TimesFM (Time Series Foundation Model) is a pretrained decoder-only foundation model developed by Google Research for time-series forecasting. It works zero-shot — feed it any univariate time series and it returns point forecasts with calibrated quantile prediction intervals, no training required.
This skill wraps TimesFM for safe, agent-friendly local inference. It includes a mandatory preflight system checker that verifies RAM, GPU memory, and disk space before the model is ever loaded so the agent never crashes a user's machine.
Key numbers: TimesFM 2.5 uses 200M parameters (~800 MB on disk, ~1.5 GB in RAM on CPU, ~1 GB VRAM on GPU). The archived v1/v2 500M-parameter model needs ~32 GB RAM. Always run the system checker first.
Use this skill when:
Do not use this skill when:
statsmodels
aeon
statsmodels
scikit-learn
Note on Anomaly Detection: TimesFM does not have built-in anomaly detection, but you can use the quantile forecasts as prediction intervals — values outside the 90% CI (q10–q90) are statistically unusual. See the
examples/anomaly-detection/directory for a full example.
CRITICAL — ALWAYS run the system checker before loading the model for the first time.
python scripts/check_system.py
This script checks:
timesfm and torch are installedNote: Model weights are NOT stored in this repository. TimesFM weights (~800 MB) download on-demand from HuggingFace on first use and cache in
~/.cache/huggingface/. The preflight checker ensures sufficient resources before any download begins.
flowchart TD
accTitle: Preflight System Check
accDescr: Decision flowchart showing the system requirement checks that must pass before loading TimesFM.
start["🚀 Run check_system.py"] --> ram{"RAM ≥ 4 GB?"}
ram -->|"Yes"| gpu{"GPU available?"}
ram -->|"No (2-4 GB)"| warn_ram["⚠️ Warning: tight RAM<br/>CPU-only, small batches"]
ram -->|"No (< 2 GB)"| block["🛑 BLOCKED<br/>Insufficient memory"]
warn_ram --> disk
gpu -->|"CUDA / MPS"| vram{"VRAM ≥ 2 GB?"}
gpu -->|"CPU only"| cpu_ok["✅ CPU mode<br/>Slower but works"]
vram -->|"Yes"| gpu_ok["✅ GPU mode<br/>Fast inference"]
vram -->|"No"| cpu_ok
gpu_ok --> disk{"Disk ≥ 2 GB free?"}
cpu_ok --> disk
disk -->|"Yes"| ready["✅ READY<br/>Safe to load model"]
disk -->|"No"| block_disk["🛑 BLOCKED<br/>Need space for weights"]
classDef ok fill:#dcfce7,stroke:#16a34a,stroke-width:2px,color:#14532d
classDef warn fill:#fef9c3,stroke:#ca8a04,stroke-width:2px,color:#713f12
classDef block fill:#fee2e2,stroke:#dc2626,stroke-width:2px,color:#7f1d1d
classDef neutral fill:#f3f4f6,stroke:#6b7280,stroke-width:2px,color:#1f2937
class ready,gpu_ok,cpu_ok ok
class warn_ram warn
class block,block_disk block
class start,ram,gpu,vram,disk neutral
| Model | Parameters | RAM (CPU) | VRAM (GPU) | Disk | Context |
|---|---|---|---|---|---|
| TimesFM 2.5 (recommended) | 200M | ≥ 4 GB | ≥ 2 GB | ~800 MB | up to 16,384 |
| TimesFM 2.0 (archived) | 500M | ≥ 16 GB | ≥ 8 GB | ~2 GB | up to 2,048 |
| TimesFM 1.0 (archived) | 200M | ≥ 8 GB | ≥ 4 GB | ~800 MB | up to 2,048 |
Recommendation: Always use TimesFM 2.5 unless you have a specific reason to use an older checkpoint. It is smaller, faster, and supports 8× longer context.
