Real projects. Real answers.

Documentation

Everything you need to know about using Cairn AI effectively

Quick Start Guide

Get up and running with Cairn AI in just a few minutes. Follow these steps to start getting context-aware assistance for your coding projects.

1 Download Cairn

Visit the download page and get the Cairn AI application for your operating system. Install and launch the application.

2 Sign In with Google

Use the Google login option to securely authenticate with Cairn AI. This creates your Carin AI account.

3 Navigate to Subscriptions

Click on the "Subscriptions" tab in the main interface to access your billing and plan options.

4 Set Up Billing

Click the "Billing and Subscriptions" button to be redirected to our secure Stripe payment portal. Enter your payment information to enable LLM usage charges.

5 Return to Cairn

Once your payment method is configured, return to the Cairn AI application to complete your setup.

6 Choose Your Plan

Select either the Basic tier (free with 100% LLM surcharge) or Pro tier ($10/month with only 20% LLM surcharge) based on your expected usage.

7 Create Your First Project

Set up a new project by connecting it to your local directory or remote repository via SSH. This gives Cairn access to your codebase for context-aware assistance.

8 Create a Task

Within your project, create a focused task for the specific work you're doing. Tasks help organize conversations and maintain relevant context for better AI responses.

9 Start Coding with AI

Enter your task and begin asking questions! Cairn will provide context-aware responses based on your actual codebase, helping you debug, refactor, and build more effectively.

Project and Task Management

Multiple Project Support

Create and manage multiple coding projects

Local & Remote Directories

Connect to both local directories and remote code repositories via SSH

Real-time Code Monitoring

Local and remote directories are continuously monitored to ensure AI responses are based on your most up-to-date code

Directory and File Management

Selectively include or exclude directories from AI analysis to focus responses

Task Organization

Create separate tasks for different aspects of your project. Focused chats help produce great results.

LLM Integration

Multiple AI Models

Choose from the various LLM models provided by OpenAI, Anthropic, and Google

Model Selection Per Prompt

Use the best tool for the job. You get to select whichever model you want to use for every prompt. Mix and match!

Context-Aware Assistance

Context Library

Store project-specific notes, requirements, or specifications that will be included in every conversation. Your context snippets stored in the context library are simply added to the top of every chat in the project

Code-Aware Responses

Cairn understands your files and their relationships. This allows Cairn to provide the best possible context to your selected model, resulting in the best possible answer to your question

Conversation Management

Minimizable Messages

Collapse long messages by hitting the chat bubble's minimize button to keep the chat interface clean

Message Exclusion

Remove messages from the chat history without deleting them by clicking the chat bubble's 'X' button

Chat History

Conversation history is specific to each task

Data Security and Privacy

Automatic Data Cleanup

If a project has not been interacted with in 2 weeks, all code artifacts are deleted from the backend automatically.

Manual Data Deletion

To delete all code artifacts from the backend at any time, go to the Directories tab, uncheck all of your directories, then send a prompt to Cairn.

All data is encrypted in transit and while being stored

Modern security best practices are followed while handling your data

Privacy Commitment

Nothing about your project is ever looked at, shared, sold, or trained on. The only way in which your project is interacted with is when the Cairn's Context Selection Agent is looking at it in order to provide the best possible context to your selected LLM.

Subscription Tiers

Cairn AI offers two flexible pricing tiers designed to accommodate different usage patterns and budgets. Both tiers provide full access to all platform features, with the primary difference being the surcharge applied to your LLM usage costs.

How Pricing Works

Cairn AI uses a transparent pay-as-you-go model for LLM costs. When you interact with AI models through Cairn, you pay the base cost charged by the AI provider (OpenAI, Anthropic, Google) plus a surcharge that varies by tier. This ensures you only pay for what you actually use, with no hidden fees or unused quota waste.

Basic Tier - $0/month + 100% Surcharge on LLM Usage

Perfect for trying out Cairn AI or light usage scenarios

  • Full access to all Cairn AI features
  • All AI models available (GPT-4, Claude, Gemini, etc.)
  • Unlimited projects and tasks
  • Pay-as-you-go: 100% surcharge on LLM usage

Example Usage & Costs

Light Usage:

Base LLM cost ($5) + Surcharge ($5) + Monthly subscription ($0) = Total Monthly Cost ($10)

Best for:

  • Occasional coding assistance
  • Trying out Cairn AI
  • Small personal projects

Pro Tier - $10/month + 20% Surcharge on LLM Usage

Ideal for professional developers and teams with regular AI assistance needs

  • Full access to all Cairn AI features
  • All AI models available (GPT-4, Claude, Gemini, etc.)
  • Unlimited projects and tasks
  • Pay-as-you-go: Only 20% surcharge on LLM usage
  • Priority support

Example Usage & Costs

Heavy Usage:

Base LLM cost ($20) + Surcharge ($4) + Monthly subscription ($10) = Total Monthly Cost ($34)

Compare to Basic tier: $20 + $20 + $0 = $40/month

Savings Breakdown:

The Pro tier becomes cost-effective when your monthly LLM usage exceeds ~$12.50. At that point, the 80% surcharge reduction more than covers the $10 monthly fee.

Best for:

  • Professional developers
  • Development teams
  • Regular coding assistance needs
  • Commercial projects
  • Users who value priority support

Model Costs Vary

Different AI models have different base costs. For example, o3 is more expensive than 4o, while Claude and Gemini have their own pricing structures. Be aware of approximate model costs and of what model you are using, because expenses accrue quickly if you are always using the most expensive models.

No Minimum Usage

Both tiers have no minimum usage requirements. If you don't use Cairn in a given month, Basic tier users pay nothing, while Pro tier users only pay the $10 subscription fee.

Transparent Billing

As you use Cairn, you can always go to the billing page to see your current usage costs. No surprises, no hidden fees.

Easy Tier Switching

You can upgrade or downgrade between tiers at any time through your account settings. Changes take effect immediately for upgrades after you have paid a prorated subscription fee (if you upgrade halfway through your billing cycle, you will pay $5 instead of $10). Downgrades happen at the end of the billing cycle; you keep the 20% surcharge until the start of the next billing cycle, at which point you get moved to the 100% surcharge.