Claude Fable 5.2 vs GPT-6 Astra
GPT-6 Astra is the lower-priced of the two on Router One at base-tier rates (GPT-6 Astra: request input ≤ 272,000 tokens) — about 58% less on a 1M-input + 1M-output mix. Both carry a 1.05M context window. Claude Fable 5.2 answers on /v1/chat/completions and /v1/messages (Claude Code); GPT-6 Astra on /v1/chat/completions and /v1/responses (Codex CLI). Claude Fable 5.2 is in no plan and bills the wallet; GPT-6 Astra counts against the Flagship models allowance on Max and Ultra.
Claude Fable 5.2 and GPT-6 Astra compared on current per-token rates, context window, and capabilities — both callable through one OpenAI-compatible endpoint that logs each request it forwards.
Claude Fable 5.2 vs GPT-6 Astra: rates, context window, and capabilities
| Spec | Claude Fable 5.2 | GPT-6 Astra |
|---|---|---|
| Input / 1M tokens | $4.80 | $2.00 |
| Output / 1M tokens | $24.00 | $10.00 |
| Cached input / 1M tokens | $0.12 | $0.20 |
| Context window | 1.05M | 1.05M |
| Capabilities | Chat, Streaming, Tool calling, Vision | Chat, Streaming, Tool calling, Vision |
| Subscription plans | Not in any plan — wallet | Flagship models — Max, Ultra |
| Detail page | Claude Fable 5.2 | GPT-6 Astra |
GPT-6 Astra: request input ≤ 272,000 tokens: Input $2.00 / 1M tokens, Output $10.00 / 1M tokens, Cache write $2.50 / 1M tokens, Cached input $0.20 / 1M tokens; request input > 272,000 tokens: Input $4.00 / 1M tokens, Output $15.00 / 1M tokens, Cache write $5.00 / 1M tokens, Cached input $0.40 / 1M tokens. The total input tokens in each request select the tier; its rates apply to the whole request, not only tokens above the threshold.
What does 1M tokens cost on Claude Fable 5.2 vs GPT-6 Astra?
Base-tier rates: For a workload of 1M input plus 1M output tokens at current rates: Claude Fable 5.2 comes to $28.80, GPT-6 Astra comes to $12.00 — GPT-6 Astra is about 58% cheaper on this mix. Real workloads skew heavily toward input tokens, so weigh the input rate by your own ratio; the cached-input row above is the posted catalog rate for that model.
Switch between Claude Fable 5.2 and GPT-6 Astra
The API key and base URL stay the same, but this is not a one-string switch for every client or request. Router One serves Claude Fable 5.2 on /v1/messages and /v1/chat/completions and GPT-6 Astra on the OpenAI-format endpoints /v1/chat/completions and /v1/responses, so /v1/chat/completions is the one endpoint both share: Claude Code (/v1/messages) runs only the Claude side, Codex CLI (/v1/responses) only the GPT side, and Router One answers a model sent to an endpoint it does not serve with HTTP 400 invalid_request_error (code INVALID_REQUEST). Per Anthropic's Claude Fable 5.2 overview and what's new pages and its effort docs (checked 2026-11-12), Claude Fable 5.2 always thinks adaptively and its thinking cannot be turned off; effort is set with output_config.effort, from low, medium, high (the API default), xhigh and max; Anthropic says to omit temperature, top_p and top_k; and on Anthropic's own API disabled thinking, a manual thinking budget and forced tool use (tool_choice any or tool) each return a 400 error. Per OpenAI's GPT-6 Astra model page and GPT-6 guide (checked 2026-11-12), effort is set with reasoning.effort on the Responses API and reasoning_effort on Chat Completions; GPT-6 Astra accepts low, medium, high, xhigh and max but not none (OpenAI suggests low instead) and takes tool calls only on the Responses API; OpenAI says to remove temperature, top_p and top_logprobs; and its pages do not state a default effort for GPT-6 Astra. So code that sends tools has to change path as well as model, neither model has a none level, and a request written for both leaves out the sampling parameters named above. On a Max or Ultra plan the billing differs: as of the 2026-11-12 plan response, GPT-6 Astra counts against the Flagship models allowance, while Claude Fable 5.2, in no plan tier, bills the wallet per token.
curl https://api.router.one/v1/chat/completions \
-H "Authorization: Bearer sk-your-router-one-key" \
-H "Content-Type: application/json" \
-d '{"model": "anthropic/claude-fable-5.2", "messages": [{"role": "user", "content": "Hello"}]}'
# Same request, other model — change one string:
# "model": "openai/gpt-6-astra"FAQ
Is Claude Fable 5.2 cheaper than GPT-6 Astra?