python scripts/check_system.py
# Using uv (recommended by this repo)
uv pip install timesfm[torch]
# Or using pip
pip install timesfm[torch]
# For JAX/Flax backend (faster on TPU/GPU)
uv pip install timesfm[flax]
# CUDA 12.1 (NVIDIA GPU)
pip install torch>=2.0.0 --index-url https://download.pytorch.org/whl/cu121
# CPU only
pip install torch>=2.0.0 --index-url https://download.pytorch.org/whl/cpu
# Apple Silicon (MPS)
pip install torch>=2.0.0 # MPS support is built-in
import timesfm
import numpy as np
print(f"TimesFM version: {timesfm.__version__}")
print("Installation OK")
import torch, numpy as np, timesfm
torch.set_float32_matmul_precision("high")
model = timesfm.TimesFM_2p5_200M_torch.from_pretrained(
"google/timesfm-2.5-200m-pytorch"
)
model.compile(timesfm.ForecastConfig(
max_context=1024, max_horizon=256, normalize_inputs=True,
use_continuous_quantile_head=True, force_flip_invariance=True,
infer_is_positive=True, fix_quantile_crossing=True,
))
point, quantiles = model.forecast(horizon=24, inputs=[
np.sin(np.linspace(0, 20, 200)), # any 1-D array
])
# point.shape == (1, 24) — median forecast
# quantiles.shape == (1, 24, 10) — 10th–90th percentile bands
import pandas as pd, numpy as np
df = pd.read_csv("monthly_sales.csv", parse_dates=["date"], index_col="date")
# Convert each column to a list of arrays
inputs = [df[col].dropna().values.astype(np.float32) for col in df.columns]
point, quantiles = model.forecast(horizon=12, inputs=inputs)
# Build a results DataFrame
for i, col in enumerate(df.columns):
last_date = df[col].dropna().index[-1]
future_dates = pd.date_range(last_date, periods=13, freq="MS")[1:]
forecast_df = pd.DataFrame({
"date": future_dates,
"forecast": point[i],
"lower_80": quantiles[i, :, 2], # 20th percentile
"upper_80": quantiles[i, :, 8], # 80th percentile
})
print(f"\n--- {col} ---")
print(forecast_df.to_string(index=False))
TimesFM 2.5+ supports exogenous variables through forecast_with_covariates(). Requires timesfm[xreg].
# Requires: uv pip install timesfm[xreg]
point, quantiles = model.forecast_with_covariates(
inputs=inputs,
dynamic_numerical_covariates={"price": price_arrays},
dynamic_categorical_covariates={"holiday": holiday_arrays},
static_categorical_covariates={"region": region_labels},
xreg_mode="xreg + timesfm", # or "timesfm + xreg"
)
| Covariate Type | Description | Example |
|---|---|---|
dynamic_numerical |
Time-varying numeric | price, temperature, promotion spend |
dynamic_categorical |
Time-varying categorical | holiday flag, day of week |
static_numerical |
Per-series numeric | store size, account age |
static_categorical |
Per-series categorical | store type, region, product category |
XReg Modes:
"xreg + timesfm" (default): TimesFM forecasts first, then XReg adjusts residuals"timesfm + xreg": XReg fits first, then TimesFM forecasts residualsSee
examples/covariates-forecasting/for a complete example with synthetic retail data.
TimesFM does not have built-in anomaly detection, but the quantile forecasts naturally provide prediction intervals that can detect anomalies:
point, q = model.forecast(horizon=H, inputs=[values])
# 90% prediction interval
lower_90 = q[0, :, 1] # 10th percentile
upper_90 = q[0, :, 9] # 90th percentile
# Detect anomalies: values outside the 90% CI
actual = test_values # your holdout data
anomalies = (actual < lower_90) | (actual > upper_90)
# Severity levels
is_warning = (actual < q[0, :, 2]) | (actual > q[0, :, 8]) # outside 80% CI
is_critical = anomalies # outside 90% CI
| Severity | Condition | Interpretation |
|---|---|---|
| Normal | Inside 80% CI | Expected behavior |
| Warning | Outside 80% CI | Unusual but possible |
| Critical | Outside 90% CI | Statistically rare (< 10% probability) |
See
examples/anomaly-detection/for a complete example with visualization.
# Requires: uv pip install timesfm[xreg]
point, quantiles = model.forecast_with_covariates(
inputs=inputs,
dynamic_numerical_covariates={"temperature": temp_arrays},
dynamic_categorical_covariates={"day_of_week": dow_arrays},
static_categorical_covariates={"region": region_labels},
xreg_mode="xreg + timesfm", # or "timesfm + xreg"
)
TimesFM returns (point_forecast, quantile_forecast):
point_forecast: shape (batch, horizon) — the median (0.5 quantile)quantile_forecast: shape (batch, horizon, 10) — ten slices:| Index | Quantile | Use |
|---|---|---|
| 0 | Mean | Average prediction |
| 1 | 0.1 | Lower bound of 80% PI |
| 2 | 0.2 | Lower bound of 60% PI |
| 3 | 0.3 | — |
| 4 | 0.4 | — |
| 5 | 0.5 | Median (= point_forecast) |
| 6 | 0.6 | — |
| 7 | 0.7 | — |
| 8 | 0.8 | Upper bound of 60% PI |
| 9 | 0.9 | Upper bound of 80% PI |
point, q = model.forecast(horizon=H, inputs=data)
# 80% prediction interval (most common)
lower_80 = q[:, :, 1] # 10th percentile
upper_80 = q[:, :, 9] # 90th percentile
# 60% prediction interval (tighter)
lower_60 = q[:, :, 2] # 20th percentile
upper_60 = q[:, :, 8] # 80th percentile
# Median (same as point forecast)
median = q[:, :, 5]
flowchart LR
accTitle: Quantile Forecast Anatomy
accDescr: Diagram showing how the 10-element quantile vector maps to prediction intervals.
