Agentic
Like-for-like- Claude Mythos 5
- 87.0
- Claude Opus 4.8
- 80.3
- Weighted basis
- 3 vs 3 rows
- Reading
- Claude Mythos 5 leads
Claude Mythos 5 vs Claude Opus 4.8
Updated August 22, 2026. Public scores include evidence status and uncertainty. They are not guarantees for a specific workload.
Decision reading
Claude Mythos 5 has the higher public score, 82.95 versus 76.2, and the 90% score intervals do not overlap.
12 results are shared. Category rows based on different benchmark sets are marked directional and do not name a winner.
Which one for your work
Recommendations appear only when a shared evidence basis or an explicit operating constraint supports the call. Secondary and unsupported use cases stay disclosed below the initial list.
Coding work
Code generation, repair, and software-engineering tasks
Claude Mythos 5
Claude Mythos 5 leads on the same 2 weighted benchmark rows.
Confidence: limited
Agentic work
Tool use, computer use, and multi-step task completion
Claude Mythos 5
Claude Mythos 5 leads on the same 3 weighted benchmark rows.
Confidence: stronger
Chat turn cost
1K fresh input + 500 output tokens
Claude Opus 4.8
Claude Opus 4.8 has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.
Confidence: listed-rates
Show secondary and unsupported calls
Cache-heavy agent loop cost
200K cached + 20K fresh input + 10K output tokens
Claude Mythos 5
Claude Mythos 5 has the lower estimated token cost for this stated workload. Claude Opus 4.8 has no published cached-input rate, so cached tokens use its listed input rate.
Confidence: rate-fallback
Repository review cost
50K fresh input + 3K output tokens
Claude Opus 4.8
Claude Opus 4.8 has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.
Confidence: listed-rates
Long documents
Prompts that approach the documented context limit
No clear pick
The documented context windows are equal.
Confidence: documented
What is actually comparable
Shared results can support a head-to-head reading. Results present for only one model describe coverage, not superiority.
3 Claude Mythos 5 only
12 Shared
21 Claude Opus 4.8 only
- Shared results
- 12
- Claude Mythos 5 only
- 3
- Claude Opus 4.8 only
- 21
- Like-for-like categories
- 3 / 8
2 categories use different evidence sets. Those rows remain visible for coverage context but do not name a winner.
Category results, on a stated basis
Each row states whether both averages use the same weighted benchmark set. Directional and not-comparable rows remain visible, but they never receive a winner in this template.
Coding
Like-for-like- Claude Mythos 5
- 89.7
- Claude Opus 4.8
- 81.1
- Weighted basis
- 2 vs 2 rows
- Reading
- Claude Mythos 5 leads
Knowledge
Like-for-like- Claude Mythos 5
- 68.5
- Claude Opus 4.8
- 62.7
- Weighted basis
- 2 vs 2 rows
- Reading
- Claude Mythos 5 leads
Math
Directional only- Claude Mythos 5
- 97.6
- Claude Opus 4.8
- 53.9
- Weighted basis
- 1 vs 3 rows
- Reading
- Directional only
Multimodal
Directional only- Claude Mythos 5
- 93.5
- Claude Opus 4.8
- 77.0
- Weighted basis
- 1 vs 2 rows
- Reading
- Directional only
Reasoning
Not comparable- Claude Mythos 5
- Not measured
- Claude Opus 4.8
- 72.1
- Weighted basis
- 0 vs 1 rows
- Reading
- Not comparable
Multilingual
Not comparable- Claude Mythos 5
- Not measured
- Claude Opus 4.8
- Not measured
- Weighted basis
- 0 vs 0 rows
- Reading
- Not comparable
Instruction following
Not comparable- Claude Mythos 5
- Not measured
- Claude Opus 4.8
- Not measured
- Weighted basis
- 0 vs 0 rows
- Reading
- Not comparable
| Category | Claude Mythos 5 | Claude Opus 4.8 | Weighted basis | Reading |
|---|---|---|---|---|
| Agentic | 87.0 | 80.3 | Like-for-like3 vs 3 rows | Claude Mythos 5 leads |
| Coding | 89.7 | 81.1 | Like-for-like2 vs 2 rows | Claude Mythos 5 leads |
| Knowledge | 68.5 | 62.7 | Like-for-like2 vs 2 rows | Claude Mythos 5 leads |
| Math | 97.6 | 53.9 | Directional only1 vs 3 rows | Directional only |
| Multimodal | 93.5 | 77.0 | Directional only1 vs 2 rows | Directional only |
| Reasoning | Not measured | 72.1 | Not comparable0 vs 1 rows | Not comparable |
| Multilingual | Not measured | Not measured | Not comparable0 vs 0 rows | Not comparable |
| Instruction following | Not measured | Not measured | Not comparable0 vs 0 rows | Not comparable |
Shape of the matched evidence
Only shared public evidence is shown. Sparse evidence stays a ruled list rather than being closed into a radar shape.
