A free Claude skill that reviews your system design against the 7 building blocks and the non-functional "-ilities" — what scales, what breaks, and the questions a senior would ask.
Paste a design doc, describe your architecture, or share a diagram. Review with Blocks decomposes it into blocks and forces, flags the wrong and missing ones, rates the "-ilities" that actually matter for your system, and hands you the questions a senior would ask in the review. It judges the architecture, not your code style. It's the review end of design → build → review.
A design doc, an architecture description, or a diagram — including the output of Design with Blocks.
Decomposes your design into the 7 blocks + 3 forces, and flags the wrong, missing, or over-engineered ones.
Only the ones your system makes load-bearing — each holds, at-risk, or gap, with the tradeoff it costs.
The 3–5 pointed questions that expose whether the design really understood its forces.
Run on a photo-gallery design. Notice it respects the design's intentional restraint, then finds the two things that actually matter for this system.
VERDICT
The shape is right — the restraint is the design, not a flaw.
Two gaps, both on the source-of-truth file store.
FINDINGS
[BLOCKER] Durability — irreplaceable photos, only the laptop as a
second copy, no backup/replication named.
[RISK] Write-auth — "no login" is fine for reads, but the publish
endpoint still needs to authenticate the write.
[POLISH] Tag/date search scans raw files — fine now; revisit at scale
(a database today would be over-engineering).
THE -ILITIES THAT MATTER HERE
Latency ✅ holds KV caches + CDN
Availability ✅ holds static reads survive the laptop offline
Durability ⛔ gap file store has no backup story
Consistency ⚠️ at-risk partial-publish window on flaky wifi
Write-security ⚠️ at-risk publish needs a token
A SENIOR WOULD ASK
If the file store loses a disk tomorrow, what's the recovery path —
and is your laptop a real backup, or just the working copy?
Free and open source (Apache-2.0). Pick the surface you already use.
Then run /review-with-blocks and give it your design. Updates: /plugin marketplace update systemthinkinglab.
Settings → Capabilities → Skills → Add Skill. Download the repo, then upload the review-with-blocks/skills/review-with-blocks folder.
The courses are the graded reps — feedback on your own judgment, under real constraints.
The review tells you where this design holds and where it breaks. The skill to produce that judgment yourself — to look at any architecture and know which -ilities matter and which blocks buy them — is what Course I builds, through hands-on discovery labs, AI-graded design challenges, and case studies of Instagram, Netflix, and Uber.
Course I — $99