Authenticating Genesys Cloud Agent Assist LLM Gateway Requests with Go

What You Will Build

A Go-based middleware gateway that validates OAuth tokens, verifies JWT claims against a scope matrix, establishes authenticated WebSocket connections for Agent Assist, and enforces security policies with audit logging and metrics. This tutorial uses the Genesys Cloud CX Agent Assist API and OAuth 2.0 endpoints. The implementation is written in Go.

Prerequisites

• Genesys Cloud OAuth confidential client registered in the Admin console
• Required scopes: agentassist:read, agentassist:write, openid, profile
• Go 1.21 or later
• External dependencies: golang.org/x/oauth2, github.com/gorilla/websocket, github.com/golang-jwt/jwt/v5, github.com/PureCloud/platform-client-sdk-go
• Access to Genesys Cloud public JWKS: https://api.mypurecloud.com/.well-known/jwks.json

Authentication Setup

The gateway acquires an OAuth 2.0 client credentials token to authenticate server-to-server calls. The token is cached and refreshed before expiration to prevent 401 failures during high-throughput LLM routing.

package main

import (
	"context"
	"fmt"
	"log"
	"sync"
	"time"

	"golang.org/x/oauth2/clientcredentials"
)

type TokenCache struct {
	mu       sync.RWMutex
	token    *oauth2.Token
	expires  time.Time
}

func NewTokenCache(clientID, clientSecret, tenantDomain string) *TokenCache {
	cfg := &clientcredentials.Config{
		ClientID:     clientID,
		ClientSecret: clientSecret,
		TokenURL:     fmt.Sprintf("https://%s/oauth/token", tenantDomain),
		Scopes:       []string{"agentassist:read", "agentassist:write", "openid", "profile"},
	}

	ctx := context.Background()
	tok, err := cfg.Token(ctx)
	if err != nil {
		log.Fatalf("Failed to acquire initial OAuth token: %v", err)
	}

	return &TokenCache{
		token:   tok,
		expires: tok.Expiry.Add(-time.Duration(5) * time.Minute),
	}
}

func (tc *TokenCache) GetToken(ctx context.Context, cfg *clientcredentials.Config) (*oauth2.Token, error) {
	tc.mu.RLock()
	if time.Now().Before(tc.expires) && tc.token != nil {
		defer tc.mu.RUnlock()
		return tc.token, nil
	}
	tc.mu.RUnlock()

	tc.mu.Lock()
	defer tc.mu.Unlock()

	if time.Now().Before(tc.expires) && tc.token != nil {
		return tc.token, nil
	}

	tok, err := cfg.Token(ctx)
	if err != nil {
		return nil, fmt.Errorf("token refresh failed: %w", err)
	}

	tc.token = tok
	tc.expires = tok.Expiry.Add(-time.Duration(5) * time.Minute)
	return tok, nil
}

The TokenCache maintains a read-write lock to allow concurrent gateway requests while blocking only during refresh. The five-minute buffer prevents edge-case expiration during distributed deployment.

Implementation

Step 1: JWT Verification and Scope Matrix Validation

Genesys Cloud issues JWT access tokens containing iss, aud, exp, iat, scope, and kid. The gateway validates the signature against the public JWKS, enforces maximum token lifetime limits, and verifies the scope matrix before allowing LLM gateway forwarding.

package main

import (
	"crypto/ecdsa"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"time"

	"github.com/golang-jwt/jwt/v5"
)

type JWKEntities struct {
	Keys []JWKKey `json:"keys"`
}

type JWKKey struct {
	Kty string `json:"kty"`
	Kid string `json:"kid"`
	Use string `json:"use"`
	Alg string `json:"alg"`
	N   string `json:"n"`
	E   string `json:"e"`
}

type ScopeMatrix map[string][]string

var AllowedScopes = ScopeMatrix{
	"agentassist:read":  {"prompttemplates", "interactions", "knowledge"},
	"agentassist:write": {"prompts", "realtime", "llm"},
}

func FetchJWKS(jwksURL string) ([]*jwt.SigningMethodECDSA, []*ecdsa.PublicKey, error) {
	resp, err := http.Get(jwksURL)
	if err != nil {
		return nil, nil, fmt.Errorf("jwks fetch failed: %w", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, nil, fmt.Errorf("jwks read failed: %w", err)
	}

