Project Sentinel Weekly · July 6–10 (Week 3)

A clean week in the logs, and a first look at what the AI got right — and wrong.

Aditya Nagachandra Friday, July 10, 2026 ·5 min read

Week 3 is about trust in the numbers. Last week we said the next goal was making our AI-derived metrics as accurate as possible — this week that meant a new Verify tab for human ground-truthing, and a much cleaner week in the logs to prove it out. We also want to start showing our work: what the model sees, what it says, and — honestly — where it gets it wrong.

Source of truth: scrubbing through the week

The current procedure: scrub through the video timeline, add human comments, notes, and feelings at every point that matters, and at the end it all compiles into the table you see in the logs PDF below. Right now that manual scrub is doing real work of its own — it’s teaching us the construction process itself, day by day, which is already surfacing where trades could run in parallel instead of in sequence, and how to schedule deliveries and crews around the work that’s actually coming up next.

Monday (7/6) — a crew of three lays furring strips across the joists over last week’s EPS insulation, prep work with no subfloor panels down yet.

Tuesday (7/7) — the week’s biggest day: the crew demos the exterior wall for a new entry point and rolls out full 4×8 CDX plywood subfloor sheathing across Zone C, giving the extension a rigid floor diaphragm.

Wednesday (7/8) — a two-person crew lays out 2×4/2×6 wall plates around the Zone C subfloor perimeter and finishes the remaining interior flooring.

You can pull this same log up yourself, updated daily, under Logs on beta.cambrian.world — or scroll the full week right here:

Main additions

Logs

The daily log rebuilt around three simple running counters — hours worked, deliveries, active days — instead of a page of text. Each day now shows average and peak crew size, hours worked, and flags anything the system had to estimate rather than observe directly.

Documents

A new Documents tab that mirrors our shared Drive folder — permits, invoices, drawings — directly in the platform, always kept in sync. Only people with download access can see files; only people with manage access can add or change them.

Auth and reliability

Sign-in now works with one click through Google and remembers you for two weeks. We also fixed a live-stream bug and added an alert that pages us the moment a camera stops sending photos, so outages get caught in minutes, not days.

Testing VLMs

A lot of the time, watching a site through cameras makes you a passenger to the process — you see what happened, but you can’t always tell ahead of time what you’re looking at or what comes next. We wanted to see how much a VLM could help close that gap, so we started asking it questions about what’s on screen. Here’s one worth calling out: a few noticeable points of caution in what it predicted versus what actually happened on site, and the kind of common-sense probing it took to get to the right answer.

Zone C, Kelton — the frame in question.

“Before, there were only beams running from the house to the rim joists. Now it’s become like a corrugated mesh. What is this second step called?”

First answer — wrong

“The step you are looking at is the installation of subfloor sheathing panels over the joists, combined with a radiant floor heating system…”

Correction

“They just look like thin wooden planks, beams that sit on top of the beams — are they already doing work related to heating?”

Second answer — correct

“Ah I see, you are looking at a traditional structural method called furring (or furring strips/strapping), rather than a mechanical heating layer.”

What this week actually cost

Every log doubles as a cost record. Take Week 2 (Jun 29–Jul 3) as a clean example: 5 active days, one crew, one invoice.

Next steps

1. Site Global Registration
2. Drone testing
3. Platform-led development push for 2360 Kelton Ave