MCP server exposition

Otoroshi can expose tool functions and MCP connectors as MCP servers using three different transport protocols: HTTP, SSE, and WebSocket. This allows external MCP clients to connect to your Otoroshi-managed tools.

Supported MCP methods

All three transport plugins (HTTP, SSE, WebSocket) implement the full MCP protocol:

Method	Description
`initialize`	Initialize the MCP session
`tools/list`	List all available tools (from tool functions and MCP connectors)
`tools/call`	Call a tool by name with arguments
`resources/list`	List all available resources from connected MCP servers
`resources/read`	Read a resource by its URI. Returns text or binary content.
`resources/templates/list`	List all available resource templates from connected MCP servers
`prompts/list`	List all available prompts with their arguments
`prompts/get`	Get a prompt by name with arguments. Returns the prompt description and messages (each with role and content).

Resources

When listing resources, each resource includes:

uri - The resource URI
name - The resource name
description - A description of the resource
mimeType - The MIME type of the resource

When reading a resource, the content is returned as either text (with uri, mimeType, text) or binary blob (with uri, mimeType, blob).

Resource Templates

When listing resource templates, each template includes:

uriTemplate - The URI template with parameters
name - The template name
description - A description of the template
mimeType - The MIME type of resources generated by this template

Prompts

When listing prompts, each prompt includes:

name - The prompt name
description - A description of the prompt
arguments - An array of arguments, each with name, description, and required

When getting a prompt, the response includes:

description - The prompt description
messages - An array of messages, each with role (e.g. user, assistant) and content (text or image)

Filtering at the plugin level

All MCP server exposition plugins (HTTP, SSE, WebSocket) support filtering which tools, resources, resource templates, and prompts are exposed to clients. These filters are applied on top of any filters already configured on the MCP connectors themselves.

Available filters

Parameter	Type	Description
`include_functions`	array of strings	Only expose functions matching these regex patterns
`exclude_functions`	array of strings	Hide functions matching these regex patterns
`include_resources`	array of strings	Only expose resources matching these patterns
`exclude_resources`	array of strings	Hide resources matching these patterns
`include_resource_templates`	array of strings	Only expose resource templates matching these patterns
`exclude_resource_templates`	array of strings	Hide resource templates matching these patterns
`include_resource_template_uris`	array of strings	Only expose resource template URIs matching these patterns
`exclude_resource_template_uris`	array of strings	Hide resource template URIs matching these patterns
`include_prompts`	array of strings	Only expose prompts matching these patterns
`exclude_prompts`	array of strings	Hide prompts matching these patterns
`allow_rules`	object	Advanced JsonPath-based allow rules (see MCP Connectors - Advanced rules)
`disallow_rules`	object	Advanced JsonPath-based disallow rules
`emit_audit_events`	boolean	Emit audit events for every MCP method call (default: `false`)

Example plugin configuration with filters

{
  "name": "filtered-mcp-server",
  "version": "1.0.0",
  "refs": ["tool-function_xxxxx"],
  "mcp_refs": ["mcp-connector_xxxxx"],
  "include_functions": ["get_.*", "list_.*"],
  "exclude_functions": ["delete_.*"],
  "include_prompts": ["summarize"],
  "exclude_prompts": [],
  "include_resources": [],
  "exclude_resources": ["admin_.*"]
}

These plugin-level filters are merged with the filters defined on each MCP connector. This means you can have broad access on the connector itself and restrict it further at the exposition level, or vice versa.

Audit events

All MCP server exposition plugins (HTTP, SSE, WebSocket) can emit audit events for every MCP method call. This is useful for monitoring, debugging, and auditing MCP usage across your infrastructure.

Enabling audit events

Set emit_audit_events to true in the plugin configuration:

{
  "name": "my-mcp-server",
  "version": "1.0.0",
  "refs": ["tool-function_xxxxx"],
  "mcp_refs": ["mcp-connector_xxxxx"],
  "emit_audit_events": true
}

By default, this option is disabled (false).

