data/drift_patterns/drifts.yaml

# SPDX-License-Identifier: Apache-2.0
# Copyright 2026 DriftCall Team
# Authoritative catalogue: 20 drift patterns per DESIGN.md §6.3 and
# docs/modules/drift_injector.md §4.4 (5 schema + 5 policy + 5 T&C + 3 pricing
# + 2 transversal payment-auth).
# Every id MUST match drift_injector.md §4.4 exactly.
# Every from_version / to_version MUST be a v<N>.json under data/api_schemas/<domain>/.
# detection_hints are substring-matchable tokens (DESIGN.md §6.3).

# --- Schema drifts (5) -------------------------------------------------------

- id: airline.price_rename
  drift_type: schema
  domain: airline
  from_version: v1
  to_version: v2
  description: "field 'price' renamed to 'total_fare_inr'; 'currency' removed"
  mutation:
    rename: {price: total_fare_inr}
    remove: [currency]
  detection_hints:
    - total_fare_inr
    - price
    - rename

- id: airline.pax_required
  drift_type: schema
  domain: airline
  from_version: v2
  to_version: v3
  description: "booking now requires 'passenger_count' field"
  mutation:
    require_new_field: [passenger_count]
  detection_hints:
    - passenger_count
    - MISSING_PASSENGER_COUNT
    - passenger

- id: cab.fare_breakdown
  drift_type: schema
  domain: cab
  from_version: v2
  to_version: v3
  description: "field 'fare_inr' replaced by nested 'fare_breakdown' with base/surge/tolls/gst"
  mutation:
    remove: [fare_inr]
    require_new_field: [fare_breakdown, total_inr]
  detection_hints:
    - fare_breakdown
    - base
    - surge
    - tolls
    - gst

- id: restaurant.items_shape_bump
  drift_type: schema
  domain: restaurant
  from_version: v2
  to_version: v3
  description: "each item in 'items' now requires a 'modifiers' list (empty allowed)"
  mutation:
    require_new_field: [modifiers]
  detection_hints:
    - modifiers
    - INVALID_ITEMS_SHAPE
    - items

- id: hotel.gst_field
  drift_type: schema
  domain: hotel
  from_version: v2
  to_version: v3
  description: "hotel.book now requires 'gst_number' when total_with_tax > 7500"
  mutation:
    require_new_field: [gst_number]
  detection_hints:
    - gst_number
    - MISSING_GST_NUMBER
    - GST_REQUIRED

# --- Policy drifts (5) -------------------------------------------------------

- id: airline.booking_window_shrink
  drift_type: policy
  domain: airline
  from_version: v1
  to_version: v2
  description: "same-day bookings rejected after 14:00 IST (was: same-day always allowed)"
  mutation:
    time_window_shrink: {same_day_cutoff_hour_ist: 14}
  detection_hints:
    - BOOKING_WINDOW_CLOSED
    - booking_window
    - "14:00"
    - same-day

- id: cab.school_hours_mini_reject
  drift_type: policy
  domain: cab
  from_version: v1
  to_version: v2
  description: "vehicle_class=mini during 07:00-09:00 IST now auto-rejects with policy_error"
  mutation:
    policy_flag_flip: {mini_reject_school_hours: true}
  detection_hints:
    - SCHOOL_HOURS_MINI_REJECTED
    - school_hours
    - mini
    - "07:00"

- id: restaurant.min_order_bump
  drift_type: policy
  domain: restaurant
  from_version: v1
  to_version: v2
  description: "minimum order amount increased from 199 to 299"
  mutation:
    numeric_bump: {min_order_inr: 299}
  detection_hints:
    - MIN_ORDER_NOT_MET
    - min_order
    - "299"

- id: hotel.cancel_window_shrink
  drift_type: policy
  domain: hotel
  from_version: v1
  to_version: v2
  description: "free cancellation window shrunk from 24h to 6h before check-in"
  mutation:
    time_window_shrink: {cancel_window_hours: 6}
  detection_hints:
    - CANCEL_WINDOW_EXPIRED
    - cancel_window
    - 6h
    - 24h

- id: cab.vehicle_class_expand
  drift_type: policy
  domain: cab
  from_version: v1
  to_version: v2
  description: "vehicle_class enum expanded to include 'suv' and 'infant_seat_sedan'"
  mutation:
    enum_expand:
      vehicle_class: [mini, sedan, suv, infant_seat_sedan]
  detection_hints:
    - vehicle_class
    - suv
    - infant_seat_sedan
    - VEHICLE_CLASS_UNAVAILABLE

