--- title: "What is Corpus Hub?" canonical: "https://xerj.org/science/corpus-hub" updated: "2026-11-14" source: "content/science/corpus-hub.md" --- # What is Corpus Hub? **Short answer** (updated 2026-11-14): What is Corpus Hub? It is XERJ's registry of signed, licence-reviewed index packs. An agent can ask a public corpus and get file:line citations, without cloning the tree. The catalogue generated on 2026-10-18 listed 14 corpora. On a recorded 2026-10-19 run, the first snappy answer took 2,356 ms. **Key number:** The catalogue generated on 2026-10-18 listed 14 corpora. On a recorded 2026-10-19 run, the first snappy answer took 2,356 ms including the download; later answers took 30 to 40 ms. (as of 2026-10-19; source: [/answers/ask-questions-about-a-github-repo-without-cloning](/answers/ask-questions-about-a-github-repo-without-cloning)) **TL;DR** Corpus Hub is XERJ's registry of signed, licence-reviewed index packs. An agent can ask a public corpus and get file:line citations, without cloning the tree. The catalogue generated on 2026-10-18 listed 14 corpora. ## Agent prompt ```text Act as a coding agent. Read https://xerj.org/llms.txt, install XERJ, start a local node, index one folder I point you to, and run one search so I can see a cited passage. ``` *Figure: Pack sizes, the 14-corpus catalogue date, and the 2,356 ms / 30 to 40 ms timings are from the published GitHub-repo ask answer (v1.0.0-rc.97, 2026-10-19). This walkthrough does not add a new measurement.* ## How it works A corpus here is a source pinned to a commit, with its licence reviewed, and packed as an index. A signed catalogue lists those packs. The client verifies the catalogue, pulls a pack, and asks it. The answer comes back with file:line. The source tree is not cloned onto the machine that asked. Later questions can stay on the local copy of the pack, so they do not pay the download again. ## How XERJ uses it `xerj ask` pulls a signed pack, for example the 10.8 MB snappy pack, and answers with file:line. The catalogue generated on 2026-10-18 listed 14 corpora. On the recorded 2026-10-19 run, published in the [GitHub-repo ask answer](/answers/ask-questions-about-a-github-repo-without-cloning), the first snappy answer took 2,356 ms including the download; later answers took 30 to 40 ms. This walkthrough does not add a new measurement. Issue #1800 is open for any-repo ask. The product page also describes Corpus Hub packs: [product](/product). ## History and research Corpus Hub is a XERJ product name. This page rests on the published ask answer and the product docs, not on an external paper. ## Guides Start with the [Corpus Hub docs](/docs/corpus-hub). Then read [The Corpus Hub](/blog/the-corpus-hub), [Corpus Hub v2](/blog/corpus-hub-v2) and [ask questions about a GitHub repo without cloning](/answers/ask-questions-about-a-github-repo-without-cloning). ## Related terms [Syntax-aware search](/science/syntax-aware-search) and [hybrid search](/science/hybrid-search). ## FAQ ### What is Corpus Hub? It is XERJ's registry of signed, licence-reviewed index packs. An agent pulls a pack and asks it, with file:line citations, without cloning the source tree. ### What has XERJ published about it? The catalogue generated on 2026-10-18 listed 14 corpora. On the recorded 2026-10-19 run, the first snappy answer took 2,356 ms including the download; later answers took 30 to 40 ms. ### Does the client trust the pack blindly? No. The client verifies a signed catalogue. A corpus is a source pinned to a commit, with its licence reviewed, and packed as an index. ### Where is the how-to? The practical guide is the GitHub-repo ask answer, which is also the source of the timings above. Issue #1800 is open for any-repo ask. ## Evidence - The catalogue generated on 2026-10-18 listed 14 corpora. On a recorded 2026-10-19 run, the first snappy answer took 2,356 ms including the download; later answers took 30 to 40 ms. — [/answers/ask-questions-about-a-github-repo-without-cloning](/answers/ask-questions-about-a-github-repo-without-cloning) ## Related - [Chat with any GitHub repo](/answers/ask-questions-about-a-github-repo-without-cloning) - [What is syntax-aware search?](/science/syntax-aware-search) - [What is hybrid search?](/science/hybrid-search) - [Product](/product) - [What is agentic memory?](/science/agentic-memory) (same intent: Science) - [BM25 vs vector search](/science/bm25) (same intent: Science) - [What is context engineering?](/science/context-engineering) (same intent: Science)