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+# Resolution Series Design
+
+## Problem
+
+When running ComfyUI loop nodes for multi-step upscaling (e.g. 3+ resolutions at different sizes),
+managing portrait vs landscape width/height per iteration is tedious. Users need a structured way
+to define N resolution pairs in the manager UI and retrieve them by loop index in ComfyUI.
+
+## Design
+
+### Data Model
+
+Resolution series are stored as a JSON array under a user-chosen key in the sequence data:
+
+```json
+"upscale_resolutions": [[512, 512], [768, 1344], [1344, 768], [2048, 2048]]
+```
+
+- Each element is `[width, height]` (both INT)
+- Key name is chosen by the user (any string)
+- Number of entries is configurable (add/remove rows)
+- Stored in the same project JSON file and sequence — no schema change required
+- Index out of bounds → clamp to last entry
+
+### NiceGUI UI (tab_batch_ng.py)
+
+A resolution series editor is rendered in the left column of the sequence card, directly below
+the "Specific Negative" textarea.
+
+Layout:
+
+```
+── Resolution Series ──────────────────
+  key name: [upscale_resolutions    ]
+  #  Width    Height
+  1  [2048]   [2048]   [x]
+  2  [768 ]   [1344]   [x]
+  3  [1344]   [768 ]   [x]
+  [+ Add row]
+```
+
+- Key name is editable (defaults to `resolutions`)
+- Rows added/removed inline; each change calls `commit()` immediately
+- Hidden behind an "Add Resolution Series" button when no resolution key exists yet
+- A value is detected as a resolution series if it is a list of `[int, int]` pairs
+
+### ComfyUI Node (`ProjectResolution`)
+
+New node class in `project_loader.py`, sibling to `ProjectKey`.
+
+**Inputs:**
+- `source_label` (STRING) — references a `ProjectSource` by label
+- `key_name` (STRING) — the resolution series key name
+- `index` (INT, min 0) — wired from loop node's current index output
+- `manager_url`, `project_name`, `file_name`, `sequence_number` — optional, synced from `ProjectSource` via JS
+
+**Outputs:** `width` (INT), `height` (INT)
+
+**Execution:** fetches the sequence data, reads `data[key_name]`, indexes into the array with
+clamp-to-last on out-of-bounds, returns `(width, height)`.
+
+**JS (`web/project_resolution.js`):**
+- Same `_syncFromSource` mechanism as `project_key.js`
+- `key_name` widget is replaced with a combo dropdown populated with keys whose value is a
+  resolution series (list of `[int, int]` pairs), detected via the existing keys API
+- Registered in `PROJECT_NODE_CLASS_MAPPINGS` and `PROJECT_NODE_DISPLAY_NAME_MAPPINGS`
+
+### API
+
+No new endpoints. Uses existing:
+- `/json_manager/get_project_keys` — for key discovery (JS combo population)
+- `_fetch_data()` — for execution-time data fetch
+
+### Files Changed
+
+| File | Change |
+|------|--------|
+| `project_loader.py` | Add `ProjectResolution` class + register in mappings |
+| `web/project_resolution.js` | New JS extension for the node |
+| `tab_batch_ng.py` | Resolution series editor below Specific Negative |
+| `__init__.py` | Register new JS file if needed |