# Auto Mode

Auto mode is SF's autonomous execution engine. Run `/sf auto`, walk away, come back to built software with clean git history.

## How It Works

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, injects a focused prompt with all relevant context pre-inlined, and lets the LLM execute. When the LLM finishes, auto mode reads disk state again and dispatches the next unit.

### The Loop

Each slice flows through phases automatically:

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

- **Plan** — scouts the codebase, researches relevant docs, and decomposes the slice into tasks with must-haves
- **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 Milestone** — reconciliation gate after all slices complete; compares roadmap success criteria against actual results, catches gaps before sealing the milestone

## Key Properties

### Fresh Session Per Unit

Every task, research phase, and planning step gets a clean context window. No accumulated garbage. No degraded quality from context bloat. The dispatch prompt includes everything needed — task plans, prior summaries, dependency context, decisions register — so the LLM starts oriented instead of spending tool calls reading files.

### Context Pre-Loading

The dispatch prompt is carefully constructed with:

| 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](./token-optimization.md). 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):

- **`worktree`** (default): Each milestone runs in its own git worktree at `.sf/worktrees/<MID>/` on a `milestone/<MID>` branch. All slice work commits sequentially — no branch switching, no merge conflicts mid-milestone. When the milestone completes, it's squash-merged to main as one clean commit.
- **`branch`**: Work happens in the project root on a `milestone/<MID>` branch. Useful for submodule-heavy repos where worktrees don't work well.
- **`none`**: Work happens directly on your current branch. No worktree, no milestone branch. Ideal for hot-reload workflows where file isolation breaks dev tooling.

See [Git Strategy](./git-strategy.md) for details.

### Parallel Execution

When your project has independent milestones, you can run them simultaneously. Each milestone gets its own worker process and worktree. See [Parallel Orchestration](./parallel-orchestration.md) for setup and usage.

### Crash Recovery

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

**Headless auto-restart (v2.26):** When running `sf headless auto`, crashes trigger automatic restart with exponential backoff (5s → 10s → 30s cap, default 3 attempts). Configure with `--max-restarts N`. SIGINT/SIGTERM bypasses restart. Combined with crash recovery, this enables true overnight "run until done" execution.

### Provider Error Recovery

SF classifies provider errors and auto-resumes when safe:

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

No manual intervention needed for transient errors — the session pauses briefly and continues automatically.

### Incremental Memory (v2.26)

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 to it when discovering recurring issues, non-obvious patterns, or rules that future sessions should follow. This gives auto-mode cross-session memory that survives context window boundaries.

### Context Pressure Monitor (v2.26)

When context usage reaches 70%, SF sends a wrap-up signal to the agent, nudging it to finish durable output (commit, write summaries) before the context window fills. This prevents sessions from hitting the hard context limit mid-task with no artifacts written.

### Meaningful Commit Messages (v2.26)

Commits are generated from task summaries — not generic "complete task" messages. Each commit message reflects what was actually built, giving clean `git log` output that reads like a changelog.

### Stuck Detection (v2.39)

SF uses a sliding-window analysis to detect stuck loops. Instead of a simple "same unit dispatched twice" counter, the detector examines recent dispatch history for repeated patterns — catching cycles like A→B→A→B as well as single-unit repeats. On detection, SF retries once with a deep diagnostic prompt. If it fails again, auto mode stops with the exact file it expected, so you can intervene.

The sliding-window approach reduces false positives on legitimate retries (e.g., verification failures that self-correct) while catching genuine stuck loops faster.

### Post-Mortem Investigation (v2.40)

`/sf forensics` is a full-access SF debugger for post-mortem analysis of auto-mode failures. It provides:

- **Anomaly detection** — structured identification of stuck loops, cost spikes, timeouts, missing artifacts, and crashes with severity levels
- **Unit traces** — last 10 unit executions with error details and execution times
- **Metrics analysis** — cost, token counts, and execution time breakdowns
- **Doctor integration** — includes structural health issues from `/sf doctor`
- **LLM-guided investigation** — an agent session with full tool access to investigate root causes

```
/sf forensics [optional problem description]
```

See [Troubleshooting](./troubleshooting.md) for more on diagnosing issues.

### Timeout Supervision

Three timeout tiers prevent runaway sessions:

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

Recovery steering nudges the LLM to finish durable output before timing out. Configure in preferences:

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

### Cost Tracking

Every unit's token usage and cost is captured, broken down by phase, slice, and model. The dashboard shows running totals and projections. Budget ceilings can pause auto mode before overspending.

See [Cost Management](./cost-management.md).

### Adaptive Replanning

After each slice completes, the roadmap is reassessed. If the work revealed new information that changes the plan, slices are reordered, added, or removed before continuing. This can be skipped with the `balanced` or `budget` token profiles.

