feat: nemo check internal plugin

plugins/examples/README.md

@@ -15,6 +15,12 @@ External plugin adapter for NeMo Guardrails check server
 - Requires separate NeMo check server deployment
 - See [nemocheck/README.md](./nemocheck/README.md) for details
 
+### nemocheck-internal
+Internal plugin adapter for NeMo Guardrails check server
+- **Type**: Internal
+- Requires separate NeMo check server deployment
+- See [README.md](./nemocheckinternal/README.md) for details
+
 ## Usage
 
 Reference plugins in the plugin adapter config (default at `resources/config/config.yaml`):

plugins/examples/nemocheck/nemocheck/plugin.py

@@ -129,7 +129,6 @@ async def tool_pre_invoke(self, payload: ToolPreInvokePayload, context: PluginCo
                 reason="Tool Check Unavailable", description="Tool arguments check server returned error:", code=f"checkserver_http_status_code:{response.status_code}", details={}
             )
             result = ToolPreInvokeResult(continue_processing=False, violation=violation)
-        logger.info(response)
 
         return result
 

plugins/examples/nemocheckinternal/README.md

@@ -0,0 +1,42 @@
+# Internal NemoCheck Plugin
+
+## Prerequisites: Nemo-check server
+ * Refer to [orignal repo](https://github.com/m-misiura/demos/tree/main/nemo_openshift/guardrail-checks/deployment) for full instructions
+ * Instructions adpated for mcpgateway kind cluster to work with an llm proxy routing to some open ai compatable backend below
+
+   ```bash
+	docker pull quay.io/rh-ee-mmisiura/nemo-guardrails:guardrails_checks_with_tools_o1_v1
+	kind load docker-image quay.io/rh-ee-mmisiura/nemo-guardrails:guardrails_checks_with_tools_o1_v1 --name mcp-gateway
+    cd plugins-adapter/plugins/examples/nemocheck/k8deploy
+	kubectl apply -f config-tools.yaml
+	kubectl apply -f server.yaml
+
+   ```
+## Installation
+
+1. Find url of nemo-check-server service. E.g., from svc in `server.yaml`
+1. Update `${project_root}/resources/config/config.yaml`. Add the blob below, merge if other `plugin`s or `plugin_dir`s already exists. Sample file [here](/resources/config/nemocheck-internal-config.yaml)
+
+    ```yaml
+    # plugins/config.yaml - Main plugin configuration file
+    plugins:
+      - name: "NemoCheckv2"
+        kind: "plugins.examples.nemocheckinternal.plugin.NemoCheckv2"
+        description: "Adapter for nemo check server"
+        version: "0.1.0"        
+        hooks: ["tool_pre_invoke", "tool_post_invoke"]
+        mode: "enforce"  # enforce | permissive | disabled
+        config:
+          checkserver_url: "http://nemo-guardrails-service:8000/v1/guardrail/checks"    
+    # Plugin directories to scan
+    plugin_dirs:
+      - "plugins/examples/nemocheckinternal"    # Nemo Check Server plugins
+    ```
+
+1. In `config.yaml` ensure key `plugins.config.checkserver_url` points to the correct service
+1. Start plugin adapter
+
+# Test
+
+1. Open mcp-inspector to the mcp-gateway
+1. Try running a tool configured/not configured in nemo check config allow list in configmap [E.g.](/plugins/examples/nemocheck/k8deploy/config-tools.yaml)

plugins/examples/nemocheckinternal/__init__.py

@@ -0,0 +1,7 @@
+"""MCP Gateway NemoCheckv2 Plugin - Nemo Check Adapter.
+
+Copyright 2025
+SPDX-License-Identifier: Apache-2.0
+Authors: julianstephen
+
+"""

plugins/examples/nemocheckinternal/config.yaml

@@ -0,0 +1,28 @@
+plugins:
+  - name: "NemoCheckv2"
+    kind: "plugins.examples.nemocheckinternal.plugin.NemoCheckv2"
+    description: "Nemo Check Adapter"
+    version: "0.1.0"
+    author: "julianstephen"
+    hooks: ["prompt_pre_fetch", "prompt_post_fetch", "tool_pre_invoke", "tool_post_invoke"]
+    tags: ["plugin"]
+    mode: "enforce"  # enforce | permissive | disabled
+    priority: 150
+    conditions:
+      # Apply to specific tools/servers
+      - server_ids: []  # Apply to all servers
+        tenant_ids: []  # Apply to all tenants
+    config:
+      # Plugin config dict passed to the plugin constructor
+
+# Plugin directories to scan
+plugin_dirs:
+  - "nemocheckv2"
+
+# Global plugin settings
+plugin_settings:
+  parallel_execution_within_band: true
+  plugin_timeout: 30
+  fail_on_plugin_error: false
+  enable_plugin_api: true
+  plugin_health_check_interval: 60

