches docs, decomposes the slice into tasks
- **Execute** — runs each task in a fresh context window
- **Complete** — writes summary, UAT script, marks roadmap, commits
- **Reassess** — checks if the roadmap still makes sense
- **Validate** — reconciliation gate after all slices; catches gaps before sealing the milestone

## Key properties

### Fresh session per unit

Every task, research phase, and planning step gets a clean context window. The dispatch prompt includes everything needed — task plans, prior summaries, dependency context, decisions register — so the LLM starts oriented.

### Context pre-loading

| Inlined artifact | Purpose |
|------------------|---------|
| Task plan | What to build |
| Slice plan | Where this task fits |
| Prior task summaries | What's already done |
| Dependency summaries | Cross-slice context |
| Roadmap excerpt | Overall direction |
| Decisions register | Architectural context |

The amount of context inlined is controlled by your [token profile](/guides/token-optimization). Budget mode inlines minimal context; quality mode inlines everything.

### Git isolation

SF isolates milestone work using one of three modes (configured via `git.isolation` in preferences):

- **`none`** (default) — work happens on your current branch. No isolation overhead.
- **`worktree`** — each milestone runs in its own git worktree. Squash-merged to main on completion.
- **`branch`** — work happens on a `milestone/<MID>` branch in the project root. Useful for submodule-heavy repos.

See [git strategy](/guides/git-strategy) for details.

### Crash recovery

A lock file tracks the current unit. If the session dies, the next `/sf auto` synthesizes a recovery briefing from tool calls that made it to disk and resumes with full context.

**Headless auto-restart:** When running `sf headless auto`, crashes trigger automatic restart with exponential backoff (5s → 10s → 30s cap, default 3 attempts). Combined with crash recovery, this enables overnight "run until done" execution.

### Provider error recovery

| Error type | Examples | Action |
|-----------|----------|--------|
| Rate limit | 429, "too many requests" | Auto-resume after retry-after header or 60s |
| Server error | 500, 502, 503, "overloaded" | Auto-resume after 30s |
| Permanent | "unauthorized", "invalid key" | Pause indefinitely (requires manual resume) |

### Stuck detection

A sliding-window analysis detects stuck loops — catching cycles like A→B→A→B as well as single-unit repeats. On detection, SF retries once with a diagnostic prompt. If it fails again, auto mode stops with the exact file it expected.

### Timeout supervision

| Timeout | Default | Behavior |
|---------|---------|----------|
| Soft | 20 min | Warns the LLM to wrap up |
| Idle | 10 min | Detects stalls, intervenes |
| Hard | 30 min | Pauses auto mode |

Configure in preferences:

```yaml
auto_supervisor:
  soft_timeout_minutes: 20
  idle_timeout_minutes: 10
  hard_timeout_minutes: 30
```

### Incremental memory

SF maintains a `KNOWLEDGE.md` file — an append-only register of project-specific rules, patterns, and lessons learned. The agent reads it at the start of every unit and appends when discovering recurring issues or non-obvious patterns.

### Verification enforcement

```yaml
verification_commands:
  - npm run lint
  - npm run test
verification_auto_fix: true
verification_max_retries: 2
```

Failures trigger auto-fix retries — the agent sees the output and attempts to fix issues before advancing.

### HTML reports

After milestone completion, SF auto-generates a self-contained HTML report with progress tree, dependency graph, cost/token metrics, execution timeline, and changelog.

```yaml
auto_report: true    # enabled by default
```

Generate manually with `/sf export --html`, or for all milestones with `/sf export --html --all`.

### Reactive task execution

When `reactive_execution: true` is set, SF derives a dependency graph from IO annotations in task plans. Tasks that don't conflict are dispatched in parallel via subagents.

```yaml
reactive_execution: true    # disabled by default
```

## Controlling auto mode

<Steps>
  <Step title="Start">
    ```
    /sf auto
    ```
  </Step>
  <Step title="Pause">
    Press **Escape**. The conversation is preserved. You can interact with the agent, inspect state, or resume.
  </Step>
  <Step title="Resume">
    ```
    /sf auto
    ```
    Auto mode reads disk state and picks up where it left off.
  </Step>
  <Step title="Stop">
    ```
    /sf stop
    ```
    Stops auto mode gracefully. Can be run from a different terminal.
  </Step>
</Steps>

### Steer during execution

```
/sf steer
```

Hard-steer plan documents without stopping the pipeline. Changes are picked up at the next phase boundary.

### Capture thoughts

```
/sf capture "add rate limiting to API endpoints"
```

Fire-and-forget thought capture. Triaged automatically between tasks. See [captures and triage](/guides/captures-triage).

## Dashboard

`Ctrl+Alt+G` or `/sf status` shows real-time progress:

- Current milestone, slice, and task
- Auto mode elapsed time and phase
- Per-unit cost and token breakdown
- Cost projections
- Pending capture count

## Phase skipping

Token profiles can skip phases to reduce cost:

| Phase | `budget` | `balanced` | `quality` |
|-------|----------|------------|-----------|
| Milestone research | Skipped | Runs | Runs |
| Slice research | Skipped | Skipped | Runs |
| Reassess roadmap | Skipped | Runs | Runs |

See [token optimization](/guides/token-optimization) for details.
