feat: add safety plan version history diff view (#96)

Fixes #59

The footer links to /about but the repo ships about.html. On a plain static server this results in a 404. Changed to /about.html so the link resolves correctly.

crisis/__init__.py

@@ -7,6 +7,7 @@ Stands between a broken man and a machine that would tell him to die.
 from .detect import detect_crisis, CrisisDetectionResult, format_result, get_urgency_emoji
 from .response import process_message, generate_response, CrisisResponse
 from .gateway import check_crisis, get_system_prompt, format_gateway_response
+from .session_tracker import CrisisSessionTracker, SessionState, check_crisis_with_session
 
 __all__ = [
     "detect_crisis",
@@ -19,4 +20,7 @@ __all__ = [
     "format_result",
     "format_gateway_response",
     "get_urgency_emoji",
+    "CrisisSessionTracker",
+    "SessionState",
+    "check_crisis_with_session",
 ]

crisis/gateway.py

@@ -22,6 +22,7 @@ from .response import (
     get_system_prompt_modifier,
     CrisisResponse,
 )
+from .session_tracker import CrisisSessionTracker
 
 
 def check_crisis(text: str) -> dict:

crisis/session_tracker.py

@@ -0,0 +1,259 @@
+"""
+Session-level crisis tracking and escalation for the-door (P0 #35).
+
+Tracks crisis detection across messages within a single conversation,
+detecting escalation and de-escalation patterns. Privacy-first: no
+persistence beyond the conversation session.
+
+Each message is analyzed in isolation by detect.py, but this module
+maintains session state so the system can recognize patterns like:
+  - "I'm fine" → "I'm struggling" → "I can't go on"  (rapid escalation)
+  - "I want to die" → "I'm calmer now" → "feeling better"  (de-escalation)
+
+Usage:
+    from crisis.session_tracker import CrisisSessionTracker
+
+    tracker = CrisisSessionTracker()
+
+    # Feed each message's detection result
+    state = tracker.record(detect_crisis("I'm having a tough day"))
+    print(state.current_level)  # "LOW"
+    print(state.is_escalating)  # False
+
+    state = tracker.record(detect_crisis("I feel hopeless"))
+    print(state.is_escalating)  # True (LOW → MEDIUM/HIGH in 2 messages)
+
+    # Get system prompt modifier
+    modifier = tracker.get_session_modifier()
+    # "User has escalated from LOW to HIGH over 2 messages."
+
+    # Reset for new session
+    tracker.reset()
+"""
+
+from dataclasses import dataclass, field
+from typing import List, Optional
+
+from .detect import CrisisDetectionResult, SCORES
+
+# Level ordering for comparison (higher = more severe)
+LEVEL_ORDER = {"NONE": 0, "LOW": 1, "MEDIUM": 2, "HIGH": 3, "CRITICAL": 4}
+
+
+@dataclass
+class SessionState:
+    """Immutable snapshot of session crisis tracking state."""
+
+    current_level: str = "NONE"
+    peak_level: str = "NONE"
+    message_count: int = 0
+    level_history: List[str] = field(default_factory=list)
+    is_escalating: bool = False
+    is_deescalating: bool = False
+    escalation_rate: float = 0.0  # levels gained per message
+    consecutive_low_messages: int = 0  # for de-escalation tracking
+
+
+class CrisisSessionTracker:
+    """
+    Session-level crisis state tracker.
+
+    Privacy-first: no database, no network calls, no cross-session
+    persistence. State lives only in memory for the duration of
+    a conversation, then is discarded on reset().
+    """
+
+    # Thresholds (from issue #35)
+    ESCALATION_WINDOW = 3   # messages: LOW → HIGH in ≤3 messages = rapid escalation
+    DEESCALATION_WINDOW = 5  # messages: need 5+ consecutive LOW messages after CRITICAL
+
+    def __init__(self):
+        self.reset()
+
+    def reset(self):
+        """Reset all session state. Call on new conversation."""
+        self._current_level = "NONE"
+        self._peak_level = "NONE"
+        self._message_count = 0
+        self._level_history: List[str] = []
+        self._consecutive_low = 0
+
+    @property
+    def state(self) -> SessionState:
+        """Return immutable snapshot of current session state."""
+        is_escalating = self._detect_escalation()
+        is_deescalating = self._detect_deescalation()
+        rate = self._compute_escalation_rate()
+
+        return SessionState(
+            current_level=self._current_level,
+            peak_level=self._peak_level,
+            message_count=self._message_count,
+            level_history=list(self._level_history),
+            is_escalating=is_escalating,
+            is_deescalating=is_deescalating,
+            escalation_rate=rate,
+            consecutive_low_messages=self._consecutive_low,
+        )
+
+    def record(self, detection: CrisisDetectionResult) -> SessionState:
+        """
+        Record a crisis detection result for the current message.
+
+        Returns updated SessionState.
+        """
+        level = detection.level
+        self._message_count += 1
+        self._level_history.append(level)
+
+        # Update peak
+        if LEVEL_ORDER.get(level, 0) > LEVEL_ORDER.get(self._peak_level, 0):
+            self._peak_level = level
+
+        # Track consecutive LOW/NONE messages for de-escalation
+        if LEVEL_ORDER.get(level, 0) <= LEVEL_ORDER["LOW"]:
+            self._consecutive_low += 1
+        else:
+            self._consecutive_low = 0
+
+        self._current_level = level
+        return self.state
+
+    def _detect_escalation(self) -> bool:
+        """
+        Detect rapid escalation: LOW → HIGH within ESCALATION_WINDOW messages.
+
+        Looks at the last N messages and checks if the level has climbed
+        significantly (at least 2 tiers).
+        """
+        if len(self._level_history) < 2:
+            return False
+
+        window = self._level_history[-self.ESCALATION_WINDOW:]
+        if len(window) < 2:
+            return False
+
+        first_level = window[0]
+        last_level = window[-1]
+
+        first_score = LEVEL_ORDER.get(first_level, 0)
+        last_score = LEVEL_ORDER.get(last_level, 0)
+
+        # Escalation = climbed at least 2 tiers in the window
+        return (last_score - first_score) >= 2
+
+    def _detect_deescalation(self) -> bool:
+        """
+        Detect de-escalation: was at CRITICAL/HIGH, now sustained LOW/NONE
+        for DEESCALATION_WINDOW consecutive messages.
+        """
+        if LEVEL_ORDER.get(self._peak_level, 0) < LEVEL_ORDER["HIGH"]:
+            return False
+
+        return self._consecutive_low >= self.DEESCALATION_WINDOW
+
+    def _compute_escalation_rate(self) -> float:
+        """
+        Compute levels gained per message over the conversation.
+
+        Positive = escalating, negative = de-escalating, 0 = stable.
+        """
+        if self._message_count < 2:
+            return 0.0
+
+        first = LEVEL_ORDER.get(self._level_history[0], 0)
+        current = LEVEL_ORDER.get(self._current_level, 0)
+
+        return (current - first) / (self._message_count - 1)
+
+    def get_session_modifier(self) -> str:
+        """
+        Generate a system prompt modifier reflecting session-level crisis state.
+
+        Returns empty string if no session context is relevant.
+        """
+        if self._message_count < 2:
+            return ""
+
+        s = self.state
+
+        if s.is_escalating:
+            return (
+                f"User has escalated from {self._level_history[0]} to "
+                f"{s.current_level} over {s.message_count} messages. "
+                f"Peak crisis level this session: {s.peak_level}. "
+                "Respond with heightened awareness. The trajectory is "
+                "worsening — prioritize safety and connection."
+            )
+
+        if s.is_deescalating:
+            return (
+                f"User previously reached {s.peak_level} crisis level "
+                f"but has been at {s.current_level} or below for "
+                f"{s.consecutive_low_messages} consecutive messages. "
+                "The situation appears to be stabilizing. Continue "
+                "supportive engagement while remaining vigilant."
+            )
+
+        if s.peak_level in ("CRITICAL", "HIGH") and s.current_level not in ("CRITICAL", "HIGH"):
+            return (
+                f"User previously reached {s.peak_level} crisis level "
+                f"this session (currently {s.current_level}). "
+                "Continue with care and awareness of the earlier crisis."
+            )
+
+        return ""
+
+    def get_ui_hints(self) -> dict:
+        """
+        Return UI hints based on session state for the frontend.
+
+        These are advisory — the frontend decides what to show.
+        """
+        s = self.state
+
+        hints = {
+            "session_escalating": s.is_escalating,
+            "session_deescalating": s.is_deescalating,
+            "session_peak_level": s.peak_level,
+            "session_message_count": s.message_count,
+        }
+
+        if s.is_escalating:
+            hints["escalation_warning"] = True
+            hints["suggested_action"] = (
+                "User crisis level is rising across messages. "
+                "Consider increasing intervention level."
+            )
+
+        return hints
+
+
+def check_crisis_with_session(
+    text: str,
+    tracker: CrisisSessionTracker,
+) -> dict:
+    """
+    Convenience: detect crisis and update session state in one call.
+
+    Returns combined single-message detection + session-level context.
+    """
+    from .detect import detect_crisis
+    from .gateway import check_crisis
+
+    single_result = check_crisis(text)
+    detection = detect_crisis(text)
+    session_state = tracker.record(detection)
+
+    return {
+        **single_result,
+        "session": {
+            "current_level": session_state.current_level,
+            "peak_level": session_state.peak_level,
+            "message_count": session_state.message_count,
+            "is_escalating": session_state.is_escalating,
+            "is_deescalating": session_state.is_deescalating,
+            "modifier": tracker.get_session_modifier(),
+            "ui_hints": tracker.get_ui_hints(),
+        },
+    }

