{"uid":"cap_7hr0NrqCIBCEbu8JbUHfr","slug":"halowerk-crop-yield-ndvi-estimator-2c859856","name":"Halowerk Crop Yield NDVI Estimator","description":"Computes mean NDVI and an ordinary least-squares daily NDVI trend, then applies yield = intercept + mean_coefficient×mean_NDVI + trend_coefficient×daily_trend. It does not derive NDVI from imagery, account for crop stage or weather, or provide an agronomically calibrated forecast unless the caller supplies valid coefficients.","url":"https://space.halowerk.com/v1/crop-yield-ndvi","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"yield_unit":{"type":"string","maxLength":64,"minLength":1},"observations":{"type":"array","items":{"type":"object","required":["day_after_planting","ndvi"],"properties":{"ndvi":{"type":"number","maximum":1,"minimum":-1},"day_after_planting":{"type":"integer","maximum":10000,"minimum":0}},"additionalProperties":false},"maxItems":10000,"minItems":2},"yield_intercept":{"type":"number","maximum":1000000000000,"minimum":-1000000000000},"yield_per_mean_ndvi":{"type":"number","maximum":1000000000000,"minimum":-1000000000000},"yield_per_daily_ndvi_trend":{"type":"number","maximum":1000000000000000,"minimum":-1000000000000000}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.003","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.003/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.003","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.003","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_-Z0nFe29b5elxLuq4mdWA","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.003","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Estimates crop yield by computing mean NDVI and an OLS daily NDVI trend from time-series observations, then applying a caller-supplied linear model (intercept + mean_coefficient×mean_NDVI + trend_coefficient×daily_trend).","exampleAgentPrompt":"Using my NDVI observations — day 0: 0.32, day 30: 0.51, day 60: 0.74, day 90: 0.68, day 120: 0.55 — estimate crop yield in tonnes per hectare with an intercept of 1.2, a mean NDVI coefficient of 8.5, and a daily trend coefficient of 150.","exampleUseCases":[{"title":"Seasonal maize yield forecast","prompt":"I have weekly NDVI readings for a maize field over 140 days after planting. Can you estimate the yield in kg/ha using an intercept of 800, a mean NDVI coefficient of 6200, and a daily trend coefficient of 40000? Here are the readings: day 7: 0.28, day 14: 0.38, day 21: 0.52, day 28: 0.63, day 35: 0.71, day 42: 0.75, day 49: 0.72, day 56: 0.68, day 63: 0.60, day 70: 0.49, day 77: 0.39, day 84: 0.30, day 91: 0.24, day 98: 0.19, day 105: 0.15, day 112: 0.12, day 119: 0.10, day 126: 0.09, day 133: 0.08, day 140: 0.07."},{"title":"Early-season yield potential screening","prompt":"I want to check early yield potential using NDVI values at day 20: 0.41, day 40: 0.58, and day 60: 0.67. Use yield unit 'bushels/acre', intercept 45.0, mean NDVI coefficient 120.0, and daily trend coefficient 800."},{"title":"Comparing two field zones","prompt":"Compare yield estimates for two field zones: zone A has NDVI at day 0: 0.3, day 45: 0.65, day 90: 0.55; zone B has day 0: 0.25, day 45: 0.58, day 90: 0.50. For both, use yield unit 't/ha', intercept 2.0, mean NDVI coefficient 9.0, and daily trend coefficient 200. Which zone should we prioritize?"}],"resultDescription":"Returns the computed mean NDVI across all observations, the OLS-fitted daily NDVI trend slope, and the estimated yield value (intercept + mean_coefficient×mean_NDVI + trend_coefficient×daily_trend) expressed in the caller-specified yield unit. Does not derive NDVI from imagery or apply agronomic calibration beyond the supplied coefficients.","failureModes":["Fewer than 2 observations provided — validation error","NDVI values outside [-1, 1] range — schema validation failure","Missing required coefficients yields mathematically undefined output","Invalid or missing yield_unit string causes schema rejection","Poorly calibrated coefficients produce agronomically meaningless estimates with no warning","Collinear or flat NDVI time series may produce degenerate OLS trend slopes"],"whenToPreferThis":"Choose this endpoint when you already have a pre-validated linear yield model (intercept and coefficients) and a time-series of NDVI values per day after planting, and you need a fast, deterministic yield estimate without invoking a full remote-sensing pipeline. It is ideal for lightweight agronomic dashboards, automated field monitoring agents, or batch yield screening across multiple fields where NDVI data is already available from a separate source.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T06:36:14.348Z","isFirstParty":false}