input["📈 Input Series<br/>1-D array"] --> model["🤖 TimesFM<br/>compile + forecast"]
model --> point["📍 Point Forecast<br/>(batch, horizon)"]
model --> quant["📊 Quantile Forecast<br/>(batch, horizon, 10)"]
quant --> pi80["80% PI<br/>q[:,:,1] – q[:,:,9]"]
quant --> pi60["60% PI<br/>q[:,:,2] – q[:,:,8]"]
quant --> median["Median<br/>q[:,:,5]"]
classDef data fill:#dbeafe,stroke:#2563eb,stroke-width:2px,color:#1e3a5f
classDef model fill:#f3e8ff,stroke:#9333ea,stroke-width:2px,color:#581c87
classDef output fill:#dcfce7,stroke:#16a34a,stroke-width:2px,color:#14532d
class input data
class model model
class point,quant,pi80,pi60,median output
All forecasting behavior is controlled by timesfm.ForecastConfig:
timesfm.ForecastConfig(
max_context=1024, # Max context window (truncates longer series)
max_horizon=256, # Max forecast horizon
normalize_inputs=True, # Normalize inputs (RECOMMENDED for stability)
per_core_batch_size=32, # Batch size per device (tune for memory)
use_continuous_quantile_head=True, # Better quantile accuracy for long horizons
force_flip_invariance=True, # Ensures f(-x) = -f(x) (mathematical consistency)
infer_is_positive=True, # Clamp forecasts ≥ 0 when all inputs > 0
fix_quantile_crossing=True, # Ensure q10 ≤ q20 ≤ ... ≤ q90
return_backcast=False, # Return backcast (for covariate workflows)
)
| Parameter | Default | When to Change |
|---|---|---|
max_context |
0 | Set to match your longest historical window (e.g., 512, 1024, 4096) |
max_horizon |
0 | Set to your maximum forecast length |
normalize_inputs |
False | Always set True — prevents scale-dependent instability |
per_core_batch_size |
1 | Increase for throughput; decrease if OOM |
use_continuous_quantile_head |
False | Set True for calibrated prediction intervals |
force_flip_invariance |
True | Keep True unless profiling shows it hurts |
infer_is_positive |
True | Set False for series that can be negative (temperature, returns) |
fix_quantile_crossing |
False | Set True to guarantee monotonic quantiles |
flowchart TD
accTitle: Single Series Forecast Workflow
accDescr: Step-by-step workflow for forecasting a single time series with system checking.
