Add README with installation, usage, and API docs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

README.md

@@ -0,0 +1,98 @@
+# ComfyUI Node Usage Stats
+
+A ComfyUI custom node package that silently tracks which nodes and packages you actually use. Helps identify never-used packages that are safe to remove.
+
+## Features
+
+- Tracks every node used in every workflow execution
+- Maps each node to its source package
+- SQLite storage for efficient querying
+- Per-package aggregated stats (total nodes, used/unused, execution counts)
+- Frontend dialog with never-used packages highlighted for removal
+- Expandable rows to see individual node-level stats within each package
+
+## Installation
+
+```bash
+# Symlink into your custom_nodes directory
+ln -s /path/to/Comfyui_nodes_stats /path/to/ComfyUI/custom_nodes/comfyui-nodes-stats
+```
+
+Restart ComfyUI. Tracking starts immediately and silently.
+
+## Usage
+
+### UI
+
+Click the **"Node Stats"** button in the ComfyUI menu. A dialog shows:
+
+- Summary: how many packages are never-used vs used
+- **Never Used** section (highlighted) — safe to remove
+- **Used** section sorted by least-to-most executions
+- Click any row to expand and see individual node stats
+
+### API
+
+| Endpoint | Method | Description |
+|----------|--------|-------------|
+| `/nodes-stats/packages` | GET | Per-package aggregated stats |
+| `/nodes-stats/usage` | GET | Raw per-node usage data |
+| `/nodes-stats/reset` | POST | Clear all tracked data |
+
+Example:
+
+```bash
+curl http://localhost:8188/nodes-stats/packages | python3 -m json.tool
+```
+
+### Package stats response format
+
+```json
+[
+  {
+    "package": "ComfyUI-Impact-Pack",
+    "total_executions": 42,
+    "used_nodes": 5,
+    "total_nodes": 30,
+    "never_used": false,
+    "last_seen": "2026-02-22T12:00:00+00:00",
+    "nodes": [
+      {
+        "class_type": "SAMDetectorCombined",
+        "package": "ComfyUI-Impact-Pack",
+        "count": 20,
+        "first_seen": "2026-01-01T00:00:00+00:00",
+        "last_seen": "2026-02-22T12:00:00+00:00"
+      }
+    ]
+  }
+]
+```
+
+## File Structure
+
+```
+__init__.py      # Entry point: prompt handler, API routes
+mapper.py        # class_type -> package name mapping
+tracker.py       # SQLite persistence and stats aggregation
+js/
+  nodes_stats.js # Frontend: menu button + stats dialog
+pyproject.toml   # Package metadata
+```
+
+## How It Works
+
+1. Registers a prompt handler via `PromptServer.instance.add_on_prompt_handler()`
+2. On every prompt submission, extracts `class_type` from each node
+3. Maps each class_type to its source package using `RELATIVE_PYTHON_MODULE`
+4. Stores per-node counts and timestamps in SQLite (`usage_stats.db`)
+5. Also logs the full set of nodes per prompt for future trend analysis
+
+## Data Storage
+
+All data is stored in `usage_stats.db` in the package directory. Two tables:
+
+- **node_usage**: per-node counts, first/last seen timestamps
+- **prompt_log**: JSON array of nodes used per prompt, with timestamp
+
+Use `POST /nodes-stats/reset` to clear all data.