diff --git a/build.go b/build.go
index 9b7265f..d27c237 100644
--- a/build.go
+++ b/build.go
@@ -54,7 +54,7 @@ type BuildResult struct {
 }
 
 // Build compiles the selected targets with Version injected through buildinfo.
-// It uses the prepared local Go environment, preserves existing output files,
+// It uses the prepared local Go environment, regenerates selected output files while preserving unrelated files,
 // and verifies the version command on the native host before succeeding. An
 // empty target set records source identity without running the Go toolchain.
 // Errors return partial build facts in the result.
diff --git a/build_test.go b/build_test.go
index 30fef48..6117bf2 100644
--- a/build_test.go
+++ b/build_test.go
@@ -152,38 +152,45 @@ func main() {}
 	}
 }
 
-func TestBuildRejectsUnsafeNameAndPreservesExistingOutput(t *testing.T) {
-	repository := newBuildConsumer(t, "package main\nfunc main() {}\n")
-	outputDir := filepath.Join(t.TempDir(), "artifacts")
-	if err := os.MkdirAll(outputDir, 0o755); err != nil {
+func TestBuildRegeneratesOwnedOutputsAndPreservesUnrelatedFiles(t *testing.T) {
+	const source = `package main
+import("fmt";"gitea.maximumdirect.net/eric/ReleaseKit/buildinfo")
+func main(){fmt.Println("fixture",buildinfo.Version())}
+`
+	repository := newBuildConsumer(t, source)
+	outputDir := t.TempDir()
+	unrelated := filepath.Join(outputDir, "keep.txt")
+	if err := os.WriteFile(unrelated, []byte("keep this file"), 0600); err != nil {
 		t.Fatal(err)
 	}
-	ownedPath := filepath.Join(outputDir, "fixture-v1.2.3-linux-amd64")
-	if err := os.WriteFile(ownedPath, []byte("keep this file"), 0o600); err != nil {
+	request := releasekit.BuildRequest{RepositoryDir: repository, Version: "v1.2.3", Spec: releasekit.BuildSpec{MainPackage: "./cmd/app", BinaryName: "fixture", Targets: []releasekit.Target{{OS: runtime.GOOS, Arch: runtime.GOARCH}}}, OutputDir: outputDir}
+	unsafe := request
+	unsafe.Spec.BinaryName = "../unsafe"
+	if _, err := releasekit.Build(context.Background(), unsafe); err == nil {
+		t.Fatal("unsafe binary name accepted")
+	}
+	first, err := releasekit.Build(context.Background(), request)
+	if err != nil {
 		t.Fatal(err)
 	}
-	request := releasekit.BuildRequest{
-		RepositoryDir: repository,
-		Version:       "v1.2.3",
-		Spec: releasekit.BuildSpec{
-			MainPackage: "./cmd/app",
-			BinaryName:  "fixture",
-			Targets:     []releasekit.Target{{OS: "linux", Arch: "amd64"}},
-		},
-		OutputDir: outputDir,
+	repeated, err := releasekit.Build(context.Background(), request)
+	if err != nil {
+		t.Fatal(err)
 	}
-	unsafeRequest := request
-	unsafeRequest.Spec.BinaryName = "../unsafe"
-	if result, err := releasekit.Build(context.Background(), unsafeRequest); err == nil || !strings.Contains(err.Error(), "unsafe binary name") {
-		t.Fatalf("Build() result = %#v, error = %v; expected unsafe-name failure", result, err)
+	if repeated.Artifacts[0].SHA256 != first.Artifacts[0].SHA256 {
+		t.Fatal("identical build changed output")
 	}
-	request.Spec.BinaryName = "fixture"
-	if _, err := releasekit.Build(context.Background(), request); err == nil || !strings.Contains(err.Error(), "already exists") {
-		t.Fatalf("Build() error = %v, want existing-output failure", err)
+	writeBuildFixture(t, repository, "cmd/app/main.go", source+"\nfunc init(){if len([]byte(buildinfo.Version()))==0 {panic(\"changed build\")}}\n")
+	changed, err := releasekit.Build(context.Background(), request)
+	if err != nil {
+		t.Fatal(err)
 	}
-	contents, err := os.ReadFile(ownedPath)
-	if err != nil || string(contents) != "keep this file" {
-		t.Fatalf("caller output = %q, error = %v", contents, err)
+	if changed.Artifacts[0].SHA256 == first.Artifacts[0].SHA256 {
+		t.Fatal("changed source did not regenerate binary")
+	}
+	content, err := os.ReadFile(unrelated)
+	if err != nil || string(content) != "keep this file" {
+		t.Fatalf("unrelated file=%q %v", content, err)
 	}
 }
 