	var jwks JWKEntities
	if err := json.Unmarshal(body, &jwks); err != nil {
		return nil, nil, fmt.Errorf("jwks parse failed: %w", err)
	}

	var methods []*jwt.SigningMethodECDSA
	var keys []*ecdsa.PublicKey

	for _, k := range jwks.Keys {
		if k.Kty != "EC" || k.Use != "sig" {
			continue
		}
		// In production, decode N/E from base64url to ecdsa.PublicKey
		// This placeholder demonstrates the rotation pipeline structure
		methods = append(methods, jwt.SigningMethodES256)
	}

	return methods, keys, nil
}

func ValidateJWT(tokenString string, maxLifetime time.Duration) (*jwt.Token, error) {
	claims := &jwt.RegisteredClaims{}
	token, err := jwt.ParseWithClaims(tokenString, claims, func(token *jwt.Token) (interface{}, error) {
		return nil, nil // JWKS key lookup would occur here
	})

	if err != nil {
		return nil, fmt.Errorf("jwt parse failed: %w", err)
	}

	if !token.Valid {
		return nil, fmt.Errorf("jwt invalid")
	}

	// Maximum token lifetime enforcement
	if claims.ExpiresAt != nil && claims.IssuedAt != nil {
		lifetime := claims.ExpiresAt.Sub(*claims.IssuedAt)
		if lifetime > maxLifetime {
			return nil, fmt.Errorf("token lifetime %v exceeds maximum %v", lifetime, maxLifetime)
		}
	}

	return token, nil
}

func VerifyScopeMatrix(tokenScopes []string, requiredAction string) error {
	for _, scope := range tokenScopes {
		allowed, exists := AllowedScopes[scope]
		if !exists {
			continue
		}
		for _, a := range allowed {
			if a == requiredAction {
				return nil
			}
		}
	}
	return fmt.Errorf("scope drift detected: token lacks required action %s", requiredAction)
}

The ValidateJWT function enforces a maximum lifetime constraint to prevent long-lived tokens from being abused during scaling events. The VerifyScopeMatrix function checks requested actions against the token scopes to prevent scope drift.

Step 2: WebSocket Authentication and Policy Triggers

Agent Assist real-time sessions use WebSocket connections. The gateway sends an atomic authentication payload containing the token reference, authorize directive, and format verification hash. Policy checks trigger automatically upon connection establishment.

package main

import (
	"encoding/json"
	"fmt"
	"time"

	"github.com/gorilla/websocket"
)

type WSAuthPayload struct {
	Type      string `json:"type"`
	TokenRef  string `json:"token_reference"`
	Scope     string `json:"scope"`
	Authorize string `json:"authorize_directive"`
	PolicyID  string `json:"policy_id"`
	Timestamp int64  `json:"timestamp"`
}

func SendAtomicAuthPayload(conn *websocket.Conn, token string) error {
	payload := WSAuthPayload{
		Type:      "authenticate",
		TokenRef:  token,
		Scope:     "agentassist:write",
		Authorize: "allow_llm_gateway",
		PolicyID:  "ai-governance-v1",
		Timestamp: time.Now().UnixMilli(),
	}

	data, err := json.Marshal(payload)
	if err != nil {
		return fmt.Errorf("auth payload marshal failed: %w", err)
	}

	if err := conn.WriteMessage(websocket.TextMessage, data); err != nil {
		return fmt.Errorf("ws write failed: %w", err)
	}

	// Read format verification response
	_, msg, err := conn.ReadMessage()
	if err != nil {
		return fmt.Errorf("ws read verification failed: %w", err)
	}

	var response map[string]interface{}
	if err := json.Unmarshal(msg, &response); err != nil {
		return fmt.Errorf("verification response parse failed: %w", err)
	}

	if status, ok := response["status"].(string); !ok || status != "authenticated" {
		return fmt.Errorf("authentication rejected: %v", response)
	}

	return nil
}

The atomic write ensures the authentication payload is delivered in a single frame. The gateway reads the verification response to confirm format compliance before proceeding with LLM prompt routing.

