diff --git a/src/domain/javascriptSemanticAnalysis.builtin_defaults.test.ts b/src/domain/javascriptSemanticAnalysis.builtin_defaults.test.ts
new file mode 100644
index 000000000..0e4b2c22a
--- /dev/null
+++ b/src/domain/javascriptSemanticAnalysis.builtin_defaults.test.ts
@@ -0,0 +1,39 @@
+import { expect, it } from "vitest";
+import { analyzeJavaScriptSemantics } from "./javascriptSemanticAnalysis.js";
+
+it.each(["namespace", "default", "named-default"])(
+  "retains Node built-in effects from %s imports",
+  (mode) => {
+    const imports = ["fs", "child_process", "timers", "http"]
+      .map((name, index) => {
+        const declaration =
+          mode === "namespace"
+            ? `* as m${String(index)}`
+            : mode === "default"
+              ? `m${String(index)}`
+              : `{default as m${String(index)}}`;
+        return `import ${declaration} from 'node:${name}';`;
+      })
+      .join("\n");
+    const ir = analyzeJavaScriptSemantics(`${imports}
+    const text = m0.readFileSync('config.json','utf8');
+    const stream = m0.createReadStream('config.json'); stream.destroy();
+    const child = m1.spawn('/usr/bin/tool', ['--version']);
+    const timer = m2.setTimeout(work,1000); m2.clearTimeout(timer);
+    const request = m3.get('http://localhost/');
+  `);
+    expect(ir.configurationOperations).toHaveLength(1);
+    expect(ir.resourceOperations).toHaveLength(2);
+    expect(ir.childProcessSpawns).toHaveLength(1);
+    expect(ir.timerOperations).toHaveLength(2);
+    expect(ir.requestOperations).toHaveLength(1);
+  },
+);
+
+it.each([
+  "import fs from './fs.js'; fs.createReadStream('config.json');",
+  "import {constants as fs} from 'node:fs'; fs.createReadStream('config.json');",
+  "function run(fs) { fs.createReadStream('config.json'); }",
+])("does not invent a built-in namespace for %s", (source) => {
+  expect(analyzeJavaScriptSemantics(source).resourceOperations).toEqual([]);
+});
diff --git a/src/domain/javascriptSemanticAsyncEffects.ts b/src/domain/javascriptSemanticAsyncEffects.ts
index 6dade9485..07d489890 100644
--- a/src/domain/javascriptSemanticAsyncEffects.ts
+++ b/src/domain/javascriptSemanticAsyncEffects.ts
@@ -1,5 +1,7 @@
 import * as t from "@babel/types";
 
+import { semanticBuiltinNamespacePath } from "./javascriptSemanticProvenance.js";
+
 import type {
   JavaScriptSemanticCallable,
   JavaScriptSemanticEventOperation,
@@ -338,7 +340,7 @@ const timerNamespaceBinding = (
 ): boolean =>
   binding?.directOrigins.some(
     ({ specifier, importedPath }) =>
-      timerModule(specifier) && importedPath.length === 0,
+      timerModule(specifier) && semanticBuiltinNamespacePath(importedPath),
   ) ?? false;
 
 const timerModule = (specifier: string): boolean =>
diff --git a/src/domain/javascriptSemanticChildProcesses.ts b/src/domain/javascriptSemanticChildProcesses.ts
index d1666bbc5..cdc127b1a 100644
--- a/src/domain/javascriptSemanticChildProcesses.ts
+++ b/src/domain/javascriptSemanticChildProcesses.ts
@@ -1,5 +1,7 @@
 import * as t from "@babel/types";
 
+import { semanticBuiltinNamespacePath } from "./javascriptSemanticProvenance.js";
+
 import type {
   JavaScriptSemanticCallable,
   JavaScriptSemanticChildProcessInteraction,
@@ -305,7 +307,8 @@ const childProcessNamespace = (
 ): boolean =>
   binding?.directOrigins.some(
     ({ specifier, importedPath }) =>
-      childProcessModule(specifier) && importedPath.length === 0,
+      childProcessModule(specifier) &&
+      semanticBuiltinNamespacePath(importedPath),
   ) ?? false;
 
 const childProcessModule = (specifier: string): boolean =>
diff --git a/src/domain/javascriptSemanticDataEffectHelpers.ts b/src/domain/javascriptSemanticDataEffectHelpers.ts
index dc0254ddd..3a7975535 100644
--- a/src/domain/javascriptSemanticDataEffectHelpers.ts
+++ b/src/domain/javascriptSemanticDataEffectHelpers.ts
@@ -1,5 +1,7 @@
 import * as t from "@babel/types";
 
+import { semanticBuiltinNamespacePath } from "./javascriptSemanticProvenance.js";
+
 import { semanticCallableIdForNode } from "./javascriptSemanticProjection.js";
 import {
   resolveSemanticBindingState,
@@ -157,7 +159,8 @@ export const builtinDataEffectMethod = (
   );
   const namespace = binding?.directOrigins.some(
     ({ specifier, importedPath }) =>
-      specifiers.includes(specifier) && importedPath.length === 0,
+      specifiers.includes(specifier) &&
+      semanticBuiltinNamespacePath(importedPath),
   );
   return namespace
     ? semanticStaticPropertyName(callee.property, callee.computed)
diff --git a/src/domain/javascriptSemanticDataEffects.ts b/src/domain/javascriptSemanticDataEffects.ts
index 839c50fd9..6cebc959e 100644
--- a/src/domain/javascriptSemanticDataEffects.ts
+++ b/src/domain/javascriptSemanticDataEffects.ts
@@ -1,5 +1,7 @@
 import * as t from "@babel/types";
 
