diff --git a/docs/re/METHOD.md b/docs/re/METHOD.md
index f25c26a3..8f634072 100644
--- a/docs/re/METHOD.md
+++ b/docs/re/METHOD.md
@@ -3384,3 +3384,42 @@ separately, because it is the actual discipline:
 was preceded by a screenshot that was looked at. The navigation was wrong twice
 and the measurement was never in doubt, because nothing downstream trusted the
 button presses.
+
+## A finding is only as portable as the tool that produced it, and a recipe that reads as complete is the dangerous kind
+
+Four commits on Canary's `sylpheed-re` branch existed **only inside the container**
+and were on no remote. Findings resting on them cited them the way one cites a
+public reference — *"canary sylpheed-re `d90d14e02`, already built"* — a line that
+reads as a complete recipe and is reachable from nowhere but that one box.
+
+The exposure was not marginal:
+
+| the commit adds | without it |
+|---|---|
+| `blend=` per draw | a draw log carries **no blend state at all**, so the 35-element oracle that decoded the blend bit — and let the port delete an authored map — could not be re-derived. Not approximately; not at all |
+| vertex dump 8 → 64 | the log **silently drops** four quads of a six-quad batch, which is why four additive elements read as absent |
+| RT state / resolves / PS constants | *"is there a post-process pass?"* cannot be asked, because it is a question about render targets |
+| a texture **content** hash | a rotating triple buffer is **indistinguishable** from one decode per present — the confusion that cost two withdrawn positions on `units/second` in one day |
+
+⚠️ **The failure is silent and delayed by design.** The recipe looks complete, so
+nobody checks it; it fails only for someone on a different machine, long after the
+person who wrote it could still say what the flag did. Nothing in the repository
+disagrees with itself in the meantime, so no consistency check fires.
+
+📌 **Citation checkers do not cover this class**, and it is worth knowing why: they
+scan for *repository paths* that fail to resolve. An instrument living in another
+container is not a path at all, so it never enters the check. The port's
+`check-citations` catches a stale pointer to a committed artefact — the
+*recoverable* case — and slides straight past an artefact that does not exist
+outside a container.
+
+**The discipline:** when a finding's reproduce recipe names a sha, a branch, a
+binary or a flag, ask *where that lives*. If the answer is "this machine", the
+finding is not reproducible and the fix is to export the thing, not to describe it
+better. `tools/canary-patches/` exists for exactly that.
+
+⚠️ **And the audit only works pointed at yourself.** Both agents ran the same audit
+on the same day. One found a stale path to an artefact that *was* committed —
+recoverable. The other found four artefacts that existed nowhere else — lost.
+Neither could have found the other's, because each is invisible from the far side
+of the wall.