---
title: "Fusion Response"
description: "Fusion parameters, fields, exposure paths, sources, and coverage limits."
canonical: https://y2.dev/docs/ontology/reference/fusion/
---

Ontology & Fusion

# Fusion Response

Fusion parameters, fields, exposure paths, sources, and coverage limits.

`GET /api/v2/entities/{entityId}/fusion` and the in-app **Cyber-market exposure** panel return the same view for an organization or vendor entity.

## Parameters

| Parameter       | Default | Range | Meaning                                                        |
| --------------- | ------- | ----- | -------------------------------------------------------------- |
| `windowDays`    | 90      | 1–365 | Days of history ending at request time                         |
| `adjacencyDays` | 7       | 1–90  | How long after a cyber event a market event counts as adjacent |

## Response fields

| Field            | Meaning                                                                                                                     |
| ---------------- | --------------------------------------------------------------------------------------------------------------------------- |
| `entity`         | The resolved company (after catalog merge redirects)                                                                        |
| `window`         | `start`, `end`, and `adjacencyDays` actually used                                                                           |
| `counterparties` | Up to 12 parties on the exposure path, with `relation`, `provenance`, and, for ledger ties, `confidence` and `verification` |
| `identifiers`    | Live designations of ledger subjects anchored to the company                                                                |
| `topics`         | Workspace topics whose subject is the company or a counterparty, with the path relation                                     |
| `timeline`       | Up to 200 dated events in the window, newest first                                                                          |
| `undated`        | Events without a source time, never placed at a guessed date                                                                |
| `summaries`      | Per domain: event count, highest severity, latest event time                                                                |
| `adjacencies`    | Up to 50 cyber → market pairs within `adjacencyDays`, same-path pairs first                                                 |
| `coverage`       | `truncated` and plain-language notes on read budgets and source limits                                                      |

## Exposure paths

| Relation          | From a catalog relation                                                   | From a ledger claim                                          |
| ----------------- | ------------------------------------------------------------------------- | ------------------------------------------------------------ |
| `supplier`        | The party `supplies` the company                                          | The party's subject `supplies` the company's subject         |
| `customer`        | The company `supplies` the party                                          | The company's subject `supplies` the party's subject         |
| `parent`          | The company is `subsidiary_of` the party                                  | The company's subject is `subsidiary-of` the party's subject |
| `subsidiary`      | The party is `subsidiary_of` the company                                  | The party's subject is `subsidiary-of` the company's subject |
| `operated-system` | The company `operates` or `uses` a software, API service, or model entity | The company's subject `operates` a system subject            |

A ledger tie wins over a catalog tie to the same entity because it carries evidence and a verification state.

Catalog paths use current resolved relationships. Changing `windowDays` filters events but does not reconstruct earlier catalog relationships. Ledger paths use claims valid at `window.end`.

## Event sources

| Domain         | Sources                                                                                                     |
| -------------- | ----------------------------------------------------------------------------------------------------------- |
| `cyber`        | Relevant CVEs, threat actors, readable cyber signals, and cyber incidents                                   |
| `market`       | Readable market signals, workspace financial facts, relevant prediction markets, and economic incidents     |
| `supply_chain` | Ledger supply and ownership ties, readable supply-chain signals, maritime incidents, and aviation incidents |
| `geopolitical` | Readable geopolitical, military, and policy signals, plus conflict and political incidents                  |

Signals are readable when they are global or community, belong to the key's workspace, or are the caller's own private signals.

## Provenance

| Value       | Meaning                                                               |
| ----------- | --------------------------------------------------------------------- |
| `catalog`   | Y2's shared catalog: entities, relations, signals, incidents, markets |
| `ledger`    | Your workspace's entity ledger                                        |
| `workspace` | Your workspace's research, such as company financial history          |

## Read budgets

Each source has a read limit.

| Source                             | Limit                                                           |
| ---------------------------------- | --------------------------------------------------------------- |
| Catalog relationships              | 150 in each direction                                           |
| Cyber relationships per path party | 10 most recently added `affects` and 10 `targets` relationships |
| Signal subjects per path party     | 15 within the selected window                                   |
| Financial history                  | 12 most recently recorded facts                                 |
| Anchored ledger subjects           | 5                                                               |
| Workspace topics                   | 200                                                             |
| Incidents and prediction markets   | 100 most recently updated records per source                    |
| Timeline output                    | 200 events                                                      |
| Cyber-market pairs                 | 50                                                              |

Financial facts use their information dates. Ledger ties use `valid_from` when available. `coverage.notes` reports source limits. `coverage.truncated` is true when any source or output limit omits records. A truncated result can therefore contain fewer than 200 events. Sources naming both the company and a counterparty retain the direct company path.