Claude Mythos 5 vs Claude Mythos Preview
Wins 2 of 4 areas
Coding · Agents
Wins 2 of 4 areas
Reasoning · Images and charts
The two are evenly matched.Claude Mythos 5 is better at coding and agents; Claude Mythos Preview at reasoning and images and charts.
Scores updated · 16 tests both models report · How we compare
Where each one wins
Tests won in each of the four areas where both have results. Each piece is one test, so a longer bar means more evidence; grey means the two scored within a point of each other.
- CodingWriting and fixing software20Claude Mythos 52 of 3 tests · 1 tie
- AgentsCarrying out multi-step tasks on its own10Claude Mythos 51 of 1 test
- ReasoningHard problems that need careful thinking01Claude Mythos Preview1 of 1 test
- Images and chartsUnderstanding pictures, charts and video01Claude Mythos Preview1 of 1 test
Agents, reasoning and images and charts rest on a single test each.
What it costs
Prices per million tokens, roughly 750,000 words. The bars show the cost of a million tokens read plus a million written.
The biggest differences
The tests each model wins by the widest margin, up to three each. Scores are out of 100.
Where Claude Mythos 5 pulls ahead
- Completes tasks by operating a computer desktopOSWorld-Verified+5.4points ahead
- Long, multi-file coding tasks in real codebasesSWE-bench Pro+2.2points ahead
- Fixes real GitHub issues in Python projectsSWE-bench Verified+1.6points ahead
Where Claude Mythos Preview pulls ahead
- Very hard expert questions across many subjectsHumanity's Last Exam+6.9points ahead
- Reasoning about charts from research papersCharXiv (RQ)+4.3points ahead
Every test, side by side
All 16 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingClaude Mythos 5
- SWE-bench ProClaude Mythos 5 by 2.28077.8+2.2
- SWE-bench VerifiedClaude Mythos 5 by 1.695.593.9+1.6
- SWE-bench Multilingualtie86.687.3tie
ReasoningClaude Mythos Preview
- Humanity's Last ExamClaude Mythos Preview by 6.957.864.7+6.9
Images and chartsClaude Mythos Preview
- CharXiv (RQ)Claude Mythos Preview by 4.388.993.2+4.3
Other results10 tests, not counted
Tests outside the eight areas. They are not counted above: several are summary scores built from other tests, or the same test under another name.
- RiemannBenchClaude Mythos 5 by 125543+12
- GraphWalks BFS 256KClaude Mythos 5 by 5.491.185.7+5.4
- SWE-bench MultimodalClaude Mythos Preview by 4.954.159+4.9
- Legal Agent Benchmark, Full Public SetClaude Mythos 5 by 3.516.913.4+3.5
- HealthBenchClaude Mythos 5 by 1.662.761.1+1.6
- HealthBench ProfessionalClaude Mythos Preview by 1.463.364.7+1.4
- CharXiv Reasoning (With tools)Claude Mythos 5 by 193.592.5+1
- HLE (with tools)tie63.864.7tie
- BrowseComp (single-agent)tie8887.9tie
- GraphWalks — Parents task, 256K-token context subsettie10099.9tie
Questions people ask
Which is better, Claude Mythos 5 or Claude Mythos Preview?
Claude Mythos 5 and Claude Mythos Preview each win two of the four areas where both have results. Claude Mythos 5 wins coding and agents; Claude Mythos Preview wins reasoning and images and charts.
Which is better for coding?
Claude Mythos 5. It wins 2 of the 3 coding tests both models report; Claude Mythos Preview wins none, and 1 is a tie.
How do you compare the two?
We use the 16 benchmark tests both models have published scores on. The verdict counts the 6 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 10 are listed but not counted, because several are summary scores or repeat a test. Each score is the one shown on the model's own page.