Course / Lesson 4 of 6
16 min · sanitized real case
Visual inspection discipline
Objective: Decide when a model may inspect an image — and why below a pixel threshold the answer is "never", by rule rather than by judgment.
First, in plain language
Ask a vision model to describe a large image and it errs once in a while. Ask it to describe a tiny image and it does not say "I can't see" — it invents, confidently. In the real mission, a small logo became a "multi-agent system diagram" and a 1×1 pixel became a "chart".
The fix is not a better model or a stricter prompt. It is a permanent rule: any image with ≤128px in any dimension is never model-inspected. It gets a safe kind and null structure claims — by rule, no exceptions.
Open the technical layer
The media phase covered 5,386 paths (5,186 images + 200 videos): 5,340 inspection records (99.1%) + 46 named blocked + 0 uninspected. Coverage was not the problem — fabrication was:
| Fact | Number |
|---|---|
| Proven fabrications on ≤128px images | 11 |
| Re-fabrications in the "strict" re-inspection (30 reinstates) | 15 |
| Accumulated grounded : fabricated sampling | 43 : 1 (the 1 flagged) |
| Records marked visual_suspect | 40 |
Three hard lessons:
1. Quarantine worked; re-inspection did not. Of 30 items reinstated with an "if too small, say you can't see" prompt, 15 re-hallucinated. The model does not gain humility from instructions — hence a pixel rule, not a prompt rule.
2. Rule > model flag. A flag stored in a metadata field dies on the next ledger rebuild. The ≤128px rule was encoded in the builder: every rebuild re-applies it, and the flags propagate.
3. "Safe by rule" is a result, not a gap. A 1×1 image with a safe kind and null structure claims has an honest final state — better than a pretty invented description.
Which images may a model inspect?
Rule: if any dimension is ≤128px, the answer is "never by model" — no matter how sharp the image looks.
img-01 · 1×1 px
Single pixel, likely tracking residue.
img-02 · 48×48 px
A crisp favicon of a known brand.
img-03 · 128×128 px
A well-defined square avatar, "almost large".
img-04 · 64×900 px
A very tall side strip of a page.
img-05 · 129×64 px
A wide, short banner — the width "escapes" by 1px.
img-06 · 640×480 px
A readable line-chart screenshot.
img-07 · 300×300 px
A square photo of a whiteboard.
img-08 · 2048×1536 px
A high-resolution photo of a room.