Head-to-head comparison across 1benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
Claude Mythos 5
99
Composer 2.5
81
Verified leaderboard positions: Claude Mythos 5 #1 · Composer 2.5 unranked
Pick Claude Mythos 5 if you want the stronger benchmark profile. Composer 2.5 only becomes the better choice if you want the cheaper token bill.
Agentic
+17.7 difference
Claude Mythos 5
Composer 2.5
$10 / $50
$0.5 / $2.5
N/A
N/A
N/A
N/A
1M+
200K
Pick Claude Mythos 5 if you want the stronger benchmark profile. Composer 2.5 only becomes the better choice if you want the cheaper token bill.
Claude Mythos 5 is clearly ahead on the provisional aggregate, 99 to 81. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Claude Mythos 5's sharpest advantage is in agentic, where it averages 87 against 69.3. The single biggest benchmark swing on the page is Terminal-Bench 2.0, 88% to 69.3%.
Claude Mythos 5 is also the more expensive model on tokens at $10.00 input / $50.00 output per 1M tokens, versus $0.50 input / $2.50 output per 1M tokens for Composer 2.5. That is roughly 20.0x on output cost alone. Claude Mythos 5 gives you the larger context window at 1M+, compared with 200K for Composer 2.5.
Claude Mythos 5 is ahead on BenchLM's provisional leaderboard, 99 to 81. The biggest single separator in this matchup is Terminal-Bench 2.0, where the scores are 88% and 69.3%.
Claude Mythos 5 has the edge for agentic tasks in this comparison, averaging 87 versus 69.3. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
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