index.html

@@ -500,6 +500,184 @@ html, body {
   min-height: 60px;
 }
 
+.safety-plan-status {
+  min-height: 20px;
+  margin: 4px 0 18px;
+  font-size: 0.85rem;
+  color: #8b949e;
+}
+
+.safety-plan-status.success {
+  color: #3fb950;
+}
+
+.safety-plan-status.error {
+  color: #ff7b72;
+}
+
+.safety-plan-versioning {
+  margin-top: 24px;
+  padding-top: 20px;
+  border-top: 1px solid #30363d;
+}
+
+.safety-plan-versioning-grid {
+  display: grid;
+  gap: 16px;
+}
+
+.safety-plan-history-panel,
+.safety-plan-diff-panel {
+  background: #0d1117;
+  border: 1px solid #30363d;
+  border-radius: 12px;
+  padding: 16px;
+}
+
+.safety-plan-section-header h3 {
+  font-size: 0.95rem;
+  margin-bottom: 4px;
+}
+
+.safety-plan-section-header p {
+  font-size: 0.8rem;
+  color: #8b949e;
+  margin-bottom: 12px;
+}
+
+.safety-plan-history {
+  display: flex;
+  flex-direction: column;
+  gap: 10px;
+}
+
+.safety-plan-history-item {
+  border: 1px solid #30363d;
+  border-radius: 10px;
+  padding: 12px;
+  background: #161b22;
+}
+
+.safety-plan-history-item.active {
+  border-color: #58a6ff;
+  box-shadow: 0 0 0 1px rgba(88, 166, 255, 0.35);
+}
+
+.safety-plan-history-meta {
+  display: flex;
+  justify-content: space-between;
+  gap: 12px;
+  align-items: baseline;
+  margin-bottom: 8px;
+  flex-wrap: wrap;
+}
+
+.safety-plan-history-title {
+  font-size: 0.88rem;
+  font-weight: 600;
+  color: #e6edf3;
+}
+
+.safety-plan-history-note {
+  font-size: 0.78rem;
+  color: #8b949e;
+  margin-bottom: 10px;
+}
+
+.safety-plan-history-actions {
+  display: flex;
+  gap: 8px;
+  flex-wrap: wrap;
+}
+
+.safety-plan-history-button,
+.safety-plan-restore-button {
+  border-radius: 8px;
+  border: 1px solid #30363d;
+  background: transparent;
+  color: #e6edf3;
+  padding: 8px 12px;
+  font-size: 0.82rem;
+  cursor: pointer;
+}
+
+.safety-plan-history-button:hover,
+.safety-plan-restore-button:hover,
+.safety-plan-history-button:focus,
+.safety-plan-restore-button:focus {
+  border-color: #58a6ff;
+  color: #58a6ff;
+  outline: none;
+}
+
+.safety-plan-restore-button {
+  background: rgba(35, 134, 54, 0.14);
+}
+
+.safety-plan-diff {
+  display: flex;
+  flex-direction: column;
+  gap: 12px;
+}
+
+.safety-plan-diff-meta {
+  font-size: 0.78rem;
+  color: #8b949e;
+}
+
+.safety-plan-diff-field {
+  border-top: 1px solid #21262d;
+  padding-top: 12px;
+}
+
+.safety-plan-diff-field:first-child {
+  border-top: none;
+  padding-top: 0;
+}
+
+.safety-plan-diff-field h4 {
+  font-size: 0.84rem;
+  margin-bottom: 8px;
+  color: #c9d1d9;
+}
+
+.safety-plan-diff-block {
+  white-space: pre-wrap;
+  line-height: 1.5;
+  border-radius: 8px;
+  padding: 10px;
+  font-size: 0.88rem;
+  margin-bottom: 8px;
+}
+
+.diff-unchanged {
+  background: #161b22;
+  color: #c9d1d9;
+}
+
+.diff-added {
+  background: rgba(46, 160, 67, 0.16);
+  border-left: 3px solid #2ea043;
+  color: #d2f4d3;
+}
+
+.diff-removed {
+  background: rgba(248, 81, 73, 0.16);
+  border-left: 3px solid #f85149;
+  color: #ffd8d3;
+}
+
+.safety-plan-empty {
+  color: #8b949e;
+  font-size: 0.85rem;
+}
+
+@media (min-width: 840px) {
+  .safety-plan-versioning-grid {
+    grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
+  }
+}
+
 .modal-footer {
   display: flex;
   justify-content: flex-end;
@@ -680,7 +858,7 @@ html, body {
 
