{"schema_version":"newruntime-agent-readable-v0.2","type":"raw_signal","stable_id":"signal:claude-md-prompt-cruft-shrinkage","id":"nr-09cc7147-claude-md-cruft","slug":"claude-md-prompt-cruft-shrinkage","title":"Claude.md Shrinkage Says the Harness Is Learning What Not to Say","description":"A reported 80 percent reduction in Claude Code prompt material points to a maturing harness discipline around concise system context.","retrieval_nugget":"A reported 80 percent reduction in Claude Code prompt material points to a maturing harness discipline around concise system context. Agent harnesses are starting to compete on context discipline. Less always-on instruction can mean lower cost, clearer behavior, and fewer stale rules fighting the task. Novelty is notable; verification is source-linked. This New Runtime record is an evidence-linked retrieval unit.","observed_at":"2026-07-29","record_date":"2026-07-29","date_kind":"observed_at","why_it_matters":"Agent harnesses are starting to compete on context discipline. Less always-on instruction can mean lower cost, clearer behavior, and fewer stale rules fighting the task.","novelty":"notable","verification_level":"source-linked","signal_type":"tool","evidence_kind":"creator-source","status":"published","source_platform":"newsletter","source_record_id":"09cc7147-claude-md-cruft","source_url":"https://x.com/trq212/status/2080710971228918066","topics":["coding-agents","ai-infrastructure"],"entities":["Claude Code","system prompts","skills","Claude.md"],"related_patterns":["harness-architecture-outlives-model-choice","skills-become-portable-capability-layer","agent-economics-moves-to-completed-work"],"source_urls":["https://x.com/trq212/status/2080710971228918066"],"import_batch":"newsletter-09cc7147-e5c3-42b7-8ced-84531f2b390d","routes":{"html":"https://newruntime.com/signals/claude-md-prompt-cruft-shrinkage/","markdown":"https://newruntime.com/signals/claude-md-prompt-cruft-shrinkage.md","json":"https://newruntime.com/signals/claude-md-prompt-cruft-shrinkage.json"},"source_format":"editorial-inbox-sanitized-batch","next_reads":[{"type":"pattern","path":"/patterns/harness-architecture-outlives-model-choice/","reason":"Pattern connected to this observed signal.","url":"https://newruntime.com/patterns/harness-architecture-outlives-model-choice/","title":"Harness architecture outlives model choice","media_type":"text/html"},{"type":"pattern","path":"/patterns/skills-become-portable-capability-layer/","reason":"Pattern connected to this observed signal.","url":"https://newruntime.com/patterns/skills-become-portable-capability-layer/","title":"Skills become a portable capability layer","media_type":"text/html"},{"type":"pattern","path":"/patterns/agent-economics-moves-to-completed-work/","reason":"Pattern connected to this observed signal.","url":"https://newruntime.com/patterns/agent-economics-moves-to-completed-work/","title":"Agent economics moves to completed work","media_type":"text/html"},{"type":"topic","path":"/topics/ai-infrastructure/","reason":"Explore the ai infrastructure topic hub.","url":"https://newruntime.com/topics/ai-infrastructure/","title":"AI Infrastructure - New Runtime","media_type":"text/html"},{"type":"topic","path":"/topics/coding-agents/","reason":"Explore the coding agents topic hub.","url":"https://newruntime.com/topics/coding-agents/","title":"Coding agents - New Runtime","media_type":"text/html"}]}