daily diff ยท weclaudecodehttps://weclaudecode.com/diffWhat changed in Claude, Claude Code and agent tooling. Short and sourced.enTue, 27 Oct 2026 00:00:00 GMTClaude Code 2.1.312 changes prompts for custom cloud model names and stops a safety eventhttps://weclaudecode.com/diff/2026-10-27-claude-code-2-1-312https://weclaudecode.com/diff/2026-10-27-claude-code-2-1-312Tue, 27 Oct 2026 00:00:00 GMTClaude Code 2.1.312 shortens the system prompt for custom model names on cloud providers and drops an OpenTelemetry event. Teams on Bedrock, Vertex or Foundry should check both.Claude Code 2.1.311: model settings load from a signed file, ultrathink runs at xhighhttps://weclaudecode.com/diff/2026-10-26-claude-code-2-1-311https://weclaudecode.com/diff/2026-10-26-claude-code-2-1-311Mon, 26 Oct 2026 00:00:00 GMTClaude Code 2.1.311 changes where Bedrock, Vertex and Foundry model settings come from, and what ultrathink costs. Teams on cloud providers should check both.Claude API version 2026-10-21 ships with new SDK major versionshttps://weclaudecode.com/diff/2026-10-21-api-version-2026-10-21-and-sdk-majorshttps://weclaudecode.com/diff/2026-10-21-api-version-2026-10-21-and-sdk-majorsWed, 21 Oct 2026 00:00:00 GMTA new API version and major SDK and CLI releases arrived on 21 October 2026. Teams that upgrade SDKs get the new version by default, plus breaking changes.User profiles let platforms scope Claude safety actions to one end customerhttps://weclaudecode.com/diff/2026-10-20-user-profiles-and-organization-webhookshttps://weclaudecode.com/diff/2026-10-20-user-profiles-and-organization-webhooksTue, 20 Oct 2026 00:00:00 GMTAnthropic launched user profiles on 20 October 2026. Platforms and resellers can tag each request with an end customer, so enforcement need not hit the whole organization.Claude Code 2.1.304 adds auto mode setup and a Managed Agents security checkhttps://weclaudecode.com/diff/2026-10-19-claude-code-2-1-304https://weclaudecode.com/diff/2026-10-19-claude-code-2-1-304Mon, 19 Oct 2026 00:00:00 GMTThe 19 October 2026 release adds guided auto mode setup, a settings comparison for Managed Agents, review levels for Code Review, and gateway tool search retry.Claude Code 2.1.302: fork subagents on by default and a cap on parallel hookshttps://weclaudecode.com/diff/2026-10-16-claude-code-2-1-302https://weclaudecode.com/diff/2026-10-16-claude-code-2-1-302Fri, 16 Oct 2026 00:00:00 GMTFork subagents now run by default in claude -p and the Agent SDK, and prompt and agent hooks are capped at 12 at a time. Check scripted and CI use.Fast mode for Claude Opus 5.5 leaves research previewhttps://weclaudecode.com/diff/2026-10-15-fast-mode-opus-5-5-general-availabilityhttps://weclaudecode.com/diff/2026-10-15-fast-mode-opus-5-5-general-availabilityThu, 15 Oct 2026 00:00:00 GMTNo access request and no beta header needed for Claude Opus 5.5 fast mode. Opus 5 and Opus 4.8 stay in preview and still need the header.Claude API adds OpenTelemetry export in beta, with SDK and API traceshttps://weclaudecode.com/diff/2026-10-14-opentelemetry-export-claude-apihttps://weclaudecode.com/diff/2026-10-14-opentelemetry-export-claude-apiWed, 14 Oct 2026 00:00:00 GMTTrace Messages API requests and Managed Agents sessions in the observability tool you already use. Beta since 14 October, for any team running Claude in production.Claude Code 2.1.296: per-subagent compaction and longer MCP tool descriptionshttps://weclaudecode.com/diff/2026-10-09-claude-code-2-1-296https://weclaudecode.com/diff/2026-10-09-claude-code-2-1-296Fri, 09 Oct 2026 00:00:00 GMTSubagents can compact on their own schedule, workflow agents can share one model, and MCP servers get twice the room for tool descriptions.Claude Haiku 5.5 is out, and Haiku 4.5 code can break on ithttps://weclaudecode.com/diff/2026-10-07-haiku-5-5-what-breakshttps://weclaudecode.com/diff/2026-10-07-haiku-5-5-what-breaksWed, 07 Oct 2026 00:00:00 GMTThe new small model has a 1M token context window and adaptive thinking. Several request shapes that worked on Haiku 4.5 now return a 400 error.