diff --git a/tests/tools/test_local_env_blocklist.py b/tests/tools/test_local_env_blocklist.py
index 0377d59b3..1e437911d 100644
--- a/tests/tools/test_local_env_blocklist.py
+++ b/tests/tools/test_local_env_blocklist.py
@@ -93,6 +93,26 @@ class TestProviderEnvBlocklist:
         for var in registry_vars:
             assert var not in result_env, f"{var} leaked into subprocess env"
 
+    def test_aws_sdk_provider_vars_are_stripped(self):
+        """AWS SDK credential-chain vars must not leak to subprocesses."""
+        aws_vars = {
+            "AWS_ACCESS_KEY_ID": "AKIAIOSFODNN7EXAMPLE",
+            "AWS_SECRET_ACCESS_KEY": "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY",
+            "AWS_SESSION_TOKEN": "session-token",
+            "AWS_PROFILE": "production",
+            "AWS_SHARED_CREDENTIALS_FILE": "/home/user/.aws/credentials",
+            "AWS_CONFIG_FILE": "/home/user/.aws/config",
+            "AWS_WEB_IDENTITY_TOKEN_FILE": "/var/run/secrets/token",
+            "AWS_CONTAINER_CREDENTIALS_RELATIVE_URI": "/v2/credentials/123",
+            "AWS_CONTAINER_CREDENTIALS_FULL_URI": "http://169.254.170.2/v2/credentials/123",
+            "AWS_CONTAINER_AUTHORIZATION_TOKEN": "container-token",
+            "AWS_BEARER_TOKEN_BEDROCK": "bedrock-bearer",
+        }
+        result_env = _run_with_env(extra_os_env=aws_vars)
+
+        for var in aws_vars:
+            assert var not in result_env, f"{var} leaked into subprocess env"
+
     def test_non_registry_provider_vars_are_stripped(self):
         """Extra provider vars not in PROVIDER_REGISTRY must also be blocked."""
         extra_provider_vars = {
@@ -213,6 +233,28 @@ class TestBlocklistCoverage:
                     f"(provider={pconfig.id}) missing from blocklist"
                 )
 
+    def test_aws_sdk_provider_vars_are_in_blocklist(self):
+        """auth_type='aws_sdk' providers rely on credential-chain vars, not API keys."""
+        aws_vars = {
+            "AWS_ACCESS_KEY_ID",
+            "AWS_SECRET_ACCESS_KEY",
+            "AWS_SESSION_TOKEN",
+            "AWS_SECURITY_TOKEN",
+            "AWS_PROFILE",
+            "AWS_DEFAULT_PROFILE",
+            "AWS_SHARED_CREDENTIALS_FILE",
+            "AWS_CONFIG_FILE",
+            "AWS_WEB_IDENTITY_TOKEN_FILE",
+            "AWS_ROLE_ARN",
+            "AWS_ROLE_SESSION_NAME",
+            "AWS_CONTAINER_CREDENTIALS_RELATIVE_URI",
+            "AWS_CONTAINER_CREDENTIALS_FULL_URI",
+            "AWS_CONTAINER_AUTHORIZATION_TOKEN",
+            "AWS_CONTAINER_AUTHORIZATION_TOKEN_FILE",
+            "AWS_BEARER_TOKEN_BEDROCK",
+        }
+        assert aws_vars.issubset(_HERMES_PROVIDER_ENV_BLOCKLIST)
+
     def test_extra_auth_vars_covered(self):
         """Non-registry auth vars (ANTHROPIC_TOKEN, CLAUDE_CODE_OAUTH_TOKEN)
         must also be in the blocklist."""
diff --git a/tools/environments/local.py b/tools/environments/local.py
index 7e9e7c184..6bc4caa4e 100644
--- a/tools/environments/local.py
+++ b/tools/environments/local.py
@@ -75,6 +75,25 @@ def _resolve_safe_cwd(cwd: str) -> str:
 # Hermes-internal env vars that should NOT leak into terminal subprocesses.
 _HERMES_PROVIDER_ENV_FORCE_PREFIX = "_HERMES_FORCE_"
 
+_AWS_SDK_CREDENTIAL_ENV_VARS = frozenset({
+    "AWS_ACCESS_KEY_ID",
+    "AWS_SECRET_ACCESS_KEY",
+    "AWS_SESSION_TOKEN",
+    "AWS_SECURITY_TOKEN",
+    "AWS_PROFILE",
+    "AWS_DEFAULT_PROFILE",
+    "AWS_SHARED_CREDENTIALS_FILE",
+    "AWS_CONFIG_FILE",
+    "AWS_WEB_IDENTITY_TOKEN_FILE",
+    "AWS_ROLE_ARN",
+    "AWS_ROLE_SESSION_NAME",
+    "AWS_CONTAINER_CREDENTIALS_RELATIVE_URI",
+    "AWS_CONTAINER_CREDENTIALS_FULL_URI",
+    "AWS_CONTAINER_AUTHORIZATION_TOKEN",
+    "AWS_CONTAINER_AUTHORIZATION_TOKEN_FILE",
+    "AWS_BEARER_TOKEN_BEDROCK",
+})
+
 
 def _build_provider_env_blocklist() -> frozenset:
     """Derive the blocklist from provider, tool, and gateway config."""
@@ -84,6 +103,8 @@ def _build_provider_env_blocklist() -> frozenset:
         from hermes_cli.auth import PROVIDER_REGISTRY
         for pconfig in PROVIDER_REGISTRY.values():
             blocked.update(pconfig.api_key_env_vars)
+            if pconfig.auth_type == "aws_sdk":
+                blocked.update(_AWS_SDK_CREDENTIAL_ENV_VARS)
             if pconfig.base_url_env_var:
                 blocked.add(pconfig.base_url_env_var)
     except ImportError: