retencion

Retención en la Fuente

Compute retenciones from extracted invoice data. References in references/ are the source of truth for rates, thresholds, and regime rules.

Input

Structured data from Gemini PDF extraction or manual entry:

document_type: "factura" | "cuenta_de_cobro" | "unknown"
vendor_name: string
vendor_nit: string
vendor_regime: string
vendor_tipo: string
vendor_autorretenedor: string[]    # e.g. ["renta", "ica"]
vendor_ciiu: string                # CIIU code if available
invoice_number: string
invoice_date: string
subtotal: number                   # before taxes (COP)
iva: number                        # IVA charged
total: number                      # total invoice value
concept: string                    # service description

Computation

Step 1 — Validate extraction. Arithmetic gate: |subtotal + iva - total| < 1000 COP. If fails: flag but continue (mark as unverified).

Step 2 — Classify document type. See references/document-types.md. If cuenta_de_cobro: IVA-related retentions = N/A.

Step 3 — Classify concept and check UVT thresholds. Map concept using the classification table in references/retenciones-2026.md. Check UVT floor from references/uvt.md: if subtotal < UVT_floor × UVT_value: zero retention for that concept.

Step 4 — Check autorretenedor status. For each retention type (renta, IVA, ICA), check vendor_autorretenedor[] against the matrix in references/regimen-matrix.md. If vendor self-retains: skip that retention.

Step 5 — Apply rates.

Retention	Base	Rate source
ReteRenta	subtotal	references/retenciones-2026.md by concept + declarante status
ReteIVA	iva	15% of IVA (if applicable)
ReteICA	subtotal	references/retenciones-2026.md by CIIU or Bogotá default 0.966%

Step 6 — Compute net. net_to_vendor = subtotal + iva - reteRenta - reteIVA - reteICA

Output

📋 Factura #[number] — [Vendor Name]
📄 Tipo: Factura electrónica | Cuenta de cobro
Subtotal: $X | IVA: $X | Total: $X ✓

Retenciones calculadas:
• ReteRenta [X%]: $X
• ReteIVA [15%]: $X
• ReteICA [X%]: $X
Neto a pagar: $X

Régimen: [regime]
Tipo contribuyente: [tipo]

Flags

Append when relevant:

• "📄 Cuenta de cobro — no IVA, no ReteIVA"
• "🔄 Vendor es autorretenedor de [X] — no se aplica rete[X]"
• "ℹ️ Subtotal bajo umbral UVT — sin retención [concept]"
• "⚠️ Arithmetic mismatch — verificar PDF"
• "⚠️ ReteICA no calculado — CIIU o municipio desconocido"
• "⚠️ Régimen no confirmado — asumiendo declarante"
• "⚠️ Concepto ambiguo — clasificación incierta, verificar con contador"

Dedup

An invoice is unique by invoice_number + vendor_nit. Duplicates should be flagged, not reprocessed.