Agent Graph Engineering — Stack · Agent Architecture and Orchestration

Legacy handbook baseline: May 2026. Source-verified additions reviewed 2026-10-13. Tool examples are based on the linked documentation, without a comparative performance claim.

Selection criteria

Inspect state schemas and update rules, conditional transitions, fan-out joins, nested runs, interrupts, and persistent continuation. Check whether a resumed node restarts and which operations might repeat. A diagram or successful compilation does not prove that a business guard holds on every path.

Runtime choices

Option	Fit	Design responsibility
LangGraph Graph API	Explicit state, nodes, edges, reducers, and agent-containing nodes	Choose meaningful contracts and guards; test concurrent updates
LangGraph persistence	Recorded execution state and resumable graph work	Match checkpoint behavior to external effects and application state
Temporal workflows	Durable control flow with external operations in activities	Honor replay constraints and handle activity retries without duplicate effects
An application-owned state machine	A small number of stable transitions	Implement atomic transitions, waiting, and recovery with explicit records

Prototype one interrupted path and one ambiguous external write, not just the ordinary success sequence. Compare operational burden and trace clarity for that workload before committing to a runtime. Avoid adding a graph solely to obtain a visual representation.