feat: LangGraph integration helpers and example #33

ryoppippi · 2025-09-02T21:16:23Z

This PR adds first-class LangGraph support:

New helpers in stackone_ai.integrations.langgraph:
- to_tool_node and to_tool_executor
- bind_model_with_tools and create_react_agent
Updated example: examples/langgraph_tool_node.py now builds a ToolNode and ToolExecutor
README: LangGraph section with a minimal agent loop (tools_condition + typed state)
pyproject: include langgraph in the examples extra

Motivation

Make it trivial to plug StackOne tools into LangGraph prebuilt nodes.
Provide a minimal, conventional graph pattern (LLM -> tools -> LLM) that aligns with the docs.

Notes

Helpers accept either our Tools collection or plain LangChain tools.
Functions perform local imports to keep base installation light.

Testing

Pre-commit hooks pass (ruff, mypy).

Summary by cubic

Adds first-class LangGraph integration to make StackOne tools plug-and-play with LangGraph prebuilt nodes. Enables a simple LLM -> tools -> LLM loop with minimal setup.

New Features
- Added helpers: to_tool_node, to_tool_executor, bind_model_with_tools, create_react_agent.
- Updated example (examples/langgraph_tool_node.py) to build a ToolNode and ToolExecutor.
- README: new LangGraph section with a minimal typed-state agent loop using tools_condition.
- Helpers accept StackOne Tools or LangChain tools and use local imports to keep the base install light.
Dependencies
- Added langgraph>=0.2.0 to the examples extra.

Copilot

Pull Request Overview

This PR introduces first-class LangGraph integration for StackOne tools, making it easy to use StackOne tools within LangGraph workflows and agents.

Adds new integration helpers in stackone_ai.integrations.langgraph for converting tools to LangGraph components
Updates the example to demonstrate actual LangGraph integration with ToolNode and ToolExecutor
Includes comprehensive documentation with a complete agent loop example in the README

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
stackone_ai/integrations/langgraph.py	New module with helper functions to convert StackOne tools to LangGraph prebuilt components
stackone_ai/integrations/init.py	New init file exposing the LangGraph integration helpers
pyproject.toml	Adds langgraph dependency to the examples extra
examples/langgraph_tool_node.py	Updated example demonstrating ToolNode and ToolExecutor creation
README.md	Adds LangGraph integration section with complete agent loop example

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Copilot · 2025-09-02T21:16:53Z

stackone_ai/integrations/langgraph.py

+def _ensure_langgraph() -> None:
+    try:
+        from langgraph import prebuilt as _  # noqa: F401
+    except Exception as e:  # pragma: no cover


Using a bare Exception catch is too broad. Consider catching ImportError or ModuleNotFoundError specifically since this is checking for missing dependencies.

Suggested change

except Exception as e: # pragma: no cover

except ImportError as e: # pragma: no cover

Copilot · 2025-09-02T21:16:53Z

stackone_ai/integrations/langgraph.py

+if TYPE_CHECKING:  # pragma: no cover - only for typing
+    try:
+        from langgraph.prebuilt import ToolExecutor, ToolNode
+    except Exception:  # pragma: no cover


Using a bare Exception catch is too broad. Consider catching ImportError or ModuleNotFoundError specifically since this is checking for missing dependencies.

Suggested change

except Exception: # pragma: no cover

except ImportError: # pragma: no cover

cubic-dev-ai

1 issue found across 5 files

_{React with 👍 or 👎 to teach cubic. You can also tag @cubic-dev-ai to give feedback, ask questions, or re-run the review.}

cubic-dev-ai · 2025-09-02T21:28:07Z

README.md

+    llm = ChatOpenAI(model="gpt-4o-mini")
+    llm = bind_model_with_tools(llm, langchain_tools)
+    resp = llm.invoke(state["messages"])  # returns AIMessage with optional tool_calls
+    return {"messages": state["messages"] + [resp]}


With add_messages, returning state["messages"] + [resp] duplicates messages; return only the new message so the reducer can append it.

