Mercury 2.5 vs Claude Mythos 5 vs DeepSeek V4 Flash Vision Exp
DeepSeek V4 Flash Vision Exp comes out ahead, 65 to 55 and 33 on our weighted score, and it is the cheaper option too.
InceptionMercury 2.5
55/100- ECI—
- Price$0.20 / $0.75
- Context260K
AnthropicClaude Mythos 5
33/100- ECI—
- Price$10.00 / $50.00
- Context1M
- Our pick
DeepSeekDeepSeek V4 Flash Vision Exp
65/100- ECI—
- Price$0.216 / $0.647
- Context1M
DeepSeek V4 Flash Vision Exp is our pick
DeepSeek V4 Flash Vision Exp is the better all-round choice, scoring 65/100 against Mercury 2.5 (55) and Claude Mythos 5 (33). Claude Mythos 5 wins on inputs & features. 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 priceDeepSeek V4 Flash Vision ExpDeepSeek V4 Flash Vision Exp $0.323 · Mercury 2.5 $0.338 · Claude Mythos 5 $20.00 per 1M tokens (3:1 blend)
- Longest contextClaude Mythos 5 and DeepSeek V4 Flash Vision ExpClaude Mythos 5 1,000,000 · DeepSeek V4 Flash Vision Exp 1,000,000 · Mercury 2.5 260,000 tokens
- Widest inputsClaude Mythos 5Mercury 2.5: Text · Claude Mythos 5: Text, Images, PDFs · DeepSeek V4 Flash Vision Exp: Text, Images
- Self-hostingDeepSeek V4 Flash Vision ExpPublishes downloadable weights (MIT)
| Measure | Weight | Mercury 2.5 | Claude Mythos 5 | DeepSeek V4 Flash Vision Exp |
|---|---|---|---|---|
| Price | 50% | 69 | 0 | 70 |
| Inputs & features | 30% | 45 | 70 | 60 |
| Context window | 20% | 36 | 60 | 60 |
| Overall | 100% | 55/100 | 33/100 | 65/100 |
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 | Mercury 2.5Inception | Claude Mythos 5Anthropic | DeepSeek V4 Flash Vision ExpDeepSeek |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | — | — | — |
| ECI rank | — | — | — |
| Price per million tokens | |||
| Input | $0.20 (best) | $10.00 | $0.216 |
| Output | $0.75 | $50.00 | $0.647 (best) |
| Cached input | $0.02 | — | — |
| Blended (3:1) | $0.338 | $20.00 | $0.323 (best) |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Official Inception API | Median of 2 providers | Median of 14 providers |
| Limits | |||
| Context window | 260,000 tokens | 1,000,000 tokens (best) | 1,000,000 tokens (best) |
| Max output | 65,536 tokens | 128,000 tokens | 384,000 tokens (best) |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | No | Yes | Yes |
| PDFs | No | Yes | No |
| Audio | No | No | No |
| Video | No | No | No |
| Reasoning | Yeslow · medium · high | Yes | Yes |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | No | No |
| Availability | |||
| Weights | Proprietary | Proprietary | OpenMIT |
| API model ID | mercury-2.5 | — | — |
| API providers | 6 | 2 | 15 (best) |
| Released | Sep 8, 2026 | Jun 9, 2026 | Aug 21, 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.
- Mercury 2.5$3.50
- Claude Mythos 5$200.00
- DeepSeek V4 Flash Vision Exp$3.45
Which should you choose?
Which is better: Mercury 2.5, Claude Mythos 5 or DeepSeek V4 Flash Vision Exp?
DeepSeek V4 Flash Vision Exp is the better all-round choice, scoring 65/100 against Mercury 2.5 (55) and Claude Mythos 5 (33). Claude Mythos 5 wins on inputs & features. 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, Mercury 2.5, Claude Mythos 5 or DeepSeek V4 Flash Vision Exp?
DeepSeek V4 Flash Vision Exp is cheaper at $0.216 input / $0.647 output per million tokens (median across 14 API providers). Mercury 2.5 costs $0.20 input / $0.75 output per million tokens (official Inception 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 $0.323 per million tokens for DeepSeek V4 Flash Vision Exp versus $0.338 for Mercury 2.5 (1× as much) and $20.00 for Claude Mythos 5 (62× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers all three models yet. Mercury 2.5 has not been scored yet, Claude Mythos 5 has not been scored yet and DeepSeek V4 Flash Vision Exp has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Mercury 2.5, Claude Mythos 5 and DeepSeek V4 Flash Vision Exp yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. All three support tool calling for agent workflows.
Which has the bigger context window?
Claude Mythos 5 and DeepSeek V4 Flash Vision Exp have the largest context windows (1,000,000 and 1,000,000 tokens), against 260,000 for Mercury 2.5. Maximum output per response: Mercury 2.5 up to 65,536, Claude Mythos 5 up to 128,000, DeepSeek V4 Flash Vision Exp up to 384,000 tokens.
Which can read images, PDFs, audio or video?
Mercury 2.5 accepts text; Claude Mythos 5 accepts text, images and PDFs; DeepSeek V4 Flash Vision Exp accepts text and images. Claude Mythos 5 handles the widest range of inputs.
Are any of these open source?
DeepSeek V4 Flash Vision Exp publishes its weights (MIT) and can be self-hosted; Mercury 2.5 and Claude Mythos 5 is proprietary.
Which is newer?
Mercury 2.5 is the newest, released Sep 8, 2026. DeepSeek V4 Flash Vision Exp came out Aug 21, 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 Nov 2, 2026.