Audit event payload

Each MCP method call will produce an AuditEvent with the audit type McpAudit. The event contains the following fields:

Field	Type	Description
`mcp_method`	string	The MCP JSON-RPC method called (e.g. `tools/call`, `resources/list`, `initialize`)
`mcp_id`	number	The JSON-RPC request id
`mcp_request_payload`	object	The full JSON-RPC request payload
`mcp_response`	object	The JSON-RPC response (available for WebSocket transport, `null` for HTTP and SSE)
`transport`	string	The transport protocol used: `http`, `sse`, or `websocket`
`duration`	number	The request duration in milliseconds
`status`	string	`success` or `error`
`error`	string	Error message if the request failed, `null` otherwise
`user`	object	The authenticated user information (if available)
`apikey`	object	The API key used for the request (if available)
`route`	object	The Otoroshi route that handled the request

Example audit event

{
  "@type": "AuditEvent",
  "audit": "McpAudit",
  "mcp_method": "tools/call",
  "mcp_id": 3,
  "mcp_request_payload": {
    "jsonrpc": "2.0",
    "id": 3,
    "method": "tools/call",
    "params": {
      "name": "get_weather",
      "arguments": { "city": "Paris" }
    }
  },
  "mcp_response": null,
  "transport": "http",
  "duration": 142,
  "status": "success",
  "error": null,
  "user": null,
  "apikey": { "clientId": "xxx", "clientName": "my-api-key" },
  "route": { "id": "route_xxx", "name": "mcp-server" }
}

Filtering audit events in data exporters

You can use Otoroshi's data exporter filtering to collect only MCP audit events:

{
  "include": [
    {
      "@type": "AuditEvent",
      "audit": "McpAudit"
    }
  ]
}

MCP Http Plugin

Configuration

{
  "_loc": {
    "tenant": "default",
    "teams": [
      "default"
    ]
  },
  "id": "route_2629d12c2-130b-42d5-aba5-b584b95961c9",
  "name": "MCP HTTP server exposition",
  "description": "MCP HTTP server exposition",
  "tags": [],
  "metadata": {},
  "enabled": true,
  "debug_flow": false,
  "export_reporting": false,
  "capture": false,
  "groups": [
    "default"
  ],
  "bound_listeners": [],
  "frontend": {
    "domains": [
      "mcp-http-expo.oto.tools"
    ],
    "strip_path": true,
    "exact": false,
    "headers": {},
    "query": {},
    "methods": []
  },
  "backend": {
    "targets": [
      {
        "id": "target_1",
        "hostname": "request.otoroshi.io",
        "port": 443,
        "tls": true,
        "weight": 1,
        "predicate": {
          "type": "AlwaysMatch"
        },
        "protocol": "HTTP/1.1",
        "ip_address": null,
        "tls_config": {
          "certs": [],
          "trusted_certs": [],
          "enabled": false,
          "loose": false,
          "trust_all": false
        }
      }
    ],
    "root": "/",
    "rewrite": false,
    "load_balancing": {
      "type": "RoundRobin"
    },
    "client": {
      "retries": 1,
      "max_errors": 20,
      "retry_initial_delay": 50,
      "backoff_factor": 2,
      "call_timeout": 30000,
      "call_and_stream_timeout": 120000,
      "connection_timeout": 10000,
      "idle_timeout": 60000,
      "global_timeout": 30000,
      "sample_interval": 2000,
      "proxy": {},
      "custom_timeouts": [],
      "cache_connection_settings": {
        "enabled": false,
        "queue_size": 2048
      }
    },
    "health_check": {
      "enabled": false,
      "url": "",
      "timeout": 5000,
      "healthyStatuses": [],
      "unhealthyStatuses": []
    }
  },
  "backend_ref": null,
  "plugins": [
    {
      "enabled": true,
      "debug": false,
      "plugin": "cp:otoroshi.next.plugins.OverrideHost",
      "include": [],
      "exclude": [],
      "config": {},
      "bound_listeners": [],
      "plugin_index": {
        "transform_request": 0
      },
      "nodeId": "cp:otoroshi.next.plugins.OverrideHost"
    },
    {
      "enabled": true,
      "debug": false,
      "plugin": "cp:otoroshi_plugins.com.cloud.apim.otoroshi.extensions.aigateway.plugins.McpRespEndpoint",
      "include": [],
      "exclude": [],
      "config": {
        "name": "first-mcp-http-server",
        "version": "1.0.0",
        "refs": [
          "tool-function_0511ff44-0ce5-487d-aa1c-d1980ac9a4b8"
        ],
        "mcp_refs": []
      },
      "bound_listeners": [],
      "plugin_index": {},
      "nodeId": "cp:otoroshi_plugins.com.cloud.apim.otoroshi.extensions.aigateway.plugins.McpRespEndpoint"
    }
  ],
  "kind": "proxy.otoroshi.io/Route"
}

