--- title: "What are grounded answers?" canonical: "https://xerj.org/science/grounded-answers" updated: "2026-11-14" source: "content/science/grounded-answers.md" --- # What are grounded answers? **Short answer** (updated 2026-11-14): What are grounded answers? They are answers taken from the documents, not from a guess. In XERJ Reader-1, every value comes back with the formula that produced it and the words it was read from. If the documents do not support an answer, Reader-1 replies Not Found. That is a refusal, not a guess. **TL;DR** A grounded answer is one where every claim traces back to a source you can open and check. In XERJ Reader-1, every value comes back with the formula that produced it and the words it was read from. If the evidence is missing, the answer is Not Found. ## 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: The Not Found behaviour and the formula-with-the-value description come from the published Reader-1 waitlist and 24-hour launch posts. This page does not add a new accuracy number.* ## How it works Grounding is a property you can test. Take each claim in the answer and ask three questions: 1. **Is there a source?** The claim names a document, a file and line, or a passage. 2. **Does the source say it?** The cited words support the claim, not just the topic. 3. **Can someone repeat the check?** Another person, or another program, can open the same source and reach the same answer. A model with no sources can still sound right. Retrieval helps, because the model sees real passages before it answers. But retrieval alone does not make the answer grounded. The model can still add a detail that is in none of the passages, or cite a passage that says something else. Grounding is the last step: every claim is tied to evidence, and a claim with no evidence is dropped. So a grounded system needs a way to say no. If the sources do not answer the question, the grounded result is a refusal. ## How XERJ uses it XERJ grounds answers at two levels. - **Search.** XERJ returns passages with their file path and line, so an agent can quote and cite them. A lookup for a symbol that is not in the corpus returns no match. The guide is [retrieval that says not found, with file and line citations](/answers/retrieval-that-says-not-found-with-file-line-citations). - **Answers.** XERJ Reader-1 writes a formula over the exact words of the document. A separate engine calculates the value. Every value comes back with the formula and the words it was read from. If the documents do not support an answer, it replies Not Found. The product description is on the [Reader-1 waitlist](/blog/xerj-reader-1-waitlist), and [Reader-1 after 24 hours](/blog/reader-1-launch-24-hours) explains why that refusal matters. XERJ Query-1 answers with a program and the facts it used, on [the Query-1 page](/xerj-query-1). Taking answers straight from the source text has its own name, [extractive answering](/science/extractive-answering). Both models sit inside [neurosymbolic models](/science/neurosymbolic-models). This page does not add a new accuracy number, and it does not claim that every answer from every model is grounded. ## History and research Retrieval augmented generation put a search step in front of the model so that answers could draw on real documents. Work on attribution and faithfulness then asked the harder question: does the answer stay with what the sources say? The Not Found refusal is XERJ's own wording. The model that writes the formula, and the engine that runs it, are described under [symbolic execution](/science/symbolic-execution). ## Guides Check claims yourself: [verify AI report claims against sources](/answers/verify-ai-report-claims-against-sources) and [answer questions about a docs folder with citations](/answers/answer-questions-about-a-docs-folder-with-citations). ## Related terms [Extractive answering](/science/extractive-answering), [neurosymbolic AI](/science/neurosymbolic-ai), [neurosymbolic models](/science/neurosymbolic-models), and [symbolic execution](/science/symbolic-execution). ## FAQ ### What are grounded answers? They are answers taken from evidence in the documents, returned with that evidence, instead of an unsupported claim. ### How does XERJ Reader-1 do this? Reader-1 writes a formula over a document, and the value is calculated from the words on the page. If the documents do not support an answer, it replies Not Found. ### What does Not Found mean? It is a refusal. The documents do not support an answer, so the model does not invent one. ### Is this the same as extractive answering? They are related. Extractive answering is about where the words come from: the source text. Grounding is about whether each claim can be traced to a source and checked. An extractive answer is grounded by design. A written answer can be grounded too, if every claim carries a source that supports it. ### How do I check that an answer is grounded? Open each cited source and confirm it says what the answer claims. A citation that points at a real file but does not support the claim is not grounding. ## Related - [What is extractive answering?](/science/extractive-answering) - [What are neurosymbolic models?](/science/neurosymbolic-models) - [Neurosymbolic AI vs LLMs](/science/neurosymbolic-ai) - [Symbolic execution for LLMs](/science/symbolic-execution) - [XERJ Reader-1](/blog/xerj-reader-1-waitlist) - [Reader-1 launch](/blog/reader-1-launch-24-hours) - [XERJ Query-1](/xerj-query-1) - [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)