---
title: "Typed runtime state · agent building block · Agent Fieldbook"
url: https://agentfieldbook.org/design/building_blocks/typed-state/
description: "The agent's working state is a typed schema (TypedDict / Pydantic) the graph reads and writes at each step: a structured, inspectable model of the run."
section: "Design · Building Blocks · Ontology"
source: Agent Fieldbook — generated from the published page
---

# Typed runtime state

The agent's working state is a typed schema (TypedDict / Pydantic) the graph reads and writes at each step: a structured, inspectable model of the run.

## How it works

## At a glance

| Field | Value |
| --- | --- |
| Kind | Ontology· Typed state |
| Example | LangGraph |

## Basis

- [langchain-ai.github.io](https://langchain-ai.github.io/langgraph/)