diff --git a/src/management/shared-manager.ts b/src/management/shared-manager.ts
index 7edfcddc..65ea5ed1 100644
--- a/src/management/shared-manager.ts
+++ b/src/management/shared-manager.ts
@@ -194,6 +194,44 @@ class SharedManager {
         }
       }
     }
+
+    // Normalize plugin registry paths after linking
+    this.normalizePluginRegistryPaths();
+  }
+
+  /**
+   * Normalize plugin registry paths to use canonical ~/.claude/ paths
+   * instead of instance-specific ~/.ccs/instances/<name>/ paths.
+   *
+   * This ensures installed_plugins.json is consistent regardless of
+   * which CCS instance installed the plugin.
+   */
+  normalizePluginRegistryPaths(): void {
+    const registryPath = path.join(this.claudeDir, 'plugins', 'installed_plugins.json');
+
+    // Skip if registry doesn't exist
+    if (!fs.existsSync(registryPath)) {
+      return;
+    }
+
+    try {
+      const original = fs.readFileSync(registryPath, 'utf8');
+
+      // Replace instance paths with canonical claude path
+      // Pattern: /.ccs/instances/<instance-name>/ -> /.claude/
+      const normalized = original.replace(/\/\.ccs\/instances\/[^/]+\//g, '/.claude/');
+
+      // Only write if changes were made
+      if (normalized !== original) {
+        // Validate JSON before writing
+        JSON.parse(normalized);
+        fs.writeFileSync(registryPath, normalized, 'utf8');
+        console.log(ok('Normalized plugin registry paths'));
+      }
+    } catch (err) {
+      // Log warning but don't fail - registry may be malformed
+      console.log(warn(`Could not normalize plugin registry: ${(err as Error).message}`));
+    }
   }
 
   /**
diff --git a/tests/unit/shared-manager.test.ts b/tests/unit/shared-manager.test.ts
new file mode 100644
index 00000000..f9124a58
--- /dev/null
+++ b/tests/unit/shared-manager.test.ts
@@ -0,0 +1,104 @@
+/**
+ * Unit tests for SharedManager - plugin registry path normalization
+ */
+import { describe, it, expect, beforeEach, afterEach } from 'bun:test';
+import * as fs from 'fs';
+import * as path from 'path';
+import * as os from 'os';
+
+// Test the normalization regex pattern directly
+const normalizePluginPaths = (content: string): string => {
+  return content.replace(/\/\.ccs\/instances\/[^/]+\//g, '/.claude/');
+};
+
+describe('SharedManager', () => {
+  describe('normalizePluginRegistryPaths', () => {
+    describe('regex pattern', () => {
+      it('should replace instance paths with canonical claude path', () => {
+        const input = '/home/user/.ccs/instances/ck/plugins/cache/plugin/0.0.2';
+        const expected = '/home/user/.claude/plugins/cache/plugin/0.0.2';
+        expect(normalizePluginPaths(input)).toBe(expected);
+      });
+
+      it('should handle different instance names', () => {
+        const inputs = [
+          '/home/user/.ccs/instances/work/plugins/cache/plugin/1.0.0',
+          '/home/user/.ccs/instances/personal/plugins/cache/plugin/1.0.0',
+          '/home/user/.ccs/instances/test-account/plugins/cache/plugin/1.0.0',
+        ];
+        for (const input of inputs) {
+          expect(normalizePluginPaths(input)).toContain('/.claude/');
+          expect(normalizePluginPaths(input)).not.toContain('/.ccs/instances/');
+        }
+      });
+
+      it('should handle multiple occurrences', () => {
+        const input = JSON.stringify({
+          plugins: {
+            'plugin-a': [{ installPath: '/home/user/.ccs/instances/ck/plugins/a' }],
+            'plugin-b': [{ installPath: '/home/user/.ccs/instances/work/plugins/b' }],
+          },
+        });
+        const result = normalizePluginPaths(input);
+        expect(result).not.toContain('/.ccs/instances/');
+        expect(result.match(/\.claude/g)?.length).toBe(2);
+      });
+
+      it('should not modify already-canonical paths', () => {
+        const input = '/home/user/.claude/plugins/cache/plugin/0.0.2';
+        expect(normalizePluginPaths(input)).toBe(input);
+      });
+
+      it('should be idempotent', () => {
+        const input = '/home/user/.ccs/instances/ck/plugins/cache/plugin/0.0.2';
+        const first = normalizePluginPaths(input);
+        const second = normalizePluginPaths(first);
+        expect(first).toBe(second);
+      });
+
+      it('should preserve JSON structure', () => {
+        const original = {
+          version: 2,
+          plugins: {
+            'claude-hud@claude-hud': [
+              {
+                scope: 'user',
+                installPath: '/home/kai/.ccs/instances/ck/plugins/cache/claude-hud/claude-hud/0.0.2',
+                version: '0.0.2',
+              },
+            ],
+          },
+        };
+        const input = JSON.stringify(original, null, 2);
+        const result = normalizePluginPaths(input);
+
+        // Should be valid JSON
+        expect(() => JSON.parse(result)).not.toThrow();
+
+        // Should have normalized path
+        const parsed = JSON.parse(result);
+        expect(parsed.plugins['claude-hud@claude-hud'][0].installPath).toBe(
+          '/home/kai/.claude/plugins/cache/claude-hud/claude-hud/0.0.2'
+        );
+      });
+    });
+
+    describe('edge cases', () => {
+      it('should handle empty object', () => {
+        const input = JSON.stringify({});
+        expect(normalizePluginPaths(input)).toBe(input);
+      });
+
+      it('should handle plugins without installPath', () => {
+        const input = JSON.stringify({ plugins: {} });
+        expect(normalizePluginPaths(input)).toBe(input);
+      });
+
+      it('should handle Windows-style paths (backslash)', () => {
+        // Windows paths use backslashes, regex should not match
+        const input = 'C:\\Users\\user\\.ccs\\instances\\ck\\plugins\\cache';
+        expect(normalizePluginPaths(input)).toBe(input);
+      });
+    });
+  });
+});