/claude-opus-4-5-migration

Effort Parameter (Beta)

Add effort set to "high" during migration. This is the default configuration for best performance with Opus 4.5.

Overview

Effort controls how eagerly Claude spends tokens. It affects all tokens: thinking, text responses, and function calls.

Implementation

Requires beta flag effort-2025-11-24 in API calls.

Python SDK:

response = client.messages.create(
    model="claude-opus-4-5-20251101",
    max_tokens=1024,
    betas=["effort-2025-11-24"],
    output_config={
        "effort": "high"  # or "medium" or "low"
    },
    messages=[...]
)

TypeScript SDK:

const response = await client.messages.create({
  model: "claude-opus-4-5-20251101",
  max_tokens: 1024,
  betas: ["effort-2025-11-24"],
  output_config: {
    effort: "high"  // or "medium" or "low"
  },
  messages: [...]
});

Raw API:

{
  "model": "claude-opus-4-5-20251101",
  "max_tokens": 1024,
  "anthropic-beta": "effort-2025-11-24",
  "output_config": {
    "effort": "high"
  },
  "messages": [...]
}

Effort vs. Thinking Budget

Effort is independent of thinking budget:

• High effort + no thinking = more tokens, but no thinking tokens
• High effort + 32k thinking = more tokens, but thinking capped at 32k

Recommendations

1. First determine effort level, then set thinking budget
2. Best performance: high effort + high thinking budget
3. Cost/latency optimization: medium effort
4. Simple high-volume queries: low effort