### Verification Enforcement (v2.26)

Configure shell commands that run automatically after every task execution:

```yaml
verification_commands:
  - npm run lint
  - npm run test
verification_auto_fix: true    # auto-retry on failure (default)
verification_max_retries: 2    # max retry attempts (default: 2)
```

Failures trigger auto-fix retries — the agent sees the verification output and attempts to fix the issues before advancing. This ensures code quality gates are enforced mechanically, not by LLM compliance.

### Slice Discussion Gate (v2.26)

For projects where you want human review before each slice begins:

```yaml
require_slice_discussion: true
```

Auto-mode pauses before each slice, presenting the slice context for discussion. After you confirm, execution continues. Useful for high-stakes projects where you want to review the plan before the agent builds.

### HTML Reports (v2.26)

After a milestone completes, SF auto-generates a self-contained HTML report in `.sf/reports/`. Reports include project summary, progress tree, slice dependency graph (SVG DAG), cost/token metrics with bar charts, execution timeline, changelog, and knowledge base. No external dependencies — all CSS and JS are inlined.

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

Generate manually anytime with `/sf export --html`, or generate reports for all milestones at once with `/sf export --html --all` (v2.28).

### Failure Recovery (v2.28)

v2.28 hardens auto-mode reliability with multiple safeguards: atomic file writes prevent corruption on crash, OAuth fetch timeouts (30s) prevent indefinite hangs, RPC subprocess exit is detected and reported, and blob garbage collection prevents unbounded disk growth. Combined with the existing crash recovery and headless auto-restart, auto-mode is designed for true "fire and forget" overnight execution.

### Pipeline Architecture (v2.40)

The auto-loop is structured as a linear phase pipeline rather than recursive dispatch. Each iteration flows through explicit stages:

1. **Pre-Dispatch** — validate state, check guards, resolve model preferences
2. **Dispatch** — execute the unit with a focused prompt
3. **Post-Unit** — close out the unit, update caches, run cleanup
4. **Verification** — optional validation gate (lint, test, etc.)
5. **Stuck Detection** — sliding-window pattern analysis

This linear flow is easier to debug, uses less memory (no recursive call stack), and provides cleaner error recovery since each phase has well-defined entry and exit conditions.

### Real-Time Health Visibility (v2.40)

Doctor issues (from `/sf doctor`) now surface in real time across three places:

- **Dashboard widget** — health indicator with issue count and severity
- **Workflow visualizer** — issues shown in the status panel
- **HTML reports** — health section with all issues at report generation time

Issues are classified by severity: `error` (blocks auto-mode), `warning` (non-blocking), and `info` (advisory). Auto-mode checks health at dispatch time and can pause on critical issues.

### Skill Activation in Prompts (v2.39)

Configured skills are automatically resolved and injected into dispatch prompts. The agent receives an "Available Skills" block listing skills that match the current context, based on:

- `always_use_skills` — always included
- `prefer_skills` — included with preference indicator
- `skill_rules` — conditional activation based on `when` clauses

See [Configuration](./configuration.md) for skill routing preferences.

## Controlling Auto Mode

### Start

```
/sf auto
```

### Pause

Press **Escape**. The conversation is preserved. You can interact with the agent, inspect state, or resume.

### Resume

```
/sf auto
```

Auto mode reads disk state and picks up where it left off.

### Stop

```
/sf stop
```

Stops auto mode gracefully. Can be run from a different terminal.

### Steer

```
/sf steer
```

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

### Capture

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

Fire-and-forget thought capture. Captures are triaged automatically between tasks. See [Captures & Triage](./captures-triage.md).

### Visualize

```
/sf visualize
```

Open the workflow visualizer — interactive tabs for progress, dependencies, metrics, and timeline. See [Workflow Visualizer](./visualizer.md).

## 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
- Completed and in-progress units
- Pending capture count (when captures are awaiting triage)
- Parallel worker status (when running parallel milestones — includes 80% budget alert)

## Phase Skipping

Token profiles can skip certain 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](./token-optimization.md) for details.

## Dynamic Model Routing

When enabled, auto-mode automatically selects cheaper models for simple units (slice completion, UAT) and reserves expensive models for complex work (replanning, architectural tasks). See [Dynamic Model Routing](./dynamic-model-routing.md).

## Reactive Task Execution (v2.38)

When `reactive_execution: true` is set in preferences, SF derives a dependency graph from IO annotations in task plans. Tasks that don't conflict (no shared file reads/writes) are dispatched in parallel via subagents, while dependent tasks wait for their predecessors to complete.

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

The graph derivation is pure and deterministic — it resolves a ready-set of tasks, detects conflicts, and guards against deadlocks. Verification results carry forward across parallel batches, so tasks that pass verification don't need to be re-verified when subsequent tasks in the same slice complete.

The implementation lives in `reactive-graph.ts` (graph derivation, ready-set resolution, conflict/deadlock detection) with integration into `auto-dispatch.ts` and `auto-prompts.ts`.
