diff --git a/Barchart/README.md b/Barchart/README.md
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+# Barchart utilities
+
+The `Barchart` package contains:
+
+- `BarchartHistoricalData`, a session-based client for Barchart historical
+ time-series responses.
+- `ContinuousFuturesBuilder`, which builds nearby futures series from explicit
+ contract data or a fetcher.
+
+## Install
+
+Install the runtime dependencies with:
+
+```powershell
+python -m pip install -r Barchart/requirements.txt
+```
+
+For the rendered Corn futures demo, install the optional notebook dependencies:
+
+```powershell
+python -m pip install -r Barchart/requirements-demo.txt
+```
+
+## Example
+
+```python
+from Barchart import BarchartFetcher, BarchartHistoricalData, ContinuousFuturesBuilder
+
+client = BarchartHistoricalData()
+fetcher = BarchartFetcher(client)
+builder = ContinuousFuturesBuilder(fetcher=fetcher, verbose=False)
+
+series = builder.build_from_root(
+ "KC",
+ line_number=1,
+ start="2024-01-01",
+ end="2024-12-31",
+)
+```
+
+## Corn futures demo
+
+Open `corn_futures_demo.ipynb` in Jupyter or VS Code. It uses CME/CBOT Corn
+futures (`ZC`) and demonstrates:
+
+- contract-level histories with realistic availability windows;
+- first and second nearby lines;
+- roll segments and nearby spreads; and
+- an optional live Barchart path controlled by `USE_LIVE_DATA`.
+
+The notebook runs on deterministic offline data by default, so it does not
+require credentials or a live network request to display the workflow.
+
+The client uses Barchart's web-session cookie handshake and endpoint, so it is
+subject to Barchart availability and any access terms that apply to your use
+of the service. No credentials are stored by this package.
+
+## Tests
+
+Run the Barchart tests with:
+
+```powershell
+python -m unittest discover -s Barchart/tests -v
+```
diff --git a/Barchart/corn_futures_demo.ipynb b/Barchart/corn_futures_demo.ipynb
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+{
+ "cells": [
+ {
+ "cell_type": "markdown",
+ "id": "5e527936",
+ "metadata": {},
+ "source": [
+ "# CME/CBOT Corn futures: a continuous nearby series\n",
+ "\n",
+ "This demo uses the CME Group / CBOT Corn futures root ZC and shows how the\n",
+ "Barchart utilities turn individual contract histories into nearby lines.\n",
+ "It uses deterministic offline data by default. Set USE_LIVE_DATA to True in\n",
+ "the final cell to fetch current histories from Barchart.\n",
+ "\n"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 1,
+ "id": "2fa266e5",
+ "metadata": {
+ "execution": {
+ "iopub.execute_input": "2026-08-21T18:11:09.690173Z",
+ "iopub.status.busy": "2026-08-21T18:11:09.690173Z",
+ "iopub.status.idle": "2026-08-21T18:11:11.380306Z",
+ "shell.execute_reply": "2026-08-21T18:11:11.379787Z"
+ }
+ },
+ "outputs": [],
+ "source": [
+ "from pathlib import Path\n",
+ "import sys\n",
+ "\n",
+ "candidate_roots = [Path.cwd(), *Path.cwd().parents]\n",
+ "repo_root = next(\n",
+ " (candidate for candidate in candidate_roots if (candidate / \"Barchart\").is_dir()),\n",
+ " None,\n",
+ ")\n",
+ "if repo_root is None:\n",
+ " raise RuntimeError(\"Run this demo from a checkout containing the Barchart folder.\")\n",
+ "sys.path.insert(0, str(repo_root))\n",
+ "\n",
+ "import matplotlib.pyplot as plt\n",
+ "import numpy as np\n",
+ "import pandas as pd\n",
+ "from IPython.display import display\n",
+ "\n",
+ "from Barchart import (\n",
+ " BarchartFetcher,\n",
+ " BarchartHistoricalData,\n",
+ " ContinuousFuturesBuilder,\n",
+ " expiry_key,\n",
+ " parse_symbol,\n",
+ ")\n",
+ "\n",
+ "START = \"2024-01-02\"\n",
+ "END = \"2025-12-31\"\n",
+ "CORN_ROOT = \"ZC\"\n",
+ "CORN_CYCLE = [\"H\", \"K\", \"N\", \"U\", \"Z\"]\n",
+ "\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "0b6b279b",
+ "metadata": {},
+ "source": [
+ "## 1. Build a deterministic offline contract set\n",
+ "\n",
+ "The synthetic histories share a market path but have contract-level offsets\n",
+ "and noise. Each contract is only available during a plausible pre-expiry\n",
+ "window, making nearby selection and roll segments visible without presenting\n",
+ "synthetic values as market prices.\n",
+ "\n"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 2,
+ "id": "36b08c81",
+ "metadata": {
+ "execution": {
+ "iopub.execute_input": "2026-08-21T18:11:11.384316Z",
+ "iopub.status.busy": "2026-08-21T18:11:11.383320Z",
+ "iopub.status.idle": "2026-08-21T18:11:11.419491Z",
+ "shell.execute_reply": "2026-08-21T18:11:11.418474Z"
+ }
+ },
+ "outputs": [
+ {
+ "data": {
+ "text/html": [
+ "\n",
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\n",
+ " \n",
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