Breaking Down Claude's 26k+ Token System Prompt

a year ago

Claude's system prompt was revealed, showing it's 16,739 words long, much longer than OpenAI's o4-mini prompt.
The system prompt includes tool definitions, instructions, and behavior guidelines for Claude.
Nearly 80% of the prompt pertains to tools, detailing how and when to use them.
The prompt includes hotfixes to address common LLM issues, such as counting characters accurately and avoiding hackneyed poetry.
Anthropic uses XML-style tags for structure, but managing and versioning such a large prompt remains a challenge.
The prompt highlights that chatbots are more than just models; they involve extensive tooling and iterative design.

Hasty Briefsbeta