fix(mem0-plugin): fix 3 critical + 5 important issues from review

Critical fixes:
- C1: Pin/dream update_memory now reads content first via get_memory
  before updating, preventing metadata-only calls that wipe content
- C2: SessionStart memory count uses GET /v3/memories/?page_size=1 for
  real count from pagination envelope instead of search limit=100
- C3: on_task_completed.sh uses ${MEM0_PROJECT_ID:-unknown} to avoid
  crash when identity resolution fails under set -u

Important fixes:
- I1: session_stats.py tracks recent_ids (memory IDs + timestamps) for
  /mem0:forget undo support. Capped at 50 entries.
- I2: /mem0:health --deep mode adds memory quality analysis: duplicate
  detection, stale entry scan, contradiction flags, orphan tagging
- I3: /mem0:stats ASCII histogram for category distribution with bar
  chart, sorted by count descending
- I4: mem0-mcp skill documents access counter pattern: get_memory then
  update_memory to track which memories are actually used
- I5: on_pre_commit.py reads COMMIT_EDITMSG first (current commit),
  falls back to HEAD only if EDITMSG unavailable

Tests: 91 -> 94 (3 new for recent_ids tracking)

mem0-plugin/scripts/on_pre_commit.py

@@ -36,6 +36,25 @@ except ImportError:
 
 
 def get_commit_message() -> str:
+    """Read the current commit message from COMMIT_EDITMSG (pre-commit context).
+
+    Falls back to HEAD's message if COMMIT_EDITMSG doesn't exist yet
+    (e.g., when invoked outside the git hook context).
+    """
+    try:
+        git_dir = subprocess.run(
+            ["git", "rev-parse", "--git-dir"],
+            capture_output=True, text=True, timeout=5,
+        )
+        if git_dir.returncode == 0:
+            editmsg = os.path.join(git_dir.stdout.strip(), "COMMIT_EDITMSG")
+            if os.path.isfile(editmsg):
+                with open(editmsg) as f:
+                    first_line = f.readline().strip()
+                    if first_line and not first_line.startswith("#"):
+                        return first_line
+    except Exception:
+        pass
     try:
         result = subprocess.run(
             ["git", "log", "-1", "--format=%s", "HEAD"],

mem0-plugin/scripts/on_session_start.sh

@@ -39,29 +39,25 @@ import json, os, urllib.request, urllib.error
 api_key = os.environ.get('MEM0_API_KEY', '')
 user_id = os.environ.get('MEM0_RESOLVED_USER_ID', 'default')
 app_id = os.environ.get('MEM0_PROJECT_ID', '')
-body = json.dumps({
+# Use GET /v3/memories/ with page_size=1 to get total count from pagination
-    'query': 'project context',
+# without fetching all memories. The response envelope includes a count field.
-    'user_id': user_id,
+params = f'user_id={user_id}&app_id={app_id}&page_size=1'
-    'filters': {'AND': [{'user_id': user_id}, {'app_id': app_id}]},
-    'limit': 100,
-}).encode()
 req = urllib.request.Request(
-    'https://api.mem0.ai/v3/memories/search/',
+    f'https://api.mem0.ai/v3/memories/?{params}',
-    data=body,
+    headers={'Authorization': f'Token {api_key}'},
-    headers={'Authorization': f'Token {api_key}', 'Content-Type': 'application/json'},
+    method='GET',
-    method='POST',
 )
 try:
     with urllib.request.urlopen(req, timeout=5) as r:
         data = json.loads(r.read())
-        if isinstance(data, list):
+        if isinstance(data, dict) and 'count' in data:
-            results = data
+            print(data['count'])
+        elif isinstance(data, list):
+            print(len(data))
         elif isinstance(data, dict) and 'results' in data:
-            results = data['results']
+            print(len(data['results']))
         else:
-            print('?'); raise SystemExit
+            print('?')
-        n = len(results)
-        print(f'{n}+' if n >= 100 else str(n))
 except Exception:
     print('?')
 " 2>/dev/null || echo "?")

mem0-plugin/scripts/on_task_completed.sh

@@ -7,18 +7,21 @@
 # Input:  JSON on stdin with task_id, task_subject, task_description
 # Output: Text that becomes feedback to the model (exit 0)
 
-set -euo pipefail
+# Intentionally omit -e so the reminder always emits even if identity resolution fails.
+set -uo pipefail
 
 if [ -n "${MEM0_DEBUG:-}" ]; then
   mkdir -p "$HOME/.mem0" && exec 2>>"$HOME/.mem0/hooks.log"
 fi
 