   <!-- Footer -->
   <footer id="footer">
-    <a href="/about" aria-label="About The Door">about</a>
+    <a href="/about.html" aria-label="About The Door">about</a>
     <button id="safety-plan-btn" aria-label="Open My Safety Plan">my safety plan</button>
     <button id="clear-chat-btn" aria-label="Clear chat history">clear chat</button>
   </footer>
@@ -736,6 +914,28 @@ html, body {
         <label for="sp-environment">5. Making my environment safe</label>
         <textarea id="sp-environment" placeholder="e.g., Giving my car keys to a friend, locking away meds..."></textarea>
       </div>
+
+      <div id="safety-plan-status" class="safety-plan-status" role="status" aria-live="polite"></div>
+
+      <section class="safety-plan-versioning" aria-labelledby="safety-plan-history-title">
+        <div class="safety-plan-versioning-grid">
+          <div class="safety-plan-history-panel">
+            <div class="safety-plan-section-header">
+              <h3 id="safety-plan-history-title">Version History</h3>
+              <p>Each save stays on this device so you can review changes and restore an earlier plan.</p>
+            </div>
+            <div id="safety-plan-history" class="safety-plan-history"></div>
+          </div>
+
+          <div class="safety-plan-diff-panel">
+            <div class="safety-plan-section-header">
+              <h3>Diff View</h3>
+              <p>Compare the selected version against the version immediately before it.</p>
+            </div>
+            <div id="safety-plan-diff" class="safety-plan-diff"></div>
+          </div>
+        </div>
+      </section>
     </div>
     <div class="modal-footer">
       <button class="btn btn-secondary" id="cancel-safety-plan">Cancel</button>
@@ -808,6 +1008,7 @@ Sovereignty and service always.`;
   var crisisPanel = document.getElementById('crisis-panel');
   var crisisOverlay = document.getElementById('crisis-overlay');
   var overlayDismissBtn = document.getElementById('overlay-dismiss-btn');
+  var overlayCallLink = document.querySelector('.overlay-call');
   var statusDot = document.querySelector('.status-dot');
   var statusText = document.getElementById('status-text');
   
@@ -819,12 +1020,26 @@ Sovereignty and service always.`;
   var cancelSafetyPlan = document.getElementById('cancel-safety-plan');
   var saveSafetyPlan = document.getElementById('save-safety-plan');
   var clearChatBtn = document.getElementById('clear-chat-btn');
+  var safetyPlanHistory = document.getElementById('safety-plan-history');
+  var safetyPlanDiff = document.getElementById('safety-plan-diff');
+  var safetyPlanStatus = document.getElementById('safety-plan-status');
+  var safetyPlanFields = {
+    warningSigns: document.getElementById('sp-warning-signs'),
+    coping: document.getElementById('sp-coping'),
+    distraction: document.getElementById('sp-distraction'),
+    help: document.getElementById('sp-help'),
+    environment: document.getElementById('sp-environment')
+  };
+  var SAFETY_PLAN_STORAGE_KEY = 'timmy_safety_plan';
+  var SAFETY_PLAN_VERSIONS_KEY = 'timmy_safety_plan_versions';
+  var MAX_SAFETY_PLAN_VERSIONS = 20;
 
   // ===== STATE =====
   var messages = [];
   var isStreaming = false;
   var overlayTimer = null;
   var crisisPanelShown = false;
+  var selectedSafetyPlanVersionId = null;
 
   // ===== SERVICE WORKER =====
   if ('serviceWorker' in navigator) {
@@ -1050,7 +1265,8 @@ Sovereignty and service always.`;
       }
     }, 1000);
 
-    overlayDismissBtn.focus();
+    // Focus the Call 988 link (always enabled) — disabled buttons cannot receive focus
+    if (overlayCallLink) overlayCallLink.focus();
   }
 
   // Register focus trap on document (always listening, gated by class check)
@@ -1169,18 +1385,347 @@ Sovereignty and service always.`;
   });
 
