Model Effort Levels

Anthropic’s configurable reasoning budget hierarchy for Claude models. Controls how many reasoning tokens the model allocates per turn.

Hierarchy

none → low → medium → high → max → X high (Opus 4.7 exclusive)

Key points

• Effort levels control thinking depth, not model weights ^[010]
• Opus 4.6 was silently set to “medium” default on 2026-02-09 via adaptive thinking parameter changes — not a model weight change. This caused the widespread reports of Opus 4.6 degradation ^[010]
• “X high” is exclusive to Opus 4.7 — Anthropic’s stated maximum reasoning allocation ^[010]
• Higher effort = more thinking tokens = more expensive. The “ultra think” keyword in Claude Code allocates maximum thinking budget (~32K tokens) before responding ^[011]
• Community guidance: use “X high” / “ultra think” for architecture decisions and hard debugging; use lower effort for routine tasks to preserve quota ^[011]

Related entities

• Claude Opus 4 7 — introduces X high level
• Anthropic — defines and controls the effort hierarchy

Related concepts

• Adaptive Thinking — mechanism that selects effort level per turn
• Token Economics — effort level is the primary lever on reasoning token spend

Source references

• ^[010] Nate Herk — Cloud agents & model releases cluster (2026-04-14 to 2026-04-17)
• ^[011] Nate Herk — Claude Code power features cluster (2026-04-20 to 2026-04-27)