Too few matched category axes support a radar. The ruled list below shows only shared benchmark results; positions use each benchmark’s normalized display scale when available.
Terminal-Bench 2.0
Agentic
Claude Mythos 5: 88%Claude Opus 4.8: 74.6%Normalized gap 13.4Claude Mythos 5 source Claude Opus 4.8 sourceSWE-bench Pro
Coding
Claude Mythos 5: 80.3%Claude Opus 4.8: 69.2%Normalized gap 11.1Claude Mythos 5 source Claude Opus 4.8 sourceSWE-bench Verified
Coding
Claude Mythos 5: 95.5%Claude Opus 4.8: 88.6%Normalized gap 6.9Claude Mythos 5 source Claude Opus 4.8 sourceHLE
Knowledge
Claude Mythos 5: 64.5%Claude Opus 4.8: 57.9%Normalized gap 6.6Claude Mythos 5 source Claude Opus 4.8 sourceBrowseComp
Agentic
Claude Mythos 5: 88%Claude Opus 4.8: 84.3%Normalized gap 3.7Claude Mythos 5 source Claude Opus 4.8 source
What each workload costs
Three fixed token mixes turn per-token rates into comparable decisions. Each scenario states context fit and whether cached input had to fall back to the published list-input rate.
Chat turn
1K fresh input + 500 output tokens
- Claude Mythos 5
- $0.035
- Fits in one request
- Claude Opus 4.8
- $0.0175
- Fits in one request
Claude Opus 4.8 has the lower modeled cost
Costs use the listed standard API rates.
Repository review
50K fresh input + 3K output tokens
- Claude Mythos 5
- $0.65
- Fits in one request
- Claude Opus 4.8
- $0.325
- Fits in one request
Claude Opus 4.8 has the lower modeled cost
Costs use the listed standard API rates.
Cache-heavy agent loop
200K cached + 20K fresh input + 10K output tokens
- Claude Mythos 5
- $0.9
- Fits in one request
- Claude Opus 4.8
- $1.35
- Fits in one request
- Cached input priced at the published list-input rate
Claude Mythos 5 has the lower modeled cost
Claude Opus 4.8 has no published cached-input rate, so cached tokens use its listed input rate.
Specification differences
Sourced differences are shown directly. Missing facts stay explicit instead of being inferred from a model name or family.
SpecificationClaude Mythos 5Claude Opus 4.8
Context window
Maximum documented context; output-token limits may be lower.
Claude Mythos 5
Claude Opus 4.8
API model ID
Claude Mythos 5
claude-mythos-5
Anthropic model overviewClaude Opus 4.8
claude-opus-4-8
Anthropic model overviewCached-input rate
A missing cached-input rate falls back to the listed input rate only in the stated workload estimate.
Claude Mythos 5
$1 per 1M cached input tokens
Claude API pricingClaude Opus 4.8
Not published
Documented inputs
Claude Mythos 5
text, image
Anthropic model overviewClaude Opus 4.8
text, image
Anthropic model overviewDocumented outputs
Claude Mythos 5
Claude Opus 4.8
Provider availability
Claude Mythos 5
Limited Access · Claude API
Anthropic model overviewClaude Opus 4.8
Generally Available · Claude API
Anthropic model overviewReasoning profile
Claude Mythos 5
Reasoning
Claude Opus 4.8
Reasoning
Weight access
Claude Mythos 5
Proprietary
Claude Opus 4.8
Proprietary
License
Claude Mythos 5
Proprietary
Claude Opus 4.8
Proprietary
Release date
Claude Mythos 5
2026-06-09
Claude Opus 4.8
2026-05-28
If you already use one of these models
- Deployment change
- Both entries list Anthropic as the provider. Confirm endpoint, model ID, limits, and feature support before switching.
- Quality signal
- Claude Mythos 5 has the higher public score, 82.95 versus 76.2, and the 90% score intervals do not overlap.
- Workload cost
- Repository review: $0.65 vs $0.325. Cache-heavy agent loop: $0.9 vs $1.35.
- Context tradeoff
- Both models list 1M.
Run the same representative tasks against both endpoints before changing production traffic.
Benchmark evidence
The full public result ledger is available for audit without forcing a wide desktop table onto a phone.