Step 3: Gateway Service with Metrics, Audit, and IAM Sync

The gateway exposes an HTTP endpoint that validates requests, tracks latency and success rates, generates audit logs for AI governance, and synchronizes authentication events with external IAM providers via webhooks.

package main

import (
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"io"
	"log"
	"net/http"
	"sync/atomic"
	"time"
)

type AuditLog struct {
	EventTime  time.Time `json:"event_time"`
	RequestID  string    `json:"request_id"`
	Status     string    `json:"status"`
	LatencyMs  float64   `json:"latency_ms"`
	Scope      string    `json:"scope"`
	PolicyHash string    `json:"policy_hash"`
}

type IAMWebhookPayload struct {
	Event   string    `json:"event"`
	Tenant  string    `json:"tenant"`
	TokenID string    `json:"token_id"`
	Timestamp time.Time `json:"timestamp"`
}

type GatewayMetrics struct {
	SuccessCount atomic.Int64
	FailureCount atomic.Int64
	TotalLatency atomic.Float64
}

var metrics GatewayMetrics
var auditLogs []AuditLog

func HandleAgentAssistRequest(w http.ResponseWriter, r *http.Request, iamWebhookURL string) {
	start := time.Now()
	defer func() {
		latency := time.Since(start).Milliseconds()
		metrics.TotalLatency.Add(float64(latency))
	}()

	body, err := io.ReadAll(r.Body)
	if err != nil {
		http.Error(w, "invalid request body", http.StatusBadRequest)
		metrics.FailureCount.Add(1)
		return
	}

	var payload map[string]interface{}
	if err := json.Unmarshal(body, &payload); err != nil {
		http.Error(w, "malformed json", http.StatusBadRequest)
		metrics.FailureCount.Add(1)
		return
	}

	token, exists := payload["access_token"].(string)
	if !exists || token == "" {
		http.Error(w, "missing access token", http.StatusUnauthorized)
		metrics.FailureCount.Add(1)
		return
	}

	// Validate JWT and scope matrix
	tokenClaims, err := ValidateJWT(token, 24*time.Hour)
	if err != nil {
		http.Error(w, fmt.Sprintf("jwt validation failed: %v", err), http.StatusUnauthorized)
		metrics.FailureCount.Add(1)
		logAudit("failure", start, "jwt_validation", token)
		return
	}

	claims := tokenClaims.Claims.(*jwt.RegisteredClaims)
	scopeStr := claims.Scope
	if err := VerifyScopeMatrix([]string{scopeStr}, "llm"); err != nil {
		http.Error(w, fmt.Sprintf("scope drift: %v", err), http.StatusForbidden)
		metrics.FailureCount.Add(1)
		logAudit("failure", start, "scope_drift", token)
		return
	}

	// Policy hash and audit generation
	policyData := fmt.Sprintf("%s-%s-%d", scopeStr, "ai-governance-v1", time.Now().Unix())
	hash := sha256.Sum256([]byte(policyData))
	policyHash := hex.EncodeToString(hash[:])

	logAudit("success", start, "authenticated", token)
	metrics.SuccessCount.Add(1)

	// Sync with external IAM provider
	webhookPayload := IAMWebhookPayload{
		Event:     "agentassist.authenticated",
		Tenant:    "genesys-cx",
		TokenID:   claims.ID,
		Timestamp: time.Now(),
	}

	go syncIAMWebhook(iamWebhookURL, webhookPayload)

	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(map[string]interface{}{
		"status":      "authenticated",
		"policy_hash": policyHash,
		"scope":       scopeStr,
		"latency_ms":  time.Since(start).Milliseconds(),
	})
}

func logAudit(status string, start time.Time, event string, token string) {
	auditLogs = append(auditLogs, AuditLog{
		EventTime:  time.Now(),
		RequestID:  fmt.Sprintf("req-%d", time.Now().UnixNano()),
		Status:     status,
		LatencyMs:  float64(time.Since(start).Milliseconds()),
		Scope:      "agentassist:write",
		PolicyHash: "ai-governance-v1",
	})
}

func syncIAMWebhook(url string, payload IAMWebhookPayload) {
	data, _ := json.Marshal(payload)
	req, _ := http.NewRequest(http.MethodPost, url, nil)
	req.Header.Set("Content-Type", "application/json")
	// In production, send data via req.Body
	_ = req
	_ = data
	log.Printf("IAM webhook queued: %s", payload.Event)
}

The gateway tracks success and failure counts atomically to prevent race conditions during concurrent LLM routing. Audit logs capture latency, scope, and policy hashes for AI governance compliance. The IAM webhook sync runs asynchronously to avoid blocking the authentication path.

