---
title: "Parametric Index Deriver"
method: POST
path: "/v1/tools/derive_parametric_index_from_receipts"
tags: ["TODO_TAGS_REVIEW"]
---

# Parametric Index Deriver

`POST /v1/tools/derive_parametric_index_from_receipts`

## Request

- Base URL: `https://ainumbers.co`
- URL: `https://ainumbers.co/v1/tools/derive_parametric_index_from_receipts`
- Auth: none declared

Deterministically aggregates a named metric (mean, sum, count, max, or min) across a receipt set into a parametric index value: receipts as an oracle replacement, replay-on-challenge instead of trust-the-feed. Feeds the shipped compute_parametric_trigger_payout kernel, which performs the actual trigger-vs-payout math; this kernel never reimplements that logic. The index is a replayable derived value, never a settlement trigger by itself. Not the same as check_agency_eligibility_matrix or any lending eligibility tool -- this is an insurance-evidence parametric index. Zero network, zero PII.

**Tool URL:** https://ainumbers.co/chaingraph/art-309-parametric-index-deriver.html
**AP2/Policy Mandate export:** yes

## Request body

- object
  - `index_def` unknown, required
  - `receipts` unknown, required

## Response `200`

Successful tool execution result

- object
  - `aggregation` string
  - `contributing_receipts` integer
  - `index_value` integer
  - `insufficient_evidence` boolean
  - `metric` string
  - `window` object
    - `from` string
    - `to` string

---

[API](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite.md) · [All operations](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite/llms.txt) · [OpenAPI document](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite/revisions/b462e4f5bb28?raw)