diff --git a/docs/maintainer/diagram-artifact-export-cli.md b/docs/maintainer/diagram-artifact-export-cli.md
index 52e24e45..33d95e83 100644
--- a/docs/maintainer/diagram-artifact-export-cli.md
+++ b/docs/maintainer/diagram-artifact-export-cli.md
@@ -9,7 +9,7 @@ topic: diagram-artifact-export-cli
 
 `scripts/export-diagram-artifact.js` is the offline CLI boundary for the diagram figure work that came from the Cloudy-style technical-diagram reference and the Drawnix reference spike.
 
-It accepts a checked `DiagramSpec` JSON file and writes one artifact without requiring Obsidian, `obsidian-cli`, diagrams.net Desktop, Drawnix, Plait, or a browser runtime.
+It accepts a checked `DiagramSpec` JSON file and writes one artifact without requiring Obsidian, `obsidian-cli`, diagrams.net Desktop, Drawnix, Plait, or a browser runtime. The input may be UTF-8 with or without a BOM, which keeps files produced by Windows PowerShell usable without a separate normalization step.
 
 ```bash
 npm run diagram:export-artifact -- --input spec.json --target editable-html-svg --output figure.html
diff --git a/docs/maintainer/diagram-artifact-export-cli.zh-CN.md b/docs/maintainer/diagram-artifact-export-cli.zh-CN.md
index e1b9c49a..e50f8e68 100644
--- a/docs/maintainer/diagram-artifact-export-cli.zh-CN.md
+++ b/docs/maintainer/diagram-artifact-export-cli.zh-CN.md
@@ -9,7 +9,7 @@ topic: diagram-artifact-export-cli
 
 `scripts/export-diagram-artifact.js` 是图形扩展工作的离线 CLI 边界，覆盖 Cloudy 风格技术图参考与 Drawnix 参考 spike 产生的 artifact 导出需求。
 
-它读取已验证结构的 `DiagramSpec` JSON 文件，并写出一个 artifact；不需要 Obsidian、`obsidian-cli`、diagrams.net Desktop、Drawnix、Plait 或浏览器运行时。
+它读取已验证结构的 `DiagramSpec` JSON 文件，并写出一个 artifact；不需要 Obsidian、`obsidian-cli`、diagrams.net Desktop、Drawnix、Plait 或浏览器运行时。输入文件可以是带 BOM 或不带 BOM 的 UTF-8，这样 Windows PowerShell 生成的 JSON 不需要额外归一化也能直接使用。
 
 ```bash
 npm run diagram:export-artifact -- --input spec.json --target editable-html-svg --output figure.html
diff --git a/scripts/export-diagram-artifact.js b/scripts/export-diagram-artifact.js
index 6be84d97..bdb5c5f2 100644
--- a/scripts/export-diagram-artifact.js
+++ b/scripts/export-diagram-artifact.js
@@ -79,7 +79,8 @@ function assertSupportedTarget(target) {
 }
 
 function loadDiagramSpec(inputPath) {
-  return JSON.parse(fs.readFileSync(inputPath, 'utf8'));
+  const source = fs.readFileSync(inputPath, 'utf8').replace(/^\uFEFF/, '');
+  return JSON.parse(source);
 }
 
 function ensureOutputDirectory(outputPath) {
diff --git a/src/tests/diagramArtifactExportCli.test.ts b/src/tests/diagramArtifactExportCli.test.ts
index ca7e27db..a71f833a 100644
--- a/src/tests/diagramArtifactExportCli.test.ts
+++ b/src/tests/diagramArtifactExportCli.test.ts
@@ -50,6 +50,8 @@ describe('diagram artifact export CLI', () => {
             expect(runbook).toContain('DiagramSpec');
             expect(runbook).toContain('SemanticFigureModel');
             expect(runbook).toContain('no Obsidian runtime');
+            expect(runbook).toContain('UTF-8');
+            expect(runbook).toContain('BOM');
         }
     });
 
@@ -125,6 +127,40 @@ describe('diagram artifact export CLI', () => {
         }
     }, 30000);
 
+    test('accepts UTF-8 BOM DiagramSpec files produced by Windows PowerShell', () => {
+        const tempRoot = fs.mkdtempSync(path.join(os.tmpdir(), 'notemd-diagram-artifact-cli-bom-'));
+        const specPath = path.join(tempRoot, 'spec.json');
+        const outputPath = path.join(tempRoot, 'figure.drawio');
+        fs.writeFileSync(specPath, `\uFEFF${JSON.stringify(createSpec(), null, 2)}`, 'utf8');
+
+        try {
+            const stdout = execFileSync(
+                process.execPath,
+                [
+                    scriptPath,
+                    '--input', specPath,
+                    '--target', 'drawio',
+                    '--output', outputPath
+                ],
+                {
+                    cwd: repoRoot,
+                    encoding: 'utf8'
+                }
+            );
+
+            const result = JSON.parse(stdout);
+            expect(result).toEqual(expect.objectContaining({
+                target: 'drawio',
+                outputPath,
+                nodeCount: 3,
+                edgeCount: 2
+            }));
+            expect(fs.readFileSync(outputPath, 'utf8')).toContain('<mxfile');
+        } finally {
+            fs.rmSync(tempRoot, { recursive: true, force: true });
+        }
+    }, 30000);
+
     test('fails before writing output for unsupported targets', () => {
         const tempRoot = fs.mkdtempSync(path.join(os.tmpdir(), 'notemd-diagram-artifact-cli-bad-target-'));
         const specPath = path.join(tempRoot, 'spec.json');