Which components in transformer language models are responsible for discourse understanding? We hypothesize that sparse computational graphs, termed as discursive circuits, control how models process discourse relations. Unlike simpler tasks, discourse relations involve longer spans and complex reasoning. To make circuit discovery feasible, we introduce a task called Completion under Discourse Relation (CuDR), where a model completes a discourse given a specified relation. To support this task, we construct a corpus of minimal contrastive pairs tailored for activation patching in circuit discovery. Experiments show that sparse circuits ($\approx 0.2\%$ of a full GPT-2 model) recover discourse understanding in the English PDTB-based CuDR task. These circuits generalize well to unseen discourse frameworks such as RST and SDRT. Further analysis shows lower layers capture linguistic features such as lexical semantics and coreference, while upper layers encode discourse-level abstractions. Feature utility is consistent across frameworks (e.g., coreference supports Expansion-like relations).

A multifunctional special operations team infiltrates into the Ad Dali' Province of western Yemen as part of a coalition effort that supports the UN recognized government of President Mansour Hadi, based in the southern capital of Aden. The team is one of several that have begun to infiltrate the tribal areas within the span of control of the Houthi rebel army that is based in Sana'a. The purpose of these specialized teams is simple: foment rebellion within the Yemeni tribes against their Houthi oppressors and return control of their tribal areas to the legitimate government as directed by the UN. The team leader for the team that has infiltrated into Ad Dali' is Captain Adam MacDonald of the British Army, who is leading part of his team into the ruined home of Sheikh Abdul Jaleel al-Hudaifi, in the war torn village of Najd al-Mukalla, in the al-Harsha district, just outside of the Ad Dali' provincial capital. The previous Saturday, on February 12, 2025, militia fighters operating under the al-Houthi movement blew up the primary home of the tribal leader of the al-Harsha district using dynamite.