diff --git a/packages/angular/cli/src/commands/mcp/tools/projects.ts b/packages/angular/cli/src/commands/mcp/tools/projects.ts
index 8c6eb5d332f6..c53adb7828df 100644
--- a/packages/angular/cli/src/commands/mcp/tools/projects.ts
+++ b/packages/angular/cli/src/commands/mcp/tools/projects.ts
@@ -467,7 +467,7 @@ async function loadAndParseWorkspace(
     const projects = [];
     const workspaceRoot = dirname(configFile);
     for (const [name, project] of ws.projects.entries()) {
-      const sourceRoot = posix.join(project.root, project.sourceRoot ?? 'src');
+      const sourceRoot = project.sourceRoot ?? posix.join(project.root, 'src');
       const fullSourceRoot = join(workspaceRoot, sourceRoot);
       const unitTestFramework = getUnitTestFramework(project.targets.get('test'));
       const styleLanguage = await getProjectStyleLanguage(project, ws, fullSourceRoot);
diff --git a/tests/e2e/tests/mcp/projects-sourceroot-resolution.ts b/tests/e2e/tests/mcp/projects-sourceroot-resolution.ts
new file mode 100644
index 000000000000..01ebb8c1ca05
--- /dev/null
+++ b/tests/e2e/tests/mcp/projects-sourceroot-resolution.ts
@@ -0,0 +1,47 @@
+import { exec, ProcessOutput, silentNpm } from '../../utils/process';
+import { updateJsonFile } from '../../utils/project';
+import assert from 'node:assert/strict';
+
+const MCP_INSPECTOR_PACKAGE_NAME = '@modelcontextprotocol/inspector-cli';
+const MCP_INSPECTOR_PACKAGE_VERSION = '0.16.2';
+const MCP_INSPECTOR_COMMAND_NAME = 'mcp-inspector-cli';
+
+async function runInspector(...args: string[]): Promise<ProcessOutput> {
+  return exec(MCP_INSPECTOR_COMMAND_NAME, '--cli', 'npx', '--no', '@angular/cli', 'mcp', ...args);
+}
+
+export default async function () {
+  await silentNpm(
+    'install',
+    '--ignore-scripts',
+    '-g',
+    `${MCP_INSPECTOR_PACKAGE_NAME}@${MCP_INSPECTOR_PACKAGE_VERSION}`,
+  );
+
+  try {
+    // 1. Add a sample project with a non-root path to angular.json
+    await updateJsonFile('angular.json', (workspaceJson) => {
+      workspaceJson.projects ??= {};
+      workspaceJson.projects['sample-lib'] = {
+        root: 'projects/sample-lib',
+        sourceRoot: 'projects/sample-lib/src',
+        projectType: 'library',
+      };
+    });
+
+    // 2. Call list_projects
+    const { stdout } = await runInspector('--method', 'tools/call', '--tool-name', 'list_projects');
+
+    // 3. Verify output
+    assert.match(stdout, /"name": "sample-lib"/);
+    // Assert that sourceRoot is NOT duplicated
+    assert.match(stdout, /"sourceRoot": "projects\/sample-lib\/src"/);
+    assert.doesNotMatch(stdout, /"sourceRoot": "projects\/sample-lib\/projects\/sample-lib\/src"/);
+  } finally {
+    // 4. Cleanup angular.json
+    await updateJsonFile('angular.json', (workspaceJson) => {
+      delete workspaceJson.projects['sample-lib'];
+    });
+    await silentNpm('uninstall', '-g', MCP_INSPECTOR_PACKAGE_NAME);
+  }
+}