diff --git a/.github/workflows/sast-semgrep.yml b/.github/workflows/sast-semgrep.yml
index f8ab04b865..76c759064a 100644
--- a/.github/workflows/sast-semgrep.yml
+++ b/.github/workflows/sast-semgrep.yml
@@ -100,7 +100,7 @@ jobs:
                   *) code=true ;;
                 esac
                 case "$changed_path" in
-                  requirements*.txt|*/requirements*.txt|pyproject.toml|*/pyproject.toml|uv.lock|*/uv.lock|pylock.*.toml|*/pylock.*.toml|package.json|*/package.json|package-lock.json|*/package-lock.json|pnpm-lock.yaml|*/pnpm-lock.yaml|yarn.lock|*/yarn.lock|Cargo.toml|*/Cargo.toml|Cargo.lock|*/Cargo.lock|go.mod|*/go.mod|go.sum|*/go.sum|pom.xml|*/pom.xml|build.gradle|*/build.gradle|build.gradle.kts|*/build.gradle.kts|DESCRIPTION|*/DESCRIPTION) deps=true ;;
+                  requirements*.txt|*/requirements*.txt|pyproject.toml|*/pyproject.toml|uv.lock|*/uv.lock|pylock.*.toml|*/pylock.*.toml|package.json|*/package.json|package-lock.json|*/package-lock.json|pnpm-lock.yaml|*/pnpm-lock.yaml|yarn.lock|*/yarn.lock|Cargo.toml|*/Cargo.toml|Cargo.lock|*/Cargo.lock|go.mod|*/go.mod|go.sum|*/go.sum|pom.xml|*/pom.xml|build.gradle|*/build.gradle|build.gradle.kts|*/build.gradle.kts|DESCRIPTION|*/DESCRIPTION|poetry.lock|*/poetry.lock|pdm.lock|*/pdm.lock|Pipfile|*/Pipfile|Pipfile.lock|*/Pipfile.lock|setup.py|*/setup.py|setup.cfg|*/setup.cfg|environment.yml|*/environment.yml|environment.yaml|*/environment.yaml|bun.lock|*/bun.lock|bun.lockb|*/bun.lockb|deno.lock|*/deno.lock|Gemfile|*/Gemfile|Gemfile.lock|*/Gemfile.lock|gems.rb|*/gems.rb|gems.locked|*/gems.locked|composer.json|*/composer.json|composer.lock|*/composer.lock|conanfile.txt|*/conanfile.txt|conanfile.py|*/conanfile.py|conan.lock|*/conan.lock|vcpkg.json|*/vcpkg.json|packages.config|*/packages.config|packages.lock.json|*/packages.lock.json|deps.json|*/deps.json|Directory.Packages.props|*/Directory.Packages.props|settings.gradle|*/settings.gradle|settings.gradle.kts|*/settings.gradle.kts|gradle.lockfile|*/gradle.lockfile|buildscript-gradle.lockfile|*/buildscript-gradle.lockfile|libs.versions.toml|*/libs.versions.toml|verification-metadata.xml|*/verification-metadata.xml|mix.exs|*/mix.exs|mix.lock|*/mix.lock|pubspec.yaml|*/pubspec.yaml|pubspec.lock|*/pubspec.lock|Package.swift|*/Package.swift|Package.resolved|*/Package.resolved|Podfile|*/Podfile|Podfile.lock|*/Podfile.lock|Cartfile.resolved|*/Cartfile.resolved|renv.lock|*/renv.lock|stack.yaml.lock|*/stack.yaml.lock|flake.lock|*/flake.lock|go.work|*/go.work|go.work.sum|*/go.work.sum|deno.json|*/deno.json|deno.jsonc|*/deno.jsonc|MODULE.bazel|*/MODULE.bazel|MODULE.bazel.lock|*/MODULE.bazel.lock|WORKSPACE|*/WORKSPACE|WORKSPACE.bazel|*/WORKSPACE.bazel|maven_install.json|*/maven_install.json|Manifest.toml|*/Manifest.toml|Project.toml|*/Project.toml|.terraform.lock.hcl|*/.terraform.lock.hcl|*.MODULE.bazel|*.tf|*.tofu|*.csproj|*.fsproj|*.vbproj|*.gemspec|*.nuspec) deps=true ;;
                 esac
               done <<<"$changed"
             else
diff --git a/.github/workflows/security-scan.yml b/.github/workflows/security-scan.yml
index e04d7bf8f3..351e9d01a1 100644