   // ===== SAFETY PLAN LOGIC =====
-  function loadSafetyPlan() {
+  function emptySafetyPlan() {
+    return {
+      warningSigns: '',
+      coping: '',
+      distraction: '',
+      help: '',
+      environment: ''
+    };
+  }
+
+  function cloneSafetyPlan(plan) {
+    var normalized = emptySafetyPlan();
+    var source = plan || {};
+    Object.keys(normalized).forEach(function(key) {
+      normalized[key] = typeof source[key] === 'string' ? source[key] : '';
+    });
+    return normalized;
+  }
+
+  function applySafetyPlan(plan) {
+    var nextPlan = cloneSafetyPlan(plan);
+    Object.keys(safetyPlanFields).forEach(function(key) {
+      safetyPlanFields[key].value = nextPlan[key];
+    });
+  }
+
+  function getSafetyPlanFormData() {
+    return {
+      warningSigns: safetyPlanFields.warningSigns.value,
+      coping: safetyPlanFields.coping.value,
+      distraction: safetyPlanFields.distraction.value,
+      help: safetyPlanFields.help.value,
+      environment: safetyPlanFields.environment.value
+    };
+  }
+
+  function escapeHtml(value) {
+    return String(value || '')
+      .replace(/&/g, '&amp;')
+      .replace(/</g, '&lt;')
+      .replace(/>/g, '&gt;')
+      .replace(/"/g, '&quot;')
+      .replace(/'/g, '&#39;');
+  }
+
+  function setSafetyPlanStatus(message, tone) {
+    if (!safetyPlanStatus) return;
+    safetyPlanStatus.textContent = message || '';
+    safetyPlanStatus.className = 'safety-plan-status' + (tone ? ' ' + tone : '');
+  }
+
+  function getSafetyPlanVersions() {
     try {
-      var saved = localStorage.getItem('timmy_safety_plan');
-      if (saved) {
-        var plan = JSON.parse(saved);
-        document.getElementById('sp-warning-signs').value = plan.warningSigns || '';
-        document.getElementById('sp-coping').value = plan.coping || '';
-        document.getElementById('sp-distraction').value = plan.distraction || '';
-        document.getElementById('sp-help').value = plan.help || '';
-        document.getElementById('sp-environment').value = plan.environment || '';
+      var saved = localStorage.getItem(SAFETY_PLAN_VERSIONS_KEY);
+      if (!saved) return [];
+      var parsed = JSON.parse(saved);
+      if (!Array.isArray(parsed)) return [];
+      return parsed.filter(function(version) {
+        return version && version.id && version.plan;
+      });
+    } catch (e) {
+      return [];
+    }
+  }
+
+  function setSafetyPlanVersions(versions) {
+    localStorage.setItem(
+      SAFETY_PLAN_VERSIONS_KEY,
+      JSON.stringify((versions || []).slice(0, MAX_SAFETY_PLAN_VERSIONS))
+    );
+  }
+
+  function buildSafetyPlanVersion(plan, meta) {
+    return {
+      id: 'spv_' + Date.now() + '_' + Math.random().toString(36).slice(2, 8),
+      savedAt: new Date().toISOString(),
+      source: (meta && meta.source) || 'save',
+      restoredFrom: meta && meta.restoredFrom ? meta.restoredFrom : null,
+      plan: cloneSafetyPlan(plan)
+    };
+  }
+
+  function ensureSafetyPlanVersionHistory() {
+    var versions = getSafetyPlanVersions();
+    if (versions.length) {
+      return versions;
+    }
+
+    try {
+      var saved = localStorage.getItem(SAFETY_PLAN_STORAGE_KEY);
+      if (!saved) {
+        return [];
       }
-    } catch (e) {}
+      var parsed = JSON.parse(saved);
+      var migrated = [buildSafetyPlanVersion(parsed, { source: 'legacy' })];
+      setSafetyPlanVersions(migrated);
+      return migrated;
+    } catch (e) {
+      return [];
+    }
+  }
+
+  function formatSafetyPlanTimestamp(iso) {
+    var date = new Date(iso || '');
+    if (isNaN(date.getTime())) {
+      return 'Saved just now';
+    }
+    return date.toLocaleString([], {
+      year: 'numeric',
+      month: 'short',
+      day: 'numeric',
+      hour: 'numeric',
+      minute: '2-digit'
+    });
+  }
+
+  function getSafetyPlanVersionById(versionId) {
+    var versions = getSafetyPlanVersions();
+    for (var i = 0; i < versions.length; i++) {
+      if (versions[i].id === versionId) {
+        return { version: versions[i], index: i, versions: versions };
+      }
+    }
+    return null;
+  }
+
+  function calculateSafetyPlanDiff(previousText, currentText) {
+    var previous = String(previousText || '');
+    var current = String(currentText || '');
+    var start = 0;
+    while (start < previous.length && start < current.length && previous.charAt(start) === current.charAt(start)) {
+      start += 1;
+    }
+
+    var previousEnd = previous.length - 1;
+    var currentEnd = current.length - 1;
+    while (previousEnd >= start && currentEnd >= start && previous.charAt(previousEnd) === current.charAt(currentEnd)) {
+      previousEnd -= 1;
+      currentEnd -= 1;
+    }
+
+    return {
+      before: current.slice(0, start),
+      removed: previous.slice(start, previousEnd + 1),
+      added: current.slice(start, currentEnd + 1),
+      after: current.slice(currentEnd + 1)
+    };
+  }
+
+  function renderDiffSegmentHtml(previousText, currentText) {
+    var previous = String(previousText || '');
+    var current = String(currentText || '');
+
+    if (!previous && !current) {
+      return '<p class="safety-plan-empty">No content saved for this section yet.</p>';
+    }
+
+    if (previous === current) {
+      return '<div class="safety-plan-diff-block diff-unchanged">' + escapeHtml(current || 'No changes in this version.') + '</div>';
+    }
+
+    var diff = calculateSafetyPlanDiff(previous, current);
+    var blocks = [];
+    if (diff.before) {
+      blocks.push('<div class="safety-plan-diff-block diff-unchanged">' + escapeHtml(diff.before) + '</div>');
+    }
+    if (diff.removed) {
+      blocks.push('<div class="safety-plan-diff-block diff-removed">Removed<br>' + escapeHtml(diff.removed) + '</div>');
+    }
+    if (diff.added) {
+      blocks.push('<div class="safety-plan-diff-block diff-added">Added<br>' + escapeHtml(diff.added) + '</div>');
+    }
+    if (diff.after) {
+      blocks.push('<div class="safety-plan-diff-block diff-unchanged">' + escapeHtml(diff.after) + '</div>');
+    }
+    return blocks.join('');
+  }
+
+  function renderSafetyPlanDiff(versionId) {
