Building BoardRoom on Qwen Cloud for the Global AI Hackathon Series. (Track 3: Agent Society)

Lluis Estape — Sat, 18 Jul 2026 13:01:28 +0000

I built a society of AI agents to review circuit boards. Then I tried to prove it was better, and nearly fooled myself three times.

Every hardware engineer knows the specific dread of clicking "order boards." Three weeks
and a few hundred euros later, a package arrives, and you discover you forgot a
decoupling capacitor, or your I²C bus has no pull-ups. Nothing to do but respin.

So for the Qwen Cloud hackathon I built BoardRoom: not one AI reviewer, but a
society of five — power integrity, signal integrity, connectivity/ERC, DFM & layout,
and firmware bring-up — that inspect a real KiCad project through the KiCad MCP server,
file findings that must cite tool evidence, and argue with each other under a Moderator
before signing off.

The build went fine. It's what happened when I tried to prove the society was better
than a single big agent that turned out to be the interesting part. Three separate times,
my benchmark was quietly lying in my favor. Here's each one, because I think the bugs are
more instructive than the architecture.

The setup

The measurable claim Track 3 asks for is "a demonstrable efficiency gain over
single-agent baselines." So:

Corpus: stock KiCad demo boards.
Seeding: a script injects reproducible defects with a ground-truth manifest — removed decoupling cap, swapped SDA/SCL, missing I²C pull-ups, floated enable pin, renamed power rail. One board (a pure-analog valve preamp) gets no defects, as an honesty check that nobody invents findings.
Two configs, same inputs, same token gateway: the society (five cheap specialists on qwen-flash/qwen3-vl/qwen3-coder, one qwen3-max Moderator) versus a baseline of one qwen3-max agent with all the tools and a generalist prompt.

Then I ran it. Recall: 0.00. The society caught zero of the seeded defects.

Lie #1: my agents were right, my scoring was wrong

Rather than tune anything, I dumped the actual findings. And there it was:

[critical] connectivity_erc: Hierarchical label VCC_PIC has no matching sheet pin
                             in the parent sheet, creating an unconnected rail

That's exactly the defect I'd seeded. The society found it. The scorer called it a miss.

Why? The matcher compares structured fields — affected_nets, affected_components —
and the agents had left them empty, naming the net only in the prose of the claim.

That's not a benchmark artifact. That's a product bug I'd have shipped: the report's
headline visualization — a blast-radius graph linking findings to the nets and parts they
touch — is built entirely from those fields. My centerpiece visual was silently empty
and I hadn't noticed, because I'd been reading the claims, which looked great.

The prompts already asked for those fields politely. qwen-flash ignored it. Making the
final instruction blunt ("a claim that names a net while leaving these arrays empty is
INVALID — the impact graph is built from these fields, not from your prose") took
structured coverage from 0/9 findings to 9/15, and recall from 0.00 to 0.50.

Lesson: when a model "ignores" a field, check whether anything downstream actually
depends on it. Mine did, and the benchmark found the bug my eyes didn't.

Lie #2: I'd accidentally built a strawman

Now the baseline. It scored 0.00, produced zero findings, and burned 6.8K tokens in 29
seconds. I could have shipped that. "Single agent finds nothing, society wins" — a
beautiful chart.

Except: 6.8K tokens is nothing. A generalist reviewing a whole board can't be done in
29 seconds. So I looked.

I'd named the baseline agent moderator so it would inherit the wildcard "all tools"
entry from my default allowlist. But registry.yaml overrides the moderator down to
three overview tools — because in the society, the chair doesn't do analysis. My
"single agent with all 24 tools" had been reviewing boards nearly blind.

A tool-starved baseline isn't a baseline. It's a strawman, and it's exactly the thing
a judge should nuke a submission for. Fixed: the baseline now builds its allowlist from
defaults, genuinely getting every tool. Its token use went 6.8K → 63K.

Lie #3: I was grading the baseline on handwriting

Still 0.00, but now doing real work. Fine — maybe one agent really does drown in 24
tools? That's a great narrative. I nearly wrote it.

