“Anthropic withheld Claude Mythos Preview in April 2026 for having too high a blast radius and reports that model-layer defenses are strong but imperfect—Claude Opus 4.7 holds prompt-injection attack success to about 0.1% on single attempts and roughly 5–6% after 100 adaptive attempts—so overlapping defenses across environment, model, and external content are required.”

#2 📝 Anthropic Engineering How we contain Claude across products - Anthropic deploys three agentic products—claude.ai, Claude Code, and Claude Cowork—using two containment strategies: human-in-the-loop approvals (users approved roughly 93% of permission prompts) and environmental containment (sandboxes, VMs, filesystem and egress controls); Claude Code’s auto mode automates safer approvals and catches roughly 83% of overeager behaviors before they execute. Anthropic withheld Claude Mythos Preview in April 2026 for having too high a blast radius and reports that model-layer defenses are strong but imperfect—Claude Opus 4.7 holds prompt-injection attack success to about 0.1% on single attempts and roughly 5–6% after 100 adaptive attempts—so overlapping defenses across environment, model, and external content are required.

“Layered defenses—environmental sandboxes/VMs/egress controls, model-layer system prompts/classifiers/training, and limiting external content—are used across claude.ai, Claude Code, and Cowork; telemetry shows users approved roughly 93% of permission prompts, Claude Code auto mode blocks about 83% of overeager behaviors before execution, Claude Opus 4.7 holds prompt-injection success to ~0.1% on single attempts (~5–6% after 100 adaptive attempts), and Claude Mythos Preview was judged too high-risk to ship in April 2026.”

The model is cited as part of Anthropic's security and robustness evaluation. It is used to quantify how well the system handles prompt injection attempts.

“Telemetry showed users approved ~93% of permission prompts, Claude Code auto mode blocks roughly 83% of overeager behaviors before execution, and Claude Opus 4.7 resists prompt-injection with about 0.1% success on single attempts and ~5–6% after 100 adaptive attempts.”

📝 Anthropic Engineering How we contain Claude across products - Anthropic has deployed Claude across claude.ai, Claude Code, and Claude Cowork while containing blast radius via environment controls (sandboxes, VMs, filesystem/egress limits), model-layer controls (system prompts, classifiers, probes, training), and restricting external-content/tool access, noting Claude Mythos Preview was judged too risky to ship in April 2026. Telemetry showed users approved ~93% of permission prompts, Claude Code auto mode blocks roughly 83% of overeager behaviors before execution, and Claude Opus 4.7 resists prompt-injection with about 0.1% success on single attempts and ~5–6% after 100 adaptive attempts.

“They acknowledge model defenses aren’t perfect—Claude Opus 4.7 shows ≈0.1% attack success on single prompt-injection attempts and ≈5–6% after 100 adaptive attempts—cited Mythos Preview as too high a blast radius to ship in April 2026, and argue combined environment, model, and external-content controls are necessary to cap agents’ blast radius.”

Anthropic ships Claude Code auto mode #1 📝 Anthropic Engineering How we contain Claude across products - Anthropic says it has shipped claude.ai, Claude Code, and Claude Cowork and moved from human-in-the-loop approvals—which users accepted about 93% of the time, producing approval fatigue—toward containment (sandboxes, VMs, egress controls) and automated defenses like Claude Code auto mode, which catches roughly 83% of overeager behaviors. They acknowledge model defenses aren’t perfect—Claude Opus 4.7 shows ≈0.1% attack success on single prompt-injection attempts and ≈5–6% after 100 adaptive attempts—cited Mythos Preview as too high a blast radius to ship in April 2026, and argue combined environment, model, and external-content controls are necessary to cap agents’ blast radius.

“#1 ▶️ Codex 5.5 vs Claude Opus 4.7 Polymarket Trading Challenge All About AI Codex 5.5 vs Claude Opus 4.7 Polymarket Trading Challenge All About AI • May 25, 2026”

AI Updates Today #1 ▶️ Codex 5.5 vs Claude Opus 4.7 Polymarket Trading Challenge All About AI All About AI • May 25, 2026 Summary not available in expected format. Key Takeaways: Unable to extract specific content from this video. Please refer to the original video for details. The AI was unable to structure the response correctly.

“#12 ▶️ Codex 5.5 vs Claude Opus 4.7 Polymarket Trading Challenge All About AI They compared Codex CLI 5.5 and Claude Opus 4.7 (both on high-think settings) trading Polymarket’s 5-minute Bitcoin up/down market for one hour with identical prompts and a $50 starting bankroll.”

#12 ▶️ Codex 5.5 vs Claude Opus 4.7 Polymarket Trading Challenge All About AI They compared Codex CLI 5.5 and Claude Opus 4.7 (both on high-think settings) trading Polymarket’s 5-minute Bitcoin up/down market for one hour with identical prompts and a $50 starting bankroll. Each agent was funded with $50 in a Polymarket wallet (plus MATIC for gas) and ran continuous 5-minute BTC up/down trades over a 1-hour period.

“#12 𝕏 Cursor launched a Fast mode for Claude Opus 4.7 in Cursor, running 2.5× faster at 6× the cost.”

#12 𝕏 Cursor launched a Fast mode for Claude Opus 4.7 in Cursor, running 2.5× faster at 6× the cost. They recommend sticking with standard speed for most tasks.

“Claude Opus 4.7 is now powering Amp's smart mode, improving ability to solve harder problems.”

#4 📝 Ampcode Chronicle Opus 4.7 - Claude Opus 4.7 is now powering Amp's smart mode, improving ability to solve harder problems. However, it is less forgiving of vague prompts and may produce weaker results when prompts lack clarity. #5 𝕏 Google Research is demoing on-device Sensitive Content Warnings in Google Messages, an AI feature that filters unwanted content locally while keeping all processing private.

“A detailed look at how Anthropic's Claude system prompt changed between Opus 4.6 and 4.7, using their published system prompts as the basis for analysis.”

#2 📝 Simon Willison Changes in the system prompt between Claude Opus 4.6 and 4.7 - A detailed look at how Anthropic's Claude system prompt changed between Opus 4.6 and 4.7, using their published system prompts as the basis for analysis. The post highlights the value of Anthropic publishing system prompts and links to deeper notes and artifacts used in the research.

“Claude Opus 4.7 uses adaptive thinking to allocate less inference time on perceived-easy tasks, which improves its performance over Opus 4.6 on most standard benchmarks but leads to regressions on trick questions (Simple Bench), web browsing (browse_comp), and OCR tests (vs. Gemini 3 Flash).”

#17 𝕏 Claude launched the Opus 4.7 hackathon, inviting builders worldwide to collaborate with the team for a week. A $100K API-credit prize pool is up for grabs. #18 ▶️ Claude Opus 4.7 - A New Frontier, in Performance … and Drama AI Explained Claude Opus 4.7 uses adaptive thinking to allocate less inference time on perceived-easy tasks, which improves its performance over Opus 4.6 on most standard benchmarks but leads to regressions on trick questions (Simple Bench), web browsing (browse_comp), and OCR tests (vs. Gemini 3 Flash). On the Simple Bench trick-question benchmark, Claude Opus 4.7 scored lower than Opus 4.6 because it underestimates task difficulty and reduces inference compute.