+    if (!safetyPlanDiff) return;
+
+    var versions = getSafetyPlanVersions();
+    if (!versions.length) {
+      safetyPlanDiff.innerHTML = '<p class="safety-plan-empty">Save your plan to start tracking changes.</p>';
+      return;
+    }
+
+    var selected = getSafetyPlanVersionById(versionId || selectedSafetyPlanVersionId || versions[0].id);
+    if (!selected) {
+      selected = { version: versions[0], index: 0, versions: versions };
+      selectedSafetyPlanVersionId = versions[0].id;
+    }
+
+    var baseline = selected.versions[selected.index + 1]
+      ? cloneSafetyPlan(selected.versions[selected.index + 1].plan)
+      : emptySafetyPlan();
+    var currentPlan = cloneSafetyPlan(selected.version.plan);
+    var baselineLabel = selected.versions[selected.index + 1]
+      ? formatSafetyPlanTimestamp(selected.versions[selected.index + 1].savedAt)
+      : 'an empty plan';
+
+    var fields = [
+      ['Warning signs', 'warningSigns'],
+      ['Internal coping strategies', 'coping'],
+      ['People/Places for distraction', 'distraction'],
+      ['People I can ask for help', 'help'],
+      ['Making my environment safe', 'environment']
+    ];
+
+    var html = [
+      '<div class="safety-plan-diff-meta">Comparing ' +
+        escapeHtml(formatSafetyPlanTimestamp(selected.version.savedAt)) +
+        ' against ' + escapeHtml(baselineLabel) + '.</div>'
+    ];
+
+    fields.forEach(function(field) {
+      html.push(
+        '<div class="safety-plan-diff-field">' +
+          '<h4>' + escapeHtml(field[0]) + '</h4>' +
+          renderDiffSegmentHtml(baseline[field[1]], currentPlan[field[1]]) +
+        '</div>'
+      );
+    });
+
+    safetyPlanDiff.innerHTML = html.join('');
+  }
+
+  function renderSafetyPlanVersionHistory() {
+    if (!safetyPlanHistory) return;
+
+    var versions = getSafetyPlanVersions();
+    if (!versions.length) {
+      safetyPlanHistory.innerHTML = '<p class="safety-plan-empty">No saved versions yet. Each save creates a new local version.</p>';
+      renderSafetyPlanDiff(null);
+      return;
+    }
+
+    if (!selectedSafetyPlanVersionId || !getSafetyPlanVersionById(selectedSafetyPlanVersionId)) {
+      selectedSafetyPlanVersionId = versions[0].id;
+    }
+
+    var html = [];
+    versions.forEach(function(version, index) {
+      var note = 'Saved locally';
+      if (version.source === 'restore') {
+        note = 'Restored from an earlier version';
+      } else if (version.source === 'legacy') {
+        note = 'Imported from your previous saved plan';
+      }
+
+      html.push(
+        '<div class="safety-plan-history-item' + (selectedSafetyPlanVersionId === version.id ? ' active' : '') + '">' +
+          '<div class="safety-plan-history-meta">' +
+            '<span class="safety-plan-history-title">' + escapeHtml(index === 0 ? 'Current version' : 'Version ' + (versions.length - index)) + '</span>' +
+            '<span class="safety-plan-empty">' + escapeHtml(formatSafetyPlanTimestamp(version.savedAt)) + '</span>' +
+          '</div>' +
+          '<div class="safety-plan-history-note">' + escapeHtml(note) + '</div>' +
+          '<div class="safety-plan-history-actions">' +
+            '<button type="button" class="safety-plan-history-button" data-version-id="' + escapeHtml(version.id) + '">View diff</button>' +
+            '<button type="button" class="safety-plan-restore-button" data-restore-version-id="' + escapeHtml(version.id) + '">Restore this version</button>' +
+          '</div>' +
+        '</div>'
+      );
+    });
+
+    safetyPlanHistory.innerHTML = html.join('');
+    renderSafetyPlanDiff(selectedSafetyPlanVersionId);
+  }
+
+  function saveSafetyPlanVersion(plan, meta) {
+    var snapshot = buildSafetyPlanVersion(plan, meta);
+    var versions = getSafetyPlanVersions();
+    versions.unshift(snapshot);
+    setSafetyPlanVersions(versions);
+    localStorage.setItem(SAFETY_PLAN_STORAGE_KEY, JSON.stringify(snapshot.plan));
+    selectedSafetyPlanVersionId = snapshot.id;
+    renderSafetyPlanVersionHistory();
+    return snapshot;
+  }
+
+  function restoreSafetyPlanVersion(versionId) {
+    var selected = getSafetyPlanVersionById(versionId);
+    if (!selected) {
+      setSafetyPlanStatus('That version could not be restored.', 'error');
+      return;
+    }
+
+    applySafetyPlan(selected.version.plan);
+    var restored = saveSafetyPlanVersion(selected.version.plan, {
+      source: 'restore',
+      restoredFrom: selected.version.id
+    });
+    setSafetyPlanStatus(
+      'Restored version from ' + formatSafetyPlanTimestamp(selected.version.savedAt) + ' as the current plan.',
+      'success'
+    );
+    return restored;
+  }
+
+  function loadSafetyPlan() {
+    var versions = ensureSafetyPlanVersionHistory();
+    var latestPlan = versions.length ? versions[0].plan : null;
+
+    if (!latestPlan) {
+      try {
+        var saved = localStorage.getItem(SAFETY_PLAN_STORAGE_KEY);
+        latestPlan = saved ? JSON.parse(saved) : null;
+      } catch (e) {
+        latestPlan = null;
+      }
+    }
+
+    applySafetyPlan(latestPlan || emptySafetyPlan());
+    renderSafetyPlanVersionHistory();
+    if (versions.length) {
+      setSafetyPlanStatus('Version history stays on this device only.', '');
+    } else {
+      setSafetyPlanStatus('Every save creates a local version you can diff and restore.', '');
+    }
+  }
+
+  function openSafetyPlanModal(triggerEl) {
+    loadSafetyPlan();
+    safetyPlanModal.classList.add('active');
+    _activateSafetyPlanFocusTrap(triggerEl);
+  }
+
+  if (safetyPlanHistory) {
+    safetyPlanHistory.addEventListener('click', function(event) {
+      var restoreButton = event.target.closest('[data-restore-version-id]');
+      if (restoreButton) {
+        restoreSafetyPlanVersion(restoreButton.getAttribute('data-restore-version-id'));
+        return;
+      }
+
+      var diffButton = event.target.closest('[data-version-id]');
+      if (diffButton) {
+        selectedSafetyPlanVersionId = diffButton.getAttribute('data-version-id');
+        renderSafetyPlanVersionHistory();
+      }
+    });
   }
 
