diff --git a/contributing/samples/agent_governance/README.md b/contributing/samples/agent_governance/README.md
index 22fef09..81ad8fd 100644
--- a/contributing/samples/agent_governance/README.md
+++ b/contributing/samples/agent_governance/README.md
@@ -7,7 +7,7 @@ An ADK plugin that enforces policy-as-code rules before tool execution using the
 ## Install
 
 ```bash
-pip install google-adk-community agentmesh-platform
+pip install google-adk-community agent-governance-toolkit-core
 ```
 
 ## Usage
@@ -57,7 +57,7 @@ contract). Allowed calls return `None`, letting the tool proceed normally.
 
 ## Fail-closed by default
 
-If `agentmesh-platform` is not installed, the plugin raises `ImportError`
+If `agent-governance-toolkit-core` is not installed, the plugin raises `ImportError`
 at construction time. Pass `fail_open=True` to degrade gracefully instead
 (all calls pass through with a logged warning).
 
diff --git a/src/google/adk_community/plugins/agent_governance_plugin.py b/src/google/adk_community/plugins/agent_governance_plugin.py
index 05baae3..422d031 100644
--- a/src/google/adk_community/plugins/agent_governance_plugin.py
+++ b/src/google/adk_community/plugins/agent_governance_plugin.py
@@ -18,7 +18,7 @@
 Governance Toolkit (https://github.com/microsoft/agent-governance-toolkit).
 Denied tool calls are short-circuited with a policy violation response.
 
-Requires: ``pip install agentmesh-platform``
+Requires: ``pip install agent-governance-toolkit-core``
 """
 
 from __future__ import annotations
@@ -37,7 +37,7 @@
 
 
 class _GovernanceUnavailableError(ImportError):
-    """Raised when agentmesh-platform is not installed and fail_open=False."""
+    """Raised when agent-governance-toolkit-core is not installed and fail_open=False."""
 
 
 class AgentGovernancePlugin(BasePlugin):
@@ -52,7 +52,7 @@ class AgentGovernancePlugin(BasePlugin):
             ``*.yaml`` policy files. Resolved relative to the caller's
             working directory. Must be provided explicitly.
         agent_did: Decentralized identifier for the agent.
-        fail_open: If ``True``, tool calls proceed when ``agentmesh-platform``
+        fail_open: If ``True``, tool calls proceed when ``agent-governance-toolkit-core``
             is not installed (logs a warning). If ``False`` (default), raises
             ``ImportError`` at construction time.
         strict: If ``True``, raises on policy load errors instead of
@@ -61,7 +61,7 @@ class AgentGovernancePlugin(BasePlugin):
             Defaults to ``False``.
 
     Raises:
-        ImportError: If ``agentmesh-platform`` is not installed and
+        ImportError: If ``agent-governance-toolkit-core`` is not installed and
             ``fail_open`` is False.
         RuntimeError: If ``strict`` is True and a policy file fails to load.
 
@@ -122,12 +122,12 @@ def _setup(self, *, fail_open: bool, strict: bool) -> None:
         except ImportError:
             if not fail_open:
                 raise _GovernanceUnavailableError(
-                    "agentmesh-platform is required for governance enforcement. "
-                    "Install with: pip install agentmesh-platform"
+                    "agent-governance-toolkit-core is required for governance enforcement. "
+                    "Install with: pip install agent-governance-toolkit-core"
                 )
             logger.warning(
-                "agentmesh-platform not installed; governance checks disabled. "
-                "Install with: pip install agentmesh-platform"
+                "agent-governance-toolkit-core not installed; governance checks disabled. "
+                "Install with: pip install agent-governance-toolkit-core"
             )
 
     async def before_tool_callback(
diff --git a/tests/plugins/test_agent_governance_plugin.py b/tests/plugins/test_agent_governance_plugin.py
index 2e4c27e..8f5acaf 100644
--- a/tests/plugins/test_agent_governance_plugin.py
+++ b/tests/plugins/test_agent_governance_plugin.py
@@ -14,7 +14,7 @@
 
 """Tests for AgentGovernancePlugin.
 
-These tests mock the agentmesh-platform dependency so they run without
+These tests mock the agent-governance-toolkit-core dependency so they run without
 it installed, verifying the plugin's integration with the ADK plugin API.
 """
 
@@ -34,7 +34,7 @@
 
 
 # ---------------------------------------------------------------------------
-# Mock fixtures for agentmesh-platform
+# Mock fixtures for agent-governance-toolkit-core
 # ---------------------------------------------------------------------------
 
 
@@ -169,19 +169,34 @@ def policy_dir(tmp_path: Path) -> Path:
     return policies
 
 
+@pytest.fixture()
+def block_agentmesh():
+    """Make every agentmesh import fail, even if the package is installed."""
+    with patch.dict(sys.modules):
+        _uninstall_fake_agentmesh()
+        # A None parent makes agentmesh and all of its submodules unimportable.
+        sys.modules["agentmesh"] = None
+        yield
+
+
 class TestAgentGovernancePlugin:
     """Tests for AgentGovernancePlugin construction and behavior."""
 
+    @pytest.mark.usefixtures("block_agentmesh")
     def test_raises_import_error_when_agentmesh_missing(self, tmp_path: Path):
-        """Plugin raises ImportError by default when agentmesh is missing."""
-        # Simulate agentmesh not being importable by patching _setup
-        with patch.object(
-            AgentGovernancePlugin,
-            "_setup",
-            side_effect=ImportError("agentmesh-platform is required"),
+        """Plugin raises ImportError naming the package to install."""
+        with pytest.raises(
+            ImportError, match="pip install agent-governance-toolkit-core"
         ):
-            with pytest.raises(ImportError, match="agentmesh-platform"):
-                AgentGovernancePlugin(policy_dir=tmp_path)
+            AgentGovernancePlugin(policy_dir=tmp_path)
+
+    @pytest.mark.usefixtures("block_agentmesh")
+    def test_fail_open_warns_with_install_hint_when_agentmesh_missing(
+        self, tmp_path: Path, caplog: pytest.LogCaptureFixture
+    ):
+        """With fail_open=True, the warning names the package to install."""
+        AgentGovernancePlugin(policy_dir=tmp_path, fail_open=True)
+        assert "pip install agent-governance-toolkit-core" in caplog.text
 
     def test_fail_open_mode_allows_construction(self, tmp_path: Path):
         """With fail_open=True, plugin degrades when engine returns no policies."""