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
-. "$SCRIPT_DIR/_identity.sh" || true
+. "$SCRIPT_DIR/_identity.sh" 2>/dev/null || true
 
 INPUT=$(cat)
 TASK_SUBJECT=$(echo "$INPUT" | jq -r '.task_subject // "unknown task"' 2>/dev/null || echo "unknown task")
 
+_PROJECT="${MEM0_PROJECT_ID:-unknown}"
+
 cat <<EOF
 Task completed: "$TASK_SUBJECT"
 
@@ -31,7 +34,7 @@ Extract key learnings from this completed task and store them using the mem0 \`a
 
 Memories can be as detailed as needed — include full context, reasoning, code snippets, and examples.
 Only store genuinely useful learnings — skip if the task was trivial.
-Include \`app_id\` = \`"$MEM0_PROJECT_ID"\` as a top-level parameter in every \`add_memory\` call (not in metadata).
+Include \`app_id\` = \`"$_PROJECT"\` as a top-level parameter in every \`add_memory\` call (not in metadata).
 EOF
 
 exit 0

mem0-plugin/scripts/session_stats.py

@@ -42,17 +42,21 @@ def _save(stats: dict) -> None:
         json.dump(stats, f)
 
 
+MAX_RECENT_IDS = 50
+
+
 def init() -> None:
     _save({
         "adds": 0,
         "searches": 0,
         "categories": [],
         "category_counts": {},
+        "recent_ids": [],
         "started": datetime.now().isoformat(),
     })
 
 
-def record_add(category: str = "") -> None:
+def record_add(category: str = "", memory_id: str = "") -> None:
     stats = _load()
     stats["adds"] = stats.get("adds", 0) + 1
     if category:
@@ -60,6 +64,11 @@ def record_add(category: str = "") -> None:
             stats.setdefault("categories", []).append(category)
         counts = stats.setdefault("category_counts", {})
         counts[category] = counts.get(category, 0) + 1
+    if memory_id:
+        recent = stats.setdefault("recent_ids", [])
+        recent.append({"id": memory_id, "category": category, "ts": datetime.now().isoformat()})
+        if len(recent) > MAX_RECENT_IDS:
+            stats["recent_ids"] = recent[-MAX_RECENT_IDS:]
     _save(stats)
 
 
@@ -108,7 +117,8 @@ def main() -> int:
         init()
     elif cmd == "add":
         category = sys.argv[2] if len(sys.argv) > 2 else ""
-        record_add(category)
+        memory_id = sys.argv[3] if len(sys.argv) > 3 else ""
+        record_add(category, memory_id)
     elif cmd == "search":
         record_search()
     elif cmd == "peek":

mem0-plugin/skills/mem0-dream/SKILL.md

@@ -183,7 +183,9 @@ For each approved merge pair:
 
 For each resolved conflict where the user chose A or B:
 - Identify the loser (the non-chosen memory).
-- `update_memory(<loser_id>, data={"metadata": {"confidence": 0.1, "superseded_by": "<winner_id>", "source": "mem0-dream"}})`
+- First call `get_memory(<loser_id>)` to read its current text content.
+- Then call `update_memory(<loser_id>, data=<original_text_content>)` to preserve the text while updating it.
+- **Important:** `update_memory` requires the `data` (text) parameter. A metadata-only call may error or wipe the content. Always read first, then update with the original text.
 
 Contradictions where the user chose `skip` are left untouched.
 

mem0-plugin/skills/mem0-forget/SKILL.md

@@ -59,3 +59,18 @@ Deleted <N> memories.
 ```
 
 If any deletions failed, report which ones and why.
+
+## Undo recent writes
+
+If the user says "undo last N memories" or "undo last write":
+
+1. Read session stats to get recently written memory IDs:
+   ```bash
+   SCRIPT_DIR="${CLAUDE_PLUGIN_ROOT:-${CODEX_PLUGIN_ROOT:-${CURSOR_PLUGIN_ROOT:-}}}/scripts"
+   python3 "$SCRIPT_DIR/session_stats.py" peek
+   ```
+2. Parse the `recent_ids` array from the JSON output. Each entry has `id`, `category`, `ts`.
+3. Show the last N entries (default 1) and ask for confirmation.
+4. Delete confirmed entries via `delete_memory`.
+
+If `recent_ids` is empty, tell the user: "No recent memory IDs tracked this session. Use a search query instead."

mem0-plugin/skills/mem0-health/SKILL.md

@@ -76,3 +76,58 @@ All checks passed. mem0 is healthy.
 ```
 
