Agentic data cracking is a method designed to reduce the high computational costs of using LLM agents to reason over large, unstructured document collections. By adaptively and speculatively structuring data as a byproduct of the reasoning process, the system allows future queries to bypass expensive document loading, instead retrieving answers from a structured store.
The Cost of Data Reasoning
LLM agents are highly effective at answering complex questions by searching through documents, extracting facts, and performing multi-step reasoning. However, this process is "prefill-intensive," meaning the agent must repeatedly load large documents into its context window to extract scattered evidence. According to researchers Milad Rezaei Hajidehi, Qitong Wang, and Stratos Idreos of Harvard University, a single question can consume up to one million tokens and cost nearly one dollar. While pre-structuring all data into a database would make these tasks significantly cheaper, it is infeasible because documents contain far more information than any specific workload requires, and the necessary structure is unknown until queries arrive.
How Agentic Data Cracking Works
The proposed system functions by integrating a "cracking sub-agent" into the reasoning workflow. When a primary agent opens a document to answer a question, the sub-agent forks from the existing context at a marginal cost. It uses semantic reasoning to identify and extract "cracked objects"—grounded entities, attributes, and relations—that are likely to be useful for future, related queries.
These objects are stored in a catalog. When a subsequent query is made, the agent first checks this catalog. If the required information is already structured, the agent performs a low-cost database lookup instead of re-opening and re-processing the raw document. If the information is missing, the system falls back to the original document, ensuring that accuracy is maintained.
Performance and Efficiency
In experiments using the FanOutQA benchmark, the researchers found that reasoning over an ideal pre-structured store is 28 times cheaper than reasoning over raw documents. When applying agentic data cracking to the benchmark—extended to include at least one related question per test question—the system reduced costs by 53% while preserving answer accuracy. At the 10th percentile of savings, the system performed 9 times cheaper than the baseline. The researchers note that these savings accumulate over time as the system builds a "data moat," where the structured knowledge becomes a durable asset that improves with use.
Considerations for Implementation
The effectiveness of this approach relies on "semantic locality," where users or automated systems tend to ask related questions that target the same documents or overlapping sets of entities. The system is designed to be adaptive, meaning it only extracts structure that is actually demanded by the workload, avoiding the waste of exhaustive, upfront extraction.
A key limitation is that the system requires a "miss" on the initial query to trigger the extraction of new structure. Furthermore, the researchers note that the current schema is limited to strings, integers, and dates. Because the system relies on the agent's ability to resolve entity names and relation labels, mismatches in these labels can prevent the retrieval of stored objects, necessitating a fallback to raw document access.
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