fix: pin langchain to prevent upgrade

[willkill07]

Description

langchain 1.0.0 has officially been released.

To prevent pip from pulling this down, we should proactively pin to the last release before 1.0

Closes

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• When the PR is ready for review, new or existing tests cover these changes.
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Summary by CodeRabbit

• Chores
  • Added a new dependency (langchain) to the project dependencies to keep libraries up to date and ensure compatibility with related components.
  • Updated dependency list to reflect the change and maintain ecosystem alignment.

[coderabbitai]

Walkthrough

Added a new dependency constraint langchain~=0.3.27 to packages/nvidia_nat_langchain/pyproject.toml, inserted after the existing nvidia-nat~=1.3 dependency.

Changes

Cohort / File(s)	Summary
Dependency Management packages/nvidia_nat_langchain/pyproject.toml	Added langchain~=0.3.27 to the [project.dependencies] list, positioned after nvidia-nat~=1.3.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

Pre-merge checks and finishing touches

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title Check	✅ Passed	The pull request title "fix: pin langchain to prevent upgrade" is directly relevant to the changeset, which adds a pinned langchain dependency (langchain~=0.3.27) to pyproject.toml to prevent upgrading past version 0.3.27. The title accurately summarizes the main change and intent of the PR, which aligns with the PR objectives noting that the pin is proactive to avoid pulling langchain 1.0.0. The title is concise at 37 characters (well under the 72-character limit), uses clear imperative action language ("pin"), and is fully descriptive of what was changed and why.
Docstring Coverage	✅ Passed	No functions found in the changes. Docstring coverage check skipped.

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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[AnuradhaKaruppiah]

Thx for taking care of this @willkill07

[dagardner-nv]

Approving for deps (not a change just a pin)

[coderabbitai]

Actionable comments posted: 1

📜 Review details

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 06b98c9 and ae663b6.

⛔ Files ignored due to path filters (1)

• uv.lock is excluded by !**/*.lock

📒 Files selected for processing (1)

• packages/nvidia_nat_langchain/pyproject.toml (1 hunks)

🧰 Additional context used

📓 Path-based instructions (4)

packages/*/pyproject.toml

📄 CodeRabbit inference engine (.cursor/rules/general.mdc)

packages/*/pyproject.toml: Each package must contain a pyproject.toml
In packages, declare a dependency on nvidia-nat or packages starting with nvidia-nat-
Use ~= version constraints (e.g., ~=1.0) for dependencies

Files:

• packages/nvidia_nat_langchain/pyproject.toml

{packages/*/pyproject.toml,uv.lock}

📄 CodeRabbit inference engine (.cursor/rules/general.mdc)

Add new dependencies to both pyproject.toml (alphabetically) and uv.lock via uv pip install --sync

Files:

• packages/nvidia_nat_langchain/pyproject.toml

**/*

⚙️ CodeRabbit configuration file

**/*: # Code Review Instructions

• Ensure the code follows best practices and coding standards. - For Python code, follow
  PEP 20 and
  PEP 8 for style guidelines.
• Check for security vulnerabilities and potential issues. - Python methods should use type hints for all parameters and return values.
  Example:

  def my_function(param1: int, param2: str) -> bool:
      pass

• For Python exception handling, ensure proper stack trace preservation:
  • When re-raising exceptions: use bare raise statements to maintain the original stack trace,
    and use logger.error() (not logger.exception()) to avoid duplicate stack trace output.
  • When catching and logging exceptions without re-raising: always use logger.exception()
    to capture the full stack trace information.

Documentation Review Instructions - Verify that documentation and comments are clear and comprehensive. - Verify that the documentation doesn't contain any TODOs, FIXMEs or placeholder text like "lorem ipsum". - Verify that the documentation doesn't contain any offensive or outdated terms. - Verify that documentation and comments are free of spelling mistakes, ensure the documentation doesn't contain any

words listed in the ci/vale/styles/config/vocabularies/nat/reject.txt file, words that might appear to be
spelling mistakes but are listed in the ci/vale/styles/config/vocabularies/nat/accept.txt file are OK.

Misc. - All code (except .mdc files that contain Cursor rules) should be licensed under the Apache License 2.0,

and should contain an Apache License 2.0 header comment at the top of each file.

• Confirm that copyright years are up-to date whenever a file is changed.

Files:

• packages/nvidia_nat_langchain/pyproject.toml

packages/**/*

⚙️ CodeRabbit configuration file

packages/**/*: - This directory contains optional plugin packages for the toolkit, each should contain a pyproject.toml file. - The pyproject.toml file should declare a dependency on nvidia-nat or another package with a name starting
with nvidia-nat-. This dependency should be declared using ~=<version>, and the version should be a two
digit version (ex: ~=1.0).

• Not all packages contain Python code, if they do they should also contain their own set of tests, in a
  tests/ directory at the same level as the pyproject.toml file.

Files:

• packages/nvidia_nat_langchain/pyproject.toml

🧠 Learnings (2)

📓 Common learnings

Learnt from: CR
PR: NVIDIA/NeMo-Agent-Toolkit#0
File: .cursor/rules/general.mdc:0-0
Timestamp: 2025-09-23T18:39:15.023Z
Learning: Applies to packages/*/pyproject.toml : In packages, declare a dependency on nvidia-nat or packages starting with nvidia-nat-

📚 Learning: 2025-09-23T18:39:15.023Z

Learnt from: CR
PR: NVIDIA/NeMo-Agent-Toolkit#0
File: .cursor/rules/general.mdc:0-0
Timestamp: 2025-09-23T18:39:15.023Z
Learning: Applies to packages/*/pyproject.toml : In packages, declare a dependency on nvidia-nat or packages starting with nvidia-nat-

Applied to files:

• packages/nvidia_nat_langchain/pyproject.toml

[willkill07]

/merge