How to Build Autonomous Coding Agents on Claude Fable 5 Claude Fable 5 scores 80.3% on SWE-Bench Pro, 25–30% faster than predecessors. Build, budget, and operate production coding agents with working Python code. June 15, 2026 • Luka Mrkić claude-fable-5 autonomous-agents anthropic-api ai-development multi-agent