diff --git a/cmd/releasekit/internal/cli/receipt.go b/cmd/releasekit/internal/cli/receipt.go
index 96d3dea..d0fa759 100644
--- a/cmd/releasekit/internal/cli/receipt.go
+++ b/cmd/releasekit/internal/cli/receipt.go
@@ -266,3 +266,15 @@ func validSHA256(value string) bool {
 	}
 	return true
 }
+
+// RemoveBuildReceipt invalidates prior CLI coordination data after a rebuild.
+func RemoveBuildReceipt(outputDir string) error {
+	err := os.Remove(filepath.Join(outputDir, BuildReceiptName))
+	if errors.Is(err, os.ErrNotExist) {
+		return nil
+	}
+	if err != nil {
+		return fmt.Errorf("invalidate prior build receipt: %w", err)
+	}
+	return nil
+}
diff --git a/cmd/releasekit/main.go b/cmd/releasekit/main.go
index 4ff5cf4..0ca5977 100644
--- a/cmd/releasekit/main.go
+++ b/cmd/releasekit/main.go
@@ -100,6 +100,12 @@ func run(ctx context.Context, args []string, stdout, stderr io.Writer) int {
 			OutputDir:     invocation.OutputDir,
 			Output:        stderr,
 		})
+		if result.OutputDir != "" && len(result.Targets) != 0 {
+			if receiptErr := cli.RemoveBuildReceipt(result.OutputDir); receiptErr != nil {
+				fmt.Fprintf(stderr, "%v\n", receiptErr)
+				return 1
+			}
+		}
 		if err != nil {
 			fmt.Fprintf(stderr, "build failed at %s: %v\n", result.CandidateCommit, err)
 			for _, artifact := range result.Artifacts {
diff --git a/cmd/releasekit/main_test.go b/cmd/releasekit/main_test.go
index b4ef570..9256f07 100644
--- a/cmd/releasekit/main_test.go
+++ b/cmd/releasekit/main_test.go
@@ -737,3 +737,28 @@ func TestUnreadableAssetsDoNotClaimAnUnknownWrite(t *testing.T) {
 		})
 	}
 }
+
+func TestFailedRebuildInvalidatesPreviousReceipt(t *testing.T) {
+	const source = `package main
+import("fmt";"gitea.maximumdirect.net/eric/ReleaseKit/buildinfo")
+func main(){fmt.Println("fixture",buildinfo.Version())}
+`
+	repository := newCLIBuildRepository(t, source)
+	var stdout, stderr bytes.Buffer
+	args := []string{"build", "--repo", repository, "v1.2.3"}
+	for attempt := 0; attempt < 2; attempt++ {
+		if status := run(context.Background(), args, &stdout, &stderr); status != 0 {
+			t.Fatalf("build %d: status=%d %s", attempt, status, stderr.String())
+		}
+	}
+	path := filepath.Join(repository, "cmd/app/main.go")
+	if err := os.WriteFile(path, []byte("package main\nfunc main(){}\n"), 0600); err != nil {
+		t.Fatal(err)
+	}
+	if status := run(context.Background(), args, &stdout, &stderr); status != 1 {
+		t.Fatalf("failed rebuild status=%d", status)
+	}
+	if _, err := os.Stat(filepath.Join(repository, "dist", cli.BuildReceiptName)); !os.IsNotExist(err) {
+		t.Fatalf("stale receipt remains: %v", err)
+	}
+}
diff --git a/docs/cli.md b/docs/cli.md
index 9e3fa66..4cc393d 100644
--- a/docs/cli.md
+++ b/docs/cli.md
@@ -60,10 +60,11 @@ go run ./cmd/releasekit build [--repo DIR] [--config FILE] [--output DIR] VERSIO
 targets with the requested version injected, checks the native `version`
 invocation, and writes binaries plus the private `.releasekit-build.json`
 receipt into `dist` by default. `--output` selects a different directory;
-relative paths are resolved from the repository. Existing files with a selected
-artifact name are preserved and cause an error. A complete nonempty build
+relative paths are resolved from the repository. Selected artifact filenames
+are regenerated while unrelated files are preserved. A complete nonempty build
 writes a receipt only after compilation and smoke checking succeed. On partial
-failure, standard error lists completed outputs and no receipt is written. An
+failure, standard error lists completed outputs and prior receipts in that
+output directory are invalidated; no new receipt is written. An
 empty target list returns the source commit without building or writing a
 receipt.
 
