https://github.com/ckpxgfnksd-max/prompt-compressor-openclaw

Saves 20-40% of LLM tokens by teaching the agent to write compressed responses, compressed memory logs, and compressed pre-compaction summaries. Works via SOUL.md instructions — no hooks, no extra process, no dependencies. Also provides explicit compression when the user asks to compress a prompt. Use when the user asks about reducing token costs, optimizing API spend, compressing prompts, or making the agent more efficient.

Prompt Compressor

Saves tokens on turns 2+ by making all agent output compressed from the start.

How it works

This is NOT a hook (hooks require newer OpenClaw versions). Instead, it works by adding instructions to SOUL.md that make the agent:

1. Write compressed responses — no filler, no hedging, lead with answers
2. Write compressed MEMORY.md — one fact per line, no narrative
3. Write compressed daily logs — decisions only, not discussions
4. Compress pre-compaction flushes — facts not paragraphs

The savings compound: compressed responses → compressed history → compressed compaction summaries → fewer tokens on every subsequent turn.

Install

Append the contents of soul-snippet.md to the user's SOUL.md:

cat {baseDir}/soul-snippet.md >> ~/.openclaw/SOUL.md

Or if using a workspace SOUL.md:

cat {baseDir}/soul-snippet.md >> <workspace>/SOUL.md

Then start a new session (/new) so the updated SOUL.md loads.

When user asks to compress a specific prompt

Apply these rules manually to their text:

Remove

• Greetings: "Hello", "Hi", "Hey", "Good morning"
• Sign-offs: "Thanks", "Best regards", "Cheers"
• Hedging: "Could you please", "I was wondering if", "Would you be able to"
• Filler: "just", "really", "very", "basically", "actually", "literally", "honestly"
• Padding: "I think that", "In my opinion", "It is worth mentioning"

Shorten

• "due to the fact that" → "because"
• "in order to" → "to"
• "with regard to" → "about"
• "take into consideration" → "consider"
• "come up with" → "create"
• "figure out" → "determine"
• "a large number of" → "many"
• "at this point in time" → "now"
• "for the purpose of" → "to"
• "it is important to note that" → "note:"
• "it would be a good idea to" → remove entirely

Normalize

• "yeah", "yep", "yup" → "yes"
• "nah", "nope" → "no"

Never touch

• Code blocks, inline code, URLs, quoted strings, numbers, file paths, ALL_CAPS

Rules

• When installing, ALWAYS append to SOUL.md, never overwrite it
• Tell the user to run /new after installation so the new SOUL.md loads
• Show a before/after example so the user sees the difference