How to use Claude Opus 5.5 and Fable 5.1 with millions of free tokens

You can use powerful Anthropic models like Claude Opus 5.5 and Fable 5.1 without paying for a Claude Pro subscription. By connecting Claude Desktop to third-party gateways that offer generous free token allowances, you can learn, experiment, and even build full projects like games at zero cost.

This guide walks through the full setup: installing Claude Desktop, enabling developer mode, connecting it to external providers, and testing everything by building a complete pixel-style virtual pet browser game.

Why use free tokens with Claude Desktop?

Claude is excellent for coding, prototyping, and creative projects—but a paid plan can be a real barrier for students, beginners, and hobbyists. Third-party providers offer an alternative: they expose Anthropic models through their own APIs, often with large free token quotas.

By plugging these APIs into Claude Desktop’s developer mode, you can:

• Access multiple Claude variants (Opus, Sonnet, Fable, Muse) in one interface
• Experiment with real-world coding projects without worrying about immediate costs
• Learn how API-based AI workflows actually work in practice

If you’re especially interested in what game development looks like with large Claude budgets, you may also want to see what 7.8B Claude Opus 5.5 tokens can really build in game dev.

Step 1: Download and install Claude Desktop

1. Open the official Claude website.
Use your browser to search for the official Claude site and go to the download section.

2. Choose your platform.
Select the installer that matches your operating system (for example, Windows).

3. Run the installer.
Open the downloaded file and follow the setup steps until Claude Desktop finishes installing.

4. Launch Claude Desktop.
Once installed, open the app so you can enable developer features.

Step 2: Enable developer mode in Claude Desktop

To connect Claude Desktop to external gateways, you need to turn on developer mode.

1. Open the menu.
Click the menu button in the top-left corner of Claude Desktop.

2. Go to troubleshooting.
Navigate to Help → Troubleshooting.

3. Enable developer mode.
Find the option for Claude’s developer mode and click Enable developer mode. Confirm when prompted.

4. Restart Claude Desktop.
The app will restart. When it reopens, check the menu again to confirm that a Developer option is now visible. If you see it, developer mode is successfully enabled.

Step 3: Open third-party inference settings

Now you’ll connect Claude Desktop to an external gateway that provides free tokens.

1. Open the Developer menu.
Click Developer in the top-left menu.

2. Choose third-party inference.
Select Configure third party inference. This opens a panel where you can plug in another provider’s API.

3. Set the connection type.
Under Connection, keep it set to Gateway.

4. Choose credential kind.
Set Credential kind to Static API key. This means you’ll paste a single API key from the provider.

5. Set the authentication scheme.
Set Authentication scheme to Bearer.

Leave this window open—you’ll fill in the base URL and API key after you create them on the provider’s site.

Step 4: Connect Claude Desktop to Radox AI

Radox AI is one example of a gateway that exposes Anthropic models with a free token allowance.

Important: All limits, prices, and available models can change at any time. Always check the current details on the provider’s website before relying on free usage.

Create your Radox AI account and API key

1. Visit the Radox AI website.
Open the Radox AI platform in your browser.

2. Check the free token info.
According to the information shown at the time of recording, Radox AI offers approximately 500,000 free tokens. Treat this as a rough guideline, not a permanent guarantee.

3. Sign in.
Sign in using your Google account (or another supported method).

4. Go to the API keys section.
Once you’re on the dashboard, find and open the API keys area.

5. Create a new API key.
Click Create API key, give it a simple name (for example, claude-test), and generate the key. Copy the key immediately and keep it safe.

Add the Radox AI gateway details to Claude Desktop

Now switch back to Claude Desktop’s third-party inference settings.

1. Paste the API key.
In the Gateway API key field, paste the API key you just copied from Radox AI.

2. Copy the base URL from Radox AI.
On the Radox AI site, find the API base URL. Carefully copy the base URL, but do not include the trailing /v1 part if it’s shown. You want only the root gateway URL.

3. Paste the base URL.
Paste this value into the Gateway base URL field in Claude Desktop.

4. Confirm all settings.
Make sure you have:
• Connection: Gateway
• Credential kind: Static API key
• Gateway base URL: Correct API base URL (without /v1)
• Gateway API key: Your Radox AI key
• Authentication scheme: Bearer

5. Test the connection.
Click Test connection. If the indicator turns green, the connection is working. If it doesn’t work on the first try, click again a couple of times—sometimes it connects on a second attempt.

6. Apply changes.
Click Apply changes. Claude Desktop may restart once more; wait for it to relaunch.

Step 5: Confirm that external Claude models are available

After Claude Desktop restarts, open the model selector.

You should see a list of models provided through the gateway. In the example setup, the list included:

• Claude Opus 5.5
• Claude Opus 4.8
• Claude Opus 4.6
• Claude Muse
• Claude Fable 5.1
• Fable 5
• Sonnet

The exact names and versions you see might differ, because providers can update their offerings at any time.

To verify everything works:

• Select Claude Opus 5.5, send a simple message like “Hi”, and check that it responds.
• Switch to another model such as Fable 5 and send another short message to confirm it also replies correctly.

If both models respond normally, your gateway connection is set up correctly and you’re ready to build something real.

Step 6: Create a clean project folder

Before starting a coding project with Claude, it’s helpful to use a dedicated folder. This gives the assistant a clear workspace for your files.

You can either:

• Create a new folder on your computer and point Claude to it, or
• Let Claude create and manage the project structure directly from the chat, as long as you’re careful about where the files are saved.

