diff --git a/plans/fizzy-puzzling-candy.md b/plans/fizzy-puzzling-candy.md
new file mode 100644
index 0000000..3e984b8
--- /dev/null
+++ b/plans/fizzy-puzzling-candy.md
@@ -0,0 +1,150 @@
+# Plan: Session Summarization Hook
+
+## Problem
+
+Sessions are tracked in `~/.claude/state/personal-assistant/history/index.json` but:
+1. No conversation logs are captured to our history folder
+2. Sessions never get marked as summarized
+3. Memory files remain empty (decisions, preferences, projects, facts)
+
+## Root Cause
+
+Missing `SessionEnd` hook to trigger summarization when sessions end.
+
+## Solution
+
+Add a `SessionEnd` hook that:
+1. Reads the transcript from Claude's built-in storage (`transcript_path`)
+2. Extracts key information (decisions, preferences, project context, facts)
+3. Saves to appropriate memory files
+4. Updates history index to mark session as summarized
+
+## Files to Modify
+
+| File | Action |
+|------|--------|
+| `~/.claude/hooks/hooks.json` | Add `SessionEnd` hook entry |
+| `~/.claude/hooks/scripts/session-end.sh` | **Create** - orchestrates summarization |
+| `~/.claude/hooks/scripts/summarize-transcript.py` | **Create** - Python script to process transcript |
+
+## Implementation Details
+
+### 1. Hook Configuration (`hooks.json`)
+
+Add `SessionEnd` hook that calls the summarization script:
+
+```json
+"SessionEnd": [
+  {
+    "hooks": [
+      {
+        "type": "command",
+        "command": "~/.claude/hooks/scripts/session-end.sh",
+        "timeout": 120
+      }
+    ]
+  }
+]
+```
+
+### 2. Session End Script (`session-end.sh`)
+
+- Receives JSON via stdin with `session_id`, `transcript_path`, `reason`
+- Calls Python summarization script
+- Handles errors gracefully (session end shouldn't fail)
+
+### 3. Summarization Script (`summarize-transcript.py`)
+
+The script will:
+
+1. **Parse transcript** - Read the `.jsonl` file from `transcript_path`
+2. **Extract key items** - Use heuristics to identify:
+   - Decisions: "let's use", "we decided", "I'll go with"
+   - Preferences: "I prefer", "always", "never", "I like"
+   - Project context: file paths, config references
+   - Facts: environment info, tool locations
+3. **Deduplicate** - Check against existing memory items
+4. **Save to memory files** - Append new items with UUIDs
+5. **Update history index** - Mark session as summarized, add topics
+
+### Processing Approach: Hybrid (Decision)
+
+**Step 1: Threshold check**
+- Skip sessions with < 3 user messages
+- Skip sessions that are only quick commands (no substantive discussion)
+
+**Step 2: Heuristic extraction (fast, no API)**
+- File paths mentioned → project context
+- Environment facts (tool locations, versions)
+- Simple preferences with clear keywords
+
+**Step 3: LLM extraction (if substantive content)**
+- Complex decisions with rationale
+- Nuanced preferences
+- Project context requiring interpretation
+- Use Claude API (Haiku for cost efficiency)
+
+### Transcript Storage (Decision)
+
+Reference Claude's existing transcript location (`~/.claude/projects/.../[uuid].jsonl`) rather than copying to our history folder. The history index will store the transcript path for future reference.
+
+### Memory File Format
+
+Each item:
+```json
+{
+  "id": "uuid",
+  "date": "YYYY-MM-DD",
+  "content": "Brief description",
+  "context": "Additional context",
+  "session": "session-id"
+}
+```
+
+## Implementation Steps
+
+### Step 1: Update hooks.json
+
+Add `SessionEnd` entry to `~/.claude/hooks/hooks.json`
+
+### Step 2: Create session-end.sh
+
+Shell wrapper at `~/.claude/hooks/scripts/session-end.sh`:
+- Parse JSON input from stdin
+- Extract session_id, transcript_path, reason
+- Call Python summarization script
+- Handle errors silently (don't break session exit)
+
+### Step 3: Create summarize-transcript.py
+
+Python script at `~/.claude/hooks/scripts/summarize-transcript.py`:
+
+```
+Arguments: --session-id <id> --transcript <path> [--reason <reason>]
+
+1. Load transcript (.jsonl)
+2. Count user messages → skip if < 3
+3. Heuristic pass:
+   - Extract file paths → projects.json
+   - Extract env facts → facts.json
+4. If substantive content detected:
+   - Call Claude API (Haiku) for decisions/preferences
+   - Parse response → decisions.json, preferences.json
+5. Update history/index.json:
+   - Set summarized: true
+   - Add transcript_path
+   - Add extracted topics
+```
+
+### Step 4: Update history index schema
+
+Add `transcript_path` field to session entries in `history/index.json`
+
+## Testing
+
+1. Start a test session with substantive discussion
+2. Exit session normally
+3. Verify:
+   - Hook fired (check with `--debug`)
+   - Memory files updated
+   - History index marked summarized