--- a/.github/workflows/security-scan.yml
+++ b/.github/workflows/security-scan.yml
@@ -112,7 +112,7 @@ jobs:
                   *) code=true ;;
                 esac
                 case "$changed_path" in
-                  requirements*.txt|*/requirements*.txt|pyproject.toml|*/pyproject.toml|uv.lock|*/uv.lock|pylock.*.toml|*/pylock.*.toml|package.json|*/package.json|package-lock.json|*/package-lock.json|pnpm-lock.yaml|*/pnpm-lock.yaml|yarn.lock|*/yarn.lock|Cargo.toml|*/Cargo.toml|Cargo.lock|*/Cargo.lock|go.mod|*/go.mod|go.sum|*/go.sum|pom.xml|*/pom.xml|build.gradle|*/build.gradle|build.gradle.kts|*/build.gradle.kts|DESCRIPTION|*/DESCRIPTION) deps=true ;;
+                  requirements*.txt|*/requirements*.txt|pyproject.toml|*/pyproject.toml|uv.lock|*/uv.lock|pylock.*.toml|*/pylock.*.toml|package.json|*/package.json|package-lock.json|*/package-lock.json|pnpm-lock.yaml|*/pnpm-lock.yaml|yarn.lock|*/yarn.lock|Cargo.toml|*/Cargo.toml|Cargo.lock|*/Cargo.lock|go.mod|*/go.mod|go.sum|*/go.sum|pom.xml|*/pom.xml|build.gradle|*/build.gradle|build.gradle.kts|*/build.gradle.kts|DESCRIPTION|*/DESCRIPTION|poetry.lock|*/poetry.lock|pdm.lock|*/pdm.lock|Pipfile|*/Pipfile|Pipfile.lock|*/Pipfile.lock|setup.py|*/setup.py|setup.cfg|*/setup.cfg|environment.yml|*/environment.yml|environment.yaml|*/environment.yaml|bun.lock|*/bun.lock|bun.lockb|*/bun.lockb|deno.lock|*/deno.lock|Gemfile|*/Gemfile|Gemfile.lock|*/Gemfile.lock|gems.rb|*/gems.rb|gems.locked|*/gems.locked|composer.json|*/composer.json|composer.lock|*/composer.lock|conanfile.txt|*/conanfile.txt|conanfile.py|*/conanfile.py|conan.lock|*/conan.lock|vcpkg.json|*/vcpkg.json|packages.config|*/packages.config|packages.lock.json|*/packages.lock.json|deps.json|*/deps.json|Directory.Packages.props|*/Directory.Packages.props|settings.gradle|*/settings.gradle|settings.gradle.kts|*/settings.gradle.kts|gradle.lockfile|*/gradle.lockfile|buildscript-gradle.lockfile|*/buildscript-gradle.lockfile|libs.versions.toml|*/libs.versions.toml|verification-metadata.xml|*/verification-metadata.xml|mix.exs|*/mix.exs|mix.lock|*/mix.lock|pubspec.yaml|*/pubspec.yaml|pubspec.lock|*/pubspec.lock|Package.swift|*/Package.swift|Package.resolved|*/Package.resolved|Podfile|*/Podfile|Podfile.lock|*/Podfile.lock|Cartfile.resolved|*/Cartfile.resolved|renv.lock|*/renv.lock|stack.yaml.lock|*/stack.yaml.lock|flake.lock|*/flake.lock|go.work|*/go.work|go.work.sum|*/go.work.sum|deno.json|*/deno.json|deno.jsonc|*/deno.jsonc|MODULE.bazel|*/MODULE.bazel|MODULE.bazel.lock|*/MODULE.bazel.lock|WORKSPACE|*/WORKSPACE|WORKSPACE.bazel|*/WORKSPACE.bazel|maven_install.json|*/maven_install.json|Manifest.toml|*/Manifest.toml|Project.toml|*/Project.toml|.terraform.lock.hcl|*/.terraform.lock.hcl|*.MODULE.bazel|*.tf|*.tofu|*.csproj|*.fsproj|*.vbproj|*.gemspec|*.nuspec) deps=true ;;
                 esac
               done <<<"$changed"
             else
diff --git a/.github/workflows/strix.yml b/.github/workflows/strix.yml
index f15b29f564..125a880bf1 100644
--- a/.github/workflows/strix.yml
+++ b/.github/workflows/strix.yml
@@ -171,7 +171,7 @@ jobs:
                   *) code=true ;;
