Is Progressive Disclosure All You Need for Long-Context Agents?

Yifeng He, Yinzhe Zhao, Jicheng Wang, Hao Chen


Abstract
Long-document question answering usually forces a choice between loading the whole document into the context window and bolting on a separate retriever. Agentic AI suggests a broader option, giving the agent the document path and letting it decide how and what to read. Agent Skills, a standard for packaging expertise into folders an agent loads on demand, supply a ready mechanism: progressive disclosure, which exposes only what a query needs, from a short description down to the specific passages. Practitioners rapidly adopted this pattern for book-length understanding tasks, but the evidence to support such choices has been anecdotal. We run the first controlled study of the pattern, comparing raw-document navigation and several designs of Agent Skills packs against a classical hybrid retriever across three agent harnesses and three model families on ∞Bench. On a single book, the gain depends on the harness, running large when the agent navigates the raw document poorly but near zero when a strong agent harness already divides and retrieves on its own. When scaling up to tasks that span many books, raw-document navigation collapses while one-level progressive disclosure degrades more slowly and pulls ahead. A second, deeper routing level never helps and sometimes breaks accuracy outright, so one level is enough. Progressive disclosure buys context, not intelligence: it is redundant while a strong agent can locate the right passages itself, and decisive once the corpus grows too large to navigate by reading.
Anthology ID:
2026.realm-1.14
Volume:
Proceedings of the Second Workshop for REsearch on Agent Language Models (REALM 2026)
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Ehsan Kamalloo, Nicolas Gontier, Nikolai Rozanov, Maryam Hashemzadeh, Akhil Arora
Venues:
REALM | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
187–203
Language:
URL:
https://aclanthology.org/2026.realm-1.14/
DOI:
Bibkey:
Cite (ACL):
Yifeng He, Yinzhe Zhao, Jicheng Wang, and Hao Chen. 2026. Is Progressive Disclosure All You Need for Long-Context Agents?. In Proceedings of the Second Workshop for REsearch on Agent Language Models (REALM 2026), pages 187–203, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Is Progressive Disclosure All You Need for Long-Context Agents? (He et al., REALM 2026)
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PDF:
https://aclanthology.org/2026.realm-1.14.pdf