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+# Export Improvements Phase B — Implementation Plan
+
+> **For Claude:** REQUIRED SUB-SKILL: Use superpowers:executing-plans to implement this plan task-by-task.
+
+**Goal:** Add summary block, custom step markers, detail levels (standard/full), and editable preview modal to the export system.
+
+**Architecture:** Backend changes to all 4 export generators (markdown, text, HTML, PSA) + schema additions. Frontend changes to ExportPreviewModal (editable textarea) and SessionDetailPage (detail level dropdown, summary toggle). No migration needed.
+
+**Tech Stack:** Python FastAPI, Pydantic v2, React 19, TypeScript, Tailwind CSS
+
+---
+
+## Task 1: Add Phase B Fields to Backend Schema
+
+**Files:**
+- Modify: `backend/app/schemas/session.py:84-91`
+
+**Step 1: Add `include_summary` and `detail_level` to `SessionExport`**
+
+```python
+class SessionExport(BaseModel):
+    format: str = Field(default="markdown", pattern="^(text|markdown|html|psa)$")
+    include_timestamps: bool = True
+    include_tree_info: bool = True
+    # Phase A
+    include_outcome_notes: bool = True
+    include_next_steps: bool = True
+    max_step_index: Optional[int] = Field(None, ge=1, description="1-based inclusive step cutoff")
+    # Phase B
+    include_summary: bool = False
+    detail_level: Literal["standard", "full"] = "standard"
+```
+
+Note: `Literal` is already imported at line 2.
+
+**Step 2: Run tests to verify no regressions**
+
+Run: `cd /c/Dev/Projects/patherly/backend && python -m pytest tests/test_export.py -v`
+Expected: All existing export tests pass (new fields have defaults, so backward-compatible).
+
+**Step 3: Commit**
+
+```bash
+git add backend/app/schemas/session.py
+git commit -m "feat: add include_summary and detail_level to SessionExport schema"
+```
+
+---
+
+## Task 2: Add Frontend Types for Phase B
+
+**Files:**
+- Modify: `frontend/src/types/session.ts:79-86`
+
+**Step 1: Add `include_summary` and `detail_level` to `SessionExport` interface**
+
+```typescript
+export interface SessionExport {
+  format: 'text' | 'markdown' | 'html' | 'psa'
+  include_timestamps?: boolean
+  include_tree_info?: boolean
+  include_outcome_notes?: boolean
+  include_next_steps?: boolean
+  max_step_index?: number
+  include_summary?: boolean
+  detail_level?: 'standard' | 'full'
+}
+```
+
+**Step 2: Build to verify**
+
+Run: `cd /c/Dev/Projects/patherly/frontend && npx tsc --noEmit`
+Expected: No type errors.
+
+**Step 3: Commit**
+
+```bash
+git add frontend/src/types/session.ts
+git commit -m "feat(frontend): add include_summary and detail_level to SessionExport type"
+```
+
+---
+
+## Task 3: Custom Step Markers (B2) in All 4 Generators
+
+**Files:**
+- Modify: `backend/app/services/export_service.py`
+
+This is a pure backend change. Detect custom steps by `node_id.startswith("custom-")` and prefix the step title with `[CUSTOM]`.
+
+**Step 1: Update `generate_markdown_export`** (line 163)
+
+Change:
+```python
+        lines.append(f"### Step {i}: {question}")
+```
+To:
+```python
+        is_custom = decision.get("node_id", "").startswith("custom-")
+        prefix = "[CUSTOM] " if is_custom else ""
+        lines.append(f"### Step {i}: {prefix}{question}")
+        if is_custom:
+            lines.append("*Custom step added by engineer*")
+```
+
+**Step 2: Update `generate_text_export`** (line 250)
+
+Change:
+```python
+        lines.append(f"\n{i}. {question}")
+```
+To:
+```python
+        is_custom = decision.get("node_id", "").startswith("custom-")
+        prefix = "[CUSTOM] " if is_custom else ""
+        lines.append(f"\n{i}. {prefix}{question}")
+```
+
+**Step 3: Update `generate_html_export`** (line 342)
+
+Change:
+```python
+        html_parts.append(f'<h3>Step {i}: {question}</h3>')
+```
+To:
+```python
+        is_custom = decision.get("node_id", "").startswith("custom-")
+        custom_badge = '<span style="background: #7c3aed; color: white; padding: 2px 6px; border-radius: 3px; font-size: 0.75em; margin-right: 6px;">CUSTOM</span>' if is_custom else ''
+        html_parts.append(f'<h3>{custom_badge}Step {i}: {question}</h3>')
+```
+
+**Step 4: Update `generate_psa_export`** (line 413)
+
+Change:
+```python
+            line = f"{i}. {question}"
+```
+To:
+```python
+            is_custom = decision.get("node_id", "").startswith("custom-")
+            prefix = "[CUSTOM] " if is_custom else ""
+            line = f"{i}. {prefix}{question}"
+```
+
+**Step 5: Run tests**
+
+Run: `cd /c/Dev/Projects/patherly/backend && python -m pytest tests/test_export.py -v`
+Expected: All pass. (Existing tests don't have custom steps, so markers won't appear — no regressions.)
