{"@type":"StructuredNewsArticle","access":{"license":"neupai_standard","structured_data":"free","full_text_access":null,"full_text_available":false,"attribution_required":true},"content":{"claims":[{"id":"c1","type":"fact","as_of":"2026-03-04","figures":null,"insight":null,"as_of_raw":"March 4","statement":"On March 4, the default reasoning effort level was downgraded from 'high' to 'medium'","comparison":null,"expiry_hint":null,"source_type":"company_disclosure","as_of_explicit":true},{"id":"c2","type":"fact","as_of":"2026-04-07","figures":null,"insight":null,"as_of_raw":"April 7","statement":"On April 7, Opus 4.7 default was restored to 'xhigh'","comparison":null,"expiry_hint":null,"source_type":"company_disclosure","as_of_explicit":true},{"id":"c3","type":"fact","as_of":"2026-03-26","figures":null,"insight":null,"as_of_raw":"March 26","statement":"On March 26, a prompt caching optimization bug was deployed","comparison":null,"expiry_hint":null,"source_type":"company_disclosure","as_of_explicit":true},{"id":"c4","type":"fact","as_of":"2026-04-10","figures":null,"insight":null,"as_of_raw":"April 10","statement":"On April 10, the prompt caching bug was fixed in version v2.1.101","comparison":null,"expiry_hint":null,"source_type":"company_disclosure","as_of_explicit":true},{"id":"c5","type":"fact","as_of":"2026-04-16","figures":null,"insight":null,"as_of_raw":"April 16","statement":"On April 16, added system prompt brevity instruction limiting responses between tool calls to 25 words","comparison":null,"expiry_hint":null,"source_type":"company_disclosure","as_of_explicit":true},{"id":"c6","type":"fact","as_of":"2026-04-16","figures":null,"insight":null,"as_of_raw":"April 16","statement":"Limited final responses to within 100 words","comparison":null,"expiry_hint":null,"source_type":"company_disclosure","as_of_explicit":false},{"id":"c7","type":"fact","as_of":"2026-04-16","figures":null,"insight":null,"as_of_raw":"April 16","statement":"A 3% decline occurred in coding quality evaluation","comparison":"baseline","expiry_hint":null,"source_type":"company_disclosure","as_of_explicit":false},{"id":"c8","type":"fact","as_of":"2026-04-20","figures":null,"insight":null,"as_of_raw":"April 20","statement":"On April 20, reverted the system prompt brevity instruction","comparison":null,"expiry_hint":null,"source_type":"company_disclosure","as_of_explicit":true},{"id":"c9","type":"fact","as_of":"2026-04","figures":null,"insight":null,"as_of_raw":"analyzed","statement":"Analyzed 6,852 session files and over 234,000 tool calls","comparison":null,"expiry_hint":null,"source_type":"research_paper","as_of_explicit":false},{"id":"c10","type":"fact","as_of":"2026-04-23","figures":null,"insight":null,"as_of_raw":"as of April 23","statement":"As of April 23, reset usage limits for all subscribers","comparison":null,"expiry_hint":null,"source_type":"company_disclosure","as_of_explicit":true}],"topics":["ai","software"],"summary":"Anthropic released an official post-mortem analysis report identifying three product layer changes as the causes of Claude code's performance degradation. 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