diff --git a/pyproject.toml b/pyproject.toml
index 7744aef87..293c5707d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -59,7 +59,7 @@ backend = [
   # yet; pinned to a specific commit, same pattern as rankweave. Ships a
   # PyO3/maturin Rust core with no fallback wheel, so building this from
   # source needs a Rust toolchain -- see backend/Dockerfile.
-  "fast-mlsirm @ git+https://github.com/ContextualWisdomLab/fast-mlsirm.git@d025b7d237d8db7ca97a5611606c6285d5870895",
+  "fast-mlsirm @ git+https://github.com/ContextualWisdomLab/fast-mlsirm.git@09f762ded35786dd1078222a4577ff09d649816f",
 ]
 
 [tool.setuptools.packages.find]
diff --git a/tests/test_fast_mlsirm_release_dependency.py b/tests/test_fast_mlsirm_release_dependency.py
new file mode 100644
index 000000000..271ffa7e4
--- /dev/null
+++ b/tests/test_fast_mlsirm_release_dependency.py
@@ -0,0 +1,43 @@
+"""Consumer contract for the released fast-mlsirm owner dependency."""
+
+from __future__ import annotations
+
+from pathlib import Path
+import tomllib
+
+
+ROOT = Path(__file__).parents[1]
+PYPROJECT = ROOT / "pyproject.toml"
+UV_LOCK = ROOT / "uv.lock"
+OWNER_RELEASE_VERSION = "0.9.1"
+OWNER_RELEASE_COMMIT = "09f762ded35786dd1078222a4577ff09d649816f"
+OWNER_REPOSITORY = "https://github.com/ContextualWisdomLab/fast-mlsirm.git"
+STALE_CONSUMER_COMMIT = "d025b7d237d8db7ca97a5611606c6285d5870895"
+
+
+def test_backend_extra_consumes_exact_released_fast_mlsirm_owner_commit() -> None:
+    """Keep psychometric code owner-pinned to the immutable v0.9.1 release target."""
+    pyproject = PYPROJECT.read_text(encoding="utf-8")
+    assert STALE_CONSUMER_COMMIT not in pyproject
+    assert f"fast-mlsirm @ git+{OWNER_REPOSITORY}@{OWNER_RELEASE_COMMIT}" in pyproject
+
+
+def test_universal_lock_binds_fast_mlsirm_package_to_the_released_owner_source() -> None:
+    """Bind version, repository, revision, and resolved commit in one lock record."""
+    lock_text = UV_LOCK.read_text(encoding="utf-8")
+    assert STALE_CONSUMER_COMMIT not in lock_text
+
+    lock = tomllib.loads(lock_text)
+    packages = [
+        package
+        for package in lock.get("package", [])
+        if package.get("name") == "fast-mlsirm"
+    ]
+    assert len(packages) == 1
+
+    package = packages[0]
+    expected_source = (
+        f"{OWNER_REPOSITORY}?rev={OWNER_RELEASE_COMMIT}#{OWNER_RELEASE_COMMIT}"
+    )
+    assert package.get("version") == OWNER_RELEASE_VERSION
+    assert package.get("source") == {"git": expected_source}
diff --git a/uv.lock b/uv.lock
index f94e79cf4..3da51f51e 100644
--- a/uv.lock
+++ b/uv.lock
@@ -483,8 +483,8 @@ wheels = [
 
 [[package]]
 name = "fast-mlsirm"
-version = "0.8.0"
-source = { git = "https://github.com/ContextualWisdomLab/fast-mlsirm.git?rev=d025b7d237d8db7ca97a5611606c6285d5870895#d025b7d237d8db7ca97a5611606c6285d5870895" }
+version = "0.9.1"
+source = { git = "https://github.com/ContextualWisdomLab/fast-mlsirm.git?rev=09f762ded35786dd1078222a4577ff09d649816f#09f762ded35786dd1078222a4577ff09d649816f" }
 dependencies = [
     { name = "numpy" },
 ]
@@ -725,7 +725,7 @@ requires-dist = [
     { name = "certifi", specifier = ">=2024.0.0" },
     { name = "coverage", marker = "extra == 'dev'", specifier = ">=7.6" },
     { name = "cryptography", specifier = ">=42.0" },
-    { name = "fast-mlsirm", marker = "extra == 'backend'", git = "https://github.com/ContextualWisdomLab/fast-mlsirm.git?rev=d025b7d237d8db7ca97a5611606c6285d5870895" },
+    { name = "fast-mlsirm", marker = "extra == 'backend'", git = "https://github.com/ContextualWisdomLab/fast-mlsirm.git?rev=09f762ded35786dd1078222a4577ff09d649816f" },
     { name = "fastapi", marker = "extra == 'backend'", specifier = ">=0.141.1" },
     { name = "httpx", marker = "extra == 'dev'", specifier = ">=0.27.0" },
     { name = "httpx2", marker = "extra == 'dev'", specifier = ">=2.12.0" },