Data as of October 20, 2026 · How the score is built
Claude Mythos 5
Decision readingClaude Mythos 5 is tracked, but not publicly ranked yet. The profile exposes 20 sourced benchmark rows and leaves unsupported fields blank until a published record exists.
Released Jun 9, 2026 — see all recent releases
Decision snapshot
Each value carries a field reference instead of floating alone. Markers compare this model with the current ranked and priced catalog; they are not absolute quality thresholds.
Capability
Unranked
field median 49.8Not eligible for a public rank
Price
$10input / $50 output
input median $0.72cached $1 · batch + cache $0.50 · blended $30
Speed
Not measured
field median 93.5 tok/sTime to first token not measured
Context
1Mtokens
field median 256,000Maximum output length is tracked separately
Strongest published evidence
Published rows are visible, but no category has enough eligible evidence for a comparative rank.
Validate before choosing
20 published rows leave some tracked benchmark slots empty. Independent runtime speed has not been measured.
Source-linked · 20 displayable benchmark rows
Category score record
Scores and ranks appear only where published evidence can be displayed. The table keeps the score, weight, cohort, and evidence state together.
| Category | Score | Rank | Percentile | Weight | Benchmarks | Evidence |
|---|---|---|---|---|---|---|
| AgenticRank Not rankedWeight 22%4 benchmarksVerified | 84.1 | 4 benchmarks | Verified | |||
| CodingRank Not rankedWeight 20%3 benchmarksVerified | 88.1 | 3 benchmarks | Verified | |||
| ReasoningWeight 17%0 benchmarksNot measured | Not measured | 0 benchmarks | Not measured | |||
| MultimodalRank Not rankedWeight 12%3 benchmarksVerified | 89.7 | 3 benchmarks | Verified | |||
| KnowledgeRank Not rankedWeight 12%3 benchmarksVerified | 92.4 | 3 benchmarks | Verified | |||
| MultilingualRank Not rankedWeight 7%1 benchmarkVerified | 92.7 | 1 benchmark | Verified | |||
| Inst. FollowingWeight 5%0 benchmarksNot measured | Not measured | 0 benchmarks | Not measured | |||
| MathRank Not rankedWeight 5%1 benchmarkVerified | 97.6 | 1 benchmark | Verified |
20 of 726 tracked benchmark slots have displayable evidence · bars run 0–100
Coverage detailsHow much of this is verified
Coverage is split by category so a strong number never hides a thin evidence base. Verified means the row is tied to a published source; provisional rows remain visible but separate.
- Agentic4/4 verified
- Coding3/3 verified
- ReasoningNot measured
- Multimodal3/3 verified
- Knowledge3/3 verified
- Multilingual1/1 verified
- Inst. FollowingNot measured
- Math1/1 verified
Benchmark ledger
Coding opens by default. The marker compares each value with the best source-verified result in the catalog; provisional leaders do not set the reference. Expand the remaining categories for every published row.
Coding3 rows
| Benchmark | Score | Versus best verified row | Gap | Weight | Evidence |
|---|---|---|---|---|---|
| SWE-bench Pro | Score80.3% | Versus best verified row Best verified: Claude Opus 5.5 · 89.9% | Gap9.6 behind | Weight26% ref. weight | |
| Terminal-Bench 2.1 | Score88.0% | Versus best verified row Best verified: SWE-2 · 92.8% | Gap4.8 behind | WeightScored in Agentic | |
| SWE-bench VerifiedSoftware Engineering Benchmark Verified | Score95.5% | Versus best verified row Best verified: Claude Opus 5 · 96% | Gap0.5 behind | WeightDisplay only |
Agentic4 rows
| Benchmark | Score | Versus best verified row | Gap | Weight | Evidence |
|---|---|---|---|---|---|
| Terminal-Bench 2.1 | Score88.0% | Versus best verified row Best verified: SWE-2 · 92.8% | Gap4.8 behind | Weight8% ref. weight | |
| BrowseComp | Score88% | Versus best verified row Best verified: Atria Dawn Preview · 92.5% | Gap4.5 behind | Weight8% ref. weight | |
| OSWorld-Verified | Score85% | Versus best verified row Best verified: Qwen3.8 Max · 86.1% | Gap1.1 behind | Weight7% ref. weight | |
| CyberGym | Score83.8% | Versus best verified row Best verified: MiMo-V2.6-Flash · 95.1% | Gap11.3 behind | WeightDisplay only |
Multimodal3 rows
| Benchmark | Score | Versus best verified row | Gap | Weight | Evidence |
|---|---|---|---|---|---|
| CharXivCharXiv Reasoning | Score93.5% | Versus best verified row Best verified: Qwen3.8 Max · 93.5% | GapBest verified | WeightWeighted 20% | |
| SWE-bench Multimodal | Score54.9% | Versus best verified row Best verified: Claude Mythos 5 · 54.9% | GapBest verified | WeightDisplay only | |
| CharXiv w/o toolsCharXiv Reasoning without tools | Score88.9% | Versus best verified row Best verified: Claude Mythos 5 · 88.9% | GapBest verified | WeightDisplay only |
Knowledge3 rows
| Benchmark | Score | Versus best verified row | Gap | Weight | Evidence |
|---|---|---|---|---|---|
| HLEHumanity's Last Exam | Score64.5% | Versus best verified row Best verified: Claude Fable 5.1 · 65% | Gap0.5 behind | Weight44% ref. weight | |
| HLE w/o toolsHumanity's Last Exam without tools | Score59% | Versus best verified row Best verified: Claude Opus 5.5 · 64.4% | Gap5.4 behind | Weight7% ref. weight | |
| GPQAGraduate-Level Google-Proof Q&A | Score94.1% | Versus best verified row Best verified: GPT-6 Astra · 96% | Gap1.9 behind | Weight3% ref. weight |
Multilingual1 row
| Benchmark | Score | Versus best verified row | Gap | Weight | Evidence |
|---|---|---|---|---|---|
| SWE MultilingualSWE-bench Multilingual | Score92.2% | Versus best verified row Best verified: Claude Mythos 5 · 92.2% | GapBest verified | WeightDisplay only |
Math1 row
| Benchmark | Score | Versus best verified row | Gap | Weight | Evidence |
|---|---|---|---|---|---|
| USAMO 2026United States of America Mathematical Olympiad 2026 | Score97.6% | Versus best verified row Best verified: Claude Mythos 5 · 97.6% | GapBest verified | WeightWeighted 10% |
External signals5 rows
| Benchmark | Score | Versus best verified row | Gap | Weight | Evidence |
|---|---|---|---|---|---|
| ExploitBenchExploitBench v8-bench | Score78% | Versus best verified row Best verified: GPT-6 Astra · 100% | Gap22 behind | WeightDisplay only | |
| Firefox 147 exploitsFirefox 147 Working Exploit Rate | Score88.4% | Versus best verified row Best verified: Claude Mythos 5 · 88.4% | GapBest verified | WeightDisplay only | |
| Anthropic OSS-Fuzz crashAnthropic OSS-Fuzz Any-Crash Rate | Score80.0% | Versus best verified row Best verified: Claude Mythos 5 · 80.0% | GapBest verified | WeightDisplay only | |
| Anthropic OSS-Fuzz write primitiveAnthropic OSS-Fuzz Write-Primitive-or-Higher Rate | Score32.4% | Versus best verified row Best verified: Claude Mythos 5 · 32.4% | GapBest verified | WeightDisplay only | |
| The Last Ones completionThe Last Ones Cyber Range Completion Rate | Score60% | Versus best verified row Best verified: GPT-5.6 Sol · 70% | Gap10 behind | WeightDisplay only |
Bars run 0–100; the dark tick marks the best source-verified value
All 20 rowsLineage
The sequence follows explicit supersedes links. Each score is estimated for that model; a relative can inform a sparse estimate but never sets a floor, so a newer release can score below an earlier one. Scores and prices remain blank when the corresponding public row or first-party rate is unavailable.
Spec sheet
Each documented value carries its source. Missing fields stay visible as not sourced or not published, rather than disappearing from the page.
- API model ID
- claude-mythos-5Anthropic model overview
- Context window
- 1MAnthropic model overview
- Maximum output
- Not sourced yet
- Knowledge cutoff
- Not sourced yet
- Input modalities
- text, imageAnthropic model overview
- Output modalities
- textAnthropic model overview
- Parameters
- Not disclosed by the provider
- Availability
- Claude APIAnthropic model overview
- Cloud regions
- Not tracked yet
- Lifecycle
- limited accessAnthropic model overview
- API capabilities
- Tool calling, structured outputs, and batch support are not tracked yet
- Prompt caching
- Published at $1 per million cached input tokensClaude API pricing
- Self-host
- Weights are not published
- Rate limits
- Not tracked yet
How to read this profile
The visual layer above carries the decisions. These notes preserve the model, ranking, coverage, and family context behind the numbers.
We track Claude Mythos 5, but the public leaderboard excludes this profile until enough non-generated benchmark coverage is available. Only published rows appear above.
Claude Mythos 5 is a proprietary model with a 1M context window. It uses an explicit reasoning mode, which can improve complex problem solving while adding latency and token use.
Claude Mythos 5 is restricted to Glasswing partners and trusted-access programs. Claude Fable 5 is the same underlying model made generally available with additional safeguards for cybersecurity, biology, chemistry, distillation, and frontier-AI-development requests.
Updated from Anthropic's June 9, 2026 Claude Fable 5 and Claude Mythos 5 launch pages and system card. BenchLM maps exact Mythos 5 rows, including the system card's safeguards-off cybersecurity evaluations. Anthropic says Fable 5 and Mythos 5 are the same underlying model, but the published cyber results are for Mythos 5 with safeguards off and do not describe Fable 5 behavior. Mythos is a restricted-access profile, so BenchLM keeps it on model and comparison pages and in the cybersecurity comparison while excluding it from general ranking tables.
Claude Mythos 5 sits in the Claude Mythos family with Claude Mythos 5.1, Claude Mythos Preview. 20 of 726 tracked benchmark slots currently have displayable evidence. Missing categories stay blank.
Last updated October 20, 2026. Runtime fields remain blank until a sourced snapshot exists.
Questions
How does Claude Mythos 5 perform overall in AI benchmarks?
Claude Mythos 5 has 20 source-displayable benchmark rows, but it does not qualify for a public overall rank. The available rows remain visible by category without being converted into a site-wide score. Missing evidence stays blank instead of being estimated from an earlier model.
Is Claude Mythos 5 good for knowledge and understanding?
Claude Mythos 5 has source-displayable benchmark coverage for knowledge and understanding, but the public category table does not assign it a rank there. The individual rows remain available for inspection. A missing category position means the evidence threshold was not met; it does not convert the model's unmeasured work into a zero.
Is Claude Mythos 5 good for coding and programming?
Claude Mythos 5 has source-displayable benchmark coverage for coding and programming, but the public category table does not assign it a rank there. The individual rows remain available for inspection. A missing category position means the evidence threshold was not met; it does not convert the model's unmeasured work into a zero.
Is Claude Mythos 5 good for mathematics?
Claude Mythos 5 has source-displayable benchmark coverage for mathematics, but the public category table does not assign it a rank there. The individual rows remain available for inspection. A missing category position means the evidence threshold was not met; it does not convert the model's unmeasured work into a zero.
Is Claude Mythos 5 good for agentic tool use and computer tasks?
Claude Mythos 5 has source-displayable benchmark coverage for agentic tool use and computer tasks, but the public category table does not assign it a rank there. The individual rows remain available for inspection. A missing category position means the evidence threshold was not met; it does not convert the model's unmeasured work into a zero.
Is Claude Mythos 5 good for multimodal and grounded tasks?
Claude Mythos 5 has source-displayable benchmark coverage for multimodal and grounded tasks, but the public category table does not assign it a rank there. The individual rows remain available for inspection. A missing category position means the evidence threshold was not met; it does not convert the model's unmeasured work into a zero.
Is Claude Mythos 5 good for multilingual tasks?
Claude Mythos 5 has source-displayable benchmark coverage for multilingual tasks, but the public category table does not assign it a rank there. The individual rows remain available for inspection. A missing category position means the evidence threshold was not met; it does not convert the model's unmeasured work into a zero.
Which sibling models are related to Claude Mythos 5?
Claude Mythos 5 belongs to the Claude Mythos family. Related tracked variants include Claude Mythos 5.1, Claude Mythos Preview. A sibling link indicates shared lineage or a documented configuration relationship; it does not mean the variants have identical pricing, context limits, benchmark evidence, or deployment behavior. Compare before switching.
Does Claude Mythos 5 have full benchmark coverage on BenchLM?
No. Claude Mythos 5 currently has 20 source-displayable rows. The profile exposes published, non-generated evidence and leaves missing categories blank until an exact evaluation is available. Coverage describes how much was measured; it is not a penalty added to an individual benchmark result.
What is the context window size of Claude Mythos 5?
Claude Mythos 5 has a documented context window of 1M. That figure is the maximum combined prompt and retained-conversation space reported for this exact model; it is not the maximum output length. The profile keeps output limits separate because providers often publish those limits independently.