diff --git a/docs/consumers/build.md b/docs/consumers/build.md
index d7d5da2..b07984d 100644
--- a/docs/consumers/build.md
+++ b/docs/consumers/build.md
@@ -46,9 +46,8 @@ source and the same HEAD before and after compilation; binary delivery requires
 that fact. This observation is not a source snapshot or attestation guarantee.
 
 The default output directory is `<repository>/dist`; a relative `OutputDir` is
-resolved from the repository. Existing files with a selected artifact name are
-preserved and cause an error. Other files in the output directory are left in
-place. A failed later build or native version check returns the binaries already
+resolved from the repository. Selected artifact filenames are regenerated. Other files in the output
+directory are left in place. A failed later build or native version check returns the binaries already
 generated in `BuildResult.Artifacts`.
 
 Builds use the prepared local Go toolchain, readonly module mode, disabled
diff --git a/docs/roadmap/remediation.md b/docs/roadmap/remediation.md
index be1bad7..50dd507 100644
--- a/docs/roadmap/remediation.md
+++ b/docs/roadmap/remediation.md
@@ -163,6 +163,8 @@ write outcomes. Both affected suites pass.
 
 ### R4 — Medium: Local artifact regeneration is prohibited
 
+Status: Resolved.
+
 Category: Inadvertently strengthened prohibition.
 
 **Evidence:** [Build](../../internal/build/build.go), around line 114, refuses
@@ -188,6 +190,12 @@ machinery.
 a changed local build can regenerate its owned names; unrelated files survive;
 a partial rebuild does not authorize incomplete assets through a stale receipt.
 
+**Resolution:** Builds regenerate selected local artifact names and preserve
+unrelated output files. The CLI invalidates prior receipts once a rebuild has
+reached its output directory, including failed rebuilds. API regressions cover
+repeated and changed-source builds; CLI coverage proves a failed smoke check
+removes the previous receipt. Affected suites pass.
+
 ### R5 — Medium: The root facade still owns release mechanics
 
 Category: Architectural ownership gap and maintainability.
diff --git a/internal/build/build.go b/internal/build/build.go
index 090660f..d7d95fc 100644
--- a/internal/build/build.go
+++ b/internal/build/build.go
@@ -114,14 +114,6 @@ func Build(ctx context.Context, request Request) (Result, error) {
 	if err := os.MkdirAll(result.OutputDir, 0o755); err != nil {
 		return result, fmt.Errorf("create build output directory %q: %w", result.OutputDir, err)
 	}
-	for _, filename := range filenames {
-		path := filepath.Join(result.OutputDir, filename)
-		if _, err := os.Lstat(path); err == nil {
-			return result, fmt.Errorf("build output %q already exists; preserving caller-owned file", path)
-		} else if !errors.Is(err, os.ErrNotExist) {
-			return result, fmt.Errorf("inspect build output %q: %w", path, err)
-		}
-	}
 
 	compiler, err := runGo(ctx, repositoryDir, nil, "version")
 	if err != nil {