check["1. Run check_system.py"] --> load["2. Load model<br/>from_pretrained()"]
load --> compile["3. Compile with ForecastConfig"]
compile --> prep["4. Prepare data<br/>pd.read_csv → np.array"]
prep --> forecast["5. model.forecast()<br/>horizon=N"]
forecast --> extract["6. Extract point + PI"]
extract --> plot["7. Plot or export results"]
classDef step fill:#f3f4f6,stroke:#6b7280,stroke-width:2px,color:#1f2937
class check,load,compile,prep,forecast,extract,plot step
import torch, numpy as np, pandas as pd, timesfm
# 1. System check (run once)
# python scripts/check_system.py
# 2-3. Load and compile
torch.set_float32_matmul_precision("high")
model = timesfm.TimesFM_2p5_200M_torch.from_pretrained(
"google/timesfm-2.5-200m-pytorch"
)
model.compile(timesfm.ForecastConfig(
max_context=512, max_horizon=52, normalize_inputs=True,
use_continuous_quantile_head=True, fix_quantile_crossing=True,
))
# 4. Prepare data
df = pd.read_csv("weekly_demand.csv", parse_dates=["week"])
values = df["demand"].values.astype(np.float32)
# 5. Forecast
point, quantiles = model.forecast(horizon=52, inputs=[values])
# 6. Extract prediction intervals
forecast_df = pd.DataFrame({
"forecast": point[0],
"lower_80": quantiles[0, :, 1],
"upper_80": quantiles[0, :, 9],
})
# 7. Plot
import matplotlib.pyplot as plt
fig, ax = plt.subplots(figsize=(12, 5))
ax.plot(values[-104:], label="Historical")
x_fc = range(len(values[-104:]), len(values[-104:]) + 52)
ax.plot(x_fc, forecast_df["forecast"], label="Forecast", color="tab:orange")
ax.fill_between(x_fc, forecast_df["lower_80"], forecast_df["upper_80"],
alpha=0.2, color="tab:orange", label="80% PI")
ax.legend()
ax.set_title("52-Week Demand Forecast")
plt.tight_layout()
plt.savefig("forecast.png", dpi=150)
print("Saved forecast.png")
import pandas as pd, numpy as np
# Load wide-format CSV (one column per series)
df = pd.read_csv("all_stores.csv", parse_dates=["date"], index_col="date")
inputs = [df[col].dropna().values.astype(np.float32) for col in df.columns]
# Forecast all series at once (batched internally)
point, quantiles = model.forecast(horizon=30, inputs=inputs)
# Collect results
results = {}
for i, col in enumerate(df.columns):
results[col] = {
"forecast": point[i].tolist(),
"lower_80": quantiles[i, :, 1].tolist(),
"upper_80": quantiles[i, :, 9].tolist(),
}
# Export
import json
with open("batch_forecasts.json", "w") as f:
json.dump(results, f, indent=2)
print(f"Forecasted {len(results)} series → batch_forecasts.json")
import numpy as np
# Hold out the last H points for evaluation
H = 24
train = values[:-H]
actual = values[-H:]
point, quantiles = model.forecast(horizon=H, inputs=[train])
pred = point[0]
# Metrics
mae = np.mean(np.abs(actual - pred))
rmse = np.sqrt(np.mean((actual - pred) ** 2))
mape = np.mean(np.abs((actual - pred) / actual)) * 100
# Prediction interval coverage
lower = quantiles[0, :, 1]
upper = quantiles[0, :, 9]
coverage = np.mean((actual >= lower) & (actual <= upper)) * 100
print(f"MAE: {mae:.2f}")
print(f"RMSE: {rmse:.2f}")
print(f"MAPE: {mape:.1f}%")
print(f"80% PI Coverage: {coverage:.1f}% (target: 80%)")
import torch
# Check GPU availability
if torch.cuda.is_available():
print(f"GPU: {torch.cuda.get_device_name(0)}")
print(f"VRAM: {torch.cuda.get_device_properties(0).total_mem / 1e9:.1f} GB")
elif hasattr(torch.backends, "mps") and torch.backends.mps.is_available():
print("Apple Silicon MPS available")
else:
print("CPU only — inference will be slower but still works")
# Always set this for Ampere+ GPUs (A100, RTX 3090, etc.)
torch.set_float32_matmul_precision("high")
# Start conservative, increase until OOM
# GPU with 8 GB VRAM: per_core_batch_size=64
# GPU with 16 GB VRAM: per_core_batch_size=128
# GPU with 24 GB VRAM: per_core_batch_size=256
# CPU with 8 GB RAM: per_core_batch_size=8
# CPU with 16 GB RAM: per_core_batch_size=32
# CPU with 32 GB RAM: per_core_batch_size=64
model.compile(timesfm.ForecastConfig(
max_context=1024,
max_horizon=256,
per_core_batch_size=32, # <-- tune this
normalize_inputs=True,
use_continuous_quantile_head=True,
fix_quantile_crossing=True,
))
import gc, torch
# Force garbage collection before loading
gc.collect()
if torch.cuda.is_available():
torch.cuda.empty_cache()
# Load model
model = timesfm.TimesFM_2p5_200M_torch.from_pretrained(
"google/timesfm-2.5-200m-pytorch"
)
# Use small batch size on low-memory machines
model.compile(timesfm.ForecastConfig(
max_context=512, # Reduce context if needed
max_horizon=128, # Reduce horizon if needed
per_core_batch_size=4, # Small batches
normalize_inputs=True,
use_continuous_quantile_head=True,
fix_quantile_crossing=True,
))
# Process series in chunks to avoid OOM
CHUNK = 50
all_results = []
for i in range(0, len(inputs), CHUNK):
chunk = inputs[i:i+CHUNK]
p, q = model.forecast(horizon=H, inputs=chunk)
all_results.append((p, q))
gc.collect() # Clean up between chunks
statsmodelsUse statsmodels for classical models (ARIMA, SARIMAX) as a comparison baseline:
# TimesFM forecast
tfm_point, tfm_q = model.forecast(horizon=H, inputs=[values])
# statsmodels ARIMA forecast
from statsmodels.tsa.arima.model import ARIMA
arima = ARIMA(values, order=(1,1,1)).fit()
arima_forecast = arima.forecast(steps=H)
# Compare
print(f"TimesFM MAE: {np.mean(np.abs(actual - tfm_point[0])):.2f}")
print(f"ARIMA MAE: {np.mean(np.abs(actual - arima_forecast)):.2f}")
matplotlib / scientific-visualizationPlot forecasts with prediction intervals as publication-quality figures.
