LangChain CLI

0.0.37 verified Fri May 01 auth: no python

The official CLI for scaffolding, interacting, and managing LangChain projects. Version 0.0.37, requires Python >=3.9. Release cadence is irregular; active development.

pip install langchain-cli

Common errors

error ModuleNotFoundError: No module named 'langchain_cli' ↓

cause Package not installed or installed under different name (langchain-cli vs langchain_cli).

fix

Run pip install langchain-cli and import using import langchain_cli.

error Error: No such command 'serve' ↓

cause The `serve` command was renamed to `run` in v0.0.30+.

fix

Use langchain-cli run instead of langchain-cli serve.

error Usage: langchain-cli [OPTIONS] COMMAND [ARGS]... Try 'langchain-cli --help' for help. Error: Missing argument 'COMMAND'. ↓

cause Running `langchain-cli` without any subcommand.

fix

Provide a valid subcommand like new, run, or --help.

Warnings

deprecated The `langchain` pip package itself is not needed for the CLI. Installing both can cause conflicts. ↓

fix Install langchain-cli without langchain unless you specifically need the full SDK.

gotcha The CLI uses Typer under the hood. Do not try to import from `langchain_cli` if you only installed `langchain` — you need a separate install. ↓

fix Ensure `pip list | grep langchain-cli` shows the package.

breaking In v0.0.30+, the `langchain-cli serve` command was renamed to `langchain-cli run`. Old scripts using `serve` will break. ↓

fix Replace `langchain-cli serve` with `langchain-cli run` in your commands.

Install

pip install langchain-cli --upgrade

Imports

langchain_cli
wrong
```
import langchaincli
```
correct
```
import langchain_cli
```
The package name has an underscore, not a hyphen.
langchain_cli.cli
wrong
```
from langchain.cli import app
```
correct
```
from langchain_cli.cli import app
```
The main module is under langchain_cli, not langchain.

Quickstart

Test CLI invocation programmatically. Shows the installed version.

import langchain_cli
from langchain_cli.cli import app
from typer.testing import CliRunner
runner = CliRunner()
result = runner.invoke(app, ["--version"])
print(result.output.strip())