LangGraph Workflow Patterns

Comprehensive patterns for building production LangGraph workflows. LangGraph 1.x is LTS (Long Term Support) — the first stable major release, powering agents at Uber, LinkedIn, and Klarna. Each category has individual rule files in rules/ loaded on-demand.

LangGraph 1.2 (Q1 2026) — new in this bump:

• Deferred nodes (defer=True on add_node) — the node runs only after all other upstream nodes have completed, so its execution is deferred until the run is about to end. This makes "aggregate once everyone else is done" patterns a one-liner instead of a custom reducer.
• Model middleware (before_model / after_model) on create_agent(...) (from langchain.agents) — inject compression, summarization, or PII redaction without subclassing. Note: the legacy pre_model_hook / post_model_hook params only existed on the now-deprecated create_react_agent; the current equivalent is middleware on create_agent.
• Node-level caching via CachePolicy(ttl=..., key_func=...) with SqliteCache and RedisCache backends (pluggable via graph.compile(cache=...)). Idempotent nodes skip recomputation on replay.

Quick Reference