docs: add anthropic api key setup tutorial

packages/docs/docs.json

@@ -40,6 +40,7 @@
           {
             "group": "Tutorials",
             "pages": [
+              "how-to-get-an-anthropic-api-key",
               "how-to-connect-a-custom-provider",
               "importing-a-skill"
             ]

packages/docs/how-to-get-an-anthropic-api-key.mdx

@@ -0,0 +1,51 @@
+---
+title: "How to get an Anthropic API key"
+description: "Create an Anthropic API key and use it in OpenWork"
+---
+
+Anthopic has disabled 3rd party authentication for their OAuth. In order to continue supporting Anthropic based models in OpenWork, we now default to manual API key entry for Anthropic. 
+That means you create the key in Anthropic first, then paste it into OpenWork.
+
+## Before you start
+
+- You need an Anthropic account at [platform.claude.com](https://platform.claude.com).
+- Your Claude subscription and your Anthropic API billing are not always the same thing, so make sure API access is enabled on your Anthropic account.
+- Treat the key like a password. Anthropic will only show the full value when you create it.
+
+## Create the key in Anthropic
+
+1. Sign in at [platform.claude.com](https://platform.claude.com).
+2. Open the `API Keys` page.
+
+<Frame>
+  ![Anthropic API Keys page](/images/anthropic-key.png)
+</Frame>
+
+3. Click `Create Key`.
+4. Give the key a recognizable name like `OpenWork`.
+
+<Frame>
+  ![Anthropic Create Key dialog](/images/anthropic-openwork-key.png)
+</Frame>
+
+5. Copy the new key right away. It should look like `sk-ant-...`.
+
+## Add the key to OpenWork
+
+
+1. Open `Settings` in OpenWork.
+2. Go to `Connect Provider` and choose `Anthropic`.
+3. Paste the API key into the manual key field.
+4. Save the provider, then choose an Anthropic model in chat.
+
+<Frame>
+  ![How to add a new provider in OpenWork](/images/openwork-providers.png)
+</Frame>
+
+## Common issues
+
+- If the key is rejected, make sure you copied the full value without extra spaces.
+- If you cannot see `API Keys`, check that your Anthropic account has API access and billing set up.
+- If you lose the key, create a new one in Anthropic and update OpenWork with the new value.
+
+The same general process applies to most providers that use manual API keys: create the key in the provider's developer console, copy it once, and paste it into OpenWork.