+import { semanticBuiltinNamespacePath } from "./javascriptSemanticProvenance.js";
+
 import type {
   JavaScriptSemanticBoundaryOperation,
   JavaScriptSemanticCallable,
@@ -377,7 +379,7 @@ const requestMethod = (
   return binding?.directOrigins.some(
     ({ specifier, importedPath }) =>
       ["http", "https", "node:http", "node:https"].includes(specifier) &&
-      importedPath.length === 0,
+      semanticBuiltinNamespacePath(importedPath),
   )
     ? method
     : null;
diff --git a/src/domain/javascriptSemanticProvenance.ts b/src/domain/javascriptSemanticProvenance.ts
index 255e457e0..824c76414 100644
--- a/src/domain/javascriptSemanticProvenance.ts
+++ b/src/domain/javascriptSemanticProvenance.ts
@@ -55,3 +55,10 @@ export const semanticPrimitiveKey = (
   value: JavaScriptSemanticPrimitive,
 ): string =>
   `${value === null ? "null" : typeof value}:${JSON.stringify(value)}`;
+
+/** Match namespace paths only after the caller has identified a Node built-in. */
+export const semanticBuiltinNamespacePath = (
+  importedPath: readonly string[],
+): boolean =>
+  importedPath.length === 0 ||
+  (importedPath.length === 1 && importedPath[0] === "default");
diff --git a/src/domain/javascriptSemanticResources.ts b/src/domain/javascriptSemanticResources.ts
index c7c9bc87e..b204aeb73 100644
--- a/src/domain/javascriptSemanticResources.ts
+++ b/src/domain/javascriptSemanticResources.ts
@@ -1,5 +1,7 @@
 import * as t from "@babel/types";
 
+import { semanticBuiltinNamespacePath } from "./javascriptSemanticProvenance.js";
+
 import type {
   JavaScriptSemanticCallable,
   JavaScriptSemanticResourceOperation,
@@ -173,7 +175,7 @@ const resourceNamespace = (
 ): boolean =>
   binding?.directOrigins.some(
     ({ specifier, importedPath }) =>
-      resourceModule(specifier) && importedPath.length === 0,
+      resourceModule(specifier) && semanticBuiltinNamespacePath(importedPath),
   ) ?? false;
 
 const resourceModule = (specifier: string): boolean =>
diff --git a/tests/acceptance/applications/javascriptBuiltinDefaultsCli.test.ts b/tests/acceptance/applications/javascriptBuiltinDefaultsCli.test.ts
new file mode 100644
index 000000000..ad8890f53
--- /dev/null
+++ b/tests/acceptance/applications/javascriptBuiltinDefaultsCli.test.ts
@@ -0,0 +1,55 @@
+import { execFile } from "node:child_process";
+import { writeFile } from "node:fs/promises";
+import { join } from "node:path";
+import { promisify } from "node:util";
+
+import { expect, it } from "vitest";
+
+import { parseEvidence } from "../../../src/domain/evidence.js";
+import { javascriptApplicationAnalysisResultSchema } from "../../../src/domain/javascriptApplicationAnalysis.js";
+import { createTestTempDirectory } from "../../fixtures/temporaryDirectory.js";
+
+const execute = promisify(execFile);
+
+it.each([
+  "import fs from 'node:fs';",
+  "import {default as fs} from 'node:fs';",
+])(
+  "retains filesystem effects in the public CLI with %s",
+  async (declaration) => {
+    const root = await createTestTempDirectory("rea-builtin-default-cli-");
+    await writeFile(
+      join(root, "app.js"),
+      `${declaration} const text=fs.readFileSync('config.json','utf8'); const stream=fs.createReadStream('config.json'); stream.destroy();`,
+    );
+    const { stdout } = await execute(
+      process.execPath,
+      ["scripts/rea.mjs", "analyze-javascript-application", root, "--json"],
+      { cwd: process.cwd(), maxBuffer: 16 * 1024 * 1024 },
+    );
+    const result = javascriptApplicationAnalysisResultSchema.parse(
+      parseEvidence(JSON.parse(stdout)).normalized_result,
+    );
+    expect(result.semantic_graph.nodes).toEqual(
+      expect.arrayContaining([
+        expect.objectContaining({
+          kind: "config-source",
+          properties: expect.objectContaining({ key: "config.json" }),
+        }),
+        expect.objectContaining({
+          kind: "resource",
+          properties: expect.objectContaining({ method: "createReadStream" }),
+        }),
+      ]),
+    );
+    expect(result.semantic_graph.relations).toEqual(
+      expect.arrayContaining([
+        expect.objectContaining({
+          relation: "releases",
+          resolution: "resolved",
+        }),
+      ]),
+    );
+  },
+  20_000,
+);