SourcesOpus 4.6 SWE-bench Ceiling Analysissimonwillison.net·high signalAnalysis of Claude Opus 4.6 performance ceiling at 80.8% SWE-bench and what it means for the next generation of coding agents.SourceSource pagesimonwillison.net↳ Follow the threadShared entity / Stack layerCoding-agent benchmark reality check: Codex CLI (GPT-5.5) tops Terminal-Bench 2.1 at 83.4%, Devin's 'real' SWE-bench nearer 9–10%CodeSOTAStack layer / Threat patternArmadin details full sandbox escape in Anthropic's Claude Cowork; Anthropic disputes, silently patchesSiliconANGLEPolicy dependency / Stack layerAnthropic Restores Global Access to Fable 5 and Mythos 5, Launches Claude for Government BetaAnthropicStack layer / Threat patternNSA issues official MCP hardening guidance after Amazon Q auto-execution CVEs (CVSS 8.5) enable AWS credential theftWizStack layer / Update threadSimon Willison Flags Tencent's Hy3 — a 295B Apache-2.0 Open MoE That Rivals GLM-5.2 and DeepSeek-V4, Free on OpenRouter Until July 21simonwillison.netStack layer / Update threadJim Fan: NVIDIA Open-Sources ASPIRE, and 'the Training Output Changes From Model Weights to a Continuously Expanding Skill Library'BigGo FinanceStack layer / ContrastGodot Bans Almost All 'Vibe-Coded' and Autonomous-Agent Contributions to Protect Volunteer MaintainersThe RegisterStack layer / Update threadPerplexity Is Building 'Teammate,' a Long-Horizon Coding Agent to Rival Cursor and OpenAIBusiness Insider