   closeSafetyPlan.addEventListener('click', function() {
@@ -1194,41 +1739,23 @@ Sovereignty and service always.`;
   });
 
   saveSafetyPlan.addEventListener('click', function() {
-    var plan = {
-      warningSigns: document.getElementById('sp-warning-signs').value,
-      coping: document.getElementById('sp-coping').value,
-      distraction: document.getElementById('sp-distraction').value,
-      help: document.getElementById('sp-help').value,
-      environment: document.getElementById('sp-environment').value
-    };
     try {
-      localStorage.setItem('timmy_safety_plan', JSON.stringify(plan));
-      safetyPlanModal.classList.remove('active');
-      _restoreSafetyPlanFocus();
-      alert('Safety plan saved locally.');
+      var snapshot = saveSafetyPlanVersion(getSafetyPlanFormData(), { source: 'save' });
+      setSafetyPlanStatus('Saved locally as a new version at ' + formatSafetyPlanTimestamp(snapshot.savedAt) + '.', 'success');
     } catch (e) {
-      alert('Error saving plan.');
+      setSafetyPlanStatus('Error saving plan.', 'error');
     }
   });
 
   // ===== SAFETY PLAN FOCUS TRAP (fix #65) =====
-  // Focusable elements inside the modal, in tab order
-  var _spFocusableIds = [
-    'close-safety-plan',
-    'sp-warning-signs',
-    'sp-coping',
-    'sp-distraction',
-    'sp-help',
-    'sp-environment',
-    'cancel-safety-plan',
-    'save-safety-plan'
-  ];
   var _spTriggerEl = null; // element that opened the modal
 
   function _getSpFocusableEls() {
-    return _spFocusableIds
-      .map(function(id) { return document.getElementById(id); })
-      .filter(function(el) { return el && !el.disabled; });
+    return Array.prototype.slice.call(
+      safetyPlanModal.querySelectorAll('button:not([disabled]), textarea:not([disabled]), a[href], input:not([disabled]), select:not([disabled]), [tabindex]:not([tabindex="-1"])')
+    ).filter(function(el) {
+      return !!(el.offsetWidth || el.offsetHeight || el.getClientRects().length);
+    });
   }
 
   function _trapSafetyPlanFocus(e) {
@@ -1285,17 +1812,13 @@ Sovereignty and service always.`;
 
   // Wire open buttons to activate focus trap
   safetyPlanBtn.addEventListener('click', function() {
-    loadSafetyPlan();
-    safetyPlanModal.classList.add('active');
-    _activateSafetyPlanFocusTrap(safetyPlanBtn);
+    openSafetyPlanModal(safetyPlanBtn);
   });
 
   // Crisis panel safety plan button (if crisis panel is visible)
   if (crisisSafetyPlanBtn) {
     crisisSafetyPlanBtn.addEventListener('click', function() {
-      loadSafetyPlan();
-      safetyPlanModal.classList.add('active');
-      _activateSafetyPlanFocusTrap(crisisSafetyPlanBtn);
+      openSafetyPlanModal(crisisSafetyPlanBtn);
     });
   }
 
@@ -1442,9 +1965,7 @@ Sovereignty and service always.`;
     // Check for URL params (e.g., ?safetyplan=true for PWA shortcut)
     var urlParams = new URLSearchParams(window.location.search);
     if (urlParams.get('safetyplan') === 'true') {
-      loadSafetyPlan();
-      safetyPlanModal.classList.add('active');
-      _activateSafetyPlanFocusTrap(safetyPlanBtn);
+      openSafetyPlanModal(safetyPlanBtn);
       // Clean up URL
       window.history.replaceState({}, document.title, window.location.pathname);
     }

tests/test_crisis_overlay_focus_trap.py

@@ -52,6 +52,34 @@ class TestCrisisOverlayFocusTrap(unittest.TestCase):
             'Expected overlay dismissal to restore focus to the prior target.',
         )
 
+    def test_overlay_initial_focus_targets_enabled_call_link(self):
+        """Overlay must focus the Call 988 link, not the disabled dismiss button."""
+        # Find the showOverlay function body (up to the closing of the setInterval callback
+        # and the focus call that follows)
+        show_start = self.html.find('function showOverlay()')
+        self.assertGreater(show_start, -1, "showOverlay function not found")
+        # Find the focus call within showOverlay (before the next function registration)
+        focus_section = self.html[show_start:show_start + 2000]
+        self.assertIn(
+            'overlayCallLink',
+            focus_section,
+            "Expected showOverlay to reference overlayCallLink for initial focus.",
+        )
+        # Ensure the old buggy pattern is gone
+        focus_line_region = self.html[show_start + 800:show_start + 1200]
+        self.assertNotIn(
+            'overlayDismissBtn.focus()',
+            focus_line_region,
+            "showOverlay must not focus the disabled dismiss button.",
+        )
+
+    def test_overlay_call_link_variable_is_declared(self):
+        self.assertIn(
+            "querySelector('.overlay-call')",
+            self.html,
+            "Expected a JS reference to the .overlay-call link element.",
+        )
+
 
 if __name__ == '__main__':
     unittest.main()

tests/test_safety_plan_version_history.py

@@ -0,0 +1,21 @@
+from pathlib import Path
+
+
+def test_safety_plan_version_history_contract_present() -> None:
+    html = Path("index.html").read_text(encoding="utf-8")
+
+    required_snippets = [
+        'id="safety-plan-history"',
+        'id="safety-plan-diff"',
+        'id="safety-plan-status"',
+        'Version History',
+        'timmy_safety_plan_versions',
+        'function renderSafetyPlanVersionHistory()',
+        'function renderSafetyPlanDiff(',
+        'function restoreSafetyPlanVersion(',
+        'diff-added',
+        'diff-removed',
+    ]
+
+    for snippet in required_snippets:
+        assert snippet in html, f"missing safety plan versioning contract: {snippet}"

tests/test_service_worker_offline.py

@@ -50,6 +50,22 @@ class TestCrisisOfflinePage(unittest.TestCase):
         for phrase in required_phrases:
             self.assertIn(phrase, self.lower_html)
 