MCP SSE Plugin

Configuration

{
  "_loc": {
    "tenant": "default",
    "teams": [
      "default"
    ]
  },
  "id": "route_73e79129a-1cc6-4473-970a-b80905e80c7b",
  "name": "mcp-sse-exposition",
  "description": "mcp-sse-exposition",
  "tags": [],
  "metadata": {},
  "enabled": true,
  "debug_flow": false,
  "export_reporting": false,
  "capture": false,
  "groups": [
    "default"
  ],
  "bound_listeners": [],
  "frontend": {
    "domains": [
      "mcp-sse-exposition.oto.tools"
    ],
    "strip_path": true,
    "exact": false,
    "headers": {},
    "query": {},
    "methods": []
  },
  "backend": {
    "targets": [
      {
        "id": "target_1",
        "hostname": "request.otoroshi.io",
        "port": 443,
        "tls": true,
        "weight": 1,
        "predicate": {
          "type": "AlwaysMatch"
        },
        "protocol": "HTTP/1.1",
        "ip_address": null,
        "tls_config": {
          "certs": [],
          "trusted_certs": [],
          "enabled": false,
          "loose": false,
          "trust_all": false
        }
      }
    ],
    "root": "/",
    "rewrite": false,
    "load_balancing": {
      "type": "RoundRobin"
    },
    "client": {
      "retries": 1,
      "max_errors": 20,
      "retry_initial_delay": 50,
      "backoff_factor": 2,
      "call_timeout": 30000,
      "call_and_stream_timeout": 120000,
      "connection_timeout": 10000,
      "idle_timeout": 60000,
      "global_timeout": 30000,
      "sample_interval": 2000,
      "proxy": {},
      "custom_timeouts": [],
      "cache_connection_settings": {
        "enabled": false,
        "queue_size": 2048
      }
    },
    "health_check": {
      "enabled": false,
      "url": "",
      "timeout": 5000,
      "healthyStatuses": [],
      "unhealthyStatuses": []
    }
  },
  "backend_ref": null,
  "plugins": [
    {
      "enabled": true,
      "debug": false,
      "plugin": "cp:otoroshi.next.plugins.OverrideHost",
      "include": [],
      "exclude": [],
      "config": {},
      "bound_listeners": [],
      "nodeId": "cp:otoroshi.next.plugins.OverrideHost",
      "plugin_index": {
        "transform_request": 0
      }
    },
    {
      "plugin_index": {},
      "nodeId": "cp:otoroshi_plugins.com.cloud.apim.otoroshi.extensions.aigateway.plugins.McpSseEndpoint-0",
      "plugin": "cp:otoroshi_plugins.com.cloud.apim.otoroshi.extensions.aigateway.plugins.McpSseEndpoint",
      "enabled": true,
      "debug": false,
      "include": [],
      "exclude": [],
      "bound_listeners": [],
      "config": {
        "name": "mcp-sse",
        "version": "1.0.0",
        "refs": [
          "tool-function_0511ff44-0ce5-487d-aa1c-d1980ac9a4b8"
        ],
        "mcp_refs": []
      }
    }
  ],
  "kind": "proxy.otoroshi.io/Route"
}

