How to write source-backed WordPress drafts with Claude

By Luis Rita · 16 October 2026

AI Blog Writer with Sources is a free WordPress plugin that turns a brief and the pages you trust into a cited draft, on your own AI key. This tutorial sets it up with Anthropic’s Claude models: getting a key, adding it to WordPress, choosing a model, and writing a first draft. It takes about ten minutes.

1. Get an API key

You need a Anthropic API key, from the Claude Console:

1. Sign in to the Claude Console, Anthropic’s developer platform. A Claude.ai subscription (Pro or Max) is a separate product and does not include API usage.
2. Buy prepaid credits under Billing. The API doesn’t work with a zero balance.
3. Open API keys, create a key in your workspace, and copy it. It starts with sk-ant- and is shown only once.
4. Optionally, set a spending limit for the workspace.

Treat the key like a password: anyone who has it can spend your credits.

2. Add the key to WordPress

1. Install and activate AI Blog Writer with Sources from Plugins → Add New Plugin.
2. Open AI Blog Writer → Settings, choose Anthropic as the AI provider, and click Save Changes.
3. Paste the key into the API key field and save again. It is encrypted before it is stored, and never shown again or sent to the browser.
4. Click Test connection. This sends only the key and a request for the list of models, no content.

To keep the key out of the database, define it in wp-config.php instead:

define( 'AIBCG_ANTHROPIC_API_KEY', 'your-key' );

3. Choose a model

Pick the model under Default model in Settings. The plugin offers:

Start with Claude Sonnet 5, the default: it balances writing quality and cost, and follows a writer profile’s voice closely. Claude Sonnet 5.5 is the newer model at the same price; we haven’t evaluated it with the plugin’s prompts yet. Choose Claude Haiku 5.5 for the lowest cost on shorter or simpler articles, and Claude Opus 5.5 when a topic needs the most careful reasoning, at about twice Sonnet’s price. Which models you can use also depends on your Anthropic account.

4. Write your first draft

1. Open AI Blog Writer → New article and give it a topic.
2. Paste three to five pages you would cite yourself under Source URLs.
3. Choose Guided to review the sources and the outline before anything is written.
4. Create the draft, then open it in the block editor. Each claim cites the source it came from.

The getting started guide walks through the brief in detail.

Costs and limits

Anthropic bills your account for every request: the outline, the draft, and tools such as section rewrites. The plugin records the usage of each job and estimates its cost from the model’s list price, and Usage and cost shows the month’s estimate for the site. Set a monthly cost ceiling in Settings, and a spending limit with Anthropic, so neither can surprise you; Anthropic’s invoice is the final figure. See usage and cost ceilings.

Data and privacy

When a job runs, the plugin sends Anthropic the brief, the writer profile, and the notes extracted from your selected sources. It never sends WordPress credentials, other database content, or visitor data. Anthropic states that it does not use data sent through its commercial API to train its models by default. See Anthropic’s commercial terms and privacy policy. The full list of what is sent is in Privacy and external services.

If something goes wrong

• The key is rejected (provider_http_401): create a new key and save it again.
• Rate limit or quota (provider_http_429): check your balance and limits with Anthropic.
• “Selected model is unavailable”: choose another model, save, and test again.

More fixes are on the troubleshooting page.