Installation

Easily setup the right tool integrations

Access to the different Pending AI services is made available through a variety of different tools. Integrations are defined at different software layers to make installation more streamlined.

Depending on your pipeline environment, there are many different available tools with more under development coming in future releases. All integrations leverage our API as the entry-point for the different Pending AI capabilities.

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Installing the CLI

For creating simple scripts or interacting with the platform from your terminal

Prerequisites: Install Python 3.9 or later (latest recommended). See here for more information. Create a Pending AI account with access to the different services.

1. Create a Python Environment (Recommended)

The CLI tool is made available via the Python PyPI repository and can be installed using your favourite dependency manager. Before installing the tool, it's recommended to set up a clean environment to avoid dependency conflicts with cheminformatics libraries like rdkit.

Setting up a venv runtime

Python's built-in venv module is the simplest way to get started with virtual environments.

1. Create a Virtual Environment: Navigate to your project directory and run the following command. This creates a new directory (.venv) containing the Python interpreter and newly added libraries.

# For macOS / Linux
python3 -m venv .venv

# For Windows
py -m venv .venv

2. Activate the Environment: Before you can use it, you need to activate the environment.

# For macOS / Linux (bash/zsh)
source .venv/bin/activate

# For Windows (Command Prompt)
.venv\Scripts\activate.bat

# For Windows (PowerShell)
.venv\Scripts\Activate.ps1

You'll know the environment is active because the terminal prompt will change to show the environment name (e.g. (.venv) Computer-Name:~ $).

Setting up a conda runtime (Recommended)

If you use the Anaconda or Miniconda distribution, conda is your go-to tool for environment management. It's particularly powerful for managing complex cheminformatics packages.

1. Create a Conda Environment: This command creates a new environment named pendingai-env with a specific Python version.

conda create --name pendingai-env python=3.13

2. Activate the Environment: Before you can use it, you need to activate the environment.

conda activate pendingai-env

You'll know the environment is active because the terminal prompt will change to show the environment name (e.g. (pendingai-env) Computer-Name:~ $).

2. Installation Methods

Once your environment is active, you can install the pendingai tool. Here are some common methods.

pip

Using pip (Standard)

pip is Python's standard package installer and is included with most Python installations. It's perfect for installing tools as part of a specific project's dependencies regardless of runtime.

pip install pendingai

To install a specific version:

pip install pendingai==0.4.0

The tool is continually being improved, to upgrade an existing installed version:

pip install --upgrade pendingai

uv

poetry

pipx

3. Verifying Your Installation

Check the installation was successful by checking CLI is available in your terminal.

pendingai --help
pendingai --version

Authentication

We provide a simple authentication flow from the CLI that will automatically redirect you to our login page. Multiple commands are provided to help manage the access control when using the different Pending AI services.

pendingai auth login        # Login to the Pending AI platform
pendingai auth refresh      # Refresh an authenticated session

Installing the SDK

Pending AI currently supports a Python-based SDK available to install following the same steps as the CLI tool as both are bundled in the same package.

Verify your installation with a simple script that sets up an authenticated client and lists our Retrosynthesis engines that are available for use:

from pendingai import PendingAiClient

pai = PendingAiClient()        # Create the client
pai.authentication.login()     # Login to the platform

# Retrieve all retrosynthesis engines
for engine in pai.retrosynthesis.engines.list():
    print(f"Engine ID: {engine.id}")

Authentication

The SDK mimics the same authentication flow as the CLI tool but from a Python script. Cached active sessions can be used without any additional code after logging in from executing a script. To maintain the active session, it needs to be routinely refreshed, otherwise you will be redirect to login again.

from pendingai import PendingAiClient

pai = PendingAiClient()    
pai.authentication.login()     # Initially calling a script must login
pai.authentication.refresh()   # Repeated scripts can refresh a session

Troubleshooting

Have a specialised use case? Contact us at [email protected] for help with building custom pipelines.

Here are some common questions and how to resolve them.

Q: I installed a tool, but my terminal says command not found. What's wrong?

A: This issues generally means your shell can't find the tool you just installed. Here are a few troubleshooting steps to try:

• Is your virtual environment active? If you used pip, uv, or conda, your terminal prompt should have a prefix like (.venv) or (pendingai-env). If it doesn't, you just need to reactivate it. Scroll up to the activation commands for venv or conda.

• Does your project use a special runtime? Tools like uv and poetry have dependency resolvers that require an extra prefix before running a command, add uv run or poetry run to the start of your command.

• Did you just install pipx? After running pipx ensurepath, you often need to open a brand new terminal window for the changes to your system's PATH to be applied.

• A handy workaround: You can often run the tool directly as a Python module. For example, instead of running pendingai --version, you can type python -m pendingai --version. This can be a good temporary fix but a new Python environment is recommended.

Q: Why am I seeing a Permission denied error when I try to install something?

A: This usually means you're trying to install a package into a protected system-wide directory without the right permissions (like using pip without sudo).

The best solution is to avoid using sudo with pip. Doing so can cause issues with your operating system. Instead, stick to one of the methods as shown above:

• Install inside a venv or conda environment.

• Use pipx for global tools.

These methods install packages in your user's home directory.

Q: The installation failed because of a dependency conflict. What does that mean?

A: This happens when the tool you're installing needs a specific version of a package ( rdkit==2025.3.5), but another package has a conflicting requirement.

It is recommended to use a new virtual environment or project-level dependency manager such as poetry to resolve this.

• Fix your environment: Create a new, clean virtual environment using venv or conda and try installing the tool again. By isolating the tool and its dependencies, you give it a fresh start without any conflicting packages to worry about.

• Fix your project: Within your project you can lock your dependencies (e.g. poetry lock or uv lock) and update the required packages to be compatible (likely by using the latest Python version). These tools guide you on how to resolve the conflicting packages.

Q: The tool installed, but it's crashing with a SyntaxError or another unexpected error.

A: Our tool is under constant development and this may be the cause of new breaking changes. When invoking a command, a message is provided to upgrade your tool to the latest for out-of-date CLI usage.

• A quick fix: Upgrade the package to the latest version using your chosen dependency manager (e.g. pip install --upgrade pendingai).

• Raise a ticket: We are constantly improving our platform, let us know about this issue and how we could improve your journey using our solutions.

Next Steps

• See the different capabilities Pending AI offers to customers like Retrosynthesis or Generative AI

• Follow one of our Guides to jump-start integrating our services into your Drug Discovery pipelines.

• See our documentation for the CLI and SDK for more information.