diff --git a/tests/package-ops.test.ts b/tests/package-ops.test.ts
index 2e94350..4727457 100644
--- a/tests/package-ops.test.ts
+++ b/tests/package-ops.test.ts
@@ -4,7 +4,7 @@ import { existsSync, lstatSync, mkdtempSync, mkdirSync, readFileSync, writeFileS
 import { tmpdir } from "node:os";
 import { join, resolve } from "node:path";
 
-import { seedBundledWorkspacePackages } from "../src/pi/package-ops.js";
+import { installPackageSources, seedBundledWorkspacePackages } from "../src/pi/package-ops.js";
 
 function createBundledWorkspace(appRoot: string, packageNames: string[]): void {
 	for (const packageName of packageNames) {
@@ -18,6 +18,17 @@ function createBundledWorkspace(appRoot: string, packageNames: string[]): void {
 	}
 }
 
+function writeSettings(agentDir: string, settings: Record<string, unknown>): void {
+	mkdirSync(agentDir, { recursive: true });
+	writeFileSync(resolve(agentDir, "settings.json"), JSON.stringify(settings, null, 2) + "\n", "utf8");
+}
+
+function writeFakeNpmScript(root: string, body: string): string {
+	const scriptPath = resolve(root, "fake-npm.mjs");
+	writeFileSync(scriptPath, body, "utf8");
+	return scriptPath;
+}
+
 test("seedBundledWorkspacePackages links bundled packages into the Feynman npm prefix", () => {
 	const appRoot = mkdtempSync(join(tmpdir(), "feynman-bundle-"));
 	const homeRoot = mkdtempSync(join(tmpdir(), "feynman-home-"));
@@ -54,3 +65,83 @@ test("seedBundledWorkspacePackages preserves existing installed packages", () =>
 	assert.equal(readFileSync(resolve(existingPackageDir, "package.json"), "utf8"), '{"name":"pi-subagents","version":"user"}\n');
 	assert.equal(lstatSync(existingPackageDir).isSymbolicLink(), false);
 });
+
+test("installPackageSources filters noisy npm chatter but preserves meaningful output", async () => {
+	const root = mkdtempSync(join(tmpdir(), "feynman-package-ops-"));
+	const workingDir = resolve(root, "project");
+	const agentDir = resolve(root, "agent");
+	mkdirSync(workingDir, { recursive: true });
+
+	const scriptPath = writeFakeNpmScript(root, [
+		`console.log("npm warn deprecated node-domexception@1.0.0: Use your platform's native DOMException instead");`,
+		'console.log("changed 343 packages in 9s");',
+		'console.log("59 packages are looking for funding");',
+		'console.log("run `npm fund` for details");',
+		'console.error("visible stderr line");',
+		'console.log("visible stdout line");',
+		"process.exit(0);",
+	].join("\n"));
+
+	writeSettings(agentDir, {
+		npmCommand: [process.execPath, scriptPath],
+	});
+
+	let stdout = "";
+	let stderr = "";
+	const originalStdoutWrite = process.stdout.write.bind(process.stdout);
+	const originalStderrWrite = process.stderr.write.bind(process.stderr);
+	(process.stdout.write as unknown as (chunk: string | Uint8Array) => boolean) = ((chunk: string | Uint8Array) => {
+		stdout += chunk.toString();
+		return true;
+	}) as typeof process.stdout.write;
+	(process.stderr.write as unknown as (chunk: string | Uint8Array) => boolean) = ((chunk: string | Uint8Array) => {
+		stderr += chunk.toString();
+		return true;
+	}) as typeof process.stderr.write;
+
+	try {
+		const result = await installPackageSources(workingDir, agentDir, ["npm:test-visible-package"]);
+		assert.deepEqual(result.installed, ["npm:test-visible-package"]);
+		assert.deepEqual(result.skipped, []);
+	} finally {
+		process.stdout.write = originalStdoutWrite;
+		process.stderr.write = originalStderrWrite;
+	}
+
+	const combined = `${stdout}\n${stderr}`;
+	assert.match(combined, /visible stdout line/);
+	assert.match(combined, /visible stderr line/);
+	assert.doesNotMatch(combined, /node-domexception/);
+	assert.doesNotMatch(combined, /changed 343 packages/);
+	assert.doesNotMatch(combined, /packages are looking for funding/);
+	assert.doesNotMatch(combined, /npm fund/);
+});
+
+test("installPackageSources skips native packages on unsupported Node majors before invoking npm", async () => {
+	const root = mkdtempSync(join(tmpdir(), "feynman-package-ops-"));
+	const workingDir = resolve(root, "project");
+	const agentDir = resolve(root, "agent");
+	const markerPath = resolve(root, "npm-invoked.txt");
+	mkdirSync(workingDir, { recursive: true });
+
+	const scriptPath = writeFakeNpmScript(root, [
+		`import { writeFileSync } from "node:fs";`,
+		`writeFileSync(${JSON.stringify(markerPath)}, "invoked\\n", "utf8");`,
+		"process.exit(0);",
+	].join("\n"));
+
+	writeSettings(agentDir, {
+		npmCommand: [process.execPath, scriptPath],
+	});
+
+	const originalVersion = process.versions.node;
+	Object.defineProperty(process.versions, "node", { value: "25.0.0", configurable: true });
+	try {
+		const result = await installPackageSources(workingDir, agentDir, ["npm:@kaiserlich-dev/pi-session-search"]);
+		assert.deepEqual(result.installed, []);
+		assert.deepEqual(result.skipped, ["npm:@kaiserlich-dev/pi-session-search"]);
+		assert.equal(existsSync(markerPath), false);
+	} finally {
+		Object.defineProperty(process.versions, "node", { value: originalVersion, configurable: true });
+	}
+});