diff --git a/src/adapters/pi/index.ts b/src/adapters/pi/index.ts
index dd9a273a2..ec3ff88ee 100644
--- a/src/adapters/pi/index.ts
+++ b/src/adapters/pi/index.ts
@@ -153,61 +153,70 @@ export class PiAdapter extends BaseAdapter implements HookAdapter {
         check: "Hook support",
         status: "pass",
         message:
-          "Pi hooks are wired via the context-mode Pi extension " +
-          "(~/.pi/extensions/context-mode/), not via JSON-stdio.",
+          "Pi hooks are wired via the context-mode Pi extension, " +
+          "not via JSON-stdio.",
       },
     ];
   }
 
+  private getExtensionPackagePaths(): string[] {
+    const agentDir = process.env.PI_CODING_AGENT_DIR
+      ?? resolve(homedir(), ".pi", "agent");
+
+    return [
+      resolve(agentDir, "npm", "node_modules", "context-mode", "package.json"),
+      resolve(homedir(), ".pi", "extensions", "context-mode", "package.json"),
+    ];
+  }
+
   checkPluginRegistration(): DiagnosticResult {
-    // Pi registers extensions by directory presence; the version-sync
-    // script writes ~/.pi/extensions/context-mode/package.json. We treat
-    // that file as the registration signal.
-    const pkgPath = resolve(
-      homedir(),
-      ".pi",
-      "extensions",
-      "context-mode",
-      "package.json",
-    );
-    try {
-      const pkg = JSON.parse(readFileSync(pkgPath, "utf-8"));
-      if (pkg?.name === "context-mode") {
-        return {
-          check: "Pi extension registration",
-          status: "pass",
-          message: `context-mode extension installed at ${pkgPath}`,
-        };
+    let unexpectedPath: string | undefined;
+
+    for (const pkgPath of this.getExtensionPackagePaths()) {
+      try {
+        const pkg = JSON.parse(readFileSync(pkgPath, "utf-8"));
+        if (pkg?.name === "context-mode") {
+          return {
+            check: "Pi extension registration",
+            status: "pass",
+            message: `context-mode extension installed at ${pkgPath}`,
+          };
+        }
+        unexpectedPath ??= pkgPath;
+      } catch {
+        // Try the next supported Pi package layout.
       }
+    }
+
+    if (unexpectedPath) {
       return {
         check: "Pi extension registration",
         status: "warn",
-        message: `Unexpected package at ${pkgPath}`,
-      };
-    } catch {
-      return {
-        check: "Pi extension registration",
-        status: "fail",
-        message: `context-mode not found at ${pkgPath}`,
-        fix: "Run: context-mode upgrade",
+        message: `Unexpected package at ${unexpectedPath}`,
       };
     }
+
+    return {
+      check: "Pi extension registration",
+      status: "fail",
+      message: "context-mode not found in Pi's managed or legacy extension directories",
+      fix: "Run: context-mode upgrade",
+    };
   }
 
   getInstalledVersion(): string {
-    try {
-      const pkgPath = resolve(
-        homedir(),
-        ".pi",
-        "extensions",
-        "context-mode",
-        "package.json",
-      );
-      const pkg = JSON.parse(readFileSync(pkgPath, "utf-8"));
-      return pkg.version ?? "unknown";
-    } catch {
-      return "not installed";
+    for (const pkgPath of this.getExtensionPackagePaths()) {
+      try {
+        const pkg = JSON.parse(readFileSync(pkgPath, "utf-8"));
+        if (pkg?.name === "context-mode") {
+          return pkg.version ?? "unknown";
+        }
+      } catch {
+        // Try the next supported Pi package layout.
+      }
     }
+
+    return "not installed";
   }
 
   // ── Upgrade ────────────────────────────────────────────
diff --git a/tests/adapters/pi-adapter.test.ts b/tests/adapters/pi-adapter.test.ts
index 3b645c765..0fd93a680 100644
--- a/tests/adapters/pi-adapter.test.ts
+++ b/tests/adapters/pi-adapter.test.ts
@@ -1,5 +1,6 @@
 import "../setup-home";
-import { describe, it, expect, beforeEach } from "vitest";
+import { describe, it, expect, beforeEach, afterEach } from "vitest";
+import { mkdirSync, rmSync, writeFileSync } from "node:fs";
 import { homedir } from "node:os";
 import { join, resolve } from "node:path";
 import { PiAdapter } from "../../src/adapters/pi/index.js";
@@ -10,10 +11,35 @@ import { hashProjectDirCanonical, resolveSessionDbPath } from "../../src/session
 describe("PiAdapter — Pi platform adapter", () => {
   let adapter: PiAdapter;
 
+  const managedExtensionDir = () => join(
+    homedir(),
+    ".pi",
+    "agent",
+    "npm",
+    "node_modules",
+    "context-mode",
+  );
+
+  const legacyExtensionDir = () => join(
+    homedir(),
+    ".pi",
+    "extensions",
+    "context-mode",
+  );
+
   beforeEach(() => {
+    delete process.env.PI_CODING_AGENT_DIR;
+    rmSync(managedExtensionDir(), { recursive: true, force: true });
+    rmSync(legacyExtensionDir(), { recursive: true, force: true });
     adapter = new PiAdapter();
   });
 
+  afterEach(() => {
+    delete process.env.PI_CODING_AGENT_DIR;
+    rmSync(managedExtensionDir(), { recursive: true, force: true });
+    rmSync(legacyExtensionDir(), { recursive: true, force: true });
+  });
+
   // ── Identity ───────────────────────────────────────────
 
   describe("identity", () => {
@@ -140,4 +166,49 @@ describe("PiAdapter — Pi platform adapter", () => {
       expect(adapter.readSettings()).toEqual({ foo: "bar" });
     });
   });
+
+  describe("extension diagnostics", () => {
+    it("detects a package installed in Pi's managed npm directory", () => {
+      mkdirSync(managedExtensionDir(), { recursive: true });
+      writeFileSync(
+        join(managedExtensionDir(), "package.json"),
+        JSON.stringify({ name: "context-mode", version: "1.2.3" }),
+      );
+
+      expect(adapter.checkPluginRegistration()).toMatchObject({ status: "pass" });
+      expect(adapter.getInstalledVersion()).toBe("1.2.3");
+    });
+
+    it("honors PI_CODING_AGENT_DIR for managed packages", () => {
+      const customAgentDir = join(homedir(), "custom-pi-agent");
+      const extensionDir = join(
+        customAgentDir,
+        "npm",
+        "node_modules",
+        "context-mode",
+      );
+      process.env.PI_CODING_AGENT_DIR = customAgentDir;
+      mkdirSync(extensionDir, { recursive: true });
+      writeFileSync(
+        join(extensionDir, "package.json"),
+        JSON.stringify({ name: "context-mode", version: "2.0.0" }),
+      );
+
+      expect(adapter.checkPluginRegistration()).toMatchObject({ status: "pass" });
+      expect(adapter.getInstalledVersion()).toBe("2.0.0");
+
+      rmSync(customAgentDir, { recursive: true, force: true });
+    });
+
+    it("keeps the legacy extension directory as a fallback", () => {
+      mkdirSync(legacyExtensionDir(), { recursive: true });
+      writeFileSync(
+        join(legacyExtensionDir(), "package.json"),
+        JSON.stringify({ name: "context-mode", version: "0.9.0" }),
+      );
+
+      expect(adapter.checkPluginRegistration()).toMatchObject({ status: "pass" });
+      expect(adapter.getInstalledVersion()).toBe("0.9.0");
+    });
+  });
 });