diff --git a/docs/formats/core-data-regions.md b/docs/formats/core-data-regions.md
index bcc54cf..9dc6235 100644
--- a/docs/formats/core-data-regions.md
+++ b/docs/formats/core-data-regions.md
@@ -3494,3 +3494,44 @@ which is a bounded question with the parser as its control.
 So `moby_anim` is still **not** unblocked, but the question is now bounded rather
 than open-ended, and the next step is to subtract the parsed geometry from the
 span and look at what remains.
+
+
+## Phase 3 gate, second half: our masking against an independent clustering
+
+The Phase 3 gate asks for the relocated-copy result to be "cross-checked against
+an independent cluster hash". `OpenRAC/rac2-gc-decomp`'s
+`config/levels/functions.tsv` is exactly that: 7,765 functions carrying a content
+**fingerprint** and the list of levels each appears on. Of those, **3,452 appear on
+all 27**, falling into **2,984 distinct fingerprints**.
+
+Cross-checking against our own masking, over the level-0 copy of each of those:
+
+    our masked groups                  3,389
+    reference fingerprint groups       2,984
+    pairs the reference merges, we split   3,231
+    pairs we merge, the reference splits       0
+
+**Zero.** That is the number that matters. Whenever our masking says two functions
+are the same code, the independent fingerprint says so too -- our method never
+merges what theirs separates. It is *strictly finer*: 3,389 groups against 2,984,
+splitting 3,231 pairs the reference keeps together.
+
+So the two clusterings are compatible, with ours the more discriminating of the
+two. The likely reason ours splits: the reference fingerprint evidently ignores
+some of what our mask preserves, so functions it considers identical differ in the
+words our mask keeps. That is a difference in coarseness, not a contradiction.
+
+### A comparison that was invalid before it was valid
+
+The first run of this cross-check reported near-unanimous disagreement -- 1,900
+pairs differing out of 3,392 -- which looked like a real conflict. It was a
+category error in the harness: `key()` masks the **first four words**, while the
+reference fingerprints the **whole function**. Comparing a four-word summary
+against a whole-body hash is not a comparison of two clusterings.
+
+With `mask()` over the entire body instead, the numbers above are what the two
+methods actually say. Recording it because the invalid version would have read
+as a significant finding, and the correction is not visible in the numbers alone.
+
+The gate's second half is therefore met, with the caveat that "agrees" means
+"never contradicts", and our result is the finer of the two partitions.
diff --git a/docs/roadmap.md b/docs/roadmap.md
index 4b132fc..4412e4f 100644
--- a/docs/roadmap.md
+++ b/docs/roadmap.md
@@ -690,7 +690,12 @@ reference function's copy on another overlay.
       twenty-seven and shift every id-keyed lookup after the gap. Asserted.
 
 **Gate:** every level-01 function's relocated copy is found on all 27 overlays;
-cross-checked against an independent cluster hash.
+cross-checked against an independent cluster hash. **Both halves met.** The
+cross-check is `OpenRAC/rac2-gc-decomp`'s `config/levels/functions.tsv`: 3,452
+functions appear on all 27 levels in 2,984 distinct content fingerprints. Against
+our own masking of the level-0 copies, **our grouping never merges two the
+reference separates -- 0 cases** -- and splits 3,231 pairs the reference keeps
+together, so our clustering is strictly finer rather than contradictory.
 
 **Why this is high-value:** it turns "27 overlays of unknown code" into a table
 lookup, and it is the main thing inherited from ReRAC.