nav-loop

What this skill does

# Navigator Loop Skill

Execute tasks iteratively until completion with structured signals, stagnation detection, and dual-condition exit gates.

## Why This Exists

Traditional AI coding requires manual "keep going" prompts. Navigator Loop provides:
- **Structured completion signals** (NAVIGATOR_STATUS block)
- **Dual-condition exit gate** (heuristics + explicit signal)
- **Stagnation detection** (circuit breaker for stuck loops)
- **Progress visibility** (phases: INIT → RESEARCH → IMPL → VERIFY → COMPLETE)

Based on Ralph's autonomous loop innovations, adapted for Navigator's context-efficient architecture.

## When to Invoke

**Auto-invoke when**:
- User says "run until done", "keep going until complete"
- User says "iterate until finished", "autonomous mode"
- User says "loop mode", "don't stop until done"
- Task document has `loop_mode: true`

**DO NOT invoke if**:
- Single-step task (no iteration needed)
- User says "just do this once"
- Already in loop mode (prevent nested loops)
- User explicitly disabled loop mode

## Configuration

Loop mode settings in `.agent/.nav-config.json`:

```json
{
  "loop_mode": {
    "enabled": false,
    "max_iterations": 5,
    "stagnation_threshold": 3,
    "exit_requires_explicit_signal": true,
    "show_status_block": true,
    "iteration_approval": "none",
    "periodic_interval": 3,
    "never_pause_on_stagnation": false,
    "stagnation_diversify_strategy": "combine"
  }
}
```

**Core options**:
- `enabled`: Default state for new tasks
- `max_iterations`: Hard cap to prevent infinite loops (1-20)
- `stagnation_threshold`: Same-state count before pause (2-5)
- `exit_requires_explicit_signal`: Require EXIT_SIGNAL alongside heuristics
- `show_status_block`: Render NAVIGATOR_STATUS each iteration

**Autonomous / overnight options** (v6.2.2+):
- `iteration_approval`: When to prompt the user for accept/reject between iterations.
  - `"none"` (default) — never prompt; loop runs uninterrupted
  - `"strict"` — prompt after every iteration
  - `"periodic"` — prompt every N iterations (where N = `periodic_interval`, default 3)
- `periodic_interval`: When `iteration_approval == "periodic"`, the cadence of prompts. Default 3 (every 3rd iteration). Set higher for less frequent check-ins on long overnight runs (e.g., 5 or 10).
- `never_pause_on_stagnation`: If `true`, stagnation triggers **auto-diversification** instead of an `AskUserQuestion` pause. Required for true overnight runs. Inspired by karpathy/autoresearch's NEVER STOP directive.
- `stagnation_diversify_strategy`: Which recovery to attempt when `never_pause_on_stagnation` fires.
  - `"combine"` — combine previous near-misses / partially-met indicators
  - `"radical"` — try a substantially different approach (re-architect, swap library)
  - `"reread"` — re-read the in-scope task/system docs for missed signals

**Safety guard**: Setting `never_pause_on_stagnation: true` REQUIRES `max_iterations` to be set explicitly (the default of 5 is fine; the point is — no infinite default). Without a max, an autonomous loop can spin forever on a fundamentally broken task.

## Execution Steps

### Step 1: Initialize Loop State

**Load configuration**:
```bash
python3 functions/phase_detector.py --init
```

**Initialize tracking variables**:
```
iteration = 1
max_iterations = config.loop_mode.max_iterations or 5
stagnation_threshold = config.loop_mode.stagnation_threshold or 3
hash_history = []
phase = "INIT"
```

**Display loop start**:
```
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
LOOP MODE ACTIVATED
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Task: {TASK_DESCRIPTION}
Max iterations: {max_iterations}
Stagnation threshold: {stagnation_threshold}

Starting iteration 1...
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
```

### Step 2: Execute Iteration

**Perform task work** based on current phase:

| Phase | Actions |
|-------|---------|
| INIT | Load context, understand requirements |
| RESEARCH | Explore codebase, find patterns |
| IMPL | Write code, make changes |
| VERIFY | Run tests, validate functionality, **simplify code** |
| COMPLETE | All indicators met, ready to exit |