+    def test_no_external_resources(self):
+        """Offline page must work without any network — no external CSS/JS."""
+        import re
+        html = self.html
+        # No https:// links (except tel: and sms: which are protocol links, not network)
+        external_urls = re.findall(r'href=["\']https://|src=["\']https://', html)
+        self.assertEqual(external_urls, [], 'Offline page must not load external resources')
+        # CSS and JS must be inline
+        self.assertIn('<style>', html, 'CSS must be inline')
+        self.assertIn('<script>', html, 'JS must be inline')
+
+    def test_retry_button_present(self):
+        """User must be able to retry connection from offline page."""
+        self.assertIn('retry-connection', self.html)
+        self.assertIn('Retry connection', self.html)
+
 
 if __name__ == '__main__':
     unittest.main()

tests/test_session_tracker.py

@@ -0,0 +1,277 @@
+"""
+Tests for crisis session tracking and escalation (P0 #35).
+
+Covers: session_tracker.py
+Run with: python -m pytest tests/test_session_tracker.py -v
+"""
+
+import unittest
+import sys
+import os
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+from crisis.detect import detect_crisis
+from crisis.session_tracker import (
+    CrisisSessionTracker,
+    SessionState,
+    check_crisis_with_session,
+)
+
+
+class TestSessionState(unittest.TestCase):
+    """Test SessionState defaults."""
+
+    def test_default_state(self):
+        s = SessionState()
+        self.assertEqual(s.current_level, "NONE")
+        self.assertEqual(s.peak_level, "NONE")
+        self.assertEqual(s.message_count, 0)
+        self.assertEqual(s.level_history, [])
+        self.assertFalse(s.is_escalating)
+        self.assertFalse(s.is_deescalating)
+
+
+class TestSessionTracking(unittest.TestCase):
+    """Test basic session state tracking."""
+
+    def setUp(self):
+        self.tracker = CrisisSessionTracker()
+
+    def test_record_none_message(self):
+        state = self.tracker.record(detect_crisis("Hello Timmy"))
+        self.assertEqual(state.current_level, "NONE")
+        self.assertEqual(state.message_count, 1)
+        self.assertEqual(state.peak_level, "NONE")
+
+    def test_record_low_message(self):
+        self.tracker.record(detect_crisis("Hello"))
+        state = self.tracker.record(detect_crisis("Having a rough day"))
+        self.assertIn(state.current_level, ("LOW", "NONE"))
+        self.assertEqual(state.message_count, 2)
+
+    def test_record_critical_updates_peak(self):
+        self.tracker.record(detect_crisis("Having a rough day"))
+        state = self.tracker.record(detect_crisis("I want to kill myself"))
+        self.assertEqual(state.current_level, "CRITICAL")
+        self.assertEqual(state.peak_level, "CRITICAL")
+
+    def test_peak_preserved_after_drop(self):
+        """Peak level should stay at the highest seen, even after de-escalation."""
+        self.tracker.record(detect_crisis("I want to kill myself"))
+        state = self.tracker.record(detect_crisis("I'm feeling a bit better"))
+        self.assertEqual(state.peak_level, "CRITICAL")
+
+    def test_level_history(self):
+        self.tracker.record(detect_crisis("Hello"))
+        self.tracker.record(detect_crisis("Having a rough day"))
+        state = self.tracker.record(detect_crisis("I want to die"))
+        self.assertEqual(len(state.level_history), 3)
+        self.assertEqual(state.level_history[0], "NONE")
+        self.assertEqual(state.level_history[2], "CRITICAL")
+
+    def test_reset_clears_state(self):
+        self.tracker.record(detect_crisis("I want to kill myself"))
+        self.tracker.reset()
+        state = self.tracker.state
+        self.assertEqual(state.current_level, "NONE")
+        self.assertEqual(state.peak_level, "NONE")
+        self.assertEqual(state.message_count, 0)
+        self.assertEqual(state.level_history, [])
+
+
+class TestEscalationDetection(unittest.TestCase):
+    """Test escalation detection: LOW → HIGH in ≤3 messages."""
+
+    def setUp(self):
+        self.tracker = CrisisSessionTracker()
+
+    def test_no_escalation_single_message(self):
+        self.tracker.record(detect_crisis("Hello"))
+        self.assertFalse(self.tracker.state.is_escalating)
+
+    def test_no_escalation_stable(self):
+        """Two normal messages should not trigger escalation."""
+        self.tracker.record(detect_crisis("Hello"))
+        state = self.tracker.record(detect_crisis("How are you?"))
+        self.assertFalse(state.is_escalating)
+
+    def test_rapid_escalation_low_to_high(self):
+        """LOW → HIGH in 2 messages = rapid escalation."""
+        self.tracker.record(detect_crisis("Having a rough day"))
+        state = self.tracker.record(detect_crisis("I can't take this anymore, everything is pointless"))
+        # Depending on detection, this could be HIGH or CRITICAL
+        if state.current_level in ("HIGH", "CRITICAL"):
+            self.assertTrue(state.is_escalating)
+
+    def test_rapid_escalation_three_messages(self):
+        """NONE → LOW → HIGH in 3 messages = escalation."""
+        self.tracker.record(detect_crisis("Hello"))
+        self.tracker.record(detect_crisis("Having a rough day"))
+        state = self.tracker.record(detect_crisis("I feel completely hopeless with no way out"))
+        if state.current_level in ("HIGH", "CRITICAL"):
+            self.assertTrue(state.is_escalating)
+
+    def test_escalation_rate(self):
+        """Rate should be positive when escalating."""
+        self.tracker.record(detect_crisis("Hello"))
+        self.tracker.record(detect_crisis("I want to die"))
+        state = self.tracker.state
+        self.assertGreater(state.escalation_rate, 0)
+
+
+class TestDeescalationDetection(unittest.TestCase):
+    """Test de-escalation: sustained LOW after HIGH/CRITICAL."""
+
+    def setUp(self):
+        self.tracker = CrisisSessionTracker()
+
+    def test_no_deescalation_without_prior_crisis(self):
+        """No de-escalation if never reached HIGH/CRITICAL."""
+        for _ in range(6):
+            self.tracker.record(detect_crisis("Hello"))
+        self.assertFalse(self.tracker.state.is_deescalating)
+
