{"abstract":"A traffic-free scheduled ride still costs the booked price.","category":"Ride-hailing fare and surge pricing","checks":7,"contract":"Scheduled rides guarantee the booked price: the rider pays the lower of booked and metered fare plus the reservation fee. If the driver never shows, nothing is charged and the reservation fee is refunded. Return charge cents and whether the fee is refunded.","contract_signature":"booked_price, metered, driver_no_show, reservation_fee","evaluation_group":"w2-ride-hailing-fare-surge-scheduled-ride-guarantee","failed_approach":"Taking the higher fare inverts the guarantee.","family":"w2-ride-hailing-fare-surge-scheduled-ride-guarantee-price-guarantee-direction","id":"FA-85816","implementations":{"attempt":{"sha256":"72995e0ce57a176491046d6ac3d3984b280dda6e113bc5738756f57b3e86d44f","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(booked_price, metered, driver_no_show, reservation_fee):\n    if driver_no_show:\n        return {'charge': 0, 'refund_fee': True}\n    return {'charge': max(booked_price, metered) + reservation_fee, 'refund_fee': False}\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression: price guarantee direction', [3200, 3199, False, 300], {'charge': 3499, 'refund_fee': False}),\n  ('partial repair probe: price guarantee direction', [3200, 4100, False, 300],\n   {'charge': 3500, 'refund_fee': False}),\n  ('second regression', [3200, 3201, False, 300], {'charge': 3500, 'refund_fee': False}),\n  ('normal control 1', [2500, 2500, False, 200], {'charge': 2700, 'refund_fee': False}),\n  ('normal control 2', [3200, 3199, True, 200], {'charge': 0, 'refund_fee': True}),\n  ('normal control 3', [4100, 5000, True, 200], {'charge': 0, 'refund_fee': True}),\n  ('normal control 4', [4100, 5000, True, 300], {'charge': 0, 'refund_fee': True})],\n [('regression: price guarantee direction', [4100, 4099, False, 200], {'charge': 4299, 'refund_fee': False}),\n  ('partial repair probe: price guarantee direction', [4100, 5000, False, 200],\n   {'charge': 4300, 'refund_fee': False}),\n  ('second regression', [3200, 4100, False, 200], {'charge': 3400, 'refund_fee': False}),\n  ('normal control 1', [3200, 3199, True, 200], {'charge': 0, 'refund_fee': True}),\n  ('normal control 2', [4100, 4100, False, 300], {'charge': 4400, 'refund_fee': False}),\n  ('normal control 3', [2500, 2500, False, 300], {'charge': 2800, 'refund_fee': False}),\n  ('normal control 4', [2500, 3400, True, 300], {'charge': 0, 'refund_fee': True})],\n [('regression: price guarantee direction', [2500, 2499, False, 300], {'charge': 2799, 'refund_fee': False}),\n  ('partial repair probe: price guarantee direction', [3200, 3201, False, 300],\n   {'charge': 3500, 'refund_fee': False}),\n  ('second regression', [2500, 3400, False, 300], {'charge': 2800, 'refund_fee': False}),\n  ('normal control 1', [3200, 3199, True, 200], {'charge': 0, 'refund_fee': True}),\n  ('normal control 2', [4100, 3400, True, 200], {'charge': 0, 'refund_fee': True}),\n  ('normal control 3', [3200, 3200, False, 300], {'charge': 3500, 'refund_fee': False}),\n  ('normal control 4', [3200, 3200, True, 300], {'charge': 0, 'refund_fee': True})],\n [('regression: price guarantee direction', [2500, 1800, False, 300], {'charge': 2100, 'refund_fee': False}),\n  ('partial repair probe: price guarantee direction', [2500, 2499, False, 300],\n   {'charge': 2799, 'refund_fee': False}),\n  ('second regression', [3200, 2500, False, 200], {'charge': 2700, 'refund_fee': False}),\n  ('normal control 1', [4100, 4099, True, 300], {'charge': 0, 'refund_fee': True}),\n  ('normal control 2', [2500, 2500, False, 300], {'charge': 2800, 'refund_fee': False}),\n  ('normal control 3', [4100, 4101, True, 300], {'charge': 0, 'refund_fee': True}),\n  ('normal control 4', [2500, 2500, False, 200], {'charge': 2700, 'refund_fee': False})],\n [('regression: price guarantee direction', [2500, 1800, False, 300], {'charge': 2100, 'refund_fee': False}),\n  ('partial repair probe: price guarantee direction', [3200, 2500, False, 200],\n   {'charge': 2700, 'refund_fee': False}),\n  ('second regression', [3200, 4100, False, 200], {'charge': 3400, 'refund_fee': False}),\n  ('normal control 1', [2500, 2501, True, 300], {'charge': 0, 'refund_fee': True}),\n  ('normal control 2', [4100, 4100, False, 300], {'charge': 4400, 'refund_fee': False}),\n  ('normal control 3', [2500, 2501, True, 200], {'charge': 0, 'refund_fee': True}),\n  ('normal control 4', [3200, 3200, False, 200], {'charge': 3400, 'refund_fee': False})]]\nfor label, args, expected in fixtures[N-1]:\n    