Browse raw public benchmark evidence36 rows
Agentic
Terminal-Bench 2.0
Claude Mythos 588%SourceClaude Opus 4.874.6%SourceClaude Mythos 5 leads this result
OSWorld-Verified
Claude Mythos 585%SourceClaude Opus 4.883.4%SourceClaude Mythos 5 leads this result
BrowseComp
Claude Mythos 588%SourceClaude Opus 4.884.3%SourceClaude Mythos 5 leads this result
CyberGym
Claude Mythos 583.8%SourceClaude Opus 4.8—Not directly comparable
Terminal-Bench 3.0
Claude Mythos 5—Claude Opus 4.821.1%SourceNot directly comparable
DeepSearchQA
Claude Mythos 5—Claude Opus 4.893.1%SourceNot directly comparable
Finance Agent v2
Claude Mythos 5—Claude Opus 4.853.9%SourceNot directly comparable
MCP Atlas
Claude Mythos 5—Claude Opus 4.882.2%SourceNot directly comparable
Toolathlon
Claude Mythos 5—Claude Opus 4.859.9%SourceNot directly comparable
Gert Labs
Claude Mythos 5—Claude Opus 4.872.97%SourceNot directly comparable
ResearchClawBench
Claude Mythos 5—Claude Opus 4.821.1%SourceNot directly comparable
OSWorld 2.0
Claude Mythos 5—Claude Opus 4.820.6%SourceNot directly comparable
Coding
SWE-bench Verified
Claude Mythos 595.5%SourceClaude Opus 4.888.6%SourceClaude Mythos 5 leads this result
SWE-bench Pro
Claude Mythos 580.3%SourceClaude Opus 4.869.2%SourceClaude Mythos 5 leads this result
Terminal-Bench 2.0
Claude Mythos 588.0%SourceClaude Opus 4.874.6%SourceClaude Mythos 5 leads this result
SWE Multilingual
Claude Mythos 5—Claude Opus 4.884.4%SourceNot directly comparable
SWE Multimodal
Claude Mythos 5—Claude Opus 4.838.4%SourceNot directly comparable
cursorBench31
Claude Mythos 5—Claude Opus 4.858.4%SourceNot directly comparable
cursorBench32
Claude Mythos 5—Claude Opus 4.862.3%SourceNot directly comparable
FrontierCode 1.1 Main
Claude Mythos 5—Claude Opus 4.846.5%SourceNot directly comparable
Reasoning
Knowledge
GPQA
Claude Mythos 594.1%SourceClaude Opus 4.893.6%SourceClaude Mythos 5 leads this result
HLE
Claude Mythos 564.5%SourceClaude Opus 4.857.9%SourceClaude Mythos 5 leads this result
HLE w/o tools
Claude Mythos 559%SourceClaude Opus 4.849.8%SourceClaude Mythos 5 leads this result
GPQA-D
Claude Mythos 5—Claude Opus 4.893.6%SourceNot directly comparable
Math
Multilingual
Multimodal
SWE-bench Multimodal
Claude Mythos 554.9%SourceClaude Opus 4.8—Not directly comparable
CharXiv
Claude Mythos 593.5%SourceClaude Opus 4.889.9%SourceClaude Mythos 5 leads this result
CharXiv w/o tools
Claude Mythos 588.9%SourceClaude Opus 4.880.5%SourceClaude Mythos 5 leads this result
OfficeQA Pro
Claude Mythos 5—Claude Opus 4.866.2%SourceNot directly comparable
ScreenSpot Pro
Claude Mythos 5—Claude Opus 4.887.9%SourceNot directly comparable
Frequently asked questions
Which is better, Claude Mythos 5 or Claude Opus 4.8?
Claude Mythos 5 has the higher public score, 82.95 versus 76.2, and the 90% score intervals do not overlap. That is the clearest overall quality signal in the current public data.
Which is better for coding, Claude Mythos 5 or Claude Opus 4.8?
Claude Mythos 5 leads the like-for-like coding comparison across 2 shared weighted benchmark rows.
Which is better for agentic tasks, Claude Mythos 5 or Claude Opus 4.8?
Claude Mythos 5 leads the like-for-like agentic tasks comparison across 3 shared weighted benchmark rows.
Which costs less, Claude Mythos 5 or Claude Opus 4.8?
For the stated presets, chat costs $0.035 on Claude Mythos 5 and $0.0175 on Claude Opus 4.8; repository review costs $0.65 and $0.325; the cache-heavy agent loop costs $0.9 and $1.35. Claude Opus 4.8 has no published cached-input rate, so cached tokens use its listed input rate.
Which has the larger context window, Claude Mythos 5 or Claude Opus 4.8?
Both models list the same context window, 1M.
Related comparisons
Last updated August 22, 2026
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