GPT-6 Astra vs Fable 5.2 is now a real choice for small IT teams: both are top-tier models, both sit in paid chat plans, and both have public API prices. On list price, Claude Fable 5.2 costs 20% less per token than GPT-6 Astra. On data handling, Astra is the easier fit for teams that need zero data retention.
Anthropic launched Fable 5.2 on November 9, which we covered in our joint Fable and Mythos 5.2 post and our Claude Fable 5.2 deep dive. OpenAI released GPT-6 Astra in September, and our post on what GPT-6 Astra actually shipped covers that launch. This post sets the two side by side for agencies, nonprofits and higher-ed IT. Every fact comes from the vendor’s own pages, and prices were read on November 10, 2026.
The short version: Fable 5.2 is cheaper per token, much cheaper on cached input, and has no long-prompt surcharge. Astra supports zero data retention for eligible API customers, while Fable 5.2 requires 30-day retention unless Anthropic approves an exception. Benchmarks favor Fable 5.2 on the three tests both vendors report, but those are vendor numbers. Test both on your own work before you commit.
Astra vs Fable 5.2: what each model is
OpenAI’s GPT-6 Astra announcement calls it "the world’s most intelligent and aligned model." OpenAI names computer use, coding, research and document work as its strengths. The OpenAI API changelog dates the API release to September 3, 2026.
Anthropic’s Fable product page calls Fable 5.2 its most capable model for technical work. Anthropic’s launch announcement says Fable 5.2 carries strong cyber and biology safeguards. Blocked cyber requests get an answer from Claude Opus 4.8, and blocked biology requests from Claude Opus 5.
Both vendors also sell a less restricted security version to vetted users. On OpenAI’s side that is GPT-6 Cyber. On Anthropic’s side it is Claude Mythos 5.2. This comparison covers only the general models.
Where you can use each one
In ChatGPT, OpenAI’s help article on GPT-6 and other models in ChatGPT splits access by plan:
- Plus: Astra in ChatGPT Work and Codex, not in Chat.
- Pro: Astra in Chat, Work and Codex. In Chat it appears as GPT-6 Pro, powered by Astra, with its own usage limits.
- Business and Enterprise: GPT-6 Pro, powered by Astra, subject to workspace permissions.
- Free and Go: no Astra.
OpenAI’s Enterprise and Edu models article says Astra is off by default at launch in eligible Enterprise and Edu workspaces. Workspace owners must turn it on for the workspace or for specific roles.
On the Claude side, the Fable page lists Pro, Max, Ultra, Team and Enterprise. Max, Ultra and Team premium seats include Fable in the plan. Pro and Team standard seats normally pay for Fable with usage credits, per Anthropic’s launch offers article. That article also gives Pro and Team standard seats Fable within their weekly limits through November 16. Our post on Fable usage limits explains the split.
For developers and cloud buyers:
| Where | GPT-6 Astra | Claude Fable 5.2 |
|---|---|---|
| Vendor API model ID | gpt-6-astra |
claude-fable-5-2 |
| Amazon | Amazon Bedrock (openai.gpt-6-astra) |
Amazon Bedrock and Claude Platform on AWS |
| Microsoft | Microsoft Azure, per the launch post | Microsoft Foundry |
| Google Cloud | Private preview | Anthropic managed and Google managed |
The Astra column comes from the GPT-6 Astra model page and the launch post. The Fable column comes from Anthropic’s API release notes for November 9.