                 esac
                 case "$changed_path" in
-                  requirements*.txt|*/requirements*.txt|pyproject.toml|*/pyproject.toml|uv.lock|*/uv.lock|pylock.*.toml|*/pylock.*.toml|package.json|*/package.json|package-lock.json|*/package-lock.json|pnpm-lock.yaml|*/pnpm-lock.yaml|yarn.lock|*/yarn.lock|Cargo.toml|*/Cargo.toml|Cargo.lock|*/Cargo.lock|go.mod|*/go.mod|go.sum|*/go.sum|pom.xml|*/pom.xml|build.gradle|*/build.gradle|build.gradle.kts|*/build.gradle.kts|DESCRIPTION|*/DESCRIPTION) deps=true ;;
+                  requirements*.txt|*/requirements*.txt|pyproject.toml|*/pyproject.toml|uv.lock|*/uv.lock|pylock.*.toml|*/pylock.*.toml|package.json|*/package.json|package-lock.json|*/package-lock.json|pnpm-lock.yaml|*/pnpm-lock.yaml|yarn.lock|*/yarn.lock|Cargo.toml|*/Cargo.toml|Cargo.lock|*/Cargo.lock|go.mod|*/go.mod|go.sum|*/go.sum|pom.xml|*/pom.xml|build.gradle|*/build.gradle|build.gradle.kts|*/build.gradle.kts|DESCRIPTION|*/DESCRIPTION|poetry.lock|*/poetry.lock|pdm.lock|*/pdm.lock|Pipfile|*/Pipfile|Pipfile.lock|*/Pipfile.lock|setup.py|*/setup.py|setup.cfg|*/setup.cfg|environment.yml|*/environment.yml|environment.yaml|*/environment.yaml|bun.lock|*/bun.lock|bun.lockb|*/bun.lockb|deno.lock|*/deno.lock|Gemfile|*/Gemfile|Gemfile.lock|*/Gemfile.lock|gems.rb|*/gems.rb|gems.locked|*/gems.locked|composer.json|*/composer.json|composer.lock|*/composer.lock|conanfile.txt|*/conanfile.txt|conanfile.py|*/conanfile.py|conan.lock|*/conan.lock|vcpkg.json|*/vcpkg.json|packages.config|*/packages.config|packages.lock.json|*/packages.lock.json|deps.json|*/deps.json|Directory.Packages.props|*/Directory.Packages.props|settings.gradle|*/settings.gradle|settings.gradle.kts|*/settings.gradle.kts|gradle.lockfile|*/gradle.lockfile|buildscript-gradle.lockfile|*/buildscript-gradle.lockfile|libs.versions.toml|*/libs.versions.toml|verification-metadata.xml|*/verification-metadata.xml|mix.exs|*/mix.exs|mix.lock|*/mix.lock|pubspec.yaml|*/pubspec.yaml|pubspec.lock|*/pubspec.lock|Package.swift|*/Package.swift|Package.resolved|*/Package.resolved|Podfile|*/Podfile|Podfile.lock|*/Podfile.lock|Cartfile.resolved|*/Cartfile.resolved|renv.lock|*/renv.lock|stack.yaml.lock|*/stack.yaml.lock|flake.lock|*/flake.lock|go.work|*/go.work|go.work.sum|*/go.work.sum|deno.json|*/deno.json|deno.jsonc|*/deno.jsonc|MODULE.bazel|*/MODULE.bazel|MODULE.bazel.lock|*/MODULE.bazel.lock|WORKSPACE|*/WORKSPACE|WORKSPACE.bazel|*/WORKSPACE.bazel|maven_install.json|*/maven_install.json|Manifest.toml|*/Manifest.toml|Project.toml|*/Project.toml|.terraform.lock.hcl|*/.terraform.lock.hcl|*.MODULE.bazel|*.tf|*.tofu|*.csproj|*.fsproj|*.vbproj|*.gemspec|*.nuspec) deps=true ;;
                 esac
               done <<<"$changed"
             else
diff --git a/tests/test_changed_scope_dependency_manifest_allowlist.py b/tests/test_changed_scope_dependency_manifest_allowlist.py
new file mode 100644
index 0000000000..c7964aa57f
--- /dev/null
+++ b/tests/test_changed_scope_dependency_manifest_allowlist.py
@@ -0,0 +1,64 @@
+"""Contract: the `changed-scope` dependency allowlist covers scannable manifests.
