This week's Claude Code releases, then a full tutorial on fleet observability and cost dashboards for parallel runs. **News (2026-06-26 to 2026-07-03, from the [Claude Code changelog](https://code.claude.com/docs/en/changelog)):** - **Claude Sonnet 5 is now the default** (v2.1.197, Jun 30): native 1M-token context, promo pricing `$2/$10` per Mtok through Aug 31. Shows in `/model`. (Some trackers misdate it to Jul 1 - the docs changelog is authoritative.) - **Background subagents by default** (v2.1.198, Jul 1): agents keep running and notify on finish; `claude agents` runs now commit, push, and open a draft PR from a worktree; `Notification` hook fires `agent_needs_input`/`agent_completed`; Explore agent inherits the session model (capped at opus); new `/dataviz` skill; the `/agents` wizard was removed. - **Stacked skills + retry controls** (v2.1.199, Jul 2): `/skill-a /skill-b` loads up to 5; `CLAUDE_CODE_RETRY_WATCHDOG` raises retries to 300; fixed subagents reporting usage-limit errors as success, plus a Linux daemon that killed all agents every ~50s. - **Org defaults + durability** (v2.1.196, Jun 29): admin org default model, stream idle watchdog on by default, background sessions survive restarts. **Tutorial - Fleet observability and cost dashboards:** - Native OpenTelemetry, opt-in via `CLAUDE_CODE_ENABLE_TELEMETRY=1` - [Monitoring docs](https://code.claude.com/docs/en/monitoring-usage). Metrics like `claude_code.cost.usage`, `claude_code.token.usage`, `claude_code.active_time.total`; log events; beta trace spans (`claude_code.interaction` root). - Reference stack: [ColeMurray/claude-code-otel](https://github.com/ColeMurray/claude-code-otel) (Collector to Prometheus + Loki to Grafana, six-section dashboard). - Cost tools: `/cost` slash command ([Manage costs](https://code.claude.com/docs/en/costs)); [ccusage](https://github.com/ccusage/ccusage) (`npx ccusage@latest`, `ccusage blocks --live`); org-level [Usage and Cost API](https://platform.claude.com/docs/en/manage-claude/usage-cost-api) and the per-user [Claude Code Analytics API](https://platform.claude.com/docs/en/manage-claude/claude-code-analytics-api). - [Headless mode](https://code.claude.com/docs/en/headless): `claude -p --output-format json` returns `total_cost_usd`, `num_turns`, `session_id`; guard with `--max-turns` and `--max-budget-usd`. - AWS worked example: [Analyzing Claude Code usage with CloudWatch and OpenTelemetry](https://aws.amazon.com/blogs/mt/analyzing-claude-code-usage-with-cloudwatch-and-opentelemetry/). - Pitfall: `OTEL_LOG_USER_PROMPTS=1` / `OTEL_LOG_TOOL_DETAILS=1` leak prompt text and credentials ([Elastic Security Labs](https://www.elastic.co/security-labs/claude-code-cowork-monitoring-otel-elastic)); one shared API key breaks per-worktree attribution.