Astra vs Fable 5.2 API prices
These are standard rates per million tokens, read on November 10, 2026. Astra figures come from OpenAI’s API pricing page and model page. Fable figures come from Anthropic’s pricing page.
| Per million tokens | GPT-6 Astra | Claude Fable 5.2 |
|---|---|---|
| Input | $10.00 | $8.00 |
| Output | $50.00 | $40.00 |
| Cached input (cache hit) | $1.00 | $0.20 |
| Cache writes | $12.50 (30 min), $25.00 (12 hours) | $10 (5 min), $16 (1 hour) |
| Batch | 50% of Standard ($5 / $25) | $4 / $20 |
| Fast mode | 2x Standard ($20 / $100) | $16 / $80 |
| Long prompts | Over 272K input tokens: 2x input and cache, 1.5x output, whole request | Full 1M window at standard rate |
| Regional or US-only processing | 10% uplift | 1.1x |
Fortune’s launch-day headline said the new models are priced 20% below GPT-6 Astra. Our math on the two vendor pages agrees: $8 against $10 on input and $40 against $50 on output are both 20% lower. The gap is wider on cached input, where Fable 5.2 costs 80% less.
Two worked examples at list price, before any token differences:
- A 50,000-token prompt with a 10,000-token answer: Astra costs $1.00 and Fable 5.2 costs $0.80.
- A 300,000-token prompt with a 20,000-token answer: Astra’s long-prompt rule applies, so it costs $7.50. Fable 5.2 costs $3.20.
Per-token prices are only half the story. The two models count text differently and spend different amounts of reasoning. Each vendor claims a cost edge on its own tests. OpenAI says Astra beat Fable 5.1 on Terminal-Bench 4.0 at about 63% lower estimated API cost per task. Anthropic says Fable 5.2 at high effort beats Astra’s best FrontierCode score at about the same cost. Our post on Fable 5.1 cost and cache hit rates shows why cost per task is the number to track.
Astra vs Fable 5.2 context windows and output limits
| Spec | GPT-6 Astra | Claude Fable 5.2 |
|---|---|---|
| Context window | 1,050,000 tokens | 1M tokens |
| Max output | 128,000 tokens | 128k tokens |
| Knowledge cutoff | April 30, 2026 | June 2026 (reliable) |
| Effort levels | low, medium, high, xhigh, max | low, medium, high, xhigh, max (API default high) |
The Astra figures are from its model page. The Fable figures are from Anthropic’s What’s new in Claude Fable 5.2 page. On paper the limits are close. The real difference is the price of using them, since Astra bills more once a prompt passes 272K tokens.
Astra vs Fable 5.2 tools: computer use, code and agents
OpenAI’s model page lists these tools for Astra in the Responses API: web search, file search, image generation, code interpreter, hosted shell, apply patch, skills, computer use, MCP and tool search. The changelog says tool calling on Astra requires the Responses API. It also added async tool calling and mid-turn steering, which we covered in async tool calling for agents.
Anthropic documents computer use on Fable 5.2 through the new computer_toolset_20260801 toolset. The older computer_20251124 tool now returns an error everywhere except Amazon Bedrock. The What’s new page also lists beta compaction on demand, mid-conversation tool changes and the advisor tool. It says forced tool use is not supported. Anthropic’s announcement says Fable 5.2 can act as an orchestrator for subagents, and it is available in Claude Code.
For agencies, the practical point is lock-in. Agent code written for one vendor’s tool format will not run on the other without changes.
Astra vs Fable 5.2 benchmarks both vendors report
We list a benchmark only if OpenAI and Anthropic both report it on their own pages. All numbers are vendor-reported. OpenAI’s page predates Fable 5.2, so it has no Fable 5.2 scores.
| Benchmark | Astra (OpenAI’s page) | Astra (Anthropic’s page) | Fable 5.2 (Anthropic’s page) |
|---|---|---|---|
| Terminal-Bench Science 0.1 | 64.6% | 68.1% | 74.6% |
| AutomationBench | 41.4% | 41.4% | 51.4% |
| Humanity’s Last Exam (with tools) | 57.2% | 57.2% | 74.2% |
Note the two Astra scores on Terminal-Bench Science. The vendors report different numbers for the same model on the same test. Settings and harnesses matter, as our post on Astra’s ARC-AGI-3 harness showed. Both pages also show OSWorld and FrontierCode, but on different versions, so we left them out.
