LG AI Research's PCBWorld-Bench scores routers on real KiCad boards. In our recorded runs, ProtoFlow Studio comes back clean on 98 of 99 small boards and all 30 attempts across 10 medium boards. Every attempt counts, failures included.
The ProtoFlow team · Published 13 October 2026
A board is a Clean Pass when every net is connected and KiCad's own design-rule check finds zero error-level violations under the benchmark's rules. One missing connection scores zero.
Every method the paper reports with one attempt per board (its Tables 21 and 22), and ours. Sorted by score.
| Method | D3-A, one attempt | Time per attempt | D3-B score | Time per attempt |
|---|---|---|---|---|
| Reference (the benchmark's own boards) | 1.00 | not reported | 1.00 | not reported |
| ProtoFlow Studio + Claude Opus 5.5 | 0.990 | median 32 s | 1.000 | median 46 s |
| ProtoFlow router (no model) | 0.919 | median 0.1 s | 0.900 | median 0.7 s |
| PPO (w/o finish) | 0.81 | 3.05 s | 0.22 | 14.44 s |
| Freerouting | 0.75 | 7.09 s | 0.64 | 9.94 s |
| KiCadRoutingTools | 0.74 | 0.65 s | 0.20 | 3.27 s |
| PPO | 0.68 | 1.83 s | 0.21 | 10.77 s |
| PPO (terminal) | 0.65 | 2.58 s | 0.15 | 12.60 s |
| GRPO | 0.64 | 3.54 s | 0.07 | 11.20 s |
| GPT-5.4 | 0.42 | 231.15 s | 0.00 | 865.83 s |
| Qwen3.5-397B | 0.19 | 81.82 s | 0.00 | 222.29 s |
| GPT-5.4-nano | 0.15 | 100.76 s | 0.00 | 510.25 s |
| GPT-5.4-mini | 0.13 | 56.85 s | 0.00 | 422.06 s |
| OrthoRoute | 0.02 | 2.20 s | 0.00 | 9.30 s |
Published rows as reported (source: arXiv 2607.05915v4). Their times are per attempt. Ours are wall-clock medians: the agent's include model time on a shared subscription, the router's include saving and checking the board. 95% intervals for our agent (Wilson, attempts treated as independent): D3-A 0.945 to 0.998; D3-B 0.886 to 1.000.
Share of attempts finished with a Clean Pass by each point in time. The solid line is ProtoFlow Studio with Opus 5.5, the dashed line ProtoFlow's router alone.
The router alone settles within seconds; the agent spends its time checking and repairing the boards the router could not finish. The agent's slowest attempts include waits on the model API while four boards ran at once.
Eight of the larger boards with a permissive license, as routed by ProtoFlow Studio on its first attempt. Copper only: top layer in copper, bottom layer in blue.
Clean Pass 1 of 1 · 68 s · 0 vias, 45 mm of track (reference: 0 vias, 52 mm) · 14 connections, 22 x 8 mm
Design by Jan Mrázek, github.com/yaqwsx/NavigationThing, MIT. Copyright (c) 2016 Jan Mrázek License. Image: ProtoFlow's modified version (re-routed copper only), October 2026.
Clean Pass 1 of 1 · 38 s · 1 via, 128 mm of track (reference: 6 vias, 116 mm) · 15 connections, 22.1 x 21.5 mm
Design by Marcin Białoń, github.com/mbialon/esp8266_wi07_3_adapter, MIT. Copyright (c) 2015 Marcin Białoń License. Image: ProtoFlow's modified version (re-routed copper only), October 2026.
Clean Pass 1 of 1 · 22 s · 0 vias, 154 mm of track (reference: 0 vias, 152 mm) · 15 connections, 26 x 18.4 mm
Design by z2amiller (Andy Miller), github.com/z2amiller/sensorboard, MIT. Copyright (c) 2015 z2amiller License. Image: ProtoFlow's modified version (re-routed copper only), October 2026.
Clean Pass 1 of 1 · 33 s · 0 vias, 93 mm of track (reference: 0 vias, 100 mm) · 22 connections, 25 x 18 mm
Design by Phillip Pearson, github.com/myelin/breakout-boards, MIT. Copyright (c) 2015 Phillip Pearson License. Image: ProtoFlow's modified version (re-routed copper only), October 2026.
Clean Pass 1 of 1 · 119 s · 5 vias, 77 mm of track (reference: 2 vias, 69 mm) · 22 connections, 11.4 x 11.4 mm
Design by OLIMEX Ltd, github.com/OLIMEX/BB-PWR-8009, Apache-2.0. License. Image: ProtoFlow's modified version (re-routed copper only), October 2026.
Clean Pass 1 of 1 · 43 s · 4 vias, 295 mm of track (reference: 3 vias, 293 mm) · 18 connections, 48.3 x 30.7 mm
Design by Mikael Andersson (mik4el), github.com/mik4el/rufs, Apache-2.0. License. Image: ProtoFlow's modified version (re-routed copper only), October 2026.
Clean Pass 3 of 3 · 28 s · 3 vias, 209 mm of track (reference: 8 vias, 210 mm) · 38 connections, 22.2 x 16.5 mm
Design by OLIMEX Ltd, github.com/OLIMEX/MOD-MPU9150, Apache-2.0. License. Image: ProtoFlow's modified version (re-routed copper only), October 2026.
Clean Pass 3 of 3 · 69 s · 1 via, 964 mm of track (reference: 3 vias, 1020 mm) · 67 connections, 69.8 x 52.1 mm
Design by James Watts, github.com/james481/cat-trainer, BSD-3-Clause-Clear. Copyright (c) 2016 – 2017, James Watts. All rights reserved. License. Image: ProtoFlow's modified version (re-routed copper only), October 2026.
Board images are modified versions of each design (re-routed copper, copper layers only), shown under that design's own license with attribution on every card. No endorsement by the designers is implied. Sources: PCBWorld, arXiv 2607.05915v4 · PCBWorld code · PCBench.
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