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Simple Prompt Switch on Opus

CLAUDE_CODE_SIMPLE_SYSTEM_PROMPT=1 on Opus 5.5. Set CLAUDE_CODE_SIMPLE_SYSTEM_PROMPT=1 and use --model claude-opus-5-5.

Size​

PartCharacters
system[0]78
system[1]62
system[2]5,627
messages[0].content[0]592
messages[0].content[1]2
messages[1].content[0]8,850
System blocks only5,767
Everything shown here15,501
Tools sent12

Sizes count the text after the placeholders are in place. Each placeholder counts at its own length.

What to Notice​

  • The text is the same as the default on Opus 5.5.

Full Text​

This variant sends exactly the same text and tools as Default, Lean Prompt. The page for that variant has the full text.

Compared to the Default​

The diff below starts from Default, Lean Prompt. Lines that start with - are only in the baseline. Lines that start with + are only here.

There are no differences in the text.

The tool list is the same as the baseline.