+
+`security-scan.yml` runs `osv-scan` and `dependency-review` only when the
+`changed-scope` classifier sets `deps=true`, and that flag is restored from a
+closed filename allowlist. A dependency introduced through a manifest or
+lockfile missing from the list silently skips both supply-chain gates (Strix
+MEDIUM finding on `.github#2143`, 2026-09-13). The list must therefore cover
+every lockfile the pinned osv-scanner v2.5.1 can scan plus the manifests the
+GitHub dependency graph reads. The three gate copies share one byte-identical
+classifier block (see `test_docs_only_pr_runner_admission.py`), so this test
+reads the line from each copy.
+"""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+WORKFLOWS_DIR = Path(__file__).resolve().parents[1] / ".github/workflows"
+GATE_COPIES = ("security-scan.yml", "sast-semgrep.yml", "strix.yml")
+
+# osv-scanner v2.5.1 `docs/supported_languages_and_lockfiles.md` names, plus
+# the manifests that declare dependencies before any lockfile exists.
+REQUIRED_MANIFESTS = (
+    "requirements*.txt", "pyproject.toml", "uv.lock", "pylock.*.toml", "poetry.lock", "pdm.lock",
+    "Pipfile", "Pipfile.lock", "setup.py", "setup.cfg", "environment.yml",
+    "package.json", "package-lock.json", "pnpm-lock.yaml", "yarn.lock", "bun.lock", "bun.lockb", "deno.lock",
+    "Cargo.toml", "Cargo.lock", "go.mod", "go.sum", "go.work", "go.work.sum",
+    "pom.xml", "build.gradle", "build.gradle.kts", "settings.gradle", "gradle.lockfile",
+    "buildscript-gradle.lockfile", "libs.versions.toml", "verification-metadata.xml",
+    "Gemfile", "Gemfile.lock", "gems.locked", "composer.json", "composer.lock", "conan.lock", "conanfile.txt",
+    "packages.lock.json", "packages.config", "deps.json", "Directory.Packages.props",
+    "mix.exs", "mix.lock", "pubspec.yaml", "pubspec.lock", "Package.swift", "Package.resolved",
+    "Podfile", "Podfile.lock", "renv.lock", "DESCRIPTION", "stack.yaml.lock", "flake.lock", "vcpkg.json",
+    "deno.json", "deno.jsonc", "MODULE.bazel", "MODULE.bazel.lock", "WORKSPACE", "WORKSPACE.bazel",
+    "maven_install.json", "Manifest.toml", "Project.toml", ".terraform.lock.hcl",
+)
+REQUIRED_SUFFIX_GLOBS = ("*.csproj", "*.fsproj", "*.vbproj", "*.gemspec", "*.nuspec", "*.MODULE.bazel", "*.tf", "*.tofu")
+
+
+def _deps_case_line(workflow_name: str) -> str:
+    """Return the single `case` pattern line that restores `deps=true`."""
+    lines = [
+        line.strip()
+        for line in (WORKFLOWS_DIR / workflow_name).read_text(encoding="utf-8").splitlines()
+        if line.rstrip().endswith(") deps=true ;;")
+    ]
+    assert len(lines) == 1, (workflow_name, len(lines))
+    return lines[0]
+
+
+def test_dependency_allowlist_names_every_scannable_manifest() -> None:
+    """Each gate copy lists every manifest at the root and under any directory."""
+    for workflow_name in GATE_COPIES:
+        patterns = set(_deps_case_line(workflow_name).split(") deps=true")[0].split("|"))
+        for manifest in REQUIRED_MANIFESTS:
+            assert manifest in patterns, (workflow_name, manifest)
+            assert f"*/{manifest}" in patterns, (workflow_name, manifest)
+        for glob in REQUIRED_SUFFIX_GLOBS:
+            assert glob in patterns, (workflow_name, glob)
+
+
+def test_dependency_allowlist_is_identical_across_gate_copies() -> None:
+    """The allowlist must not drift between the three classifier copies."""
+    assert len({_deps_case_line(name) for name in GATE_COPIES}) == 1