Fix Claude Code for Opus 4.7: 9 Key Changes
Opus 4.7 boosts coding power 13% but breaks old prompts—default to ex-high effort, adaptive thinking, literal verbs, and verification to resolve 3x more production tasks.
Adopt Ex-High Effort and Adaptive Thinking as Defaults
Opus 4.7 introduces ex-high effort level between high (4.6 default) and max, recommended verbatim by Anthropic as the new starting point for coding and agentic tasks since max yields diminishing returns and overthinking. Set max output tokens to 64,000 at ex-high or max to give the model room to think and act. Raise effort instead of rewriting shallow prompts. Adaptive thinking replaces extended thinking (which now returns HTTP 400 error on fixed budget_tokens); Claude auto-decides reasoning depth, outperforming the old mode per Anthropic evals—steer with pros like "think carefully step by step" for hard problems or "prioritize quick response" for easy ones. Tokenizer change uses ~1.35x more tokens for same text, filling context faster. Sampling params (temperature, top_p/k) also 400-error.
Treat Claude as capable engineer, not pair programmer: delegate via first-message structure stating intent, desired outcome, constraints, acceptance criteria, and file locations to minimize per-turn reasoning costs from ambiguity. Test prompts on colleagues—if confusing to them, confusing to Claude.
Build 5-Layer Prompts and Explicit Verbs for 30% Quality Gains
Use one precise verb per instruction since 4.7 follows literally: "suggest changes" yields list only, no code; "change this function" edits directly. Layer prompts as: 1) clear/direct instructions, 2) context/explanation of why, 3) 3-5 XML-tagged examples (multi-shot beats single-shot), 4) XML structure (
Enforce Context Hygiene, CLAUDE.md, and Hooks for Reliability
Context window degrades performance: 4.5-minute fresh tasks stretch to 18 minutes after autos. Use /clear post-resolution, /rewind on wrong turns. CLAUDE.md (auto-init via claude /init) reads first each session with hierarchy: org policy > ~/.claude user prefs > project-level > local gitignored > path-scoped rules—keep concise, cut ignorable lines to avoid bloat. Hooks via settings.json PreToolUse matchers block destructives pre-execution: command (shell script), HTTP (team endpoint), prompt (LM eval), agent (sub-agent verify).
Use Filesystem Memory and Verification for Long Tasks
Highest-leverage fix (per docs): always give Claude self-verification like tests/screenshots/expected output, never speculate on unopened code. For long-horizon: filesystem as memory via tests.json (passing/failing/pending, never edit/remove), progress.txt notes, git commits as checkpoints. Code reviews: drop "high-severity only" filters (suppresses 11% bug-finding gains); use "report every issue, even uncertain—filter later."
Checklist: 1) First-turn intent/constraints/acceptance, 2) ex-high default, 3) adaptive thinking, 4) CLAUDE.md, 5) pre-tool hook.