Thread

HarnessTax: How Much Does the Harness Matter for Coding Agents?

233 points · 99 comments · matt_d

jswelker · 1789605356 · focus · HN ↗
Much of the extra weight of Claude Code and Codex harness are (ostensibly?) for security and alignment purposes. Whether they are effective is an open question, but leaving those dimensions out and calling it a tax is disingenuous, just turning insecurity into a negative externality.
"Why pay the waste disposal tax? Dumping into the ocean is free!"
Pi actively omits any sort of guardrails and sandboxing in the name of speed and simplicity, so it is not shocking that it is faster and simpler.
Doubling the cost of something in the name of vague security is standard operating procedure for big enterprises, maybe even quite cheap.
1. kouteiheika · 1789630689 · focus · HN ↗
  > Much of the extra weight of Claude Code and Codex harness are (ostensibly?) for security and alignment purposes.
  Um, no? Have you actually read Claude Code's system prompt and tools?
  Here's Fable's system prompt: <a href="https://github.com/navanchauhan/agent-autopsy/blob/6d9c00e541bde8879266a14a280f09c5ae75f48c/claude-code/prompts/claude-fable-5-1.md" rel="nofollow">https://github.com/navanchauhan/agent-autopsy/blob/6d9c00e54...
  There are a few lines of what I would call "for security and alignment purposes", but it's not the majority. And the majority of the bloat is from the tool descriptions.
  The system prompt in this case has pretty much nothing to do with the built-in guard rails, that is: you cannot sidestep Claude's guard rails by editing/replacing the system prompt (which you officially can with Claude Code's `--system-prompt-file`).

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