Instead I printed its raw output:

{ "id": "B-001",
  "title": "Hierarchical label mismatch for VCC_PIC",
  "description": "...breaking connectivity.",
  "evidence_ids": ["EV-0005"] }

The baseline found the defect too. Every finding was thrown away at the schema
boundary because it wrote title/description/evidence_ids instead of
claim/evidence/recommendation.

And whose fault was that? Mine. Each specialist prompt carries a full worked JSON example
of the finding shape. The baseline prompt I'd dashed off didn't. I was measuring prompt
quality and calling it architecture.

I gave the baseline the same worked example the specialists get. I also normalized net
names in the matcher — KiCad legitimately calls the same net VCC_PIC or
/pic_sockets/VCC_PIC, and a correct answer shouldn't lose on a naming convention.

Notice the pattern: all three bugs pointed the same direction. None of them made the
society look worse. That's not coincidence — it's what motivated reasoning looks like
from the inside. You stop debugging when the number agrees with you.

What the honest numbers say

Six boards, twelve seeded defects, two independent runs per config, because LLMs are
nondeterministic and one run isn't a measurement.

	society	baseline (1× qwen3-max, all tools)
Seeded-defect recall (mean)	0.29	0.21
Cost per corpus	$0.147	$0.429
Prompt tokens	792K	312K
Findings surfaced	49–56	6–10
Hallucination rate	0.00	0.00

Read the token row and the cost row together, because that's the whole story:

The society burns 2.5× MORE tokens and costs 2.9× LESS.

Five cheap specialists doing more total work are dramatically cheaper than one
expensive generalist doing less. The win isn't "multi-agent is smarter." It's that
decomposition lets you route by role instead of by model size — you only pay
flagship prices for the one job that actually needs a flagship: adjudicating conflicts.
That number reproduced to within 2% across runs.

And the thing I'm not claiming: the society led on recall in both runs, but by exactly
one defect out of twelve. With n=2, that's noise — I watched the same config score
0.50 and 0.00 on the same board across runs. So the honest claim is "comparable, possibly
slightly better," and that's what the README says.

The most useful result is the one that makes my project look bad

Absolute recall is low for both configs — 0.21 to 0.29. I could have quietly picked
easier defects. Here's why it's low instead:

Most of the defects I seeded are invisible to every tool that exists. Removing a
decoupling cap creates an absence — no KiCad tool reports "a part that should be here
isn't." A swapped SDA/SCL is electrically valid, so ERC has nothing to say. The only
class anything reliably caught is rail-rename/floating-pin, because ERC and net listings
actually surface it.

That's not an indictment of the agents. It's a finding about EDA tooling: the reasoning
layer is now ahead of the observability layer. These models can absolutely reason about
a missing bypass cap — they just have no instrument that reports its absence. The
bottleneck isn't intelligence. It's that we never built the tool, because no human needed
one to eyeball a schematic.

I think that's the most interesting thing I learned, and it only showed up because I
reported a bad number instead of engineering around it.

What I'd tell someone starting one of these

Evidence gating works. Every finding must cite a real cached tool-call ID, and uncited claims are rejected at the boundary — not discouraged in a prompt. Hallucination rate: 0.00 across every run, both configs. Make it structural and you stop arguing with the model about honesty.
Enforce scope in code, not prose. Each specialist's tool allowlist is enforced before the call. Prompts are suggestions; allowlists are physics.
Route by role, not by size. This is where the 2.9× lives.
Debug the results that flatter you. All three of my bugs produced better numbers. If I'd stopped at the first good chart, I'd have submitted a rigged benchmark with a straight face.

One last confession: BoardRoom's negotiation engine — bounded two-round debates,
evidence-cited rulings, fully unit-tested — never fired on real data. Across the whole
corpus, no two specialists ever produced conflicting findings. Their scopes are narrow
enough that they rarely collide. The repo ships a clearly-labeled synthetic fixture to
demonstrate the viewer, and says so in the README, because the alternative is faking a
fight and calling it a demo.

That's a real limitation of the design, discovered by measuring instead of assuming. Which
is, I think, the actual point.

BoardRoom is open source (MIT): https://github.com/lluisestape-upc/boardroom — built on
Qwen models via Alibaba Cloud Model Studio, with the KiCad MCP server. Benchmark method,
raw numbers and limitations: docs/BENCHMARK.md.

DEV Community: Lluis Estape