Prompt for AI agents

Address the following comment on README.md at line 146: <comment>With add_messages, returning state["messages"] + [resp] duplicates messages; return only the new message so the reducer can append it.</comment> <file context> @@ -110,6 +110,52 @@ for tool_call in response.tool_calls: + llm = ChatOpenAI(model="gpt-4o-mini") + llm = bind_model_with_tools(llm, langchain_tools) + resp = llm.invoke(state["messages"]) # returns AIMessage with optional tool_calls + return {"messages": state["messages"] + [resp]} + +graph.add_node("llm", call_llm) </file context>

Suggested change

return {"messages": state["messages"] + [resp]}

return {"messages": [resp]}

- Add stackone_ai/integrations/langgraph with: - to_tool_node, to_tool_executor - bind_model_with_tools, create_react_agent - Add examples/langgraph_tool_node.py matching README snippet (English comments) - Update README with a minimal LangGraph agent loop (tools_condition) and prereqs - examples now document installing langgraph and langchain-openai explicitly

…ed ToolExecutor - Replace ToolExecutor import with ToolNode in TYPE_CHECKING block - Update to_tool_executor function to return ToolNode instead of deprecated ToolExecutor - Add mypy override to ignore missing imports for langgraph modules - Fix linting issue with blank line whitespace in docstring

glebedel

LGTM

ryoppippi · 2025-09-05T13:52:32Z

hmm still error

- Use class-based fallback instead of assignment for ToolNode in TYPE_CHECKING block - Add type: ignore for no-redef to handle the intentional redefinition - This fixes compatibility with Python 3.9 mypy type checking

- Run mypy on server.py only for Python 3.10+ where MCP dependencies are available - Exclude server.py for Python 3.9 to avoid MCP import errors - This ensures type checking works correctly across all supported Python versions

ryoppippi · 2025-09-05T13:58:01Z

hmm this is bad, i'll fix it

- Add comprehensive mypy overrides for mcp module - Configure mypy to install types automatically in CI - Exclude .venv directory from type checking - This resolves pattern matching syntax errors from mcp library dependencies

- Remove unused type: ignore comment for try block - Add type: ignore for MCP decorator functions to handle untyped decorators - Set mypy python_version to 3.10 to properly handle pattern matching syntax - All mypy checks now pass successfully

Copilot AI review requested due to automatic review settings September 2, 2025 21:16

Copilot AI reviewed Sep 2, 2025

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cubic-dev-ai bot reviewed Sep 2, 2025

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ryoppippi force-pushed the feat/langgraph-integration branch 2 times, most recently from 82f08cd to 8371e81 Compare September 2, 2025 21:49

ryoppippi force-pushed the feat/langgraph-integration branch from 8371e81 to 8bb3c02 Compare September 2, 2025 21:51

glebedel approved these changes Sep 4, 2025

View reviewed changes

fix: mcp mypy error

6dcf323

ryoppippi added 2 commits September 5, 2025 14:53

fix: resolve mypy type errors for langgraph ToolNode fallback

8f24d87

- Use class-based fallback instead of assignment for ToolNode in TYPE_CHECKING block - Add type: ignore for no-redef to handle the intentional redefinition - This fixes compatibility with Python 3.9 mypy type checking

ryoppippi added 2 commits September 5, 2025 15:00

fix: configure mypy to handle MCP library syntax errors

6106a82

- Add comprehensive mypy overrides for mcp module - Configure mypy to install types automatically in CI - Exclude .venv directory from type checking - This resolves pattern matching syntax errors from mcp library dependencies

fix: pin python 3.10 version

f55b44d

- Remove unused type: ignore comment for try block - Add type: ignore for MCP decorator functions to handle untyped decorators - Set mypy python_version to 3.10 to properly handle pattern matching syntax - All mypy checks now pass successfully

ryoppippi force-pushed the feat/langgraph-integration branch from 0fd75fc to f55b44d Compare September 5, 2025 14:06

Merge branch 'main' into feat/langgraph-integration

99c68c9

ryoppippi enabled auto-merge (squash) September 26, 2025 13:38

ryoppippi merged commit 983e2f7 into main Sep 26, 2025
5 checks passed

ryoppippi deleted the feat/langgraph-integration branch September 26, 2025 13:39

github-actions bot mentioned this pull request Sep 26, 2025

chore(main): release stackone-ai 0.3.3 #32

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feat: LangGraph integration helpers and example #33

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	except Exception as e: # pragma: no cover
	except ImportError as e: # pragma: no cover

	except Exception: # pragma: no cover
	except ImportError: # pragma: no cover

	return {"messages": state["messages"] + [resp]}
	return {"messages": [resp]}

feat: LangGraph integration helpers and example #33

feat: LangGraph integration helpers and example #33

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ryoppippi commented Sep 2, 2025 •

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