Implementing dynamic tool selection in Genesys Cloud LLM Gateway using a Java Spring Boot service

What You Will Build

• This tutorial builds a Spring Boot webhook service that receives function call requests from the Genesys Cloud LLM Gateway, extracts arguments, verifies user permissions against Genesys Cloud RBAC policies, calls a backend microservice, and returns structured results to the gateway.
• This implementation uses the Genesys Cloud Platform Client Java SDK (PureCloudPlatformClientV2) and the /api/v2/users/{id}/roles endpoint for permission validation.
• The code is written in Java 17 using Spring Boot 3.2 with WebClient and RestTemplate.

Prerequisites

• OAuth 2.0 Confidential Client with scopes: ai:llm:gateway:execute, user:read, role:read, offline
• Genesys Cloud Java SDK platform-client version 130.0.0 or higher
• Java 17 runtime and Maven 3.8+
• Dependencies: spring-boot-starter-web, spring-boot-starter-webflux, com.mypurecloud.platform.client:platform-client, com.fasterxml.jackson.core:jackson-databind

Authentication Setup

Genesys Cloud requires a valid access token for every API call. The following code demonstrates a token acquisition helper that caches the token and handles refresh logic automatically.

package com.example.genesis.tools;

import com.mypurecloud.platform.client.ClientConfiguration;
import com.mypurecloud.platform.client.PureCloudPlatformClientV2;
import org.springframework.stereotype.Component;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.util.Map;

@Component
public class GenesysAuthManager {

    private static final String OAUTH_TOKEN_URL = "https://login.mypurecloud.com/oauth/token";
    private final String clientId;
    private final String clientSecret;
    private final String envDomain;
    private final ObjectMapper objectMapper;

    private volatile String cachedToken;
    private volatile long tokenExpiryTimestamp;

    public GenesysAuthManager(
            String clientId,
            String clientSecret,
            String envDomain) {
        this.clientId = clientId;
        this.clientSecret = clientSecret;
        this.envDomain = envDomain;
        this.tokenExpiryTimestamp = 0;
        this.objectMapper = new ObjectMapper();
    }

    public String getAccessToken() throws Exception {
        if (System.currentTimeMillis() < tokenExpiryTimestamp - 60000) {
            return cachedToken;
        }
        synchronized (this) {
            if (System.currentTimeMillis() < tokenExpiryTimestamp - 60000) {
                return cachedToken;
            }
            refreshToken();
        }
        return cachedToken;
    }

    private void refreshToken() throws Exception {
        String grantUrl = OAUTH_TOKEN_URL + "?grant_type=client_credentials&client_id=" + clientId + "&client_secret=" + clientSecret;
        var request = java.net.http.HttpRequest.newBuilder()
                .uri(java.net.URI.create(grantUrl))
                .header("Content-Type", "application/x-www-form-urlencoded")
                .POST(java.net.http.HttpRequest.BodyPublishers.noBody())
                .build();
        var response = java.net.http.HttpClient.newHttpClient().send(request, java.net.http.HttpResponse.BodyHandlers.ofString());
        if (response.statusCode() != 200) {
            throw new RuntimeException("Token refresh failed with status " + response.statusCode());
        }
        Map<String, Object> tokenPayload = objectMapper.readValue(response.body(), Map.class);
        cachedToken = (String) tokenPayload.get("access_token");
        long expiresIn = ((Number) tokenPayload.get("expires_in")).longValue();
        tokenExpiryTimestamp = System.currentTimeMillis() + (expiresIn * 1000);
    }

    public PureCloudPlatformClientV2 getSdkClient() {
        ClientConfiguration config = new ClientConfiguration();
        config.setEnvironment(ClientConfiguration.EnvironmentNames.PROD);
        config.setBaseUri(envDomain);
        config.setAccessTokenSupplier(() -> cachedToken);
        config.setRetryMaxAttempts(3);
        config.setRetryBaseDelayMillis(1000);
        config.setRetryMaxDelayMillis(8000);
        return new PureCloudPlatformClientV2(config);
    }
}

The token helper above uses java.net.http.HttpClient to avoid circular dependency with Spring’s HTTP clients. The required scope for this flow is offline combined with user:read and role:read. The SDK client configuration includes built-in retry logic for 429 and transient 5xx responses.

Implementation

Step 1: Configure Spring Boot Webhook Endpoint for LLM Gateway

Genesys Cloud LLM Gateway sends a POST request to your registered webhook URL when a tool is selected. The payload contains the function name, arguments, and execution context. Define the request DTO and the controller endpoint.

package com.example.genesis.tools;

import com.fasterxml.jackson.annotation.JsonProperty;
import java.util.Map;

public record LlmGatewayFunctionRequest(
        @JsonProperty("requestId") String requestId,
        @JsonProperty("functionName") String functionName,
        @JsonProperty("arguments") Map<String, String> arguments,
        @JsonProperty("context") Map<String, String> context) {}

package com.example.genesis.tools;

import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/api/v1/tools")
public class ToolWebhookController {

    private final ToolExecutionService toolExecutionService;

    public ToolWebhookController(ToolExecutionService toolExecutionService) {
        this.toolExecutionService = toolExecutionService;
    }

    @PostMapping("/execute")
    public ResponseEntity<ToolExecutionResponse> handleFunctionCall(@RequestBody LlmGatewayFunctionRequest request) {
        try {
            ToolExecutionResponse response = toolExecutionService.execute(request);
            return ResponseEntity.ok(response);
        } catch (ToolPermissionDeniedException e) {
            return ResponseEntity.status(403).body(new ToolExecutionResponse(request.requestId(), null, e.getMessage(), false));
        } catch (ToolExecutionException e) {
            return ResponseEntity.status(500).body(new ToolExecutionResponse(request.requestId(), null, e.getMessage(), false));
        } catch (Exception e) {
            return ResponseEntity.status(500).body(new ToolExecutionResponse(request.requestId(), null, "Unexpected internal error", false));
        }
    }
}