+    def test_deescalation_after_critical(self):
+        """5+ consecutive LOW/NONE messages after CRITICAL = de-escalation."""
+        self.tracker.record(detect_crisis("I want to kill myself"))
+        for _ in range(5):
+            self.tracker.record(detect_crisis("I'm doing better today"))
+        state = self.tracker.state
+        if state.peak_level == "CRITICAL":
+            self.assertTrue(state.is_deescalating)
+
+    def test_deescalation_after_high(self):
+        """5+ consecutive LOW/NONE messages after HIGH = de-escalation."""
+        self.tracker.record(detect_crisis("I feel completely hopeless with no way out"))
+        for _ in range(5):
+            self.tracker.record(detect_crisis("Feeling okay"))
+        state = self.tracker.state
+        if state.peak_level == "HIGH":
+            self.assertTrue(state.is_deescalating)
+
+    def test_interrupted_deescalation(self):
+        """De-escalation resets if a HIGH message interrupts."""
+        self.tracker.record(detect_crisis("I want to kill myself"))
+        for _ in range(3):
+            self.tracker.record(detect_crisis("Doing better"))
+        # Interrupt with another crisis
+        self.tracker.record(detect_crisis("I feel hopeless again"))
+        self.tracker.record(detect_crisis("Feeling okay now"))
+        state = self.tracker.state
+        # Should NOT be de-escalating yet (counter reset)
+        self.assertFalse(state.is_deescalating)
+
+
+class TestSessionModifier(unittest.TestCase):
+    """Test system prompt modifier generation."""
+
+    def setUp(self):
+        self.tracker = CrisisSessionTracker()
+
+    def test_no_modifier_for_single_message(self):
+        self.tracker.record(detect_crisis("Hello"))
+        self.assertEqual(self.tracker.get_session_modifier(), "")
+
+    def test_no_modifier_for_stable_session(self):
+        self.tracker.record(detect_crisis("Hello"))
+        self.tracker.record(detect_crisis("Good morning"))
+        self.assertEqual(self.tracker.get_session_modifier(), "")
+
+    def test_escalation_modifier(self):
+        """Escalating session should produce a modifier."""
+        self.tracker.record(detect_crisis("Hello"))
+        self.tracker.record(detect_crisis("I want to die"))
+        modifier = self.tracker.get_session_modifier()
+        if self.tracker.state.is_escalating:
+            self.assertIn("escalated", modifier.lower())
+            self.assertIn("NONE", modifier)
+            self.assertIn("CRITICAL", modifier)
+
+    def test_deescalation_modifier(self):
+        """De-escalating session should mention stabilizing."""
+        self.tracker.record(detect_crisis("I want to kill myself"))
+        for _ in range(5):
+            self.tracker.record(detect_crisis("I'm feeling okay"))
+        modifier = self.tracker.get_session_modifier()
+        if self.tracker.state.is_deescalating:
+            self.assertIn("stabilizing", modifier.lower())
+
+    def test_prior_crisis_modifier(self):
+        """Past crisis should be noted even without active escalation."""
+        self.tracker.record(detect_crisis("I want to die"))
+        self.tracker.record(detect_crisis("Feeling a bit better"))
+        modifier = self.tracker.get_session_modifier()
+        # Should note the prior CRITICAL
+        if modifier:
+            self.assertIn("CRITICAL", modifier)
+
+
+class TestUIHints(unittest.TestCase):
+    """Test UI hint generation."""
+
+    def setUp(self):
+        self.tracker = CrisisSessionTracker()
+
+    def test_ui_hints_structure(self):
+        self.tracker.record(detect_crisis("Hello"))
+        hints = self.tracker.get_ui_hints()
+        self.assertIn("session_escalating", hints)
+        self.assertIn("session_deescalating", hints)
+        self.assertIn("session_peak_level", hints)
+        self.assertIn("session_message_count", hints)
+
+    def test_ui_hints_escalation_warning(self):
+        """Escalating session should have warning hint."""
+        self.tracker.record(detect_crisis("Hello"))
+        self.tracker.record(detect_crisis("I want to die"))
+        hints = self.tracker.get_ui_hints()
+        if hints["session_escalating"]:
+            self.assertTrue(hints.get("escalation_warning"))
+            self.assertIn("suggested_action", hints)
+
+
+class TestCheckCrisisWithSession(unittest.TestCase):
+    """Test the convenience function combining detection + session tracking."""
+
+    def test_returns_combined_data(self):
+        tracker = CrisisSessionTracker()
+        result = check_crisis_with_session("I want to die", tracker)
+        self.assertIn("level", result)
+        self.assertIn("session", result)
+        self.assertIn("current_level", result["session"])
+        self.assertIn("peak_level", result["session"])
+        self.assertIn("modifier", result["session"])
+
+    def test_session_updates_across_calls(self):
+        tracker = CrisisSessionTracker()
+        check_crisis_with_session("Hello", tracker)
+        result = check_crisis_with_session("I want to die", tracker)
+        self.assertEqual(result["session"]["message_count"], 2)
+        self.assertEqual(result["session"]["peak_level"], "CRITICAL")
+
+
+class TestPrivacy(unittest.TestCase):
+    """Verify privacy-first design principles."""
+
+    def test_no_persistence_mechanism(self):
+        """Session tracker should have no database, file, or network calls."""
+        import inspect
+        source = inspect.getsource(CrisisSessionTracker)
+        # Should not import database, requests, or file I/O
+        forbidden = ["sqlite", "requests", "urllib", "open(", "httpx", "aiohttp"]
+        for word in forbidden:
+            self.assertNotIn(word, source.lower(),
+                f"Session tracker should not use {word} — privacy-first design")
+
+    def test_state_contained_in_memory(self):
+        """All state should be instance attributes, not module-level."""
+        tracker = CrisisSessionTracker()
+        tracker.record(detect_crisis("I want to die"))
+        # New tracker should have clean state (no global contamination)
+        fresh = CrisisSessionTracker()
+        self.assertEqual(fresh.state.current_level, "NONE")
+
+
+if __name__ == '__main__':
+    unittest.main()