check(label, solve(*args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"42483e60bf673d80cda3e50520ccf079e52ff6d61b4e50d51e231add62ce356d","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(booked_price, metered, driver_no_show, reservation_fee):\n    if driver_no_show:\n        return {'charge': 0, 'refund_fee': True}\n    return {'charge': booked_price + reservation_fee, 'refund_fee': False}\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression: price guarantee direction', [3200, 3199, False, 300], {'charge': 3499, 'refund_fee': False}),\n  ('partial repair probe: price guarantee direction', [3200, 4100, False, 300],\n   {'charge': 3500, 'refund_fee': False}),\n  ('second regression', [3200, 3201, False, 300], {'charge': 3500, 'refund_fee': False}),\n  ('normal control 1', [2500, 2500, False, 200], {'charge': 2700, 'refund_fee': False}),\n  ('normal control 2', [3200, 3199, True, 200], {'charge': 0, 'refund_fee': True}),\n  ('normal control 3', [4100, 5000, True, 200], {'charge': 0, 'refund_fee': True}),\n  ('normal control 4', [4100, 5000, True, 300], {'charge': 0, 'refund_fee': True})],\n [('regression: price guarantee direction', [4100, 4099, False, 200], {'charge': 4299, 'refund_fee': False}),\n  ('partial repair probe: price guarantee direction', [4100, 5000, False, 200],\n   {'charge': 4300, 'refund_fee': False}),\n  ('second regression', [3200, 4100, False, 200], {'charge': 3400, 'refund_fee': False}),\n  ('normal control 1', [3200, 3199, True, 200], {'charge': 0, 'refund_fee': True}),\n  ('normal control 2', [4100, 4100, False, 300], {'charge': 4400, 'refund_fee': False}),\n  ('normal control 3', [2500, 2500, False, 300], {'charge': 2800, 'refund_fee': False}),\n  ('normal control 4', [2500, 3400, True, 300], {'charge': 0, 'refund_fee': True})],\n [('regression: price guarantee direction', [2500, 2499, False, 300], {'charge': 2799, 'refund_fee': False}),\n  ('partial repair probe: price guarantee direction', [3200, 3201, False, 300],\n   {'charge': 3500, 'refund_fee': False}),\n  ('second regression', [2500, 3400, False, 300], {'charge': 2800, 'refund_fee': False}),\n  ('normal control 1', [3200, 3199, True, 200], {'charge': 0, 'refund_fee': True}),\n  ('normal control 2', [4100, 3400, True, 200], {'charge': 0, 'refund_fee': True}),\n  ('normal control 3', [3200, 3200, False, 300], {'charge': 3500, 'refund_fee': False}),\n  ('normal control 4', [3200, 3200, True, 300], {'charge': 0, 'refund_fee': True})],\n [('regression: price guarantee direction', [2500, 1800, False, 300], {'charge': 2100, 'refund_fee': False}),\n  ('partial repair probe: price guarantee direction', [2500, 2499, False, 300],\n   {'charge': 2799, 'refund_fee': False}),\n  ('second regression', [3200, 2500, False, 200], {'charge': 2700, 'refund_fee': False}),\n  ('normal control 1', [4100, 4099, True, 300], {'charge': 0, 'refund_fee': True}),\n  ('normal control 2', [2500, 2500, False, 300], {'charge': 2800, 'refund_fee': False}),\n  ('normal control 3', [4100, 4101, True, 300], {'charge': 0, 'refund_fee': True}),\n  ('normal control 4', [2500, 2500, False, 200], {'charge': 2700, 'refund_fee': False})],\n [('regression: price guarantee direction', [2500, 1800, False, 300], {'charge': 2100, 'refund_fee': False}),\n  ('partial repair probe: price guarantee direction', [3200, 2500, False, 200],\n   {'charge': 2700, 'refund_fee': False}),\n  ('second regression', [3200, 4100, False, 200], {'charge': 3400, 'refund_fee': False}),\n  ('normal control 1', [2500, 2501, True, 300], {'charge': 0, 'refund_fee': True}),\n  ('normal control 2', [4100, 4100, False, 300], {'charge': 4400, 'refund_fee': False}),\n  ('normal control 3', [2500, 2501, True, 200], {'charge': 0, 'refund_fee': True}),\n  ('normal control 4', [3200, 3200, False, 200], {'charge': 3400, 'refund_fee': False})]]\nfor label, args, expected in fixtures[N-1]:\n    check(label, solve(*args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"A deterministic toy pricing contract stipulated for this example; it does not reproduce the pricing of any real ride-hailing operator or regulator. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"w2-ride-hailing-fare-surge-scheduled-ride-guarantee-price-guarantee-direction","generated_at":"2026-09-29T14:50:43.799943+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Ride-hailing prices are computed per trip at scale; ordering, unit and boundary slips become systematic over- or under-charging.","root_cause":"The charge ignores the metered fare.","sha256":"20015924f9a8913a865802c9545e4d2012cb362d81cd3a4e34e7ff17ebb315ae","title":"Rider pays the booked price when the meter is lower · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":39.059,"exit_code":1,"observations":[{"actual":{"charge":3500,"refund_fee":false},"check":"regression: price guarantee direction","expected":{"charge":3499,"refund_fee":false},"passed":false},{"actual":{"charge":4400,"refund_fee":false},"check":"partial repair probe: price guarantee direction","expected":{"charge":3500,"refund_fee":false},"passed":false},{"actual":{"charge":3501,"refund_fee":false},"check":"second regression","expected":{"charge":3500,"refund_fee":false},"passed":false},{"actual":{"charge":2700,"refund_fee":false},"check":"normal control 1","expected":{"charge":2700,"refund_fee":false},"passed":true},{"actual":{"charge":0,"refund_fee":true},"check":"normal control 2","expected":{"charge":0,"refund_fee":true},"passed":true},{"actual":{"charge":0,"refund_fee":true},"check":"normal control 3","expected":{"charge":0,"refund_fee":true},"passed":true},{"actual":{"charge":0,"refund_fee":true},"check":"normal control 4","expected":{"charge":0,"refund_fee":true},"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: price guarantee direction\", \"actual\": {\"charge\": 3500, \"refund_fee\": false}, \"expected\": {\"charge\": 3499, \"refund_fee\": false}, \"passed\": false}, {\"check\": \"partial repair probe: price guarantee direction\", \"actual\": {\"charge\": 4400, \"refund_fee\": false}, \"expected\": {\"charge\": 3500, \"refund_fee\": false}, \"passed\": false}, {\"check\": \"second regression\", \"actual\": {\"charge\": 3501, \"refund_fee\": false}, \"expected\": {\"charge\": 3500, \"refund_fee\": false}, \"passed\": false}, {\"check\": \"normal control 1\", \"actual\": {\"charge\": 2700, \"refund_fee\": false}, \"expected\": {\"charge\": 2700, \"refund_fee\": false}, \"passed\": true}, {\"check\": \"normal control 2\", \"actual\": {\"charge\": 0, \"refund_fee\": true}, \"expected\": {\"charge\": 0, \"refund_fee\": true}, \"passed\": true}, {\"check\": \"normal control 3\", \"actual\": {\"charge\": 0, \"refund_fee\": true}, \"expected\": {\"charge\": 0, \"refund_fee\": true}, \"passed\": true}, {\"check\": \"normal control 4\", \"actual\": {\"charge\": 0, \"refund_fee\": true}, \"expected\": {\"charge\": 0, \"refund_fee\": true}, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.999,"exit_code":1,"observations":[{"actual":{"charge":3500,"refund_fee":false},"check":"regression: price guarantee direction","expected":{"charge":3499,"refund_fee":false},"passed":false},{"actual":{"charge":3500,"refund_fee":false},"check":"partial repair probe: price guarantee direction","expected":{"charge":3500,"refund_fee":false},"passed":true},{"actual":{"charge":3500,"refund_fee":false},"check":"second regression","expected":{"charge":3500,"refund_fee":false},"passed":true},{"actual":{"charge":2700,"refund_fee":false},"check":"normal control 1","expected":{"charge":2700,"refund_fee":false},"passed":true},{"actual":{"charge":0,"refund_fee":true},"check":"normal control 2","expected":{"charge":0,"refund_fee":true},"passed":true},{"actual":{"charge":0,"refund_fee":true},"check":"normal control 3","expected":{"charge":0,"refund_fee":true},"passed":true},{"actual":{"charge":0,"refund_fee":true},"check":"normal control 4","expected":{"charge":0,"refund_fee":true},"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: price guarantee direction\", \"actual\": {\"charge\": 3500, \"refund_fee\": false}, \"expected\": {\"charge\": 3499, \"refund_fee\": false}, \"passed\": false}, {\"check\": \"partial repair probe: price guarantee direction\", \"actual\": {\"charge\": 3500, \"refund_fee\": false}, \"expected\": {\"charge\": 3500, \"refund_fee\": false}, \"passed\": true}, {\"check\": \"second regression\", \"actual\": {\"charge\": 3500, \"refund_fee\": false}, \"expected\": {\"charge\": 3500, \"refund_fee\": false}, \"passed\": true}, {\"check\": \"normal control 1\", \"actual\": {\"charge\": 2700, \"refund_fee\": false}, \"expected\": {\"charge\": 2700, \"refund_fee\": false}, \"passed\": true}, {\"check\": \"normal control 2\", \"actual\": {\"charge\": 0, \"refund_fee\": true}, \"expected\": {\"charge\": 0, \"refund_fee\": true}, \"passed\": true}, {\"check\": \"normal control 3\", \"actual\": {\"charge\": 0, \"refund_fee\": true}, \"expected\": {\"charge\": 0, \"refund_fee\": true}, \"passed\": true}, {\"check\": \"normal control 4\", \"actual\": {\"charge\": 0, \"refund_fee\": true}, \"expected\": {\"charge\": 0, \"refund_fee\": true}, \"passed\": true}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}