---
title: "Write-Time Fact Extraction (ADD/UPDATE/DELETE) · agent retrieval pattern · Agent Fieldbook"
url: https://agentfieldbook.org/memory/retrieval/write-time-extraction/
description: "An LLM extracts atomic facts on write and reconciles vs. existing memory as ADD / UPDATE / DELETE / NOOP."
section: "Memory · Retrieval"
source: Agent Fieldbook — generated from the published page
---

# Write-Time Fact Extraction (ADD/UPDATE/DELETE)

An LLM extracts atomic facts on write and reconciles vs. existing memory as ADD / UPDATE / DELETE / NOOP.

Verified against [arxiv.org](https://arxiv.org/abs/2504.19413)

- [arxiv.org](https://arxiv.org/abs/2504.19413)

## How it works

## At a glance

| Field | Value |
| --- | --- |
| Stage | Harvest |
| Phase | Write |
| Used by | Mem0· LangMem (memory managers) |

## Trade-off

Extra LLM call per write; extraction or conflict-resolution errors corrupt the store.

## Basis

## Verified against

- [https://arxiv.org/abs/2504.19413](https://arxiv.org/abs/2504.19413)

The corpus does not rewrite vendor documentation. Where copy is quoted verbatim it is marked as such and attributed to its source.