Compared at base-tier rates (GPT-6 Astra: request input ≤ 272,000 tokens). Input: Claude Fable 5.2 $4.80 vs GPT-6 Astra $2.00 / 1M tokens; GPT-6 Astra has the lower rate. Output: Claude Fable 5.2 $24.00 vs GPT-6 Astra $10.00 / 1M tokens; GPT-6 Astra has the lower rate. Total cost depends on the workload's input, output and cache usage. GPT-6 Astra: request input ≤ 272,000 tokens: Input $2.00 / 1M tokens, Output $10.00 / 1M tokens, Cache write $2.50 / 1M tokens, Cached input $0.20 / 1M tokens; request input > 272,000 tokens: Input $4.00 / 1M tokens, Output $15.00 / 1M tokens, Cache write $5.00 / 1M tokens, Cached input $0.40 / 1M tokens. The total input tokens in each request select the tier; its rates apply to the whole request, not only tokens above the threshold. Rates change; the /models page is the live source of truth.
Is Claude Fable 5.2 or GPT-6 Astra included in a Router One subscription?
Claude Fable 5.2 is in no Router One plan, so every call bills the wallet per token. GPT-6 Astra counts against the Flagship models allowance on Max and Ultra: Max 150 and Ultra 450 requests per 30-day cycle, shared by every model in that tier. GPT-6 Astra requests above its long-context threshold count as more than one quota request. Requests beyond a plan's allowance bill the wallet per token.
Can I switch between Claude Fable 5.2 and GPT-6 Astra without changing code?
The API key and base URL stay the same, but this is not a one-string switch for every client or request. Router One serves Claude Fable 5.2 on /v1/messages and /v1/chat/completions and GPT-6 Astra on the OpenAI-format endpoints /v1/chat/completions and /v1/responses, so /v1/chat/completions is the one endpoint both share: Claude Code (/v1/messages) runs only the Claude side, Codex CLI (/v1/responses) only the GPT side, and Router One answers a model sent to an endpoint it does not serve with HTTP 400 invalid_request_error (code INVALID_REQUEST). Per Anthropic's Claude Fable 5.2 overview and what's new pages and its effort docs (checked 2026-11-12), Claude Fable 5.2 always thinks adaptively and its thinking cannot be turned off; effort is set with output_config.effort, from low, medium, high (the API default), xhigh and max; Anthropic says to omit temperature, top_p and top_k; and on Anthropic's own API disabled thinking, a manual thinking budget and forced tool use (tool_choice any or tool) each return a 400 error. Per OpenAI's GPT-6 Astra model page and GPT-6 guide (checked 2026-11-12), effort is set with reasoning.effort on the Responses API and reasoning_effort on Chat Completions; GPT-6 Astra accepts low, medium, high, xhigh and max but not none (OpenAI suggests low instead) and takes tool calls only on the Responses API; OpenAI says to remove temperature, top_p and top_logprobs; and its pages do not state a default effort for GPT-6 Astra. So code that sends tools has to change path as well as model, neither model has a none level, and a request written for both leaves out the sampling parameters named above. On a Max or Ultra plan the billing differs: as of the 2026-11-12 plan response, GPT-6 Astra counts against the Flagship models allowance, while Claude Fable 5.2, in no plan tier, bills the wallet per token.
Where do these numbers come from?
Specs and prices on this page render from the live Router One catalog — the same data as the /models page — and refresh with it. Pricing methodology is documented on /pricing-methodology. Rates on this page were read from the live catalog on 2026-11-13 (UTC) and refresh within the hour.