MCP WebSocket Plugin

Configuration

{
  "_loc": {
    "tenant": "default",
    "teams": [
      "default"
    ]
  },
  "id": "route_62c427cac-43c9-4d86-bab4-56cb0b61040b",
  "name": "mcp-websocket-exposition",
  "description": "mcp-websocket-exposition",
  "tags": [],
  "metadata": {},
  "enabled": true,
  "debug_flow": false,
  "export_reporting": false,
  "capture": false,
  "groups": [
    "default"
  ],
  "bound_listeners": [],
  "frontend": {
    "domains": [
      "mcp-websocket-exposition.oto.tools"
    ],
    "strip_path": true,
    "exact": false,
    "headers": {},
    "query": {},
    "methods": []
  },
  "backend": {
    "targets": [
      {
        "id": "target_1",
        "hostname": "request.otoroshi.io",
        "port": 443,
        "tls": true,
        "weight": 1,
        "predicate": {
          "type": "AlwaysMatch"
        },
        "protocol": "HTTP/1.1",
        "ip_address": null,
        "tls_config": {
          "certs": [],
          "trusted_certs": [],
          "enabled": false,
          "loose": false,
          "trust_all": false
        }
      }
    ],
    "root": "/",
    "rewrite": false,
    "load_balancing": {
      "type": "RoundRobin"
    },
    "client": {
      "retries": 1,
      "max_errors": 20,
      "retry_initial_delay": 50,
      "backoff_factor": 2,
      "call_timeout": 30000,
      "call_and_stream_timeout": 120000,
      "connection_timeout": 10000,
      "idle_timeout": 60000,
      "global_timeout": 30000,
      "sample_interval": 2000,
      "proxy": {},
      "custom_timeouts": [],
      "cache_connection_settings": {
        "enabled": false,
        "queue_size": 2048
      }
    },
    "health_check": {
      "enabled": false,
      "url": "",
      "timeout": 5000,
      "healthyStatuses": [],
      "unhealthyStatuses": []
    }
  },
  "backend_ref": null,
  "plugins": [
    {
      "enabled": true,
      "debug": false,
      "plugin": "cp:otoroshi.next.plugins.OverrideHost",
      "include": [],
      "exclude": [],
      "config": {},
      "bound_listeners": [],
      "nodeId": "cp:otoroshi.next.plugins.OverrideHost",
      "plugin_index": {
        "transform_request": 0
      }
    },
    {
      "plugin_index": {},
      "nodeId": "cp:otoroshi_plugins.com.cloud.apim.otoroshi.extensions.aigateway.plugins.McpWebsocketEndpoint-0",
      "plugin": "cp:otoroshi_plugins.com.cloud.apim.otoroshi.extensions.aigateway.plugins.McpWebsocketEndpoint",
      "enabled": true,
      "debug": false,
      "include": [],
      "exclude": [],
      "bound_listeners": [],
      "config": {
        "name": "mcp-server",
        "version": "1.0.0",
        "refs": [
          "tool-function_0511ff44-0ce5-487d-aa1c-d1980ac9a4b8"
        ],
        "mcp_refs": []
      }
    }
  ],
  "kind": "proxy.otoroshi.io/Route"
}

Supported MCP methods​

Resources​

Resource Templates​

Prompts​

Filtering at the plugin level​

Available filters​

Example plugin configuration with filters​

Audit events​

Enabling audit events​

Audit event payload​

Example audit event​

Filtering audit events in data exporters​

MCP Http Plugin​

Configuration​

MCP SSE Plugin​

Configuration​

MCP WebSocket Plugin​

Configuration​

Supported MCP methods

Resources

Resource Templates

Prompts

Filtering at the plugin level

Available filters

Example plugin configuration with filters

Audit events

Enabling audit events

Audit event payload

Example audit event

Filtering audit events in data exporters

MCP Http Plugin

Configuration

MCP SSE Plugin

Configuration

MCP WebSocket Plugin

Configuration