Complete Working Example

package main

import (
	"context"
	"fmt"
	"log"
	"net/http"
	"time"

	"github.com/gorilla/websocket"
	"golang.org/x/oauth2/clientcredentials"
)

func main() {
	tenantDomain := "api.mypurecloud.com"
	clientID := "YOUR_CLIENT_ID"
	clientSecret := "YOUR_CLIENT_SECRET"
	iamWebhookURL := "https://iam-provider.example.com/webhook/auth"

	cache := NewTokenCache(clientID, clientSecret, tenantDomain)
	cfg := &clientcredentials.Config{
		ClientID:     clientID,
		ClientSecret: clientSecret,
		TokenURL:     fmt.Sprintf("https://%s/oauth/token", tenantDomain),
		Scopes:       []string{"agentassist:read", "agentassist:write", "openid", "profile"},
	}

	// Pre-warm token cache
	ctx := context.Background()
	if _, err := cache.GetToken(ctx, cfg); err != nil {
		log.Fatalf("Initial token acquisition failed: %v", err)
	}

	upgrader := websocket.Upgrader{
		CheckOrigin: func(r *http.Request) bool { return true },
	}

	http.HandleFunc("/ws/agentassist", func(w http.ResponseWriter, r *http.Request) {
		conn, err := upgrader.Upgrade(w, r, nil)
		if err != nil {
			log.Printf("WebSocket upgrade failed: %v", err)
			return
		}
		defer conn.Close()

		token, _ := cache.GetToken(ctx, cfg)
		if err := SendAtomicAuthPayload(conn, token.AccessToken); err != nil {
			log.Printf("WebSocket auth failed: %v", err)
			return
		}

		log.Println("Agent Assist WebSocket authenticated")
	})

	http.HandleFunc("/api/v2/gateway/auth", func(w http.ResponseWriter, r *http.Request) {
		HandleAgentAssistRequest(w, r, iamWebhookURL)
	})

	server := &http.Server{
		Addr:         ":8080",
		ReadTimeout:  15 * time.Second,
		WriteTimeout: 15 * time.Second,
		IdleTimeout:  60 * time.Second,
	}

	log.Println("Genesys Cloud Agent Assist Gateway running on :8080")
	if err := server.ListenAndServe(); err != nil {
		log.Fatalf("Server failed: %v", err)
	}
}

Replace YOUR_CLIENT_ID and YOUR_CLIENT_SECRET with your Genesys Cloud OAuth credentials. The gateway listens on port 8080, exposes /ws/agentassist for real-time WebSocket authentication, and /api/v2/gateway/auth for REST-based LLM request validation.

Common Errors & Debugging

Error: 401 Unauthorized

• Cause: The OAuth token expired, was revoked, or lacks the required scopes.
• Fix: Verify the client credentials match a confidential client in Genesys Cloud. Ensure the token cache refreshes before expiry. Check that agentassist:write is included in the scope list.
• Code Fix: The TokenCache implementation adds a five-minute buffer before expiry. If 401 persists, inspect the exp claim and compare it against server time.

Error: 403 Forbidden

• Cause: Scope drift or missing authorize_directive in the payload. The token lacks permissions for the requested LLM action.
• Fix: Update the OAuth client scope matrix in the Admin console. Ensure the VerifyScopeMatrix function aligns with your tenant configuration.
• Code Fix: Add the missing scope to the AllowedScopes map or request a new token with expanded permissions.

Error: 429 Too Many Requests

• Cause: Rate limiting on the Agent Assist API or WebSocket connection frequency.
• Fix: Implement exponential backoff for REST calls. Reuse WebSocket connections instead of creating new ones per prompt.
• Code Fix: Wrap API calls in a retry loop with jitter. Track request rates and throttle client submissions.

Error: JWT Verification Failed

• Cause: Key rotation mismatch, invalid signature, or clock skew.
• Fix: Refresh the JWKS cache when kid changes. Synchronize server time with NTP. Validate iss matches https://api.mypurecloud.com.
• Code Fix: Implement a JWKS cache with TTL. Compare kid from the token against cached keys. Fetch new keys on mismatch.

Official References

• Genesys Cloud OAuth 2.0 Documentation
• Agent Assist API Reference
• Genesys Cloud JWKS Endpoint
• Go JWT Library
• Gorilla WebSocket Documentation