{
  "schema_version": "1.0",
  "id": "archive:https://www.anthropic.com/engineering/april-23-postmortem",
  "slug": "april-23-postmortem-1ve86a2",
  "url": "https://feed7.dev/p/april-23-postmortem-1ve86a2",
  "title": "An update on recent Claude Code quality reports",
  "why_included": "Anthropic traces recent Claude Code degradation to three bugs — a reasoning-effort default, a thinking-cache bug, and a prompt change — all fixed in v2.1.116, with usage-limit resets as compensation.",
  "summary": "**The gist** Anthropic's postmortem identifies three separate bugs behind Claude Code quality complaints between **March 4 and April 20, 2026**: a default reasoning-effort drop from high to **medium**, a cache bug that stripped thinking blocks from sessions idle over an hour on every turn, and a prompt instruction capping responses at **100 words**. All are fixed as of **v2.1.116**.",
  "practical_implication": "**Why it matters** If Claude Code felt forgetful or burned usage limits faster this spring, it was these bugs, not the models — subscribers get **usage limit resets**. Anthropic now gates prompt changes behind **per-model evals** and staff dogfood the **exact public build**, so silent regressions should surface sooner.",
  "agent_context": "**The gist** Anthropic's postmortem identifies three separate bugs behind Claude Code quality complaints between **March 4 and April 20, 2026**: a default reasoning-effort drop from high to **medium**, a cache bug that stripped thinking blocks from sessions idle over an hour on every turn, and a prompt instruction capping responses at **100 words**. All are fixed as of **v2.1.116**.\n\n**Why it matters** If Claude Code felt forgetful or burned usage limits faster this spring, it was these bugs, not the models — subscribers get **usage limit resets**. Anthropic now gates prompt changes behind **per-model evals** and staff dogfood the **exact public build**, so silent regressions should surface sooner.\n\n**Watch out** Each bug lived in corner cases that survived code review, tests, and dogfooding — the thinking-cache bug was masked because the CLI **suppresses thinking display**. User reports were initially indistinguishable from **normal variation**, so expect future regressions to take time to confirm too.",
  "source": {
    "name": "Anthropic",
    "url": "https://www.anthropic.com/engineering/april-23-postmortem",
    "published_at": null
  },
  "source_class": "blog_post",
  "content_type": "Engineering Post",
  "layer": "tools",
  "domains": [
    "coding"
  ],
  "topics": [
    "coding-agents",
    "dev-ux",
    "agent-reliability"
  ],
  "verification": {
    "status": "official_source",
    "label": "Official Source",
    "method": "source_feed",
    "verified_at": null
  },
  "uncertainty": [
    "Each bug lived in corner cases that survived code review, tests, and dogfooding — the thinking-cache bug was masked because the CLI **suppresses thinking display**. User reports were initially indistinguishable from **normal variation**, so expect future regressions to take time to confirm too."
  ],
  "lifecycle": "Current",
  "published_at": null,
  "modified_at": null,
  "supersedes": [],
  "expires_at": null,
  "formats": {
    "html": "https://feed7.dev/p/april-23-postmortem-1ve86a2",
    "json": "https://feed7.dev/p/april-23-postmortem-1ve86a2.json",
    "markdown": "https://feed7.dev/p/april-23-postmortem-1ve86a2.md"
  }
}