Once your folder is ready, you can prompt Claude to build your project inside it.

Step 7: Prompt Claude to build a pixel virtual pet game

To test the setup, the example project is a small but complete browser game: a cute pixel-style virtual pet with status bars and interactions.

Here’s the kind of prompt you can use (you can paste or adapt this):

“Create a cute pixel style virtual pet game in this folder. Make it a complete polished interactive browser game with a retro 8-bit design. The player should be able to feed, play with, and let the pet sleep. Add status bars such as hunger, happiness, and energy. Make the pet animated and expressive. Add fun messages and a game over/art system. Use plain HTML, CSS, and JavaScript only. Do not use external images, APIs, frameworks, or a back end. Make it responsive, and make sure it runs when I open index.html in a browser. Use your creativity to design the interface and game details.”

Notice that the prompt:

• Describes the game at a high level
• Specifies core mechanics (feed, play, sleep)
• Defines the tech stack (plain HTML/CSS/JS, no external assets or frameworks)
• Requests responsiveness and polish without micromanaging every detail

This gives Claude enough freedom to design the UI and interactions creatively, while still keeping the requirements clear.

Step 8: Inspect and run the generated game

After you send the prompt, Claude will generate the project structure and files, typically including an index.html file plus accompanying CSS and JavaScript.

Once it’s done:

1. Open the main HTML file.
Locate index.html in your project folder and open it in your browser.

2. Explore the interface.
You should see:

• A pixel-style virtual pet character
• Status bars for hunger, happiness, and energy
• Buttons to feed, play, and let the pet sleep
• A retro, 8-bit-inspired layout and color scheme

3. Test the interactions.
Click each button and watch how the game responds:

• Feed: The hunger bar should change and the pet should react with a message or animation.
• Play: Happiness should increase and you should see a different reaction.
• Sleep: Energy should recover, with its own animation or message.

Behind the scenes, Claude wires these buttons to the game logic in JavaScript, updating the status bars and triggering messages or state changes.

4. Observe status changes over time.
The game logic can also change the pet’s stats as time passes, leading to different outcomes or even a “game over” state if you neglect the pet.

If you want improvements—better animations, balancing, UI tweaks—just ask Claude to refine or extend the game. It can update the existing files based on your feedback.

Step 9: Monitor your token usage on Radox AI

Once you’ve built and iterated on your project, it’s a good idea to check how many tokens you’ve used.

1. Go back to the Radox AI dashboard.
Open the dashboard in your browser and locate the usage or analytics section.

2. Review your stats.
In the example run, the dashboard showed:

• Approximately 169,000 tokens used
• 10 requests
• 3 active models
• Total cost: $0

That means a fully built and refined virtual pet game, plus all intermediate prompts, fit comfortably within the free allowance of around 500,000 tokens.

3. Plan your usage.
Your own consumption will vary based on:

• Which models you use (Opus is more expensive than smaller models)
• How long your prompts and responses are
• How many iterations and refinements you request

Keep an eye on your dashboard so you don’t get surprised if the free tier runs out.

Step 10: Try another provider with more free tokens

Radox AI isn’t the only option. Another example mentioned is CodeCraft API, which—according to its own information at the time—offers approximately 1 million free tokens per month.

Again, this is subject to change. Always verify:

• Current free token limits
• Any credit card requirements
• Supported models and rate limits
• Terms of service and usage rules

Connecting Claude Desktop to CodeCraft API

The setup process is almost identical to Radox AI:

1. Create a CodeCraft API account.
2. Generate an API key from your dashboard.
3. Copy the provider’s API base URL (again, usually without the trailing /v1 segment).
4. In Claude Desktop’s Configure third party inference panel, paste the base URL and API key.
5. Use Gateway as the connection, Static API key as the credential kind, and Bearer as the authentication scheme.
6. Test the connection and apply changes.

You can switch between providers as needed—for example, starting on one platform and moving to another when you hit token limits.

Rotating between free providers

There are multiple platforms that offer some amount of free or limited token usage for AI models. While the exact names and quotas will change over time, the basic strategy stays the same:

• Research providers that support Anthropic models and offer free tiers.
• Compare token limits, rate limits, and supported models.
• Use one provider until you approach your free quota, then consider switching.
• Always check the latest terms before relying on a platform for serious work.

For more ideas on what you can build with Claude’s creative models, especially Fable, you might like how Claude Fable 5.1 and Higsfield build faceless YouTube videos in one chat.

Key reminders and disclaimers

Before you dive in, keep these points in mind:

• Free tokens are not guaranteed forever. Providers can change or remove their free tiers, adjust limits, or alter pricing at any time.
• Model lists can change. You may not always see the exact same Claude versions (Opus, Sonnet, Fable, etc.) that others do.
• Monitor your usage. Dashboards usually show tokens used, requests made, and any associated cost. Check regularly.
• Respect provider policies. Make sure your projects comply with each platform’s terms of service and acceptable use rules.

What you can do next

With Claude Desktop connected to third-party gateways, you now have a powerful, low-cost environment for learning and experimentation. You can:

• Build more complex games, tools, or mini-apps using HTML, CSS, and JavaScript
• Use Opus for deep reasoning and architecture, then switch to smaller models for quick edits
• Practice prompt design and iterative development without burning through a paid plan

As long as you keep an eye on token usage and provider limits, this setup is a great way to explore what Claude’s higher-end models can do—starting with something as simple and fun as a retro virtual pet game.