diff --git a/src/resource-loader.ts b/src/resource-loader.ts
index 7ddc3b7ee..48a07fc35 100644
--- a/src/resource-loader.ts
+++ b/src/resource-loader.ts
@@ -393,7 +393,7 @@ function reconcileMergedNodeModules(
       // Skip the gsd-pi package itself and dotfiles
       if (entry.name === basename(packageRoot)) continue
       if (entry.name.startsWith('.')) continue
-      try { symlinkSync(join(hoisted, entry.name), join(agentNodeModules, entry.name)); linkedCount++ } catch { /* skip individual */ }
+      try { symlinkSync(join(hoisted, entry.name), join(agentNodeModules, entry.name), 'junction'); linkedCount++ } catch { /* skip individual */ }
     }
   } catch (err) {
     console.error(`[gsd] WARN: Failed to read hoisted node_modules at ${hoisted}: ${err instanceof Error ? err.message : err}`)
@@ -408,7 +408,7 @@ function reconcileMergedNodeModules(
       const link = join(agentNodeModules, entry.name)
       // Replace hoisted symlink with internal version (internal takes precedence)
       try { lstatSync(link); unlinkSync(link) } catch { /* didn't exist — will create below */ }
-      try { symlinkSync(join(internal, entry.name), link); linkedCount++ } catch { /* skip individual */ }
+      try { symlinkSync(join(internal, entry.name), link, 'junction'); linkedCount++ } catch { /* skip individual */ }
     }
   } catch (err) {
     console.error(`[gsd] WARN: Failed to read internal node_modules at ${internal}: ${err instanceof Error ? err.message : err}`)
diff --git a/src/tests/node-modules-symlink.test.ts b/src/tests/node-modules-symlink.test.ts
index 56a9d4a03..fcf94e96e 100644
--- a/src/tests/node-modules-symlink.test.ts
+++ b/src/tests/node-modules-symlink.test.ts
@@ -5,8 +5,9 @@
 import { test } from "node:test";
 import assert from "node:assert/strict";
 import { existsSync, lstatSync, mkdirSync, mkdtempSync, readFileSync, readlinkSync, readdirSync, rmSync, symlinkSync, unlinkSync, writeFileSync } from "node:fs";
-import { join } from "node:path";
+import { dirname, join } from "node:path";
 import { tmpdir } from "node:os";
+import { fileURLToPath } from "node:url";
 
 // --- Integration tests via initResources (source/monorepo path) ---
 
@@ -284,3 +285,19 @@ test("merged node_modules marker uses fingerprint including directory entries",
   const fingerprint2 = `${fakePackageRoot}\n${h2}\n${i}`;
   assert.notEqual(fingerprint, fingerprint2, "fingerprint should change when deps change");
 });
+
+test("reconcileMergedNodeModules uses junction symlinks for Windows compatibility", () => {
+  const testDir = dirname(fileURLToPath(import.meta.url));
+  const source = readFileSync(join(testDir, "..", "resource-loader.ts"), "utf-8");
+
+  assert.match(
+    source,
+    /symlinkSync\(join\(hoisted,\s*entry\.name\),\s*join\(agentNodeModules,\s*entry\.name\),\s*'junction'\)/,
+    "hoisted merged symlink must use 'junction'",
+  );
+  assert.match(
+    source,
+    /symlinkSync\(join\(internal,\s*entry\.name\),\s*link,\s*'junction'\)/,
+    "internal merged symlink must use 'junction'",
+  );
+});