Astra vs Fable 5.2 data use and retention defaults
On the API side, OpenAI’s data controls guide says API data is not used for training unless you opt in. Abuse monitoring logs are kept up to 30 days, and ZDR needs OpenAI’s approval. The Astra launch post says Astra supports ZDR for eligible API customers.
Anthropic’s API data retention page lists Fable 5.2 as a Covered Model with required 30-day retention. Anthropic’s announcement says Enterprise Frontier Safeguards, now in private beta, will make Fable models compatible with ZDR. Until then, eligible customers can use Fable 5.2 with ZDR.
For chat plans, OpenAI’s model training article says Free, Plus and Pro content may be used for training unless you opt out. Business, Enterprise and Edu are not used by default. Anthropic’s privacy article says commercial products, including the API, are not used for training by default. Claude Free, Pro and Max users control a "Help improve" setting in Privacy settings. That article does not mention Ultra.
Which to pick: GPT-6 Astra vs Fable 5.2 by job
This is guidance for the Astra vs Fable 5.2 choice, not a ranking. Run your own tests first.
- Large documents and long prompts: start with Fable 5.2. It has no surcharge past 272K tokens.
- Repeated prompts with heavy caching: Fable 5.2’s cache hit price is one fifth of Astra’s.
- Contracts that require zero data retention: Astra is the simpler path today. Fable 5.2 needs Anthropic’s approval.
- Staff on ChatGPT Plus: they already have Astra in Work and Codex at no extra cost.
- Staff on Claude Pro: Fable runs on usage credits after November 16. Max or Ultra includes it.
- Enterprise and Edu workspaces: Astra stays off until an owner turns it on. Decide who gets it first.
- Google Cloud shops: Fable 5.2 is on Google Cloud now. Astra is in private preview there.
- Everyday work: you may not need either. OpenAI sells GPT-6.1 Sol and Terra for less, and Anthropic recommends starting with Opus 5.5.
Our posts on GPT-6.1 Terra, which OpenAI model to use and Claude Opus 5.5 cover those cheaper options.
Frequently Asked Questions
Is Fable 5.2 cheaper than GPT-6 Astra?
Per token, yes. As of November 10, 2026, Fable 5.2 lists $8 input and $40 output per million tokens. GPT-6 Astra lists $10 and $50. Cost per task depends on how many tokens each model uses.
Is the “20% below GPT-6 Astra” claim accurate?
On standard list prices, yes. We checked both vendor pricing pages on November 10. Fable 5.2 is 20% lower on input and output and 80% lower on cached input.
Which has the bigger context window in Astra vs Fable 5.2?
Astra lists 1,050,000 tokens and Fable 5.2 lists 1M. Both allow 128k output tokens. Astra charges more once a prompt passes 272K input tokens.
Can I use GPT-6 Astra on ChatGPT Plus?
Yes, in ChatGPT Work and Codex. OpenAI’s help article says Plus does not include Astra in Chat.
Which Claude plans include Fable 5.2?
Anthropic lists Pro, Max, Ultra, Team and Enterprise. Max, Ultra and Team premium seats include Fable in the plan. Pro and Team standard seats normally use usage credits.
Does either model support zero data retention?
OpenAI says Astra supports ZDR for eligible API customers. Fable 5.2 requires 30-day retention unless Anthropic expressly authorizes ZDR.
Are the Astra vs Fable 5.2 benchmark results reliable?
They are vendor-reported. On Terminal-Bench Science, OpenAI reports 64.6% for Astra and Anthropic reports 68.1% for the same model. Treat them as a starting point.
Which cloud platforms offer each model?
Astra is on Amazon Bedrock and Microsoft Azure, with Google Cloud in private preview. Fable 5.2 is on Bedrock, Claude Platform on AWS, Google Cloud and Microsoft Foundry.
Do both models support computer use?
Yes. Astra supports computer use in the Responses API. Fable 5.2 uses Anthropic’s new computer use toolset, and the older tool version fails outside Bedrock.
