Effort Levels in Practice: I Benchmarked low Through max on Real Tasks

The current Claude models give you an effort knob with five settings: low , medium , high , xhigh , max . The docs tell you what each is for. I wanted numbers, so I ran the same three real tasks across all five levels and measured tokens, latency, and quality. The results changed how I set effort, and one of them surprised me. Here is the data and what I do with it now. What effort controls Effort is not just "how much the model thinks." It controls overall token spend: how much it thinks and how it acts. Lower effort means fewer, more consolidated tool calls, less preamble, terser output. Higher effort means more exploration before answering. The default is high if you omit it. const response = await client . messages . create ({ model : " claude-opus-4-8 " , max_tokens : 16000 , thinking : { type : " adaptive " }, output_config : { effort : " medium " }, // the knob messages , }); The three tasks I picked tasks that span the range of what I actually do: Classification : label a contract finding as low/medium/high/critical. Short, scoped. Code generation : write a TypeScript function with edge-case handling. Medium difficulty. Multi-step audit : analyze a 200-line contract for vulnerabilities across functions. Hard, agentic. I ran each at all five effort levels, three times, and averaged. I scored quality against a known-correct answer for tasks 1 and 3, and by manual review for task 2. The results Task 1, classification. Quality was flat across every effort level. The right label is the right label, and the model nailed it at low just as well as at max . But token usage climbed steeply: max used roughly 8x the tokens of low for an identical answer. Latency tracked tokens. The lesson: for genuinely simple, scoped tasks, high effort is pure waste. I set classification to low . Task 2, code generation. Quality improved from low to high , then plateaued. At low the model sometimes skipped an edge case. At high it caught them. xhigh and max produced essentially the sam