Configuration

Customize Fabric to match your workflow.

API Keys

Fabric supports multiple AI providers. Configure your API keys in Settings.

Adding API Keys

1. Open Settings (⌘ ,)
2. Navigate to API Keys
3. Enter your keys for each provider

Supported Providers

Provider	Models	Get API Key
Anthropic	Claude Opus 4.5, Sonnet 4.5, Haiku 4.5	console.anthropic.com
OpenAI	GPT-5 Pro, GPT-5.1, GPT-5.1 Codex, GPT-5 Nano	platform.openai.com
Google	Gemini 3.0 Pro, Gemini 2.5 Flash	aistudio.google.com
OpenRouter	All models	openrouter.ai

OpenRouter

OpenRouter provides access to many models through a single API key. Great for trying different models!

Appearance

Theme

Fabric follows your system theme by default, or you can choose:

• Light - Clean, bright interface
• Dark - Easy on the eyes
• System - Follows OS preference

Font Size

Adjust the chat and code font sizes in Settings > Appearance.

Advanced Settings

Context Window

Configure how much context to send to the AI:

# settings.json
{
  "maxContextTokens": 128000,
  "summarizeAfter": 50000
}

Custom System Prompts

Add custom instructions that apply to all chats:

1. Go to Settings > Advanced
2. Enter your system prompt
3. Save

Example:

You are a senior software engineer. Always:
- Consider edge cases
- Suggest tests
- Follow best practices

Configuration File

Fabric stores configuration in:

Platform	Location
macOS	~/Library/Application Support/Fabric/config.json
Windows	%APPDATA%\Fabric\config.json
Linux	~/.config/Fabric/config.json