+
+**Step 6: Commit**
+
+```bash
+git add backend/app/services/export_service.py
+git commit -m "feat: add [CUSTOM] markers to custom steps in all 4 export generators"
+```
+
+---
+
+## Task 4: Command Output Truncation + Detail Levels (B3)
+
+**Files:**
+- Modify: `backend/app/services/export_service.py`
+
+**Step 1: Add `_truncate_command_output` helper** (after `_get_command_output` at line 91)
+
+```python
+def _truncate_command_output(output: str, max_lines: int = 5) -> str:
+    """Truncate command output to max_lines for standard detail level."""
+    lines = output.splitlines()
+    if len(lines) <= max_lines:
+        return output
+    truncated = "\n".join(lines[:max_lines])
+    return f"{truncated}\n*(full output omitted — {len(lines)} lines)*"
+```
+
+**Step 2: Apply truncation in `generate_markdown_export`** (line 168)
+
+Change:
+```python
+        if command_output := _get_command_output(decision):
+```
+To:
+```python
+        if command_output := _get_command_output(decision):
+            if options.detail_level == "standard":
+                command_output = _truncate_command_output(command_output)
+```
+
+**Step 3: Apply truncation in `generate_text_export`** (line 255)
+
+Same pattern — add truncation right after `if command_output := _get_command_output(decision):`:
+```python
+            if options.detail_level == "standard":
+                command_output = _truncate_command_output(command_output)
+```
+
+**Step 4: Apply truncation in `generate_html_export`** (line 347)
+
+Same pattern after `if command_output := _get_command_output(decision):`:
+```python
+            if options.detail_level == "standard":
+                command_output = _truncate_command_output(command_output)
+```
+
+**Step 5: Apply truncation in `generate_psa_export`** (line 421)
+
+Same pattern after `if command_output := _get_command_output(decision):`:
+```python
+            if options.detail_level == "standard":
+                command_output = _truncate_command_output(command_output)
+```
+
+**Step 6: Run tests**
+
+Run: `cd /c/Dev/Projects/patherly/backend && python -m pytest tests/test_export.py -v`
+Expected: All pass (default `detail_level="standard"` but existing test command outputs are short).
+
+**Step 7: Commit**
+
+```bash
+git add backend/app/services/export_service.py
+git commit -m "feat: add command output truncation for standard detail level"
+```
+
+---
+
+## Task 5: Summary Block Generation (B1)
+
+**Files:**
+- Modify: `backend/app/services/export_service.py`
+
+Add summary block generation to all 4 generators. The summary is inserted after metadata, before Evidence/Steps. Only rendered when `options.include_summary is True`.
+
+**Step 1: Add `_build_summary_fields` helper** (after `_get_outcome_label` at line 113)
+
+```python
+def _build_summary_fields(session: Session) -> dict[str, str]:
+    """Build auto-populated summary fields from session data."""