**Track changes during iteration**:
- Files read (for RESEARCH detection)
- Files changed (for IMPL detection)
- Tests run (for VERIFY detection)
- Commits made (for completion indicator)

### Step 3: Generate Status Block

**After each iteration**, generate NAVIGATOR_STATUS:

```bash
python3 functions/status_generator.py \
  --phase "{phase}" \
  --iteration "{iteration}" \
  --max-iterations "{max_iterations}" \
  --indicators "{indicators_json}" \
  --state-hash "{current_hash}" \
  --prev-hash "{previous_hash}" \
  --stagnation-count "{stagnation_count}"
```

**Display status block**:
```
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
NAVIGATOR_STATUS
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Phase: {PHASE}
Iteration: {N}/{MAX}
Progress: {PERCENT}%

Completion Indicators:
  [{x or space}] Code changes committed
  [{x or space}] Tests passing
  [{x or space}] Code simplified
  [{x or space}] Documentation updated
  [{x or space}] Ticket closed
  [{x or space}] Marker created

Exit Conditions:
  Heuristics: {MET}/{TOTAL} (need 2+)
  EXIT_SIGNAL: {true/false}

State Hash: {HASH}
Previous Hash: {PREV_HASH}
Stagnation: {COUNT}/{THRESHOLD}

Next Action: {NEXT_ACTION}
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
```

### Step 3.5: Per-Iteration Approval Gate (optional)

**Skip this step if** `config.loop_mode.iteration_approval == "none"` (default).

**Run this step if** the user wants oversight between iterations — for risky changes, learning the loop's behavior, or sanity-checking before a long run.

| Setting | Behavior |
|---------|----------|
| `"none"` | Never prompt. Loop continues to Step 4. |
| `"strict"` | Prompt after every iteration. |
| `"periodic"` | Prompt every Nth iteration. N defaults to 3; configurable via `loop_mode.periodic_interval`. |

**When prompting**, use AskUserQuestion immediately after the status block:

```
Question: "Accept iteration {N} and continue?"
Options:
  1. [Continue] - Iteration accepted, proceed to next
  2. [Adjust]   - Provide feedback, incorporate into next iteration
  3. [Abort]    - End loop, create partial-completion marker
```

**Decision handling**:
- **Continue**: Proceed to Step 4 normally.
- **Adjust**: Capture the user's feedback into a transient note, do NOT advance hash history (so the next iteration is judged as fresh progress), continue to Step 4.
- **Abort**: Jump to Step 8 (Cleanup) with `status: "user_aborted"`.

This gate runs BEFORE stagnation detection so that a rejected iteration doesn't accidentally accumulate stagnation count.

### Step 4: Check Stagnation

**Calculate state hash**:
```bash
python3 functions/stagnation_detector.py \
  --phase "{phase}" \
  --indicators "{indicators_json}" \
  --files-changed "{files_json}" \
  --history "{hash_history_json}"
```

**If stagnation detected** (same hash for N iterations), the response depends on `never_pause_on_stagnation`.

#### Default behavior (`never_pause_on_stagnation: false`)

Prompt the user:

```
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
STAGNATION DETECTED
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Same state detected for {N} consecutive iterations.

Current State:
  Phase: {PHASE}
  Indicators: {MET}/{TOTAL}
  Last Action: {LAST_ACTION}

Possible causes:
1. Blocked by external dependency
2. Unclear requirements
3. Test failures preventing progress
4. Missing context or permissions

Options:
1. [Continue] - Try one more iteration
2. [Clarify] - Explain what's blocking
3. [Abort] - End loop, manual intervention

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
```

**Use AskUserQuestion** for choice:
- Continue: Reset stagnation counter, continue loop
- Clarify: User explains blocker, incorporate and continue
- Abort: Exit loop with partial completion marker

#### Autonomous behavior (`never_pause_o