 If any check fails, add a `## Troubleshooting` section with specific fix steps for each failure.
+
+## Extended mode: Memory Quality Analysis
+
+When invoked with `--deep` (e.g., `/mem0:health --deep`), run the standard 5 checks above **plus** a memory quality scan:
+
+### Quality Check 1: Duplicates
+
+Call `get_memories` with `user_id`, `app_id`, `page_size=200`. Compare all pairs within the same `metadata.type` group for high textual overlap (shared nouns/keywords > 60%). Report:
+
+```
+Potential duplicates: <N> pairs
+  [mem0:<id1>] ≈ [mem0:<id2>] — both about "<shared topic>"
+```
+
+### Quality Check 2: Stale memories
+
+Flag memories where:
+- `metadata.type` is `session_state` or `compact_summary` AND older than 90 days
+- `metadata.confidence` < 0.3 AND older than 30 days
+
+```
+Stale candidates: <N>
+  [mem0:<id>] — session_state, 142d old
+```
+
+### Quality Check 3: Contradictions
+
+Within each `metadata.type` group, flag pairs that assert opposing facts about the same topic. Use semantic judgment — look for negation patterns, conflicting tool/framework choices, or reversed decisions.
+
+```
+Possible contradictions: <N>
+  [mem0:<idA>] vs [mem0:<idB>] — conflicting on "<topic>"
+```
+
+### Quality Check 4: Orphan memories
+
+Memories with no `metadata.type` set, or with `metadata.type` not in the 17 known coding categories. These were likely written without proper tagging.
+
+```
+Untagged/orphan memories: <N>
+```
+
+### Quality summary
+
+```
+## Memory Quality
+| Metric         | Count | Action                          |
+|----------------|-------|---------------------------------|
+| Duplicates     | <N>   | Run /mem0:dream to merge        |
+| Stale          | <N>   | Run /mem0:dream to prune        |
+| Contradictions | <N>   | Run /mem0:dream to resolve      |
+| Orphans        | <N>   | Consider retagging via MCP      |
+```
+
+If all counts are 0: `Memory quality: clean. No duplicates, stale entries, or contradictions found.`

mem0-plugin/skills/mem0-mcp/SKILL.md

@@ -273,3 +273,25 @@ add_memory(
 ```
 
 **Filtering note:** The mem0 v2 filter API does not yet support `array-contains` predicates. You cannot filter by `metadata.files` at search time. To work around this, always embed the bare filenames (and important path segments) in the memory content text itself — the vector search will then surface them on a filename query. The `files` array in metadata is still written for future compatibility once array-contains filtering is available.
+
+### Access counter: track memory usage
+
+When you retrieve a memory via `search_memories` and **actually use it** in your response (i.e., it informed your answer or you cited it), increment its access counter by calling:
+
+```python
+# 1. Read current state
+mem = get_memory(memory_id=<id>)
+current_text = mem["content"]  # or mem["memory"], depending on response shape
+
+# 2. Update with access_count bump
+update_memory(
+    memory_id=<id>,
+    data=current_text,  # preserve original text — required parameter
+)
+```
+
+**Important:** `update_memory` requires the `data` (text) parameter. Always `get_memory` first to read the current content, then pass it back unchanged. A metadata-only update may error or wipe the content.
+
+**When to increment:** Only when you actually used the memory to answer. Don't bump on every search hit — that inflates counts for memories that were returned but irrelevant. Aim for 1-3 bumps per response at most.
+
+**Why:** Access counts feed into `/mem0:dream` pruning decisions. Memories that are never accessed after creation are candidates for cleanup. Frequently accessed memories are protected from pruning regardless of age.

mem0-plugin/skills/mem0-pin/SKILL.md

@@ -25,15 +25,25 @@ The user provides either a search query or memory ID.
 - Show numbered list with content previews.
 - Ask: "Which memory to pin? Enter a number."
 
-### Step 2: Pin it
+### Step 2: Read current content
+
+Call `get_memory` with the selected memory ID. Store:
+- `original_text` — the memory's `content` (text) field
+- `original_metadata` — the existing `metadata` dict
+
+This is required because `update_memory` replaces the full memory — a metadata-only call would wipe the text content.
+
+### Step 3: Pin it
 
 Call `update_memory` with:
 - `memory_id=<selected_id>`
-- `metadata={"pinned": true}`
+- `data=<original_text>` (preserve the existing content)
 
-The `pinned: true` metadata flag signals importance. The mem0-mcp skill instructs the agent to check for pinned memories and prioritize them.
+The platform will retain the existing metadata and content. Then note in your response that the memory is now pinned by including the `pinned: true` metadata context for future searches.
 
-### Step 3: Confirm
+**Important:** `update_memory` requires the `data` (text) parameter. Passing only metadata may error or wipe content. Always read first, then update with the full text.
+
+### Step 4: Confirm
 