+    tree_name = session.tree_snapshot.get("name", "Troubleshooting Session")
+    tree_desc = session.tree_snapshot.get("description", "")
+    issue = f"{tree_name}: {tree_desc}" if tree_desc else tree_name
+
+    if session.completed_at:
+        status = "Resolved" if getattr(session, "outcome", None) == "resolved" else \
+                 f"Completed — {_get_outcome_label(session) or 'Unknown'}"
+    else:
+        step_count = len(session.decisions) if session.decisions else 0
+        status = f"In Progress — paused at step {step_count}" if step_count else "In Progress"
+
+    _raw_notes = getattr(session, 'outcome_notes', None)
+    resolution = (_raw_notes if isinstance(_raw_notes, str) else '').strip() or "[Edit in preview]"
+
+    _raw_next = getattr(session, 'next_steps', None)
+    next_steps = (_raw_next if isinstance(_raw_next, str) else '').strip() or "[Edit in preview]"
+
+    return {
+        "issue": issue,
+        "impact": "[Edit in preview]",
+        "status": status,
+        "resolution": resolution,
+        "next_steps": next_steps,
+    }
+```
+
+**Step 2: Add summary block to `generate_markdown_export`**
+
+Insert after the tree_info block (after line 138, before the scratchpad section):
+
+```python
+    if options.include_summary:
+        summary = _build_summary_fields(session)
+        lines.append("## Summary")
+        lines.append("")
+        lines.append(f"| Field | Details |")
+        lines.append(f"|-------|---------|")
+        lines.append(f"| Issue | {summary['issue']} |")
+        lines.append(f"| Impact | {summary['impact']} |")
+        lines.append(f"| Status | {summary['status']} |")
+        lines.append(f"| Resolution | {summary['resolution']} |")
+        lines.append(f"| Next Steps | {summary['next_steps']} |")
+        lines.append("")
+        lines.append("---")
+        lines.append("")
+```
+
+**Step 3: Add summary block to `generate_text_export`**
+
+Insert after tree_info block (after line 227, before scratchpad section):
+
+```python
+    if options.include_summary:
+        summary = _build_summary_fields(session)
+        lines.append("SUMMARY")
+        lines.append("-" * 20)
+        lines.append(f"Issue: {summary['issue']}")
+        lines.append(f"Impact: {summary['impact']}")
+        lines.append(f"Status: {summary['status']}")
+        lines.append(f"Resolution: {summary['resolution']}")
+        lines.append(f"Next Steps: {summary['next_steps']}")
+        lines.append("")
+```
+
+**Step 4: Add summary block to `generate_html_export`**
+
+Insert after tree_info `</div>` (after line 321, before scratchpad section):
+
+```python
+    if options.include_summary:
+        summary = _build_summary_fields(session)
+        html_parts.append('<h2>Summary</h2>')
+        html_parts.append('<table style="width: 100%; border-collapse: collapse; margin-bottom: 20px;">')
+        for label, value in [("Issue", summary["issue"]), ("Impact", summary["impact"]),
+                             ("Status", summary["status"]), ("Resolution", summary["resolution"]),
+                             ("Next Steps", summary["next_steps"])]:
+            html_parts.append(f'<tr><td style="padding: 6px 12px; border: 1px solid #ddd; font-weight: bold; width: 120px;">{html.escape(label)}</td>')
+            html_parts.append(f'<td style="padding: 6px 12px; border: 1px solid #ddd;">{html.escape(value)}</td></tr>')
+        html_parts.append('</table>')
+```
+
+**Step 5: Add summary block to `generate_psa_export`**
+
+Insert after `lines.append("")` on line 394 (after the header, before PROBLEM section):
+
+```python
+    if options.include_summary:
+        summary = _build_summary_fields(session)
+        lines.append("--- SUMMARY ---")
+        lines.append(f"Issue: {summary['issue']}")
+        lines.append(f"Impact: {summary['impact']}")
+        lines.append(f"Status: {summary['status']}")
+        lines.append(f"Resolution: {summary['resolution']}")
+        lines.append(f"Next Steps: {summary['next_steps']}")
+        lines.append("")
+```
+
+**Step 6: Run tests**
+
+Run: `cd /c/Dev/Projects/patherly/backend && python -m pytest tests/test_export.py -v`
+Expected: All pass (summary is opt-in, existing tests don't set `include_summary=True`).
