WHY users should care
Claude Opus 5 is live — if you're building serious agentic stuff, the default Opus model just got a 1M context window, adaptive thinking, and a May 2026 knowledge cutoff. It's the new recommended starting point for complex enterprise/agentic work.
Subagent depth doubled — multi-agent pipelines can now go 3 levels deep by default (was 1). If you're building workflows that spawn agents, this is a structural capability unlock.
Key changes (v2.1.219)
- 🚀 Claude Opus 5 default —
claude-opus-5, 1M context, adaptive thinking on; $10/$50 MTok input/output on Anthropic API / Bedrock / Vertex
- 🚀 Nested subagent depth 3 — sub-sub-agents now work out of the box; disable with
CLAUDE_CODE_MAX_SUBAGENT_SPAWN_DEPTH=1
sandbox.network.strictAllowlist — deny non-allowlisted hosts without prompting (CI/headless hardening)DirectoryAdded hook — fires after /add-dir registers a new working dir mid-session- Dynamic workflow size — defaults to medium (<15 agents); configurable via
workflowSizeGuideline in settings
- Two new API beta headers —
server-side-fallback-2026-07-01 + fallback-credit-2026-07-01
mcp_server_errors in headless init — broken MCP servers surfaced at startup now- ⚠️ Opus 4.1 deprecating —
claude-opus-4-1-20250805 retires 2026-08-05; migrate to Opus 5
- Opus 4.7 dropped from fast mode (fast mode now = Opus 5 + Opus 4.8)
Reference
Docs PR: thevibeworks/claude-code-docs#1091
@lroolle — FYI, Opus 5 is now default. Worth a look.
WHY users should care
Claude Opus 5 is live — if you're building serious agentic stuff, the default Opus model just got a 1M context window, adaptive thinking, and a May 2026 knowledge cutoff. It's the new recommended starting point for complex enterprise/agentic work.
Subagent depth doubled — multi-agent pipelines can now go 3 levels deep by default (was 1). If you're building workflows that spawn agents, this is a structural capability unlock.
Key changes (v2.1.219)
claude-opus-5, 1M context, adaptive thinking on; $10/$50 MTok input/output on Anthropic API / Bedrock / VertexCLAUDE_CODE_MAX_SUBAGENT_SPAWN_DEPTH=1sandbox.network.strictAllowlist— deny non-allowlisted hosts without prompting (CI/headless hardening)DirectoryAddedhook — fires after/add-dirregisters a new working dir mid-sessionworkflowSizeGuidelinein settingsserver-side-fallback-2026-07-01+fallback-credit-2026-07-01mcp_server_errorsin headless init — broken MCP servers surfaced at startup nowclaude-opus-4-1-20250805retires 2026-08-05; migrate to Opus 5Reference
Docs PR: thevibeworks/claude-code-docs#1091
@lroolle — FYI, Opus 5 is now default. Worth a look.