“Boris Cherny said his unspecified group uses the same exact Fable and is working to reduce cybersecurity refusals.”

GenAI PM Daily August 25, 2026 GenAI PM Daily 🎧 Listen to this brief 3 min listen Today's top 19 insights for PM Builders, ranked by relevance from Blogs, YouTube, and LinkedIn. GPT-5.6 in Kiro advances developer price-performance #1 📝 OpenAI News Advancing price-performance for developers with GPT‑5.6 in Kiro to improve price-performance for developers, enabling more cost-effective and performant model access for applications. #16 𝕏 Boris Cherny said his unspecified group uses the same exact Fable and is working to reduce cybersecurity refusals.

“He stopped writing code by hand in November 2025 but still codes daily with agents, and said Opus 4.8 was the first model that felt better than him at coding, while stressing that Claude’s code still has bugs and inefficiencies.”

#7 𝕏 Boris Cherny commented that models are advancing through three stages—coding, coding-adjacent engineering, and most computer-based tasks—and judged Claude to have reached stage 1, part of stage 2, and early signs of stage 3 for his work. He stopped writing code by hand in November 2025 but still codes daily with agents, and said Opus 4.8 was the first model that felt better than him at coding, while stressing that Claude’s code still has bugs and inefficiencies. #10 𝕏 Boris Cherny said Opus excels at long-running work and coding but has quirks, with verbosity a major concern and broader fixes a team priority. As a temporary mitigation, users can run `claude /config outputStyle=concise`.

“Boris Cherny recommended running `/usage` for a detailed breakdown, noting that the issue is most often caused by extreme parallelism, a runaway loop, or a very inefficient skill/plugin.”

#14 𝕏 Boris Cherny recommended running `/usage` for a detailed breakdown, noting that the issue is most often caused by extreme parallelism, a runaway loop, or a very inefficient skill/plugin. #16 𝕏 Boris Cherny announced that an unnamed item, which had been worked on with customers for a while, was expected to arrive in the fall. He said Mythos-class models require additional safety measures, enterprises need to meet their own privacy and compliance rules, and customers can own and control their data while Anthropic retains none of it.

“"#11 𝕏 Boris Cherny said unspecified evaluations found that /code-review low produced a better result than other models at a fraction of the cost—less than $0.01."”

#11 𝕏 Boris Cherny said unspecified evaluations found that /code-review low produced a better result than other models at a fraction of the cost—less than $0.01. #18 𝕏 Boris Cherny commented that LLM bugs are shifting from off-by-one errors toward system design, UI usability, and missing broader context. He recommends adversarial code review—including a one-line prompt to test every edge case in an iOS simulator or Claude’s built-in /code-review—to catch many of these issues.

“𝕏 Boris Cherny shared a prompt-injection benchmark created by an unnamed independent researcher and said Anthropic has largely solved the threat in practice for Claude models, with red-team testing producing similar results.”

𝕏 Boris Cherny shared a prompt-injection benchmark created by an unnamed independent researcher and said Anthropic has largely solved the threat in practice for Claude models, with red-team testing producing similar results. He described prompt injection as the most common way scammers attack people and agents, including by using malicious website text to trick agents into disclosing credentials.

“#2 𝕏 Boris Cherny commented that the referenced harnesses support other models through proxies such as LiteLLM, but building an effective harness requires substantial model-specific tool design, prompting, and tuning.”

GenAI PM Daily August 09, 2026 GenAI PM Daily 🎧 Listen to this brief 3 min listen Today's top 10 insights for PM Builders. Claude Code sessions can now message each other #1 𝕏 Madhu Guru commented on Claude Code session-to-session messaging, using a figurative heist analogy to describe sessions communicating and operating without individual oversight. #2 𝕏 Boris Cherny commented that the referenced harnesses support other models through proxies such as LiteLLM, but building an effective harness requires substantial model-specific tool design, prompting, and tuning. #10 𝕏 Boris Cherny asked whether Claude should automatically resume using Fable after a user’s limit resets or pause and let the user decide each time.

“Boris Cherny said stacking model training, input probes, and an intent-checking classifier can bring indirect prompt injection to ~0 on unseen attacks—a result he did not expect a year ago. He also announced that auto mode would become the default in Claude Code the following week.”

#6 𝕏 Boris Cherny said stacking model training, input probes, and an intent-checking classifier can bring indirect prompt injection to ~0 on unseen attacks—a result he did not expect a year ago. He also announced that auto mode would become the default in Claude Code the following week.

“Boris Cherny uses Fable’s dynamic workflows and a profiler to iteratively tune his code until the p95 latency drops below 300 ms.”

#15 𝕏 Boris Cherny uses Fable’s dynamic workflows and a profiler to iteratively tune his code until the p95 latency drops below 300 ms. #16 in Colin Matthews suggests kickstarting AI email writing by first defining a clear “good email” rubric—using an LLM to extract criteria from sample emails—and then iterating on drafts against that rubric rather than endless ad-hoc edits.

“Boris Cherny rolled out `/checkup` in Claude Code to automate cleaning unused skills/MCPs/plugins, deduping and splitting CLAUDE.”

𝕏 clem 🤗 – Co-founder & CEO @HuggingFace launched the SkyPilot-HF Storage integration, enabling one-line provisioning of multi-cloud GPU clusters with seamless, cached mounting of Hugging Face datasets and repositories. #15 𝕏 Boris Cherny rolled out `/checkup` in Claude Code to automate cleaning unused skills/MCPs/plugins, deduping and splitting CLAUDE.

“#9 𝕏 Boris Cherny sees five key archetypes—Prototyper, Builder, Sweeper, Grower, and Maintainer—in the Claude Code team.”

The newsletter summarizes Boris Cherny's view that roles are blending across product, engineering, and design.