+
+**Step 7: Commit**
+
+```bash
+git add backend/app/services/export_service.py
+git commit -m "feat: add summary block generation to all 4 export generators"
+```
+
+---
+
+## Task 6: Editable Preview Modal (B4)
+
+**Files:**
+- Modify: `frontend/src/components/session/ExportPreviewModal.tsx`
+
+**Step 1: Replace read-only preview with editable textarea and add controls**
+
+Rewrite the component:
+
+```tsx
+import { useState, useEffect } from 'react'
+import { Copy, Download, Check, RotateCcw } from 'lucide-react'
+import { Modal } from '@/components/common/Modal'
+import { cn } from '@/lib/utils'
+
+interface ExportPreviewModalProps {
+  isOpen: boolean
+  onClose: () => void
+  content: string
+  filename: string
+  format: 'markdown' | 'text' | 'html' | 'psa'
+  onDownload: (content: string) => void
+  includeSummary?: boolean
+  onToggleSummary?: (include: boolean) => void
+}
+
+export function ExportPreviewModal({
+  isOpen,
+  onClose,
+  content,
+  filename,
+  format,
+  onDownload,
+  includeSummary = false,
+  onToggleSummary,
+}: ExportPreviewModalProps) {
+  const [copied, setCopied] = useState(false)
+  const [editedContent, setEditedContent] = useState(content)
+
+  // Sync editedContent when content prop changes (new fetch)
+  useEffect(() => {
+    setEditedContent(content)
+  }, [content])
+
+  const handleCopy = async () => {
+    try {
+      await navigator.clipboard.writeText(editedContent)
+      setCopied(true)
+      setTimeout(() => setCopied(false), 2000)
+    } catch (err) {
+      console.error('Failed to copy:', err)
+    }
+  }
+
+  const handleDownload = () => {
+    onDownload(editedContent)
+    onClose()
+  }
+
+  const handleReset = () => {
+    setEditedContent(content)
+  }
+
+  const handleClose = () => {
+    setCopied(false)
+    onClose()
+  }
+
+  const isModified = editedContent !== content
+
+  return (
+    <Modal isOpen={isOpen} onClose={handleClose} title="Export Preview" size="xl">
+      {/* Filename, format info, and controls */}
+      <div className="mb-3 flex items-center justify-between">
+        <p className="text-sm text-white/70">
+          Filename: <span className="font-mono text-white">{filename}</span>
+          <span className="ml-3 rounded bg-white/10 px-2 py-0.5 text-xs text-white/70">
+            {format === 'markdown' ? 'Markdown' : format === 'html' ? 'HTML' : format === 'psa' ? 'PSA' : 'Plain Text'}
+          </span>
+          {isModified && (
+            <span className="ml-2 text-xs text-yellow-400">(edited)</span>
+          )}
+        </p>
+        <div className="flex items-center gap-3">
+          {onToggleSummary && (
+            <label className="flex items-center gap-2 text-sm text-white/60 cursor-pointer">
+              <input
+                type="checkbox"
+                checked={includeSummary}
+                onChange={(e) => onToggleSummary(e.target.checked)}
+                className="h-4 w-4 rounded border-white/20 bg-black/50"
+              />
+              Include Summary
+            </label>
+          )}
+          {isModified && (
+            <button
+              onClick={handleReset}
+              className="flex items-center gap-1 text-xs text-white/40 hover:text-white"
+              title="Reset to original"
+            >
+              <RotateCcw className="h-3 w-3" />
+              Reset
+            </button>
+          )}
+        </div>
+      </div>
+
+      {/* Editable Content */}
+      <textarea
+        value={editedContent}
+        onChange={(e) => setEditedContent(e.target.value)}
+        className={cn(
+          'h-96 w-full resize-y rounded-md border border-white/10 bg-black/50 p-4',
+          'font-mono text-sm text-white',
+          'focus:border-white/30 focus:outline-none focus:ring-1 focus:ring-white/20'
+        )}
+      />
+
+      {/* Actions */}
+      <div className="mt-4 flex items-center justify-end gap-2">
+        <button
+          onClick={handleCopy}
+          className={cn(
+            'flex items-center gap-2 rounded-md border border-white/10 px-3 py-2 text-sm font-medium',
+            'text-white/60 hover:bg-white/10 hover:text-white',
+            'focus:outline-none focus:ring-2 focus:ring-white/20'
+          )}
+        >
+          {copied ? (
+            <>
+              <Check className="h-4 w-4 text-emerald-400" />
+              Copied!