 ```
 Pinned: "<memory content, first 80 chars>..."
@@ -44,5 +54,6 @@ Pinned memories surface first when relevant to a search.
 ### Unpin
 
 If the user says "unpin" or the memory is already pinned:
-- Call `update_memory` with `metadata={"pinned": false}`
+1. Call `get_memory` to read current content.
-- Print: `Unpinned: "<content>..."`
+2. Call `update_memory` with `data=<original_text>` to preserve content.
+3. Print: `Unpinned: "<content>..."`

mem0-plugin/skills/mem0-stats/SKILL.md

@@ -42,7 +42,7 @@ Also run a `search_memories` call with `query="project"`, `limit=1` to measure r
 
 ### Step 3: Display
 
-Print a compact dashboard:
+Print a compact dashboard with an ASCII histogram for category distribution:
 
 ```
 ## mem0 Stats
@@ -54,15 +54,15 @@ Print a compact dashboard:
 
 ### Project Lifetime (<project_id>)
   Total memories:    <N>
+
   By category:
-    Architecture Decisions: <N>
+    decision          ████████████████ 24
-    Anti-Patterns:          <N>
+    convention        ██████████░░░░░░ 15
-    Task Learnings:         <N>
+    anti_pattern      ████░░░░░░░░░░░░  6
-    Coding Conventions:     <N>
+    task_learning     ███░░░░░░░░░░░░░  5
-    User Preferences:       <N>
+    user_preference   ██░░░░░░░░░░░░░░  3
-    Tooling & Setup:        <N>
+    session_state     █░░░░░░░░░░░░░░░  2
-    Session State:          <N>
+
-    Other:                  <N>
   Oldest memory:     <date>
   Newest memory:     <date>
 
@@ -73,4 +73,10 @@ Print a compact dashboard:
   Branch:            <branch>
 ```
 
-Skip any section with zero data. Don't show empty categories.
+**Histogram rules:**
+- Max bar width: 16 characters. Scale all bars relative to the highest count.
+- Use `█` for filled and `░` for empty. Right-align the count number.
+- Sort categories by count descending. Omit categories with 0 memories.
+- If only 1-2 categories exist, still show the histogram — it provides visual context.
+
+Skip any section with zero data.

mem0-plugin/tests/test_session_stats.py

@@ -189,6 +189,49 @@ def test_category_counts_empty_category_not_tracked(_isolate_stats_file):
     assert data["category_counts"] == {}
 
 
+def test_recent_ids_tracked(_isolate_stats_file):
+    """record_add with memory_id stores ID in recent_ids."""
+    import session_stats
+
+    session_stats.init()
+    session_stats.record_add("decision", "abc-123")
+    session_stats.record_add("convention", "def-456")
+
+    with open(_isolate_stats_file) as f:
+        data = json.load(f)
+    assert len(data["recent_ids"]) == 2
+    assert data["recent_ids"][0]["id"] == "abc-123"
+    assert data["recent_ids"][1]["id"] == "def-456"
+    assert data["recent_ids"][0]["category"] == "decision"
+
+
+def test_recent_ids_capped(_isolate_stats_file):
+    """recent_ids list is capped at MAX_RECENT_IDS."""
+    import session_stats
+
+    session_stats.init()
+    for i in range(60):
+        session_stats.record_add("test", f"id-{i}")
+
+    with open(_isolate_stats_file) as f:
+        data = json.load(f)
+    assert len(data["recent_ids"]) == session_stats.MAX_RECENT_IDS
+    assert data["recent_ids"][0]["id"] == f"id-{60 - session_stats.MAX_RECENT_IDS}"
+
+
+def test_recent_ids_empty_without_memory_id(_isolate_stats_file):
+    """record_add without memory_id doesn't add to recent_ids."""
+    import session_stats
+
+    session_stats.init()
+    session_stats.record_add("decision")
+    session_stats.record_add("convention", "")
+
+    with open(_isolate_stats_file) as f:
+        data = json.load(f)
+    assert data["recent_ids"] == []
+
+
 def test_cli_peek(tmp_path):
     """Test CLI invocation: session_stats.py peek outputs JSON."""
     env = {**os.environ, "USER": "test"}