Claude Fable 5 and Claude Mythos 5 were first released on June 9, 2026. On June 12, 2026, Anthropic suspended access to both models to comply with U.
The release of llm-anthropic 0.28 introduces support for Claude Fable 5.1, enabling default display of reasoning traces for compatible models. It also adds a new llm_anthropic.ClaudeRefusal exception to handle cases where Claude returns a refusal. These updates enhance debugging and error handling for users of the library.
Anthropic has released the system prompts for its Claude consumer applications, including historic changes and an index structure that allows easy diffing of prompts. The latest update, seen in Fable 5.1, adds a comprehensive rule that Claude will not reproduce song lyrics, poems, or copyrighted passages, and will refuse any reworded requests thereafter, offering analysis instead. The prompts are accessible in Markdown via the platform.claude.com/docs site, facilitating transparent tracking of policy changes.
Claude Cowork and the standard chat interface are merging into a single Claude experience, allowing users to hand over tasks or ask quick questions that the system will continue to handle even after the laptop is closed. The rollout will begin with Pro and Max plan users across web, desktop, and mobile, and will extend to new users on these plans over the coming weeks. This integration suggests Claude is evolving into a general agent, simplifying the distinction between Cowork and regular Claude usage.
But then users start to report a weird bug. It's the 4th time your team has been trying to fix it.
The article discusses Bryan Cantrill’s response to a tweet by former Anthropic employee Jacob Coxon, who claimed that AI could kill humanity by the end of the decade. Cantrill shares a personal anecdote about how his own youthful mistakes caused undue panic among non‑technical peers and warns against repeating that pattern. He emphasizes that domain experts must be cautious when making alarmist claims, especially about complex topics like critical infrastructure, bioweapons, and extinction, and that the burden of accurate information lies with those making such statements.
The article discusses Anthropic’s Claude Fable 5.1 release, highlighting its claimed improvements in coding, knowledge work, and problem‑solving, particularly a 52.6% score on the new Terminal‑Bench‑Science 0.1 benchmark. The author examines the model’s performance on the pelican benchmark, noting that Fable 5.1’s five reasoning levels (low, medium, high, xhigh, max) sometimes skip reasoning entirely for certain prompts, as evidenced by token counts and cost metrics. The piece provides detailed transcript data for each reasoning level when generating an SVG of a pelican riding a bicycle.
The article discusses how production code generated by Claude, Anthropic’s AI, should meet higher standards than human-written code. Anthropic enforces this through numerous guardrails such as lint rules, extensive testing, Claude-driven end‑to‑end tests, daily fuzzers, automated code and security reviews, and automated refactoring. These measures aim to prevent the code from becoming difficult to maintain.
The article announces the release of llm‑anthropic version 0.29. It introduces support for the Claude Opus 5.5 model, allowing users to invoke it with the command line syntax `llm -m claude-opus-5.5 "prompt goes here"`. The release is tagged under llm and anthropic.
The article recounts a challenging debug session that was significantly aided by an AI assistant. Despite the AI initially claiming the problem was unsolvable and suggesting a report be written instead, it persisted, adding debug code and analyzing it as the author pushed forward. Ultimately, the author credits the AI with writing the commit message for the fix.
The article announces that Claude Code will now support AGENTS.md files starting with version 2.1.277. If a CLAUDE.md file is absent in a folder, Claude will automatically look for and use AGENTS.md, leveraging Claude Code mods to customize the harness. The built‑in mod is available for use, and users can also create their own custom project instructions.
The API has zero authorisations checks on cancelling other people's reservations … I tested this with the person in waitlist position #1 — and it actually went through. So you've moved from #4 to #3 already.
Datasette 1.0a39 and 0.65.4 are new security patch releases for the current alpha series and the stable 0.65.x family. The updates address security fixes that are important for public-facing Datasette instances, especially those that mix public and private tables. The patches were developed after an extensive audit using advanced AI models and collaborative review, and the process will be incorporated into future development work.