# --- T&C drifts (5) ---------------------------------------------------------

- id: airline.baggage_tnc_rewrite
  drift_type: tnc
  domain: airline
  from_version: v1
  to_version: v2
  description: "free cabin allowance reduced from 7kg to 5kg; announced via side-channel notice"
  mutation:
    tnc_text_swap: {cabin_allowance_kg: 5}
    side_channel_notice_append: "Baggage T&C updated: free cabin allowance is now 5kg (was 7kg)."
  detection_hints:
    - cabin_allowance
    - 5kg
    - 7kg
    - baggage

- id: cab.surge_policy_tnc
  drift_type: tnc
  domain: cab
  from_version: v1
  to_version: v2
  description: "surge may now apply retroactively if ride is extended; side-channel notice"
  mutation:
    tnc_text_swap: {surge_retroactive: true}
    side_channel_notice_append: "Surge policy updated: retroactive surge may apply if ride is extended."
  detection_hints:
    - surge
    - retroactive
    - surge_retroactive

- id: restaurant.veg_filter_semantic
  drift_type: tnc
  domain: restaurant
  from_version: v2
  to_version: v3
  description: "veg_only=True now excludes egg-based dishes (previously included)"
  mutation:
    # Two coupled keys: veg_only_excludes_egg is the new boolean policy flag
    # introduced in v3; veg_only is the user-facing slot whose semantics are
    # being mutated by this drift (same field, different meaning). Templates
    # tag the live slot (veg_only) — keep both so the slot_tag is targetable
    # AND the policy-flag audit trail is preserved.
    tnc_text_swap: {veg_only_excludes_egg: true, veg_only: "semantics_egg_excluded"}
    side_channel_notice_append: "Semantics update: veg_only=True now excludes egg-based dishes."
  detection_hints:
    - veg_only
    - egg
    - semantic

- id: hotel.early_checkin_tnc
  drift_type: tnc
  domain: hotel
  from_version: v1
  to_version: v2
  description: "early check-in before 12:00 now billed at 50% of nightly rate; side-channel"
  mutation:
    tnc_text_swap: {early_checkin_fee_pct: 50}
    side_channel_notice_append: "Early check-in before 12:00 now costs 50% of nightly rate."
  detection_hints:
    - early_checkin
    - 50%
    - "12:00"
    - nightly

- id: airline.reschedule_tnc
  drift_type: tnc
  domain: airline
  from_version: v2
  to_version: v3
  description: "reschedule fee previously waived; now 10% of fare + side-channel text"
  mutation:
    tnc_text_swap: {reschedule_fee_pct: 10}
    side_channel_notice_append: "Reschedule fee policy updated: 10% of fare applies."
  detection_hints:
    - reschedule
    - 10%
    - fare

# --- Pricing drifts (3) -----------------------------------------------------

- id: airline.convenience_fee_append
  drift_type: pricing
  domain: airline
  from_version: v1
  to_version: v2
  description: "hidden 199 INR convenience fee added at booking; search estimate unchanged"
  mutation:
    fee_append: {convenience_fee_inr: 199}
  detection_hints:
    - convenience_fee
    - "199"
    - hidden

- id: cab.toll_unbundle
  drift_type: pricing
  domain: cab
  from_version: v1
  to_version: v2
  description: "tolls previously included; now a separate line item on booking, not estimate"
  mutation:
    pricing_restructure: {toll_bundled: false}
  detection_hints:
    - toll
    - tolls
    - unbundle

- id: hotel.resort_fee_append
  drift_type: pricing
  domain: hotel
  from_version: v1
  to_version: v2
  description: "500 INR/night resort fee added at booking; not shown in nightly_rate"
  mutation:
    fee_append: {resort_fee_inr: 500}
  detection_hints:
    - resort_fee
    - "500"
    - resort

# --- Auth drifts (2, transversal via payment) -------------------------------

- id: payment.auth_scope_upgrade
  drift_type: auth
  domain: payment
  from_version: v1
  to_version: v2
  description: "token_v1 now returns 401; requires token_v2 with scope=payments:write:v2"
  mutation:
    auth_scope_bump: {required_scope: "payments:write:v2"}
    token_version_bump: {accepted_token_version: v2}
  detection_hints:
    - AUTH_SCOPE_INSUFFICIENT
    - scope
    - token_v2
    - "payments:write:v2"

- id: payment.mfa_required
  drift_type: auth
  domain: payment
  from_version: v1
  to_version: v2
  description: "transactions > 5000 INR now require mfa_code; auth_error with MFA_REQUIRED (payment v1 → v2, alternative auth-tightening to auth_scope_upgrade triggered by amount rather than scope)"
  mutation:
    policy_flag_flip: {mfa_required: true}
    numeric_bump: {mfa_threshold_inr: 5000}
  detection_hints:
    - MFA_REQUIRED
    - mfa_code
    - mfa
    - "5000"