diff --git a/docs/fabric-pin.md b/docs/fabric-pin.md
index 869d00b..5eac121 100644
--- a/docs/fabric-pin.md
+++ b/docs/fabric-pin.md
@@ -30,7 +30,7 @@ drift structurally impossible rather than merely noticed.
 
 AZ-06 pins the Azazel-Fabric release tag:
 
-`v0.9.0rc3`
+`v0.9.0rc4`
 
 ### Why a release candidate
 
@@ -59,6 +59,27 @@ ref, and `runtime/effect_projection.py` had to refuse them rather than flatten
 them. Rewriting a producer's identifier is not an option: `surface:http-8080`
 is a well-formed reference to a surface that does not exist.
 
+`v0.9.0rc4` is the pin now. It narrows `EffectObservation` to the two
+authority classes an observation can have observed — `observed_fact` and
+`active_materialized` (Azazel-Fabric#52) — and refuses the four others that
+`rc3` accepted. **It is the first non-additive candidate in the series**, and
+the reason this repository moves to it is not that the grammar changed
+somewhere: AZ-06 is a *producer* of `EffectObservation`, so this is the
+contract it emits under.
+
+The move costs nothing here because `runtime/effect_projection.py` already
+derives the class from the observation's status and can emit only those two —
+`observe_effect` has no parameter for it. What changes is that this became a
+guarantee of the contract instead of a habit of one function. A future edit
+introducing a third class would now be refused at the boundary rather than
+accepted and carried downstream.
+
+The pin was verified before the move rather than after: the `v0.9.0rc4` tag's
+own checkout reproduces `release/v0.9.0rc4.digest.json`, whose signature
+verifies under the release owner's key, and this repository's full suite runs
+green against it. **What is signed is that digest; the git tag itself is
+unsigned** and is not a trust boundary (Azazel-Fabric#56).
+
 That refusal was recorded as a test designed to fail when the pin moved, and it
 did. The stand-in values are gone from
 `tests/test_effect_contracts_producer.py`; AZ-06's own references now go into
@@ -208,4 +229,5 @@ updates `pyproject.toml`, this document, and the CHANGELOG together.
 | `c3154de` (2026-08-15) | `v0.5.0` → `v0.6.0` |
 | `77ad0cd` (2026-08-22) | `v0.6.0` → `v0.8.0` |
 | Deception#28 AC-7 (2026-09-20) | `v0.8.0` → `v0.9.0rc2` |
-| `effect_contracts` producer (2026-09-20) | `v0.9.0rc2` → `v0.9.0rc3` (current) — the reference grammar; see above |
+| `effect_contracts` producer (2026-09-20) | `v0.9.0rc2` → `v0.9.0rc3` — the reference grammar; see above |
+| `EffectObservation` authority narrowing (2026-09-20) | `v0.9.0rc3` → `v0.9.0rc4` (current) — AZ-06 emits this record, so it moves with the contract it emits under; see above |
diff --git a/pyproject.toml b/pyproject.toml
index 315b5b5..e0dc1a5 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -12,7 +12,7 @@ license = {text = "MIT"}
 authors = [{name = "01rabbit"}]
 dependencies = [
     "PyYAML>=6.0",
-    "azazel-fabric @ git+https://github.com/01rabbit/Azazel-Fabric.git@v0.9.0rc3",
+    "azazel-fabric @ git+https://github.com/01rabbit/Azazel-Fabric.git@v0.9.0rc4",
 ]
 
 [project.optional-dependencies]