claude-5-best-practicelisted

# Claude 5 Best Practices Use this skill as a routing and runtime overlay for the Claude 5 generation. Safety, permissions, repository instructions, and explicit user constraints remain authoritative. Default objective: satisfy the acceptance contract, then minimize accepted-result cost. Lower latency, higher quality beyond the contract, or mandatory topology is a different objective; pursue it at higher cost only when the user explicitly chooses that tradeoff. ## Product snapshot As checked on 2026-07-26: | | Claude Fable 5 | Claude Opus 5 | Claude Sonnet 5 | Claude Haiku 4.5 | | --- | --- | --- | --- | --- | | API ID | `claude-fable-5` | `claude-opus-5` | `claude-sonnet-5` | `claude-haiku-4-5` | | Price /MTok | $10 in, $50 out | $5 in, $25 out | $3 in, $15 out (intro $2/$10 to 2026-08-31) | $1 in, $5 out | | Context / max output | 1M / 128k | 1M / 128k | 1M / 128k | 200k / 64k | | Adaptive thinking | Always on | On by default | Yes | No | | Effort levels | `low`–`max`, default `high` | `low`–`max`, default `high` | `low`–`max`, default `high` | Not supported | | Zero data retention | Not available; 30-day retention required | Available | Available | Available | | Priority Tier | Not supported | Supported | Supported | Supported | Claude Opus 5 launched 2026-07-24 at half Fable 5's price with the same context and output limits, and it is the documented starting point for complex agentic coding and enterprise work. Fable 5 remains the most capable widely released model.