Which is cheaper, Claude Mythos Preview or GPT OSS 20B?
As of August 20, 2026, GPT OSS 20B is 100% cheaper on blended LLM API pricing. GPT OSS 20B costs $0.05 per million input tokens and $0.20 per million output tokens ($0.25 blended 1M-in + 1M-out). Claude Mythos Preview costs $10.00 / $50.00 per million tokens ($60.00 blended). Sources: https://platform.claude.com/docs/en/about-claude/pricing and https://developers.openai.com/api/docs/pricing. The cheapest LLM for your app still depends on how many output tokens you generate.
How much does Claude Mythos Preview vs GPT OSS 20B cost per million tokens?
Claude Mythos Preview Claude API pricing from Anthropic is $10.00 input and $50.00 output per million tokens via Anthropic. GPT OSS 20B OpenAI API pricing is $0.05 input and $0.20 output per million tokens via OpenAI. Use those four numbers, not ChatGPT Plus or Claude Pro subscription prices, when you are comparing APIs.
Which is better for coding, Claude Mythos Preview or GPT OSS 20B?
Claude Mythos Preview has a published SWE-bench Verified score of 93.9%. GPT OSS 20B does not have that eval on this page yet.
What is the context window for Claude Mythos Preview vs GPT OSS 20B?
Claude Mythos Preview supports a 1M token context window, while GPT OSS 20B supports 131K tokens. Claude Mythos Preview offers a larger context window. Filling a larger window bills more input tokens, so the cheaper-per-million model can still cost more on long documents.
Which model performs better on benchmarks, Claude Mythos Preview or GPT OSS 20B?
Claude Mythos Preview leads on 2 of 2 shared benchmarks versus GPT OSS 20B's 0 wins. Check the comparison table for GPQA Diamond, SWE-bench, MMLU, HLE, and the other evals we track. Token price and benchmark score together are the usual LLM comparison, not either number alone.
Is Claude Mythos Preview or GPT OSS 20B better for production use?
Both Claude Mythos Preview and GPT OSS 20B are production API models. For cost-sensitive production traffic, GPT OSS 20B has better economics on the blended 1M-in + 1M-out scale. For maximum capability, weight the benchmark table for your domain. Many production stacks route cheap models for drafts and a frontier model for the hard turn, which is usually cheaper than sending everything to the expensive API.
Can I switch between Claude Mythos Preview and GPT OSS 20B in my app?
Yes. Call Claude Mythos Preview through Anthropic and GPT OSS 20B through OpenAI with separate API keys, or through a gateway that already wraps both. Keep prompts in tokens, not characters, when you estimate the invoice. AnotherWrapper templates can swap providers without rewriting auth and billing.
How accurate is this Claude Mythos Preview vs GPT OSS 20B pricing data?
List rates are the latest published Claude API pricing from Anthropic and OpenAI API pricing, quoted per million tokens. Official rate sheets: https://platform.claude.com/docs/en/about-claude/pricing and https://developers.openai.com/api/docs/pricing. Prompt caching, batch APIs, and committed-use discounts can change the invoice. Benchmark scores are from official publications and independent evals, updated as new numbers land.
What is the output token limit for Claude Mythos Preview and GPT OSS 20B?
Claude Mythos Preview supports up to an unspecified number of output tokens per request, while GPT OSS 20B supports up to 33K output tokens. Output tokens are usually the expensive half of API pricing, so a higher max output cap is a capability, not a discount.
Which model has better throughput, Claude Mythos Preview or GPT OSS 20B?
GPT OSS 20B has a measured throughput of approximately 1000 tokens/second. Throughput data for Claude Mythos Preview is not yet available. Throughput (tokens per second) and time-to-first-token are why two models with the same per-million-token price can still feel different in chat and agents.
How do I switch the models in this Claude Mythos Preview vs GPT OSS 20B comparison?
Use the model pickers at the top of this LLM comparison. Search any model in the index and the URL updates. Open Claude Mythos Preview or GPT OSS 20B from the sidebar for the single-model API pricing page, or go back to the LLM pricing table to sort by cheapest blended cost.