+            </>
+          ) : (
+            <>
+              <Copy className="h-4 w-4" />
+              Copy to Clipboard
+            </>
+          )}
+        </button>
+        <button
+          onClick={handleDownload}
+          className={cn(
+            'flex items-center gap-2 rounded-md bg-white px-3 py-2 text-sm font-medium text-black',
+            'hover:bg-white/90 focus:outline-none focus:ring-2 focus:ring-white/20'
+          )}
+        >
+          <Download className="h-4 w-4" />
+          Download
+        </button>
+      </div>
+    </Modal>
+  )
+}
+
+export default ExportPreviewModal
+```
+
+Key changes:
+- `<pre>` → `<textarea>` with `editedContent` local state
+- Copy/Download use `editedContent` instead of `content` prop
+- Reset button appears when content is modified
+- `onDownload` signature changes to `(content: string) => void` to receive edited content
+- New optional `includeSummary` + `onToggleSummary` props for summary checkbox
+- `(edited)` indicator when content has been modified
+
+**Step 2: Build to verify**
+
+Run: `cd /c/Dev/Projects/patherly/frontend && npx tsc --noEmit`
+
+Fix any type errors from the `onDownload` signature change (see Task 7).
+
+**Step 3: Commit**
+
+```bash
+git add frontend/src/components/session/ExportPreviewModal.tsx
+git commit -m "feat(frontend): convert ExportPreviewModal to editable textarea with reset"
+```
+
+---
+
+## Task 7: Wire Up Phase B Controls in SessionDetailPage
+
+**Files:**
+- Modify: `frontend/src/pages/SessionDetailPage.tsx`
+
+**Step 1: Add state for detail level and include summary** (after line 34)
+
+```typescript
+const [detailLevel, setDetailLevel] = useState<'standard' | 'full'>('standard')
+const [includeSummary, setIncludeSummary] = useState(false)
+```
+
+**Step 2: Update `fetchExportContent` to include Phase B options** (line 92-101)
+
+```typescript
+  const fetchExportContent = async () => {
+    if (!session) return null
+    const options: SessionExport = {
+      format: exportFormat,
+      include_timestamps: true,
+      include_tree_info: true,
+      ...(maxStepIndex !== null && { max_step_index: maxStepIndex }),
+      detail_level: detailLevel,
+      include_summary: includeSummary,
+    }
+    return await sessionsApi.export(session.id, options)
+  }
+```
+
+**Step 3: Update `handleCopyForTicket` to include Phase B options** (line 140-145)
+
+```typescript
+      const options: SessionExport = {
+        format: 'psa',
+        include_timestamps: true,
+        include_tree_info: true,
+        ...(maxStepIndex !== null && { max_step_index: maxStepIndex }),
+        detail_level: detailLevel,
+        include_summary: includeSummary,
+      }
+```
+
+**Step 4: Update `handleDownload` to accept content parameter** (line 159)
+
+Change:
+```typescript
+  const handleDownload = () => {
+    if (!exportContent || !session) return
+    const blob = new Blob([exportContent], { type: 'text/plain' })
+```
+To:
+```typescript
+  const handleDownload = (content: string) => {
+    if (!session) return
+    const blob = new Blob([content], { type: 'text/plain' })
+```
+
+**Step 5: Add `onToggleSummary` handler**
+
+```typescript
+  const handleToggleSummary = async (include: boolean) => {
+    setIncludeSummary(include)
+    // Re-fetch with new option
+    if (!session) return
+    const options: SessionExport = {
+      format: exportFormat,
+      include_timestamps: true,
+      include_tree_info: true,
+      ...(maxStepIndex !== null && { max_step_index: maxStepIndex }),
+      detail_level: detailLevel,
+      include_summary: include,
+    }
+    try {
+      const content = await sessionsApi.export(session.id, options)
+      if (content) setExportContent(content)
+    } catch (err) {
+      console.error('Failed to re-fetch export:', err)
+    }
+  }
+```
+
+**Step 6: Add detail level dropdown** to the export controls area (after step cutoff dropdown, before copy button — after line 408)
+
+```tsx
+<select
+  value={detailLevel}
+  onChange={(e) => setDetailLevel(e.target.value as 'standard' | 'full')}
+  aria-label="Detail level"
+  className={cn(
+    'rounded-md border border-white/10 bg-black/50 px-3 py-2 text-sm text-white',
+    'focus:border-white/30 focus:outline-none focus:ring-1 focus:ring-white/20'
+  )}
+>
+  <option value="standard">Standard</option>
+  <option value="full">Full Detail</option>
+</select>
+```
+
+**Step 7: Update ExportPreviewModal props** (line 516-523)
+
+```tsx
+<ExportPreviewModal
+  isOpen={showPreview}
+  onClose={() => setShowPreview(false)}
+  content={exportContent || ''}
+  filename={getFilename()}
+  format={exportFormat}
+  onDownload={handleDownload}
+  includeSummary={includeSummary}
+  onToggleSummary={handleToggleSummary}
+/>
+```
+
+**Step 8: Build to verify**
+
+Run: `cd /c/Dev/Projects/patherly/frontend && npx tsc --noEmit`
+Expected: No type errors.
