CLAUDE CODE 2.1.86–2.1.87 TIGHTEN RELIABILITY, ADD SESSION-AWARE HEADER, AND SMOOTH LONG RUNS
Anthropic shipped Claude Code 2.1.86–2.1.87 with broad reliability fixes and a new session header that simplifies telemetry and ops. The 2.1.86 update improves...
Anthropic shipped Claude Code 2.1.86–2.1.87 with broad reliability fixes and a new session header that simplifies telemetry and ops.
The 2.1.86 update improves reliability, performance, and token efficiency, and adds an X-Claude-Code-Session-Id request header so proxies can group traffic by session without parsing bodies. It also fixes resume on older sessions, out‑of‑project file ops with conditional skills/rules, Windows config corruption from excess writes, OOM risks on /feedback with large transcripts, missing MCP tools in --bare, plugin permission errors on macOS/Linux, masked input token leaks, and several UI stability issues. See the detailed notes on Releasebot.
2.1.87 is a small follow‑up that fixes messages not delivered in Cowork Dispatch, so it’s a safe “update now” for teams. If you haven’t updated in a while, this quick guide helps keep everyone current: Run claude update. For GCP shops, Anthropic’s Vertex AI session shows enterprise paths to run Claude Code at scale: Ship Code Faster with Claude Code on Vertex AI.
Long-running and multi-session workstreams get more stable, with several crashers and resume failures addressed.
The new X-Claude-Code-Session-Id header enables clean session-level logging, throttling, and cost accounting without brittle body parsing.
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Soak-test multi-hour sessions with heavy /feedback and large transcripts to validate memory behavior and the OOM fix.
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Verify proxies and observability stacks capture and forward X-Claude-Code-Session-Id, and that aggregation dashboards group activity by session as expected.
Legacy codebase integration strategies...
- 01.
Roll out 2.1.86+ in waves, pin versions per repo, and update proxy/header allowlists to include X-Claude-Code-Session-Id.
- 02.
Recheck edge cases fixed in this release: Windows config integrity, MCP tools in --bare interactive sessions, and macOS/Linux plugin script permissions.
Fresh architecture paradigms...
- 01.
Design telemetry from day one using the session header for per-session analytics, rate limits, and cost tracking.
- 02.
Standardize CLAUDE.md, rules, and skills structure early so agents operate consistently across services and repos.