Claude Mythos 5.1 vs Seed 2.1 Pro
Benchmark Performance
Available Benchmarks
Technical Differences
Side-by-Side Facts
| Field | Claude Mythos 5.1 | Seed 2.1 Pro |
|---|---|---|
| Developer | Anthropic | ByteDance Seed |
| Family | Claude 5 1 | Seed 2 1 |
| Model | Claude Mythos 5.1 | Seed 2.1 Pro |
| Version | Claude Mythos 5.1 | Seed 2.1 Pro |
| Lifecycle | active | active |
| Released | 2026-09-01 | 2026-06-23 |
| Knowledge cutoff | 2026-06-01 | Unknown |
| Input modalities | Text, Image | Text, Image, Video |
| Output modalities | Text | Text |
| Context window | 1,000,000 | Unknown |
| 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) | Unknown |
| Capabilities | chat, generation, reasoning, tools | agents, chat, computer-use, generation, reasoning, structured_outputs, tools |
12 comparable fields · 7 material differences · Pair passes the primary-source comparison gate
Claude Mythos 5.1 Capabilities
Seed 2.1 Pro Capabilities
Internal Comparison Graph
Related Comparisons
| A | Pair | B | Context |
|---|---|---|---|
Claude Mythos 5.1Anthropic | vs |  Kimi-K3Moonshot AI | cross-developer peersimage, text |
Claude Mythos 5.1Anthropic | vs |  Gemini 3.8 Flash CyberGoogle Deepmind | cross-developer peerstext |
Seed 2.1 ProByteDance Seed | vs | Seed 2.1 TurboByteDance Seed | family variantsimage, text, video |
Seed 2.0 ProByteDance Seed | vs | Seed 2.1 ProByteDance Seed | family variantsimage, text, video |
Seed 2.0 LiteByteDance Seed | vs | Seed 2.1 ProByteDance Seed | family variantsimage, text, video |
Seed 2.1 ProByteDance Seed | vs |  Qwen3.7 FlashQwen | cross-developer peersimage, text, video |
Seed 2.1 ProByteDance Seed | vs | Qwen3.7 MaxQwen | cross-developer peersimage, text, video |
Seed 2.1 ProByteDance Seed | vs | Qwen3.7-PlusQwen | cross-developer peersimage, text, video |
Seed 2.1 ProByteDance Seed | vs | Qwen3.8-FlashQwen | cross-developer peersimage, text, video |
Seed 1.8ByteDance Seed | vs | Seed 2.1 ProByteDance Seed | family variantsimage, text |
Claude Mythos 5.1Anthropic | vs | Qwen3.7 FlashQwen | cross-developer peersimage, text |
Claude Mythos 5.1Anthropic | vs | Qwen3.7 MaxQwen | cross-developer peersimage, text |
Primary Evidence
Sources and Freshness
Questions
Claude Mythos 5.1 vs Seed 2.1 Pro FAQs
Is Claude Mythos 5.1 or Seed 2.1 Pro better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both Claude Mythos 5.1 and Seed 2.1 Pro, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, Claude Mythos 5.1 or Seed 2.1 Pro?+
Only Claude Mythos 5.1 has a directly sourced input price: $10.00 per million tokens. Only Claude Mythos 5.1 has a directly sourced output price: $50.00 per million tokens.
Which has a larger context window, Claude Mythos 5.1 or Seed 2.1 Pro?+
Neither model has a larger sourced context window in this comparison. Claude Mythos 5.1 is 1,000,000 and Seed 2.1 Pro is —.
Which performs better in benchmarks, Claude Mythos 5.1 or Seed 2.1 Pro?+
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 Seed 2.1 Pro be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. Claude Mythos 5.1 is not marked open weight; Seed 2.1 Pro is not marked open weight.
Can Claude Mythos 5.1 and Seed 2.1 Pro understand images?+
Claude Mythos 5.1 is documented with image input; Seed 2.1 Pro is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, Claude Mythos 5.1 or Seed 2.1 Pro?+
Neither has a larger sourced maximum output. Claude Mythos 5.1 is 128,000 and Seed 2.1 Pro is —.
Do Claude Mythos 5.1 and Seed 2.1 Pro support reasoning and tool use?+
Claude Mythos 5.1: reasoning, tool calling, and image input. Seed 2.1 Pro: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, Claude Mythos 5.1 or Seed 2.1 Pro?+
Claude Mythos 5.1 has 1 sourced provider route; Seed 2.1 Pro has 0, so Claude Mythos 5.1 has broader tracked availability.
Which offers better value, Claude Mythos 5.1 or Seed 2.1 Pro?+
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.