LeanREA: Same Accuracy as REA, 38% Faster and 35% Cheaper

Agent setups that lean on MCP work, but they are not free to run. A new comparison says one 8 KB skill file, LeanREA, does what REA does using plain CLI tools instead of MCP — and it comes out ahead on speed, cost and turns.

The headline: same accuracy, 38% faster, 35% cheaper, 56% fewer turns. That is measured across 36 runs, so it is a comparison and not a promise.

What Happened

LeanREA is a single skill file, 8 KB in size, built to match what REA does while skipping MCP entirely in favor of plain CLI tools.

The benchmark ran in Claude Code on Sonnet 5.5, 36 runs, LeanREA against REA. The results:

• 38% faster
• 35% cheaper
• 56% fewer turns
• Same accuracy

Why It Matters

Turns are the quiet cost of agent work. Every extra round trip is tokens spent and time lost, and the 56% drop in turns is the number that explains the other two — fewer back-and-forths means less to pay for and less to wait on. The 35% cheaper figure lands directly on whatever you budget for Claude Code, and the accuracy result says nothing was traded away to get there.

The catch worth naming: this is one benchmark, in one setup, with 36 runs, so treat it as a strong signal rather than a settled rule. If you already run REA-style agent work in Claude Code, this is a comparison to keep in mind the next time you tune your setup — plain CLI tools in a single small file may be doing more of the work than the extra layer around them.

Wrapping Up

You now have the claim and the numbers behind it: an 8 KB file, no MCP, 38% faster and 35% cheaper at the same accuracy. Whether that holds in your own projects is something only your own runs can tell you — but the turn count alone makes it worth a look.