Webrix MCP Gateway

Implements federated identity management supporting OIDC, SAML 2.0, and OAuth 2.0 providers (Okta, Azure AD, Google Workspace, custom IdPs) with token exchange and session management. Routes authentication requests through a centralized gateway layer that validates credentials against external identity providers and issues short-lived MCP access tokens, eliminating credential storage in the gateway itself.

Enforces hierarchical role definitions (admin, operator, viewer, custom roles) with fine-grained permissions mapped to specific MCP tools, resources, and operations. Uses a policy engine that evaluates role membership (derived from IdP groups or manually assigned) against requested tool invocations, supporting both allow-list (whitelist) and deny-list (blacklist) patterns with attribute-based extensions for context-aware decisions.

Implements request tracing with unique request IDs propagated through the entire request lifecycle (client → gateway → tool → response). Integrates with distributed tracing systems (Jaeger, Zipkin, Datadog APM) using OpenTelemetry instrumentation to capture request latency, error traces, and dependency chains. Traces include MCP-specific context (tool name, user identity, authorization decision) and are correlated with audit logs for end-to-end visibility.

Maintains a centralized registry of available MCP tools with metadata (name, description, schema, capabilities, health status). Supports dynamic tool registration via API or configuration file, enabling new tools to be added without restarting the gateway. Includes health checks for registered tools with automatic removal of unhealthy tools from the registry. Provides tool discovery API for clients to query available tools, supported operations, and required permissions.

Logs all MCP requests and responses with automatic masking of sensitive fields (API keys, passwords, tokens, PII) based on configurable patterns or field names. Logs include request/response payloads, headers, latency, and status codes. Supports multiple log levels (debug, info, warn, error) with per-tool or per-user log level configuration. Logs are written to files, stdout, or external logging systems (ELK, Splunk, Datadog) with optional structured logging (JSON format) for easy parsing.

Captures all authentication, authorization, and MCP tool invocation events with immutable append-only logging to prevent tampering. Each audit event includes timestamp, user identity, tool name, operation, result (success/failure), and contextual metadata (IP address, user agent, request ID). Logs are written to persistent storage (file, database, or external SIEM) with optional cryptographic signing to ensure integrity and support compliance investigations.

Provides a centralized, encrypted vault for storing MCP tool credentials (API keys, database passwords, OAuth tokens, certificates) with automatic encryption at rest using AES-256 or KMS integration. Supports credential rotation policies (automatic refresh on schedule or manual trigger), credential versioning, and audit trails for all vault access. Credentials are never exposed to client applications — instead, the gateway injects credentials into MCP tool invocations server-side, ensuring secrets remain within the secure perimeter.

Acts as a transparent proxy for MCP protocol traffic, intercepting and validating all requests and responses against MCP schema specifications. Performs request transformation (parameter sanitization, type coercion, default value injection), response filtering (removing sensitive fields, truncating large payloads), and protocol version negotiation. Implements MCP-aware request routing to backend tools with connection pooling and automatic failover to replica tools.

Evaluates access policies at request time using a policy engine that considers user identity, tool name, operation type, resource identifiers, and contextual factors (time of day, IP address, request frequency). Policies are defined in a declarative language (YAML or JSON) and support complex conditions (AND, OR, NOT) with attribute-based access control (ABAC) extensions. Policies are cached in memory with TTL-based invalidation to minimize evaluation latency while ensuring freshness.

Provides production-ready Helm charts for deploying the MCP gateway on Kubernetes with built-in support for horizontal pod autoscaling (HPA), persistent volume claims for audit logs, service mesh integration (Istio, Linkerd), and multi-replica deployments with leader election. Includes health checks (liveness, readiness probes), resource limits, and network policies for secure pod-to-pod communication. Supports both on-premise Kubernetes clusters and managed services (EKS, GKE, AKS).

Supports separate configuration profiles for dev, staging, and production environments with environment-specific policies, credentials, and access rules. Configuration is loaded from files, environment variables, or external config servers (Consul, etcd) with hot-reload support to apply changes without restarting the gateway. Includes environment variable templating to inject secrets from external vaults (AWS Secrets Manager, HashiCorp Vault) at startup.

Exposes Prometheus-compatible metrics for gateway health, request latency, error rates, authentication/authorization decisions, and tool invocation statistics. Includes built-in alerting rules for common failure scenarios (high error rate, slow response times, authentication failures) with integration to alerting systems (Prometheus AlertManager, PagerDuty, Slack). Provides a health check endpoint for Kubernetes liveness/readiness probes and custom metrics for business logic (e.g., 'tools accessed per user').

Implements token bucket or sliding window rate limiting at the gateway layer, enforcing per-user, per-tool, and per-API-key quotas to prevent abuse and ensure fair resource allocation. Quotas are configurable per environment and can be adjusted dynamically without restarting the gateway. Supports burst allowances for temporary spikes and graceful degradation when quotas are exceeded (queue requests or return 429 Too Many Requests). Rate limit state is stored in-memory with optional Redis backend for distributed deployments.