exploratory-data-analysisRun EDA on the time series before forecasting to understand trends, seasonality, and stationarity.
scripts/check_system.pyMandatory preflight checker. Run before first model load.
python scripts/check_system.py
Output example:
=== TimesFM System Requirements Check ===
[RAM] Total: 32.0 GB | Available: 24.3 GB ✅ PASS
[GPU] NVIDIA RTX 4090 | VRAM: 24.0 GB ✅ PASS
[Disk] Free: 142.5 GB ✅ PASS
[Python] 3.12.1 ✅ PASS
[timesfm] Installed (2.5.0) ✅ PASS
[torch] Installed (2.4.1+cu121) ✅ PASS
VERDICT: ✅ System is ready for TimesFM 2.5 (GPU mode)
Recommended: per_core_batch_size=128
scripts/forecast_csv.pyEnd-to-end CSV forecasting with automatic system check.
python scripts/forecast_csv.py input.csv \
--horizon 24 \
--date-col date \
--value-cols sales,revenue \
--output forecasts.csv
Detailed guides in references/:
| File | Contents |
|---|---|
references/system_requirements.md |
Hardware tiers, GPU/CPU selection, memory estimation formulas |
references/api_reference.md |
Full ForecastConfig docs, from_pretrained options, output shapes |
references/data_preparation.md |
Input formats, NaN handling, CSV loading, covariate setup |
check_system.py first.model.compile() → RuntimeError: Model is not compiled. Must call compile() before forecast().normalize_inputs=True → unstable forecasts for series with large values.fix_quantile_crossing=True → quantiles may not be monotonic (q10 > q50).per_core_batch_size on small GPU → CUDA OOM. Start small, increase.torch.set_float32_matmul_precision("high") → slower inference on Ampere+ GPUs.np.isnan(point).any().infer_is_positive=True for series that can be negative → clamps forecasts at zero. Set False for temperature, returns, etc.timeline
accTitle: TimesFM Version History
accDescr: Timeline of TimesFM model releases showing parameter counts and key improvements.
section 2024
TimesFM 1.0 : 200M params, 2K context, JAX only
TimesFM 2.0 : 500M params, 2K context, PyTorch + JAX
section 2025
TimesFM 2.5 : 200M params, 16K context, quantile head, no frequency indicator
| Version | Params | Context | Quantile Head | Frequency Flag | Status |
|---|---|---|---|---|---|
| 2.5 | 200M | 16,384 | ✅ Continuous (30M) | ❌ Removed | Latest |
| 2.0 | 500M | 2,048 | ✅ Fixed buckets | ✅ Required | Archived |
| 1.0 | 200M | 2,048 | ✅ Fixed buckets | ✅ Required | Archived |
Hugging Face checkpoints:
google/timesfm-2.5-200m-pytorch (recommended)google/timesfm-2.5-200m-flax
google/timesfm-2.0-500m-pytorch (archived)google/timesfm-1.0-200m-pytorch (archived)Three fully-working reference examples live in examples/. Use them as ground truth for correct API usage and expected output shape.