plugins/examples/nemocheckinternal/plugin-manifest.yaml

@@ -0,0 +1,10 @@
+description: "Nemo Check Adapter"
+name: NemoCheckv2
+author: "julianstephen"
+version: "0.1.0"
+available_hooks:
+  - "prompt_pre_hook"
+  - "prompt_post_hook"
+  - "tool_pre_hook"
+  - "tool_post_hook"
+default_configs:

plugins/examples/nemocheckinternal/plugin.py

@@ -0,0 +1,174 @@
+"""Nemo Check Adapter.
+
+Copyright 2025
+SPDX-License-Identifier: Apache-2.0
+Authors: julianstephen
+
+This module loads configurations for plugins.
+"""
+
+# First-Party
+from mcpgateway.plugins.framework import (
+    Plugin,
+    PluginConfig,
+    PluginContext,
+    PromptPosthookPayload,
+    PromptPosthookResult,
+    PromptPrehookPayload,
+    PromptPrehookResult,
+    ToolPostInvokePayload,
+    ToolPostInvokeResult,
+    ToolPreInvokePayload,
+    ToolPreInvokeResult,
+    PluginViolation,
+)
+
+import logging
+import os
+import requests
+import json
+
+# Initialize logging service first
+logger = logging.getLogger(__name__)
+log_level = os.getenv("LOGLEVEL", "INFO").upper()
+logger.setLevel(log_level)
+
+MODEL_NAME = os.getenv(
+    "NEMO_MODEL", "meta-llama/llama-3-3-70b-instruct"
+)  # Currently only for logging.
+CHECK_ENDPOINT = os.getenv("CHECK_ENDPOINT", "http://nemo-guardrails-service:8000")
+
+
+headers = {
+    "Content-Type": "application/json",
+}
+
+
+class NemoCheckv2(Plugin):
+    """Nemo Check Adapter."""
+
+    def __init__(self, config: PluginConfig):
+        """Entry init block for plugin.
+
+        Args:
+          logger: logger that the skill can make use of
+          config: the skill configuration
+        """
+        global CHECK_ENDPOINT
+        logger.info(f"plugin config {config}")
+        endpoint = config.config.get("checkserver_url", None)
+        if endpoint is not None:
+            CHECK_ENDPOINT = endpoint
+        logger.info(f"checkserver at {config}:{CHECK_ENDPOINT}")
+        super().__init__(config)
+
+    async def prompt_pre_fetch(
+        self, payload: PromptPrehookPayload, context: PluginContext
+    ) -> PromptPrehookResult:
+        """The plugin hook run before a prompt is retrieved and rendered.
+
+        Args:
+            payload: The prompt payload to be analyzed.
+            context: contextual information about the hook call.
+
+        Returns:
+            The result of the plugin's analysis, including whether the prompt can proceed.
+        """
+        return PromptPrehookResult(continue_processing=True)
+
+    async def prompt_post_fetch(
+        self, payload: PromptPosthookPayload, context: PluginContext
+    ) -> PromptPosthookResult:
+        """Plugin hook run after a prompt is rendered.
+
+        Args:
+            payload: The prompt payload to be analyzed.
+            context: Contextual information about the hook call.
+
+        Returns:
+            The result of the plugin's analysis, including whether the prompt can proceed.
+        """
+        return PromptPosthookResult(continue_processing=True)
+
+    async def tool_pre_invoke(
+        self, payload: ToolPreInvokePayload, context: PluginContext
+    ) -> ToolPreInvokeResult:
+        """Plugin hook run before a tool is invoked.
+
+        Args:
+            payload: The tool payload to be analyzed.
+            context: Contextual information about the hook call.
+
+        Returns:
+            The result of the plugin's analysis, including whether the tool can proceed.
+        """
+        logger.info("tool_pre_invoke....")
+        logger.info(payload)
+        tool_name = payload.name  # ("tool_name", None)
+        check_nemo_payload = {
+            "model": MODEL_NAME,
+            "messages": [
+                {
+                    "role": "assistant",
+                    "tool_calls": [
+                        {
+                            "id": "call_plug_adap_nem_check_123",
+                            "type": "function",
+                            "function": {
+                                "name": tool_name,
+                                "arguments": payload.args.get("tool_args", None),
+                            },
+                        }
+                    ],
+                }
+            ],
+        }
+        violation = None
+        response = requests.post(
+            CHECK_ENDPOINT, headers=headers, json=check_nemo_payload
+        )
+        if response.status_code == 200:
+            data = response.json()
+            status = data.get("status", "blocked")
+            logger.debug(f"rails reply:{data}")
+            if status == "success":
+                metadata = data.get("rails_status")
+                result = ToolPreInvokeResult(
+                    continue_processing=True, metadata=metadata
+                )
+            else:
+                metadata = data.get("rails_status")
+                violation = PluginViolation(
+                    reason=f"Check tool rails:{status}.",
+                    description=json.dumps(data),
+                    code=f"checkserver_http_status_code:{response.status_code}",
+                    details=metadata,
+                )
+                result = ToolPreInvokeResult(
+                    continue_processing=False, violation=violation, metadata=metadata
+                )
+
+        else:
+            violation = PluginViolation(
+                reason="Tool Check Unavailable",
+                description="Tool arguments check server returned error:",
+                code=f"checkserver_http_status_code:{response.status_code}",
+                details={},
+            )
+            result = ToolPreInvokeResult(continue_processing=False, violation=violation)
+
+        return result
+
+    async def tool_post_invoke(
+        self, payload: ToolPostInvokePayload, context: PluginContext
+    ) -> ToolPostInvokeResult:
+        """Plugin hook run after a tool is invoked.
+
+        Args:
+            payload: The tool result payload to be analyzed.
+            context: Contextual information about the hook call.
+
+        Returns:
+            The result of the plugin's analysis, including whether the tool result should proceed.
+        """
+        return ToolPostInvokeResult(continue_processing=True)

