> ## Documentation Index
> Fetch the complete documentation index at: https://docs.gdeltcloud.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Core articles

> What makes an article core to a story, how articles are ranked, and what the derived counts mean.

**Core articles are the articles that report the story's own incident.**

A story's anchor is its rank-1 article: highest article\_weight, ties broken by lowest source\_url, over the story's whole membership.

| role              | rule                                                                                                      |
| ----------------- | --------------------------------------------------------------------------------------------------------- |
| `core`            | It is the anchor, or it is same-incident compatible with the anchor — and it is not background framing.   |
| `background_only` | It is background framing: a backdrop article, or a timeline/roundup, analysis, or economic-fallout frame. |
| `related`         | It is not same-incident compatible with the anchor, but it is in the same theater.                        |
| `uncertain`       | None of the above.                                                                                        |

**Ranking.** Articles are ranked by article\_weight descending, ties broken by source\_url ascending. Rank 1 is the anchor.

**Scope.** Every rank and every count is defined over the story's whole membership, never over one ingest batch.

| derived field              | formula                                                                                                     |
| -------------------------- | ----------------------------------------------------------------------------------------------------------- |
| `core_article_count`       | count of distinct articles whose role is core                                                               |
| `background_article_count` | count of distinct articles whose role is background\_only                                                   |
| `cluster_certainty`        | core\_article\_count / article\_count                                                                       |
| `event_readiness`          | clamp01(cluster\_certainty + (article\_count >= 2 ? 0.2 : 0) - (background\_article\_count > 0 ? 0.15 : 0)) |
| `singleton_score`          | 0 for any story with 2 or more articles                                                                     |

**Invariants.**

* `core_article_count + background_article_count <= article_count`
* a story with 2 or more articles has singleton\_score = 0
* `representative_article_uid, _source_url, _title and _domain describe one and the same article`

**Known limitation.** A story's anchor changes only when a strictly higher-ranked article joins it. Roles already stamped are not re-derived when that happens, because the gate features they were derived from are not retained.