diff --git a/docs/roadmap/implementation.md b/docs/roadmap/implementation.md
index 7a136e0..984a618 100644
--- a/docs/roadmap/implementation.md
+++ b/docs/roadmap/implementation.md
@@ -8,11 +8,11 @@ accepted user intent, policy choices, required outcome, and responsibility
 boundary. This plan translates that target into bounded implementation stages
 suitable for one `gpt-5.6-terra` coding prompt apiece.
 
-All stages are pending and must be implemented in numeric order. Each stage
-must leave its owned behavior correct, tested at an appropriate stable
-boundary, and ready for the next stage. This plan supersedes the completed
-pipeline-configuration implementation plan that previously occupied this
-path; that feature's implemented behavior is now owned by current canonical
+All five stages were completed in numeric order. This document is retained as
+implementation history; current release behavior is owned by the checked-in
+scripts and canonical release documentation. This plan superseded the completed
+pipeline-configuration implementation plan that previously occupied this path;
+that feature's implemented behavior is now owned by current canonical
 documentation and code.
 
 ## Settled Implementation Decisions
diff --git a/internal/releasecheck/assets_test.go b/internal/releasecheck/assets_test.go
index 05a148e..36e4eec 100644
--- a/internal/releasecheck/assets_test.go
+++ b/internal/releasecheck/assets_test.go
@@ -11,6 +11,45 @@ import (
 	"testing"
 )
 
+func TestReleaseVersionValidationIsExact(t *testing.T) {
+	repoRoot := releaseCheckRepoRoot(t)
+	library := filepath.Join(repoRoot, "scripts", "release-lib.sh")
+	workingDirectory := t.TempDir()
+	if err := os.WriteFile(filepath.Join(workingDirectory, "2"), nil, 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	for _, test := range []struct {
+		version string
+		valid   bool
+	}{
+		{version: "v0.0.0", valid: true},
+		{version: "v1.2.3", valid: true},
+		{version: "v10.200.3000", valid: true},
+		{version: "1.2.3"},
+		{version: "v01.2.3"},
+		{version: "v1.02.3"},
+		{version: "v1.2.03"},
+		{version: "v1.2.3."},
+		{version: "v1.2.3-rc.1"},
+		{version: "v1.2.3+build"},
+		{version: "v1.*.3"},
+		{version: "v1.2.3\nv4.5.6"},
+	} {
+		t.Run(test.version, func(t *testing.T) {
+			command := exec.Command("sh", "-c", `. "$1"; narratio_release_validate_version "$2"`, "release-version-test", library, test.version)
+			command.Dir = workingDirectory
+			err := command.Run()
+			if test.valid && err != nil {
+				t.Fatalf("valid version %q rejected: %v", test.version, err)
+			}
+			if !test.valid && err == nil {
+				t.Fatalf("invalid version %q accepted", test.version)
+			}
+		})
+	}
+}
+
 func TestAssetBuilderRejectsUnsafeDestinations(t *testing.T) {
 	repoRoot := releaseCheckRepoRoot(t)
 	builder := filepath.Join(repoRoot, "scripts", "build-release-assets.sh")
@@ -62,10 +101,15 @@ func TestAssetBuilderBuildsNamedAssetsAndChecksEmbeddedVersion(t *testing.T) {
 	binDir := t.TempDir()
 	writeFakeGo(t, filepath.Join(binDir, "go"))
 	outputDir := filepath.Join(t.TempDir(), "assets")
+	goLog := filepath.Join(t.TempDir(), "go.log")
 
 	command := exec.Command("sh", builder, "v1.2.3", outputDir)
 	command.Dir = t.TempDir()
-	command.Env = append(os.Environ(), "PATH="+binDir+string(os.PathListSeparator)+os.Getenv("PATH"))
+	command.Env = append(os.Environ(),
+		"PATH="+binDir+string(os.PathListSeparator)+os.Getenv("PATH"),
+		"GOWORK=/caller/controlled/go.work",
+		"NARRATIO_RELEASE_ASSET_GO_LOG="+goLog,
+	)
 	output, err := command.CombinedOutput()
 	if err != nil {
 		t.Fatalf("asset builder error = %v\n%s", err, output)
@@ -99,6 +143,15 @@ func TestAssetBuilderBuildsNamedAssetsAndChecksEmbeddedVersion(t *testing.T) {
 	if got := versionOutput.String(); got != "narratio v1.2.3\n" {
 		t.Fatalf("embedded version output = %q", got)
 	}
+	goCommands, err := os.ReadFile(goLog)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, line := range strings.Split(strings.TrimSpace(string(goCommands)), "\n") {
+		if !strings.HasPrefix(line, "off ") {
+			t.Fatalf("asset builder Go command did not receive GOWORK=off: %q", line)
+		}
+	}
 }
 
 func TestCandidateCheckerRejectsMalformedVersionAndReleaseNotes(t *testing.T) {
@@ -233,6 +286,10 @@ func writeFakeGo(t *testing.T, path string) {
 	const fake = `#!/bin/sh
 set -eu
 
+if [ -n "${NARRATIO_RELEASE_ASSET_GO_LOG:-}" ]; then
+  printf '%s %s\n' "${GOWORK:-}" "$*" >> "$NARRATIO_RELEASE_ASSET_GO_LOG"
+fi
+
 if [ "$1" = env ]; then
   case $2 in
     GOOS) printf '%s\n' linux ;;
diff --git a/scripts/build-release-assets.sh b/scripts/build-release-assets.sh
index d55476f..b3019de 100755
--- a/scripts/build-release-assets.sh
+++ b/scripts/build-release-assets.sh
@@ -7,6 +7,11 @@ script_dir=$(CDPATH= cd "$(dirname "$0")" && pwd -P)
 
 tool_name=build-release-assets
 
+# Release builds always use the tagged module in this repository. Own this
+# setting here so direct callers and CI cannot supply an ambient Go workspace.
+GOWORK=off
+export GOWORK
+
 if [ "$#" -ne 2 ]; then
 	narratio_release_fail "$tool_name" 'usage: scripts/build-release-assets.sh VERSION OUTPUT_DIR'
 fi
diff --git a/scripts/release-lib.sh b/scripts/release-lib.sh
index 0501c80..eca9561 100755
--- a/scripts/release-lib.sh
+++ b/scripts/release-lib.sh
@@ -11,32 +11,12 @@ narratio_release_fail() {
 }
 
 narratio_release_validate_version() {
-	version=$1
-	case $version in
-		v*.*.*) ;;
-		*) return 1 ;;
+	case $1 in
+		*'
+'*) return 1 ;;
 	esac
-	components=${version#v}
-	if [ "$components" = "$version" ]; then
-		return 1
-	fi
-
-	previous_ifs=$IFS
-	IFS=.
-	set -- $components
-	IFS=$previous_ifs
-	if [ "$#" -ne 3 ]; then
-		return 1
-	fi
-	for component in "$@"; do
-		case $component in
-			0 | [1-9]*) ;;
-			*) return 1 ;;
-		esac
-		case $component in
-			*[!0-9]*) return 1 ;;
-		esac
-	done
+	printf '%s\n' "$1" |
+		grep -Eq '^v(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)$'
 }
 
 narratio_release_repo_root() (