resources/config/config.yaml

@@ -22,6 +22,7 @@ plugins:
           replace: crud
         - search: crud
           replace: yikes
+
   # Nemo example
   - name: "NemoWrapperPlugin"
     kind: "plugins.examples.nemo.nemo_wrapper_plugin.NemoWrapperPlugin"
@@ -35,17 +36,26 @@ plugins:
     config:
       foo: bar
 
+  # Nemo Check Example
+  - name: "NemoCheckv2"
+    kind: "plugins.examples.nemocheckinternal.plugin.NemoCheckv2"
+    description: "Adapter for nemo check server"
+    version: "0.1.0"
+    author: "Julian Stephen"
+    config:
+      checkserver_url: "http://nemo-guardrails-service:8000/v1/guardrail/checks"    
 # Plugin directories to scan
 plugin_dirs:
   - "plugins/native"           # Built-in plugins
   - "plugins/custom"           # Custom organization plugins
   - "/etc/mcpgateway/plugins"  # System-wide plugins
   - "plugins/examples/nemo"    # Example Nemo guardrails plugins
+  - "plugins/examples/nemocheckinternal"    # Nemo Check Server plugins
 
 # Global plugin settings
 plugin_settings:
   parallel_execution_within_band: true
   plugin_timeout: 30
   fail_on_plugin_error: false
   enable_plugin_api: true
-  plugin_health_check_interval: 60
+  plugin_health_check_interval: 60

resources/config/nemocheck-internal-config.yaml

@@ -0,0 +1,30 @@
+# plugins/config.yaml - Main plugin configuration file
+plugins:
+  # Nemo Check Example
+  - name: "NemoCheckv2"
+    kind: "plugins.examples.nemocheckinternal.plugin.NemoCheckv2"
+    description: "Adapter for nemo check server"
+    version: "0.1.0"
+    author: "Julian Stephen"
+    hooks: ["tool_pre_invoke", "tool_post_invoke"]
+    tags: ["plugin", "pre-post"]
+    mode: "enforce"  # enforce | permissive | disabled
+    priority: 150
+    config:
+      checkserver_url: "http://nemo-guardrails-service:8000/v1/guardrail/checks"
+
+# Plugin directories to scan
+plugin_dirs:
+  - "plugins/native"           # Built-in plugins
+  - "plugins/custom"           # Custom organization plugins
+  - "/etc/mcpgateway/plugins"  # System-wide plugins
+  - "plugins/examples/nemo"    # Example Nemo guardrails plugins
+  - "plugins/examples/nemocheckinternal"    # Nemo Check Server plugins
+
+# Global plugin settings
+plugin_settings:
+  parallel_execution_within_band: true
+  plugin_timeout: 30
+  fail_on_plugin_error: false
+  enable_plugin_api: true
+  plugin_health_check_interval: 60

src/server.py

@@ -18,7 +18,9 @@
     PromptPrehookPayload,
     ToolPostInvokePayload,
     ToolPreInvokePayload,
+    PluginViolation,
 )
+
 from mcpgateway.plugins.framework import PluginManager
 from mcpgateway.plugins.framework.models import GlobalContext
 
@@ -69,10 +71,14 @@ async def getToolPreInvokeResponse(body):
     )
     logger.debug(f"**** Tool Pre Invoke Result: {result} ****")
     if not result.continue_processing:
+        error_message = "No go - Tool args forbidden"
+        if result.violation is not None:
+            violation: PluginViolation = result.violation
+            error_message = f"{violation.reason} -- {violation.description}"
         error_body = {
             "jsonrpc": body["jsonrpc"],
             "id": body["id"],
-            "error": {"code": -32000, "message": "No go - Tool args forbidden"},
+            "error": {"code": -32000, "message": error_message},
         }
         body_resp = ep.ProcessingResponse(
             immediate_response=ep.ImmediateResponse(