Claude Code with CaveMan(opensoure skill): Cuts Token Use From 70 to 20 Per Reply

Some issues with Claude opus is that it burns a lot of tokens, so sessions fill up very quickly.

A skill called Caveman (OpenSource) its a compression Layer Ask a normal Claude Code session to diagnose a React re-render bug and you get something like this:

The likely cause of the re-render is that the component is receiving a new object reference on every render. Inline objects are recreated each time the component runs, so even if their contents are identical, React's shallow comparison treats them as different values. As a result, any memoized child component or dependency check will see the prop as changed and re-render. A good fix is to wrap the object creation in useMemo so React can preserve the same reference between renders unless its actual dependencies change.

That's 70 tokens. With Caveman active, the same diagnosis comes back as:

"New object ref each render. Inline object prop = new ref = re-render. Wrap in useMemo."

20 tokens. A third of the cost, same fix.

Where the tokens actually go

Your prompt is usually the smallest piece. Project context, meaning files Claude reads, CLAUDE.md, diffs, tool output, adds more. Agent work, meaning tool calls and test output, adds more on top of that.

Claude's own answer is where a surprising share of it piles up. The explanation, the recap of every file touched, the "happy to help" intro, the polished closing paragraph. Run a model like Opus 4.8 and that prose habit gets worse, not better.

None of it is necessary after a routine fix. You don't need a paragraph on what broke or a summary at the end. You need this:

Fixed auth expiry check.
Changed <= to <.
Tests pass.

That's the whole update. Caveman targets exactly that category, Claude's output, and leaves prompt handling and context management alone.

Uber is the cautionary tale worth knowing. The company burned through its entire 2026 artificial intelligence budget in four months, then capped spend at $1,500 per employee per month. Token costs are heading in a direction where more companies land in the same spot. Cutting prose you don't read is an easy fix before that kind of cap gets forced on you.

There's a second cost that doesn't show up on any invoice: your own time. A wall of explanation after a one-line fix means you read and sort through it before confirming the fix landed. Cut the wall, and you stop skimming for reassurance you didn't ask for. You just read the result.

Setting it up

Install with the official script:

# macOS / Linux / WSL / Git Bash
curl -fsSL https://raw.githubusercontent.com/JuliusBrussee/caveman/main/install.sh | bash

# Windows (PowerShell 5.1+)
irm https://raw.githubusercontent.com/JuliusBrussee/caveman/main/install.ps1 | iex

Invoke it with:

/caveman

Or toggle it mid-session with a plain prompt:

talk like a caveman

Switch back with:

stop talk like a caveman, return to normal mode

When to skip

Caveman is built for execution, not judgment. If you already know what needs to happen and just want Claude to do it and confirm, use it. If you're still figuring out the plan, it works against you.

Skip it when you're learning a new framework, tracing an unfamiliar architectural problem, or asking Claude to teach you something. A compressed answer thins out exactly the explanation you came for.

Skip it for high-stakes calls too, the ones where you want tradeoffs spelled out in full:

• Should this product move from REST to GraphQL?
• Should this monolith split into services?
• Is this authentication model secure enough?

if you're running subagents whose output feeds into another agent instead of your own eyes, terse mode is close to free. Caveman doesn't replace reasoning its for compression when you already know the answer and just need Claude to confirm it.