diff --git a/agent/anthropic_adapter.py b/agent/anthropic_adapter.py
index 252338da41..d51aec1767 100644
--- a/agent/anthropic_adapter.py
+++ b/agent/anthropic_adapter.py
@@ -34,20 +34,20 @@ from hermes_cli.version_info import get_version_info
 # ``import anthropic`` is deliberately NOT at module top: the SDK costs ~220 ms of imports and
 # every usage site is a cold user-triggered path. ``...`` = not yet tried; None = tried, missing.
 _anthropic_sdk: Any = ...
+# Why the lazy install did not make the SDK importable. A completed install that needs a restart
+# (PM activates a new dependency environment only at boot) must not be reported as "install it".
+_anthropic_install_error: Optional[Exception] = None
 
 
 def _get_anthropic_sdk():
     """Return the ``anthropic`` SDK module, importing lazily. None if not installed."""
-    global _anthropic_sdk
+    global _anthropic_sdk, _anthropic_install_error
     if _anthropic_sdk is ...:
         try:
             from pm import ensure_import
             ensure_import("anthropic")
-        except ImportError:
-            pass
-        except Exception:
-            # InstallError — fall through to ImportError handling below
-            pass
+        except Exception as exc:  # the import below decides; exc explains a miss
+            _anthropic_install_error = exc
         try:
             import anthropic as _sdk
             _anthropic_sdk = _sdk
@@ -59,6 +59,9 @@ def _get_anthropic_sdk():
 def _require_sdk(purpose: str, verb: str = "Install it with"):
     """``_get_anthropic_sdk()`` or ImportError naming the feature that needs it."""
     sdk = _get_anthropic_sdk()
+    if sdk is None and _anthropic_install_error is not None:
+        raise ImportError(f"The 'anthropic' package is required for {purpose}: "
+                          f"{_anthropic_install_error}") from _anthropic_install_error
     if sdk is None:
         raise ImportError(f"The 'anthropic' package is required for {purpose}. {verb}: "
                           f"{install_hint('anthropic')}")
diff --git a/agent/bedrock_adapter.py b/agent/bedrock_adapter.py
index fb8c5e59f4..358ee71210 100644
--- a/agent/bedrock_adapter.py
+++ b/agent/bedrock_adapter.py
@@ -87,6 +87,7 @@ _MIN_BOTO3_VERSION = (1, 34, 59)
 
 def _require_boto3():
     """Import boto3; converse_stream() needs >= 1.34.59 (a system boto3 can shadow the venv pin)."""
+    install_error = None
     try:
         # boto3 left [all] (PRs #24220, #24515); PM installs the [bedrock] extra on first use. This
         # runs at the first client build, never at import: an import-time sync would rebuild the
@@ -94,14 +95,14 @@ def _require_boto3():
         try:
             from pm import ensure_import
             ensure_import("bedrock")
-        except Exception as exc:  # the import below reports the real failure
+        except Exception as exc:  # the import below decides; exc explains a miss
             logger.warning("boto3 lazy install did not complete: %s", exc)
+            install_error = exc
         import boto3
     except ImportError:
-        raise ImportError(
-            "The 'boto3' package is required for the AWS Bedrock provider. "
-            f"Run: {install_hint('bedrock')}"
-        )
+        # A completed install that needs a restart must not be reported as "install it".
+        reason = f": {install_error}" if install_error else f". Run: {install_hint('bedrock')}"
+        raise ImportError(f"The 'boto3' package is required for the AWS Bedrock provider{reason}") from install_error
     try:
         version = tuple(int(x) for x in boto3.__version__.split(".")[:3])
     except (AttributeError, ValueError):
diff --git a/tests/agent/test_anthropic_adapter.py b/tests/agent/test_anthropic_adapter.py
index a0b4e563ad..929cd633b7 100644
--- a/tests/agent/test_anthropic_adapter.py
+++ b/tests/agent/test_anthropic_adapter.py
@@ -29,6 +29,28 @@ class TestIsOAuthToken:
         assert _is_oauth_token("sk-ant-api03-abcdef1234567890") is False
 
 
+def test_missing_sdk_error_reports_why_the_lazy_install_did_not_land(monkeypatch):
+    """A completed install that needs a restart must not tell the user to install it again."""
+    import pm
+    from agent import anthropic_adapter
+    from pm.package import InstallError
+
+    restart = InstallError("venv", "anthropic installed; restart Hermes to activate the new dependency environment")
+
+    def ensure_import(extra):
+        raise restart
+
+    monkeypatch.setattr(pm, "ensure_import", ensure_import)
+    monkeypatch.setattr(anthropic_adapter, "_anthropic_sdk", ...)
+    monkeypatch.setattr(anthropic_adapter, "_anthropic_install_error", None)
+    monkeypatch.setitem(sys.modules, "anthropic", None)
+
+    with pytest.raises(ImportError) as excinfo:
+        build_anthropic_client("sk-ant-api03-test")
+    assert str(restart) in str(excinfo.value)
+    assert pm.install_hint("anthropic") not in str(excinfo.value)
+
+
 class TestBuildAnthropicClient:
 
 
diff --git a/tests/agent/test_bedrock_adapter.py b/tests/agent/test_bedrock_adapter.py
index 1d725b856f..c710352a52 100644
--- a/tests/agent/test_bedrock_adapter.py
+++ b/tests/agent/test_bedrock_adapter.py
@@ -1437,6 +1437,24 @@ class TestRequireBoto3VersionCheck:
             with pytest.raises(RuntimeError, match="does not support converse_stream"):
                 _require_boto3()
 
+    def test_missing_boto3_error_reports_why_the_lazy_install_did_not_land(self, monkeypatch):
+        """A completed install that needs a restart must not tell the user to install it again."""
+        import pm
+        from agent.bedrock_adapter import _require_boto3
+        from pm.package import InstallError
+
+        restart = InstallError("venv", "bedrock installed; restart Hermes to activate the new dependency environment")
+
+        def ensure_import(extra):
+            raise restart
+
+        monkeypatch.setattr(pm, "ensure_import", ensure_import)
+        with patch.dict("sys.modules", {"boto3": None}):
+            with pytest.raises(ImportError) as excinfo:
+                _require_boto3()
+        assert str(restart) in str(excinfo.value)
+        assert pm.install_hint("bedrock") not in str(excinfo.value)
+
 
 
 class TestImageBase64Decoding: