--- title: Testing Claude Mythos Preview For Code Security | daily.dev description: Tenable ran Claude Mythos Preview (Anthropic's frontier LLM) against their own code repositories for 30 days as part of Project Glasswing, building an agentic... canonical: https://daily.dev/posts/testing-claude-mythos-preview-for-code-security-edbkkwrhu twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Testing Claude Mythos Preview For Code Security | daily.dev og:description: Tenable ran Claude Mythos Preview (Anthropic's frontier LLM) against their own code repositories for 30 days as part of Project Glasswing, building an agentic... og:url: https://daily.dev/posts/testing-claude-mythos-preview-for-code-security-edbkkwrhu og:image: https://api.daily.dev/og/posts/edBKkWrhU.png og:image:alt: Testing Claude Mythos Preview For Code Security og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Testing Claude Mythos Preview For Code Security **[Tenable Blog](https://daily.dev/sources/tenable-blog)** · 14 min read · 0 upvotes · 0 comments ## Summary Tenable ran Claude Mythos Preview (Anthropic's frontier LLM) against their own code repositories for 30 days as part of Project Glasswing, building an agentic security harness around it. Key findings: the model can chain low-severity findings into proven, reproducible exploits — shifting code security from ranking suspicions to verifying real bugs. The harness (orchestration layer) is the durable asset, not the model itself. Costs were significant: ~$41,718 in compute for 71 runs across 37 repos, with cache writes dominating at 60% of spend. Three passes are recommended per service due to non-deterministic model behavior. Senior security expertise remains non-negotiable — the model multiplies expert productivity but cannot replace threat modeling judgment. Practical guidance covers harness design, triage gates (reachability, automatability, impact, crown jewels), and where not to start. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Claude Mythos Preview Exposes Hidden Code Flaws Fast](https://daily.dev/posts/claude-mythos-preview-exposes-hidden-code-flaws-fast-wdwyjdo3x) · IEEE Spectrum · 0 upvotes · 0 comments --- Tags: [#security](https://daily.dev/tags/security), [#claude](https://daily.dev/tags/claude), [#code-security](https://daily.dev/tags/code-security) [View this post on daily.dev](https://daily.dev/posts/testing-claude-mythos-preview-for-code-security-edbkkwrhu) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Testing Claude Mythos Preview For Code Security","url":"https://daily.dev/posts/testing-claude-mythos-preview-for-code-security-edbkkwrhu","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/testing-claude-mythos-preview-for-code-security-edbkkwrhu"},"datePublished":"2026-08-03T10:05:19.159Z","dateModified":"2026-08-06T12:03:38.321Z","description":"Tenable ran Claude Mythos Preview (Anthropic's frontier LLM) against their own code repositories for 30 days as part of Project Glasswing, building an agentic...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/aaf04eff7d34afdd1b08e0354842304a?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/aaf04eff7d34afdd1b08e0354842304a?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Tenable Blog","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Tenable Blog","logo":"https://media.daily.dev/image/upload/s--B6GAvw3H--/f_auto,q_auto/v1780213271/logos/tenable-blog?_a=BAMAMiWQ0","url":"https://daily.dev/sources/tenable-blog"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/testing-claude-mythos-preview-for-code-security-edbkkwrhu","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"security,claude,code-security","timeRequired":"PT14M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Tenable Blog","item":"https://daily.dev/sources/tenable-blog"},{"@type":"ListItem","position":3,"name":"Testing Claude Mythos Preview For Code Security"}]} ```