The 2026-10-21 API version removes temperature, top_p, and top_k from the Messages API, returns a 400 for documents in assistant turns and citations in user turns, and replaces a few deprecated Admin and Enterprise Analytics fields. The 2023-06-01 version is not deprecated.
Agent Skills is being donated to the Agentic AI Foundation, the same body that received MCP. Since December 2025, more than 70 agent platforms have integrated the standard, including ChatGPT, Cursor, GitHub Copilot, and VS Code.
A researcher found Claude Code adding personal identifying headers to curl requests after visited pages prompted agents to identify their users. A team member flagged this as a likely prompt injection issue and asked for a /feedback transcript or a security report.
API version 2026-10-21 is now available, marking the first official versioned release since 2023-06-01. The plan is to ship versions more frequently so developers can absorb breaking changes before new models require them. The old 2023-06-01 version remains active.
Agent Skills began as an internal experiment inside Claude Code before wider industry adoption prompted Anthropic to donate it to the Agentic AI Foundation alongside MCP.
Existing skills continue working without license changes, and anyone can use or contribute to the Agent Skills standard without formally joining the Agentic AI Foundation. A cross-company Technical Steering Committee from Anthropic, Google, Microsoft, OpenAI, and OpenCode will govern it.
The Technical Steering Committee governing Agent Skills, drawn from Anthropic, Google, Microsoft, OpenAI, and others, is prioritizing versioned releases, a formal proposal process, and security guidance. The spec and GitHub discussion are open for contributions.
A researcher flagged that several AI agents, including Fable, Astra, and Gemini Pro, fail to detect advertiser cloaking attempts more than 70% of the time, and shared findings on agent exfiltration attacks. A team member followed up via DM.
A user reported Claude Code usage depleting roughly 5x faster than normal. Brian Cherny responded that no changes were made on Anthropic's end and offered a diagnostic command, 'claude -p /usage | pbcopy', to help trace the issue.
Users are reporting that Claude's Opus usage feels significantly more restricted than two weeks ago. A team member responded that limits haven't changed and asked the user to run /feedback in an affected session and share the ID for investigation.
