---
title: "Betweenness"
method: GET
path: "/api/contagion/betweenness"
tags: ["contagion"]
---

# Betweenness

`GET /api/contagion/betweenness`

## Request

- Base URL: `https://basisprotocol.xyz` (the document declares no server; this is the origin it was published from)
- URL: `https://basisprotocol.xyz/api/contagion/betweenness`
- Auth: none declared

Return betweenness centrality over the well-supported co-stress graph.

Phase 2.4 / B3 — which entities are systemic BRIDGES connecting otherwise-
separate stress clusters: shortest-path betweenness on the directed co-stress
graph, computed by the pure module ``app.contagion.betweenness`` and persisted
by the slow-cycle calibration pass.

SELF-GATING: betweenness is computed ONLY when the well-supported subgraph
(sample_floor_met AND n_joint_tail>=50) clears 120 edges / 35 nodes. When it
does NOT (true today, ~54 edges / 20 nodes), this returns a 200 with an explicit
``status='insufficient_graph_density'`` carrying the observed and required
counts — the honest "not yet", NOT an empty 200 that would read as zero
centrality. When it IS computed, returns nodes by betweenness desc + the
provenance envelope + the §6 disclaimer. Pre-calibration (no run / no B3 record)
returns ``status='not_calibrated'`` with a null envelope.

## Query parameters

- `peg_type` string

## Response `200`

Successful Response

- object

## Other responses

- `422`: Validation Error

---

[API](https://skmtc.dev/basisprotocol/apis/basis-protocol-api.md) · [All operations](https://skmtc.dev/basisprotocol/apis/basis-protocol-api/llms.txt) · [OpenAPI document](https://skmtc.dev/basisprotocol/apis/basis-protocol-api/revisions/c0067366b9c0?raw)