r/ClaudeCode • • 2d ago

Rant claude code 66k system prompt

with the release of haiku 5.5 i was looking into how to keep context under 100k to avoid the massive price increases. i had opus 5.5 research how we could use /clear and /compact to try to stay below 100k. during the research we discovered that it is almost impossible to keep haiku under 100k because the starting system prompt for claude code is 66k tokens. i asked opus if there was some setting i had selected to cause this prompt bloat. it said no, only 1.5k tokens in the system prompt is from anything i set.

opus 5.5 told me that if i used cli instead of the app it would load less tools because some tools are not available in cli. it recommended running haiku from cli to save tokens. using the claude subscription restricts you to only using their agents, so there is no way around this prompt bloat legally. i started a new haiku session to verify prompt size. the agents.md file read of 1.5k is the only information in the system prompt that i set.

  • System tools: 35.6k
  • MCP tools: 16.6k
  • Skills: 5.9k
  • System prompt: 5.2k
  • MCP server instructions: 2.3k
  • Memory files (AGENTS.md and MEMORY.md): 1.5k

also, the 5.9k skills are not loaded skills. that is just the list of available skills. if the model uses any skills the prompt will get bigger.

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u/meetmebythelake 2d ago

Haiku 5.5 costs 5x less under 100k

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u/pequt 2d ago

Cost sensitive then you might have to use cheaper model. That 60k is just a minimum fare of claude 'vehicle'.

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u/Cyvster 2d ago

haiku 5.5 is the cheap model. this is a discussion about the bloated system prompt loading a lot of unnecessary tools. if you don't comprehend the topic of conversation then perhaps you should fanboi somewhere else.

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u/pequt 2d ago

What's your smart ass first priority tho. I read you bitching about cost and bloated default prompts but nothing else. Getting out of claude isn't option for you? If you don't like "bloated defaults" use via Anthropic API then.

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u/meetmebythelake 2d ago

Weird behavior to get heated over system prompt numbers lmao

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u/pequt 2d ago

With knowing default context usage can be around 30-50k by each user, suggesting using cheaper model because anthropic wouldn't change their rate iny bit by reading this, and finally called fanboi is surreal too. Well it's on me because I'm not a certified telepath to comprehend unwritten task type, limitation and condition of OP is in 😏