Claude Mythos 5.1 vs GPT-4o
At a Glance
| Compare | Claude Mythos 5.1Anthropic |  GPT-4oOpenAI |
|---|---|---|
| Pricing and Limits | ||
| Input priceFrom · USD / 1M tokens | $10.00Anthropic ↗ · Sep 2, 2026 | $1.25Openrouter ↗ · Sep 22, 2026 |
| Output priceFrom · USD / 1M tokens | $50.00Anthropic ↗ · Sep 2, 2026 | $5.00Openrouter ↗ · Sep 22, 2026 |
| Context windowMaximum documented tokens | 1,000K | 128K |
| Model facts checked | Sep 2, 2026View model evidence → | Aug 29, 2026View model evidence → |
Token prices are the lowest available sourced USD rates; input and output may use different providers. Cost ranking estimates output spend on LiveBench, not a full request bill. Ranking methodology →
Available Benchmarks
Side-by-Side Facts
| Field | Claude Mythos 5.1 | GPT-4o |
|---|---|---|
| Developer | Anthropic | OpenAI |
| Family | Claude 5 1 | Gpt 4o |
| Model | Claude Mythos 5.1 | GPT-4o |
| Version | Claude Mythos 5.1 | GPT-4o |
| Lifecycle | active | active |
| Released | 2026-09-01 | Unknown |
| Knowledge cutoff | 2026-06-01 | 2023-10-01 |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| Context window | 1,000K | 128K |
| Total parameters | Unknown | Unknown |
| Active parameters | Unknown | Unknown |
| License | Unknown | Unknown |
| Open weights | No | No |
| API available | Yes | Yes |
| Self-hostable | No | No |
| Provider access | Anthropic (Project Glasswing) | Openai (Standard), Openrouter (Standard) |
| Capabilities | chat, generation, reasoning, tools | chat, generation, tools |
Claude Mythos 5.1 Capabilities
GPT-4o Capabilities
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Primary Evidence
Sources and Freshness
Questions
Claude Mythos 5.1 vs GPT-4o FAQs
Is Claude Mythos 5.1 or GPT-4o better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both Claude Mythos 5.1 and GPT-4o, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, Claude Mythos 5.1 or GPT-4o?+
Claude Mythos 5.1 is $10.00 and GPT-4o is $1.25 per million tokens, so GPT-4o is cheaper on this metric. Claude Mythos 5.1 is $50.00 and GPT-4o is $5.00 per million tokens, so GPT-4o is cheaper on this metric.
Which has a larger context window, Claude Mythos 5.1 or GPT-4o?+
Claude Mythos 5.1 has the larger sourced context window. Claude Mythos 5.1 supports 1,000K and GPT-4o supports 128K.
Which performs better in benchmarks, Claude Mythos 5.1 or GPT-4o?+
There is no overall benchmark winner: At least two independently verified, protocol-matched benchmarks are required for an overall winner.
Can Claude Mythos 5.1 or GPT-4o be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. Claude Mythos 5.1 is not marked open weight; GPT-4o is not marked open weight.
Can Claude Mythos 5.1 and GPT-4o understand images?+
Claude Mythos 5.1 is documented with image input; GPT-4o is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, Claude Mythos 5.1 or GPT-4o?+
Claude Mythos 5.1 has the larger sourced maximum output: Claude Mythos 5.1 supports 128K and GPT-4o supports 16K output tokens.
Do Claude Mythos 5.1 and GPT-4o support reasoning and tool use?+
Claude Mythos 5.1: reasoning, tool calling, and image input. GPT-4o: tool calling and image input. Feature support does not establish relative quality.
Which is available from more inference providers, Claude Mythos 5.1 or GPT-4o?+
Claude Mythos 5.1 has 1 sourced provider route; GPT-4o has 2, so GPT-4o has broader tracked availability.
Which offers better value, Claude Mythos 5.1 or GPT-4o?+
There is no universal value winner. Compare the input and output prices above with the matched benchmark result for your workload: cheaper tokens can be offset by different quality, token usage, latency, or provider availability.