Claude Model Selection Decision Tree

How to pick the right Claude model (every time): Step 1: Does your task require a complex answer? - No: use Haiku 4.5 or Sonnet 5. - Yes: use Opus 4.8 or Fable 5. Step 2: If your task is quick: - Need maximum speed & minimal tokens? Use Haiku 4.5 (lightweight, token-saver). Chat without files. Turn on web search. Plan in Chat, build in Cowork. - No: Sonnet 5 (fast, everyday model). Perfect for simple tasks. Connect your apps with Connectors: Slack, Google Drive, Notion, Figma, Granola, Gamma + 50 more. Step 3: Is this your hardest, most ambitious work? (multi-step reasoning, agents, long-thinking tasks) - No: Opus 4.8 (deep-work model). Use Cowork. Put Effort on High. Always. Use Skills in Projects (like /linkedin or /excel-style). - Yes: Fable 5 (the smartest model by Claude). Deep research. Analytical decisions. After Cowork: Download your file. Or convert it into a Claude Skill. Start a fresh session to save tokens. Careful with Fable 5: It costs extra (pay-per-use after July 12th). Only ~10% of tasks actually need it. Use it 1-2 turns for strategy, then switch to Opus. Long conversations = expensive. Claude re-reads the whole thread every turn. When Opus gets stuck, escalate to Fable. Everything else, route down the tree.