fluid_hypothesis:
  schema_version: "0.1"

  id: "H-000184"
  interface_id: "customer-finance-api"

  state: "PRIORITIZED"

  created_at: "2026-09-04T12:00:00Z"
  created_by:
    type: "daimon"
    id: "fluid-daimon/customer-finance-api"

  title: "Provide direct latest-invoice capability"

  observation:
    summary: >
      A significant consumer cohort retrieves invoice collections,
      sorts them by issue date, and discards all but the first item.
    evidence_refs:
      - "telemetry:invoice-pattern-2026w36"
      - "feedback:F-9821"
    affected_cohorts:
      - "partner-integrations"
      - "coding-agents"
    observation_window:
      start: "2026-08-15T00:00:00Z"
      end: "2026-09-01T00:00:00Z"

  pressure:
    classes:
      - "successful_but_inefficient_usage"
      - "repeated_expectation_mismatch"
    severity: 0.61
    confidence: 0.88

  explanation:
    claim: >
      Consumers treat "latest invoice" as a domain-level concept
      and the existing generic collection interface does not present
      that concept directly.
    reach:
      score: 0.42
      explains:
        - "P-1831"
        - "P-1834"
      notes: >
        Medium reach: explains several related request patterns
        but not broader financial-context pressure.

  proposed_adaptation:
    class: "contract"
    summary: >
      Add an explicit latest-invoice retrieval capability.
    candidate_contract:
      method: "GET"
      path: "/customers/{id}/invoices/latest"
    implementation_scope: "interface_only"

  backend_requirements:
    required: false
    requirement_refs: []

  expected_outcomes:
    - metric: "requests_per_completed_task"
      cohort: "all"
      baseline: 2.7
      target: 1.2
      direction: "lower"
    - metric: "client_side_sort_workarounds"
      cohort: "all"
      baseline: 1.0
      target: 0.2
      direction: "lower"

  guardrails:
    - metric: "p95_latency_ms"
      operator: "<="
      threshold: 315
    - metric: "authorization_scope_change"
      operator: "=="
      threshold: false
    - metric: "backend_query_count_delta"
      operator: "<="
      threshold: 0

  fitness_dimensions:
    expected:
      client_utility: 0.70
      correctness: 0.00
      reliability: 0.00
      performance: 0.10
      discoverability: 0.65
      simplicity: -0.15
      compatibility: 0.00
      security: 0.00
      maintainability: -0.05
      operational_cost: 0.00

  complexity:
    expected_delta:
      surface_area: 1
      concept_count: 0
      operation_count: 1
      semantic_overlap: 0.1
      cognitive_load: -0.2
    score: 0.18

  risk:
    level: "LOW"
    reasons:
      - "read-only operation"
      - "no authorization expansion"

  economics:
    estimated_experiment_cost: 18.00
    estimated_implementation_cost: 40.00
    currency: "EUR"
    expected_value_class: "MEDIUM"

  learning_value:
    score: 0.56
    notes: >
      Useful signal for whether first-class convenience resources
      improve agent and partner integration behavior.

  priority:
    score: 0.71
    decided_by: "optimization-policy-v3"

  success_criteria:
    expression: >
      requests_per_completed_task <= 1.2
      AND no hard guardrail violation

  failure_criteria:
    expression: >
      any hard guardrail violation
      OR adoption below 5% after 30 days when equally discoverable

  candidate_revision_refs:
    - "R-000221"

  experiment_refs:
    - "E-000093"

  outcome:
    status: null
    summary: null
    evidence_refs: []

  audit:
    decision_refs:
      - "D-2811"
    immutable_event_refs:
      - "EV-990218"