Claude 4’s system prompt just leaked. 10,000 words showing exactly how the model is told to think, respond and behave.

It’s not just trained on what to say but how to act.

The prompt is packed with layered logic.

→ Explain limitations before answering.
→ Stay on topic in long chats.
→ Use tools like APIs and web search precisely.
→ Block harmful or off-policy requests without escalation.

These constraints, behaviours and values aren’t accidental. They’re engineered.

This is alignment in action. Part philosophy, part code, part safety design.

LLMs aren’t just prediction engines anymore. They’re systems with behaviour stacks, memory scaffolds and language-based guardrails.

Every output is shaped by constraint as much as capability.

The more we understand how they’re built, the better we can use them.

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Credit: Endrit Restelica


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