Menu

Individual skill

langchain-langgraph-subgraphs

0upvotes

Not available

skills/.curated/langchain-langgraph-subgraphs/SKILL.md

Read pinned source

Source commit 0500b275e963c027f6b410e8c49c0446945c574e

What was checked

Matches the observed repository HEAD
Yes
Scanner rules are current
No
Repository scan complete
No
Skill scan complete
No
Observed behavior
Not checked yet
Last checked
Nov 12, 2026

These are observations at the recorded commit, not a guarantee of safety. Review the source before running it.

Install this skill

Choose an agent in your Stack or copy a command below. Commands fetch the pinned commit and copy only this skill directory. Existing destinations are refused. Copying a command does not install anything.

Standard SKILL.md format has not been attested at this commit. No installation command is available; inspect the source.

Repository context

Repository stars (not skill ratings)
2,917
Repository last updated
Nov 12, 2026
License
MIT

Observed agent integration: No specific integration evidence. Standard SKILL.md installation does not imply verified compatibility.

Files and excerpt

File metadata and permitted, redacted excerpts come from the recorded scan. Source links are pinned to that commit.

Browse files
Read excerpt
# LangGraph Subgraphs and Composition (Python)

## Overview

A parent `StateGraph` invokes a compiled child subgraph as a node. The child
node writes `state["answer"] = "42"` and returns. The parent's next node reads
`state["answer"]` and gets `None`. No error, no warning, no deprecation notice —
just a silent `None` that surfaces as a wrong answer three nodes later when the
router picks the "couldn't find it" branch.

The cause is pain-catalog entry **P21**: LangGraph subgraphs run on an
**independent state schema**. Only keys declared in *both* the parent's
`TypedDict` and the child's `TypedDict` propagate across the subgraph boundary.
`answer` existed in the child schema but not the parent schema, so it was
discarded on return. The fix is to declare `answer` in both schemas (with
Back to top