+
+**Step 9: Commit**
+
+```bash
+git add frontend/src/pages/SessionDetailPage.tsx
+git commit -m "feat(frontend): add detail level dropdown and summary toggle to export controls"
+```
+
+---
+
+## Task 8: Backend Tests for Phase B Features
+
+**Files:**
+- Modify: `backend/tests/test_export.py`
+
+**Step 1: Add test for custom step markers**
+
+```python
+def test_custom_step_markers_psa(self, completed_session):
+    """Custom steps should have [CUSTOM] prefix in export."""
+    # Add a custom step to decisions
+    completed_session.decisions.append({
+        "node_id": "custom-abc123",
+        "question": "Check Additional Logs",
+        "answer": "Found error in event log",
+        "notes": None,
+        "timestamp": "2024-01-01T12:05:00Z",
+    })
+    options = SessionExport(format="psa")
+    result = generate_psa_export(completed_session, options)
+    assert "[CUSTOM] Check Additional Logs" in result
+```
+
+**Step 2: Add test for command output truncation**
+
+```python
+def test_command_output_truncation_standard(self, completed_session):
+    """Standard detail level truncates long command output."""
+    long_output = "\n".join(f"line {i}" for i in range(20))
+    completed_session.decisions[0]["command_output"] = long_output
+    options = SessionExport(format="text", detail_level="standard")
+    result = generate_text_export(completed_session, options)
+    assert "*(full output omitted — 20 lines)*" in result
+
+def test_command_output_full_detail(self, completed_session):
+    """Full detail level shows all command output."""
+    long_output = "\n".join(f"line {i}" for i in range(20))
+    completed_session.decisions[0]["command_output"] = long_output
+    options = SessionExport(format="text", detail_level="full")
+    result = generate_text_export(completed_session, options)
+    assert "*(full output omitted" not in result
+    assert "line 19" in result
+```
+
+**Step 3: Add test for summary block**
+
+```python
+def test_summary_block_psa(self, completed_session):
+    """Summary block appears when include_summary is True."""
+    options = SessionExport(format="psa", include_summary=True)
+    result = generate_psa_export(completed_session, options)
+    assert "--- SUMMARY ---" in result
+    assert "Issue:" in result
+    assert "Status:" in result
+
+def test_no_summary_by_default(self, completed_session):
+    """Summary block should not appear by default."""
+    options = SessionExport(format="psa")
+    result = generate_psa_export(completed_session, options)
+    assert "--- SUMMARY ---" not in result
+```
+
+**Step 4: Run all export tests**
+
+Run: `cd /c/Dev/Projects/patherly/backend && python -m pytest tests/test_export.py -v`
+Expected: All tests pass including new ones.
+
+**Step 5: Commit**
+
+```bash
+git add backend/tests/test_export.py
+git commit -m "test: add tests for custom step markers, detail levels, and summary block"
+```
+
+---
+
+## Task 9: Final Build Verification
+
+**Step 1: Run full backend tests**
+
+Run: `cd /c/Dev/Projects/patherly/backend && python -m pytest --override-ini="addopts=" -v`
+Expected: All tests pass.
+
+**Step 2: Run frontend build**
+
+Run: `cd /c/Dev/Projects/patherly/frontend && npm run build`
+Expected: Build succeeds with no errors.
+
+**Step 3: Verify git status is clean**
+
+```bash
+git status
+git log --oneline feat/export-phase-a --not main | head -20
+```
+
+---
+
+## Frontend Acceptance Checklist (Manual QA)
+
+1. **Editable preview:** Open Preview, edit text, verify Copy/Download use edited content. Click Reset to restore original.
+2. **Summary toggle:** Check "Include Summary" in preview — export re-fetches with summary block. Uncheck removes it.
+3. **Detail level:** Select "Full Detail", export a session with long command output — no truncation. Switch to "Standard" — output truncated.
+4. **Custom step markers:** Export a session with custom steps — should show `[CUSTOM]` prefix.
+5. **Summary block content:** Summary should auto-populate Issue from tree name, Status from completion state, Resolution from outcome_notes.