Claude Mythos 5 vs Seed 2.1 Pro
Seed 2.1 Pro comes out ahead, 50 to 36 on our weighted score, and it is the cheaper option too.
AnthropicClaude Mythos 5
36/100- ECI—
- Price$10.00 / $50.00
- Context1M
- Our pick
ByteDance SeedSeed 2.1 Pro
50/100- ECI—
- Price$0.891 / $4.45
- Context256K
Add a model
Make it a three-way comparison.
Seed 2.1 Pro is our pick
Seed 2.1 Pro is the better all-round choice, scoring 50/100 against Claude Mythos 5 (36). It leads on price. Claude Mythos 5 wins on context window. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
- CapabilityNot enough dataNo independent benchmark covers every model here yet
- Lowest priceSeed 2.1 ProSeed 2.1 Pro $1.78 · Claude Mythos 5 $20.00 per 1M tokens (3:1 blend)
- Longest contextClaude Mythos 5Claude Mythos 5 1,000,000 · Seed 2.1 Pro 256,000 tokens
- Widest inputsSame inputsClaude Mythos 5: Text, Images, PDFs · Seed 2.1 Pro: Text, Images, Video
- Self-hostingNo open weightsBoth are available only through APIs
| Measure | Weight | Claude Mythos 5 | Seed 2.1 Pro |
|---|---|---|---|
| Price | 50% | 0 | 38 |
| Inputs & features | 30% | 80 | 80 |
| Context window | 20% | 60 | 36 |
| Overall | 100% | 36/100 | 50/100 |
Left out because at least one model lacks the data: capability. The remaining weights were rescaled.
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Claude Mythos 5Anthropic | Seed 2.1 ProByteDance Seed |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | — | — |
| ECI rank | — | — |
| Price per million tokens | ||
| Input | $10.00 | $0.891 (best) |
| Output | $50.00 | $4.45 (best) |
| Cached input | — | $0.178 |
| Blended (3:1) | $20.00 | $1.78 (best) |
| Long-context rate | Same rate | Same rate |
| Price source | Median of 2 providers | Official Volcengine Ark API |
| Limits | ||
| Context window | 1,000,000 tokens (best) | 256,000 tokens |
| Max output | 128,000 tokens | 256,000 tokens (best) |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | Yes | Yes |
| PDFs | Yes | No |
| Audio | No | No |
| Video | No | Yes |
| Reasoning | Yes | Yesminimal · low · medium · high · xhigh · max |
| Tool calling | Yes | Yes |
| Structured output | Yes | Yes |
| Availability | ||
| Weights | Proprietary | Proprietary |
| API model ID | — | doubao-seed-2-1-pro-260628 |
| API providers | 2 | 2 |
| Released | Jun 9, 2026 | Jun 23, 2026 |
| Knowledge cutoff | Jan 31, 2026 | — |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Claude Mythos 5$200.00
- Seed 2.1 Pro$17.81
Which should you choose?
Which is better: Claude Mythos 5 or Seed 2.1 Pro?
Seed 2.1 Pro is the better all-round choice, scoring 50/100 against Claude Mythos 5 (36). It leads on price. Claude Mythos 5 wins on context window. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
Which is cheaper, Claude Mythos 5 or Seed 2.1 Pro?
Seed 2.1 Pro is cheaper at $0.891 input / $4.45 output per million tokens (official Volcengine Ark API price). Claude Mythos 5 costs $10.00 input / $50.00 output per million tokens (median across 2 API providers). At a typical mix of three input tokens to one output token, that is $1.78 per million tokens for Seed 2.1 Pro versus $20.00 for Claude Mythos 5 (11× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers both models yet. Claude Mythos 5 has not been scored yet and Seed 2.1 Pro has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Claude Mythos 5 and Seed 2.1 Pro yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Both support tool calling for agent workflows.
Which has the bigger context window?
Claude Mythos 5 has the largest context window at 1,000,000 tokens, against 256,000 for Seed 2.1 Pro. Maximum output per response: Claude Mythos 5 up to 128,000, Seed 2.1 Pro up to 256,000 tokens.
Which can read images, PDFs, audio or video?
Claude Mythos 5 accepts text, images and PDFs; Seed 2.1 Pro accepts text, images and video. They handle the same number of input types.
Are any of these open source?
No. Claude Mythos 5 and Seed 2.1 Pro are proprietary and only available through APIs and apps.
Which is newer?
Seed 2.1 Pro is the newest, released Jun 23, 2026. Claude Mythos 5 came out Jun 9, 2026. Knowledge cutoff: Claude Mythos 5 Jan 31, 2026.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.
