"ThunderAI" Setup Guide - Claude API
The Claude API integration connects ThunderAI to Anthropic's Claude AI models.
Claude is known for producing careful, well-structured responses and handling long documents well — a great fit for reading and composing detailed emails.
| API key required | Yes |
| Free option | No [Pay-per-use billing] |
| Best for | Detailed analysis, long emails, structured writing |
Prerequisites
- An Anthropic account with API access
- A valid Claude API key
- Thunderbird with ThunderAI installed
Getting an API key
- Go to console.anthropic.com/settings/keys
- Click Create Key
- Give it a name and copy the key immediately, it will not be shown again
Setup
1. Open ThunderAI Options
In Thunderbird, click the ThunderAI menu and select Options, or go to
Tools → Add-ons and Themes → ThunderAI → Preferences.
2. Select the Claude API integration
In the Connection section, choose Claude API from the integration dropdown.
3. Enter your API key
Paste your Claude API key in the API Key field.
4. Grant the required permission
The Claude API requires ThunderAI to access the anthropic.com domain.
A button will appear on the options page to grant this permission — click it and confirm in the Thunderbird dialog.
This is an optional permission requested only when you select the Claude integration. It allows ThunderAI to communicate with Anthropic's API servers. ThunderAI does not collect any data.
5. Choose a model
Select a Claude model from the Model dropdown. Click the button to refresh the list.
6. Save and test
Click Save. Open any email, use the ThunderAI menu, and run a prompt to confirm the integration is working.
Tips
- Claude models handle large amounts of text well thanks to their extended context window, useful when processing long email threads.
- Claude tends to be thorough in its responses. If you prefer shorter outputs, add instructions like "Be concise" directly in your prompts or in a custom prompt template.
- Monitor your API usage and costs at console.anthropic.com.
Troubleshooting
"Authentication error" or "Invalid API key"
Check that the key was copied correctly. Regenerate a new key from the Anthropic console if needed.
CORS error or requests failing
Make sure you have granted the anthropic.com domain permission as described in step 4. Without it, ThunderAI cannot reach the Claude API.
"Credit balance too low" error
Add credits to your Anthropic account at console.anthropic.com/settings/billing.
No models appear in the dropdown
Verify your API key is saved and the domain permission has been granted. Try saving the options page and reopening it.