Missing Nodes Arrows In LangGraph Platform

[soufiene-slimi]

Checked other resources

• This is a bug, not a usage question. For questions, please use GitHub Discussions.
• I added a clear and detailed title that summarizes the issue.
• I read what a minimal reproducible example is (https://stackoverflow.com/help/minimal-reproducible-example).
• I included a self-contained, minimal example that demonstrates the issue INCLUDING all the relevant imports. The code run AS IS to reproduce the issue.

Example Code

from typing import TypedDict
from langgraph.graph import StateGraph, START, END

class GraphState(TypedDict):
    query: str
    documents: list
    attempts: int

def retrieve_docs(state: GraphState):
    documents = []
    return {
        "documents": documents,
        "attempts": state["attempts"] + 1
    }

def grade_data(state: GraphState):
    return {}

workflow1 = StateGraph(GraphState)
workflow1.add_node("retrieve_docs", retrieve_docs)
workflow1.add_node("grade_data", grade_data)
workflow1.add_edge(START, "retrieve_docs")
workflow1.add_edge("retrieve_docs", "grade_data")
workflow1.add_edge("grade_data", END)

workflow2 = StateGraph(GraphState)
workflow2.add_node("retrieve docs", retrieve_docs)
workflow2.add_node("grade_data", grade_data)
workflow2.add_edge(START, "retrieve docs")
workflow2.add_edge("retrieve docs", "grade_data")
workflow2.add_edge("grade_data", END)

works = workflow1.compile()
fails = workflow2.compile()

Error Message and Stack Trace (if applicable)

Description

The arrows are missing in the fails graph as shown in the pics:

OK

NOK

System Info

System Information

OS: Darwin
OS Version: Darwin Kernel Version 24.3.0: Mon Jan 6 21:59:47 PST 2025; root:xnu-11215.81.4~9/RELEASE_ARM64_T6000
Python Version: 3.12.3 | packaged by Anaconda, Inc. | (main, May 6 2024, 14:46:42) [Clang 14.0.6 ]

Package Information

langchain_core: 0.3.31
langchain: 0.3.14
langchain_community: 0.3.14
langsmith: 0.2.10
langchain_ollama: 0.2.2
langchain_openai: 0.3.1
langchain_qdrant: 0.2.0
langchain_text_splitters: 0.3.5
langgraph_api: 0.0.15
langgraph_cli: 0.1.65
langgraph_license: Installed. No version info available.
langgraph_sdk: 0.1.48
langgraph_storage: Installed. No version info available.

Optional packages not installed

langserve

Other Dependencies

aiohttp: 3.11.11
async-timeout: Installed. No version info available.
click: 8.1.8
cryptography: 43.0.3
dataclasses-json: 0.6.7
fastembed: Installed. No version info available.
httpx: 0.27.2
httpx-sse: 0.4.0
jsonpatch: 1.33
jsonschema-rs: 0.25.1
langgraph: 0.2.61
langgraph-checkpoint: 2.0.9
langsmith-pyo3: Installed. No version info available.
numpy: 2.2.1
ollama: 0.4.5
openai: 1.60.0
orjson: 3.10.14
packaging: 24.2
pydantic: 2.10.4
pydantic-settings: 2.7.1
pyjwt: 2.10.1
python-dotenv: 1.0.1
PyYAML: 6.0.2
qdrant-client: 1.13.2
requests: 2.32.3
requests-toolbelt: 1.0.0
SQLAlchemy: 2.0.36
sse-starlette: 2.1.3
starlette: 0.45.2
structlog: 24.4.0
tenacity: 8.5.0
tiktoken: 0.8.0
typing-extensions: 4.12.2
uvicorn: 0.34.0
watchfiles: 1.0.3
zstandard: Installed. No version info available.

[eyurtsev]

For context, using langgraph without langgraph platform works properly.

So we'd need to look specifically at langgraph studio to see what's going on

from IPython.display import Image, display
from langchain_core.runnables.graph import CurveStyle, MermaidDrawMethod, NodeStyles

display(
    Image(
        works.get_graph().draw_mermaid_png(
            draw_method=MermaidDrawMethod.API,
        )
    )
)


display(
    Image(
        fails.get_graph().draw_mermaid_png(
            draw_method=MermaidDrawMethod.API,
        )
    )
)

[eyurtsev]

Confirmed on langgraph platform

[eyurtsev]

Looks like bug w/ UI since the data is present

{

    "nodes": [
        {
            "id": "__start__",
            "type": "schema",
            "data": "__start__"
        },
        {
            "id": "retrieve docs",
            "type": "runnable",
            "data": {
                "id": [
                    "langgraph",
                    "utils",
                    "runnable",
                    "RunnableCallable"
                ],
                "name": "retrieve docs"
            }
        },
        {
            "id": "grade_data",
            "type": "runnable",
            "data": {
                "id": [
                    "langgraph",
                    "utils",
                    "runnable",
                    "RunnableCallable"
                ],
                "name": "grade_data"
            }
        },
        {
            "id": "__end__",
            "type": "schema",
            "data": "__end__"
        }
    ],
    "edges": [
        {
            "source": "__start__",
            "target": "retrieve docs"
        },
        {
            "source": "grade_data",
            "target": "__end__"
        },
        {
            "source": "retrieve docs",
            "target": "grade_data"
        }
    ]
}