User-facing
- [new] BashOutput, KillBash, ListMcpResources, and ReadMcpResource built-in tools.
- [new] /output-style, /pr-comments, and /vim slash commands; removed /quit.
- [new] --prompt-suggestions CLI flag.
- [new] forceLoginMethod settings key.
- [changed] sdk-tools.d.ts: added a gitOperation classification object, an AskUserQuestion.response free-text field, taskType/workflowName on background task records, and clarified args JSON handling.
Models & prompts
- New model: claude-opus-4-8 (with a matching model route and CLAUDE_4_8_OPUS environment variable).
- Prompt and schema updates: new mid-conversation system-message handling, the AskUserQuestion response field, gitOperation structured output, and workflow taskType fields, plus refreshed wording around system reminders and context management.
Internal / experimental
- 78 new ANTHROPIC_*/CLAUDE_* environment variables, including CLAUDE_CODE_ENABLE_AUTO_MODE, CLAUDE_CODE_ENABLE_OPUS_4_7_FAST_MODE, CLAUDE_CODE_TWO_STAGE_CLASSIFIER, CLAUDE_CODE_SKILL*, CLAUDE_BRIDGE_*, CLAUDE_CODE_MANAGED_SETTINGS_PATH, CLAUDE_CODE_REMOTE_HERMETIC_MODE, and many test/force/debug flags.
- 7 new environment-variable groups: CLAUDE_BYTE, CLAUDE_CONTEXT, CLAUDE_GATEWAY, CLAUDE_MOCK, CLAUDE_SERVE, CLAUDE_SNIP, CLAUDE_SSH.
- New API beta header: summarize-connector-text-2026-03-13.
- 88 new feature gates (tengu_*/claude_code_*), including auto-mode entry warnings, skill loading, MCP skills, refusal fallbacks, plugins sync, background tasks, OAuth, the Opus 4.8 launch, and two-stage-classifier signals.
- New backend routes: /api/oauth/validate, /v1/code/agent-proxy, /v1/filestore/fs/readFile.
- New MCP tool: mcp__puppeteer.
- New network endpoints: https://api.datadoghq.com, https://mcp.asana.com, https://mcp.figma.com, https://slack.mcp.claude.com.
Upgrade notes
- Binary sizes increased across all platforms.