| Example | Directory | What It Demonstrates | When To Use It |
|---|---|---|---|
| Global Temperature Forecast | examples/global-temperature/ |
Basic model.forecast() call, CSV -> PNG -> GIF pipeline, 36-month NOAA context |
Starting point; copy-paste baseline for any univariate series |
| Anomaly Detection | examples/anomaly-detection/ |
Two-phase detection: linear detrend + Z-score on context, quantile PI on forecast; 2-panel viz | Any task requiring outlier detection on historical + forecasted data |
| Covariates (XReg) | examples/covariates-forecasting/ |
forecast_with_covariates() API (TimesFM 2.5), covariate decomposition, 2x2 shared-axis viz |
Retail, energy, or any series with known exogenous drivers |
# Global temperature (no TimesFM 2.5 needed)
cd examples/global-temperature && python run_forecast.py && python visualize_forecast.py
# Anomaly detection (uses TimesFM 1.0)
cd examples/anomaly-detection && python detect_anomalies.py
# Covariates (API demo -- requires TimesFM 2.5 + timesfm[xreg] for real inference)
cd examples/covariates-forecasting && python demo_covariates.py
| Example | Key output files | Acceptance criteria |
|---|---|---|
| global-temperature | output/forecast_output.json, output/forecast_visualization.png |
point_forecast has 12 values; PNG shows context + forecast + PI bands |
| anomaly-detection | output/anomaly_detection.json, output/anomaly_detection.png |
Sep 2023 flagged CRITICAL (z >= 3.0); >= 2 forecast CRITICAL from injected anomalies |
| covariates-forecasting | output/sales_with_covariates.csv, output/covariates_data.png |
CSV has 108 rows (3 stores x 36 weeks); stores have distinct price arrays |
Run this checklist after every TimesFM task before declaring success:
point_fc shape is (n_series, horizon), quant_fc is (n_series, horizon, 10)
freq=[0] for monthly data. TimesFM 2.5: no freq flag.np.isnan(point_fc).any() should be False. Check input series for gaps first.sharex=True. All time axes must cover the same span..gitattributes (repo root already configured).tempfile.mkdtemp() and annotated in code.matplotlib.use('Agg') -- must appear before any pyplot import when running headless.infer_is_positive -- set False for temperature anomalies, financial returns, or any series that can be negative.These bugs have appeared in this skill's examples. Learn from them:
Quantile index off-by-one -- The most common mistake. quant_fc[..., 0] is the mean, not q0. q10 = index 1, q90 = index 9. Always define named constants: IDX_Q10, IDX_Q20, IDX_Q80, IDX_Q90 = 1, 2, 8, 9.
Variable shadowing in comprehensions -- If you build per-series covariate dicts inside a loop, do NOT use the loop variable as the comprehension variable. Accumulate into separate dict[str, ndarray] outside the loop, then assign.
# WRONG -- outer `store_id` gets shadowed:
covariates = {store_id: arr[store_id] for store_id in stores} # inside outer loop over store_id
# CORRECT -- use a different name or accumulate beforehand:
prices_by_store: dict[str, np.ndarray] = {}
for store_id, config in stores.items():
prices_by_store[store_id] = compute_price(config)
Wrong CSV column name -- The global-temperature CSV uses anomaly_c, not anomaly. Always print(df.columns) before accessing.
tight_layout() warning with sharex=True -- Harmless; suppress with plt.tight_layout(rect=[0, 0, 1, 0.97]) or ignore.
TimesFM 2.5 required for forecast_with_covariates() -- TimesFM 1.0 does NOT have this method. Install pip install timesfm[xreg] and use checkpoint google/timesfm-2.5-200m-pytorch.
Future covariates must span the full horizon -- Dynamic covariates (price, promotions, holidays) must have values for BOTH the context AND the forecast horizon. You cannot pass context-only arrays.
Anomaly thresholds must be defined once -- Define CRITICAL_Z = 3.0, WARNING_Z = 2.0 as module-level constants. Never hardcode 3 or 2 inline.
Context anomaly detection uses residuals, not raw values -- Always detrend first (np.polyfit linear, or seasonal decomposition), then Z-score the residuals. Raw-value Z-scores are misleading on trending data.
Use the example outputs as regression baselines. If you change forecasting logic, verify:
# Anomaly detection regression check:
python -c "
import json
d = json.load(open('examples/anomaly-detection/output/anomaly_detection.json'))
ctx = d['context_summary']
assert ctx['critical'] >= 1, 'Sep 2023 must be CRITICAL'
assert any(r['date'] == '2023-09' and r['severity'] == 'CRITICAL'
for r in d['context_detections']), 'Sep 2023 not found'
print('Anomaly detection regression: PASS')"
# Covariates regression check:
python -c "
import pandas as pd
df = pd.read_csv('examples/covariates-forecasting/output/sales_with_covariates.csv')
assert len(df) == 108, f'Expected 108 rows, got {len(df)}'
prices = df.groupby('store_id')['price'].mean()
assert prices['store_A'] > prices['store_B'] > prices['store_C'], 'Store price ordering wrong'
print('Covariates regression: PASS')"