diff --git a/.github/workflows/release-bundle.yml b/.github/workflows/release-bundle.yml
index dc8f9ab..267c50b 100644
--- a/.github/workflows/release-bundle.yml
+++ b/.github/workflows/release-bundle.yml
@@ -87,8 +87,11 @@ jobs:
 
       - name: Run release gates
         shell: bash
+        env:
+          GDS_TEST_PYTHON: ${{ runner.temp }}/gds-release-python/bin/python
         run: |
-          python3 -m pip install --quiet --require-hashes -r requirements/test.txt
+          python3 -m venv "${GDS_TEST_PYTHON%/bin/python}"
+          "$GDS_TEST_PYTHON" -m pip install --quiet --require-hashes -r requirements/test.txt
           scripts/validate_release.sh
 
       - name: Materialize bounded signed harness evidence input
diff --git a/CHANGELOG.md b/CHANGELOG.md
index aceb5e2..04b0d9d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -32,6 +32,11 @@ Versioning.
   repository identity or embedded projection templates.
 - Static analysis now covers the Go engine and Actions workflows on the public
   authority before a private estate can advance its gitlink.
+- The release workflow now installs and uses one job-scoped hash-locked Python
+  environment instead of depending on undeclared runner packages or a second
+  tool-managed interpreter.
+- The declared `gds-drakkars` plugin now has its canonical source manifest, so
+  full and release validation cannot silently stop at a redirected JSON result.
 
 ## [0.1.1] - 2026-08-16
 
diff --git a/core/releasebuilder/workflow_contract_test.go b/core/releasebuilder/workflow_contract_test.go
index 193dafb..3372564 100644
--- a/core/releasebuilder/workflow_contract_test.go
+++ b/core/releasebuilder/workflow_contract_test.go
@@ -167,11 +167,15 @@ func TestHostedReleaseWorkflowInstallsLockedPythonDependenciesBeforeReleaseGate(
 		t.Fatal(err)
 	}
 	content := string(workflow)
-	install := strings.Index(content, "python3 -m pip install --quiet --require-hashes -r requirements/test.txt")
+	install := strings.Index(content, `"$GDS_TEST_PYTHON" -m pip install --quiet --require-hashes -r requirements/test.txt`)
 	validate := strings.Index(content, "scripts/validate_release.sh")
 	if install < 0 || validate < 0 || install > validate {
 		t.Fatal("release workflow must install hash-locked Python dependencies before validation")
 	}
+	if !strings.Contains(content, "GDS_TEST_PYTHON: ${{ runner.temp }}/gds-release-python/bin/python") ||
+		!strings.Contains(content, `python3 -m venv "${GDS_TEST_PYTHON%/bin/python}"`) {
+		t.Fatal("release workflow must run tests with the Python environment it populated")
+	}
 }
 
 // The release chain runs on the estate's own fleet. What matters is that all
diff --git a/plugins/gds-drakkars/.codex-plugin/plugin.json b/plugins/gds-drakkars/.codex-plugin/plugin.json
new file mode 100644
index 0000000..6d4d708
--- /dev/null
+++ b/plugins/gds-drakkars/.codex-plugin/plugin.json
@@ -0,0 +1,20 @@
+{
+  "name": "gds-drakkars",
+  "version": "0.1.0",
+  "description": "GDS Drakkars fleet orientation, audit, triage, workflow design, optimization, onboarding, rollout, and performance verification workflows.",
+  "author": {
+    "name": "example-user"
+  },
+  "repository": "https://github.com/NDDev-OpenNetwork/github-device-sync",
+  "license": "Proprietary",
+  "skills": "./skills/",
+  "interface": {
+    "displayName": "GDS Drakkars",
+    "shortDescription": "Operate and optimize CI through Drakkars",
+    "longDescription": "Provides the profiled GDS skills for fleet audits, run triage, CI/CD workflow design, critical-path optimization, project onboarding, consumer rollout, and performance verification. Canonical skill sources remain in the public GDS engine and plugin copies are generated.",
+    "developerName": "example-user",
+    "category": "Developer Tools",
+    "capabilities": ["Read", "Write"],
+    "defaultPrompt": "Resolve the repository visibility, workflow obligations, and current fleet evidence before changing CI/CD behavior."
+  }
+}
diff --git a/scripts/validate_go_core.sh b/scripts/validate_go_core.sh
index 089fe47..bd86e8e 100755
--- a/scripts/validate_go_core.sh
+++ b/scripts/validate_go_core.sh
@@ -81,11 +81,24 @@ python3 scripts/validate_gds_schemas.py --json >/dev/null
 
 GDS_BIN="$BUILD_DIR/gds-host"
 go build -trimpath -o "$GDS_BIN" ./core/cmd/gds
+run_json_validator() {
+  local output=$1
+  shift
+  local status
+  if "$@" >"$output"; then
+    return 0
+  else
+    status=$?
+  fi
+  cat "$output" >&2
+  return "$status"
+}
 for CONTRACT in schemas repository estate skills plugins memories; do
-  "$GDS_BIN" --json validate "$CONTRACT" \
-    >"$BUILD_DIR/validate-$CONTRACT.json"
+  run_json_validator "$BUILD_DIR/validate-$CONTRACT.json" \
+    "$GDS_BIN" --json validate "$CONTRACT"
 done
-"$GDS_BIN" --json generate repository --check >"$BUILD_DIR/generate-repository.json"
+run_json_validator "$BUILD_DIR/generate-repository.json" \
+  "$GDS_BIN" --json generate repository --check
 
 if [ "$MODE" = "full" ]; then
   go test -race ./...