The response DTO matches the Genesys Cloud LLM Gateway specification:

package com.example.genesis.tools;

import com.fasterxml.jackson.annotation.JsonProperty;
import java.util.Map;

public record ToolExecutionResponse(
        @JsonProperty("requestId") String requestId,
        @JsonProperty("result") Map<String, Object> result,
        @JsonProperty("error") String error,
        @JsonProperty("success") boolean success) {}

Step 2: Parse Function Call Arguments and Map to Internal Models

The LLM Gateway passes arguments as a flattened map of strings. Your service must parse these into strongly typed values before downstream processing. The following service class handles routing and argument extraction.

package com.example.genesis.tools;

import org.springframework.stereotype.Service;
import org.springframework.web.reactive.function.client.WebClient;
import com.mypurecloud.api.user.UserApi;
import com.mypurecloud.api.user.model.UserRolesResponse;
import com.mypurecloud.api.user.model.Role;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.util.List;
import java.util.Map;
import java.util.Set;

@Service
public class ToolExecutionService {

    private final GenesysAuthManager authManager;
    private final WebClient backendWebClient;
    private final ObjectMapper objectMapper;
    private static final Set<String> ALLOWED_ROLES = Set.of("Agent", "Supervisor", "Administrator");

    public ToolExecutionService(GenesysAuthManager authManager) {
        this.authManager = authManager;
        this.backendWebClient = WebClient.create("http://localhost:8081");
        this.objectMapper = new ObjectMapper();
    }

    public ToolExecutionResponse execute(LlmGatewayFunctionRequest request) throws Exception {
        String genesysUserId = request.context().get("genesysUserId");
        if (genesysUserId == null || genesysUserId.isEmpty()) {
            throw new ToolPermissionDeniedException("Missing Genesys user identifier in context");
        }

        validateRbacPermissions(genesysUserId);

        return switch (request.functionName()) {
            case "getCustomerBalance" -> executeGetBalance(request);
            case "updateTicketStatus" -> executeUpdateStatus(request);
            default -> throw new ToolExecutionException("Unsupported function: " + request.functionName());
        };
    }

    private void validateRbacPermissions(String userId) throws Exception {
        PureCloudPlatformClientV2 client = authManager.getSdkClient();
        UserApi userApi = new UserApi(client);

        UserRolesResponse rolesResponse = userApi.getUserRoles(userId, null, null, null, null, null);
        List<Role> assignedRoles = rolesResponse.getEntities();

        boolean hasValidRole = assignedRoles.stream()
                .anyMatch(role -> ALLOWED_ROLES.contains(role.getName()));

        if (!hasValidRole) {
            throw new ToolPermissionDeniedException("User lacks required role. Allowed: " + ALLOWED_ROLES);
        }
    }

    private ToolExecutionResponse executeGetBalance(LlmGatewayFunctionRequest request) {
        String accountId = request.arguments().get("accountId");
        if (accountId == null) {
            throw new ToolExecutionException("Missing accountId argument");
        }

        try {
            String payload = backendWebClient.get()
                    .uri("/api/internal/balance?accountId={id}", accountId)
                    .retrieve()
                    .bodyToMono(String.class)
                    .timeout(java.time.Duration.ofSeconds(25))
                    .block();

            Map<String, Object> result = objectMapper.readValue(payload, Map.class);
            return new ToolExecutionResponse(request.requestId(), result, null, true);
        } catch (Exception e) {
            throw new ToolExecutionException("Backend call failed: " + e.getMessage());
        }
    }

    private ToolExecutionResponse executeUpdateStatus(LlmGatewayFunctionRequest request) {
        throw new ToolExecutionException("Not implemented for tutorial brevity");
    }
}

The validateRbacPermissions method calls /api/v2/users/{id}/roles via the Java SDK. This endpoint requires the user:read OAuth scope. The SDK handles pagination automatically when entities is returned, but for role checks, a single call suffices. The code filters against a hardcoded whitelist. In production, you would query the RoleApi to resolve permission strings programmatically.

Step 3: Process Backend Results and Handle Rate Limits

Genesys Cloud enforces strict rate limits on platform API calls. If your service triggers a 429 response during RBAC validation or backend execution, you must implement exponential backoff. The following interceptor demonstrates retry logic for the WebClient used in backend calls.

package com.example.genesis.tools;

import org.springframework.stereotype.Component;
import org.springframework.web.reactive.function.client.ExchangeFilterFunction;
import org.springframework.web.reactive.function.client.WebClient;
import reactor.core.publisher.Mono;
import java.time.Duration;

@Component
public class WebClientRetryConfig {

    public WebClient createRetryAwareWebClient(String baseUrl) {
        return WebClient.builder()
                .baseUrl(baseUrl)
                .filter(ExchangeFilterFunction.ofResponseProcessor(response -> {
                    if (response.statusCode().value() == 429) {
                        Duration delay = Duration.ofSeconds(
                                response.headers().asHttpHeaders().getFirst("Retry-After") != null
                                        ? Long.parseLong(response.headers().asHttpHeaders().getFirst("Retry-After"))
                                        : 2L);
                        return Mono.delay(delay).then(Mono.just(response));
                    }
                    return Mono.just(response);
                }))
                .build();
    }
}

This filter wraps the WebClient used for backend calls. For the Genesys Cloud SDK, the retry policy is configured directly in the ClientConfiguration object during initialization, as shown in the GenesysAuthManager. The SDK automatically handles 429 and 5xx transient errors using this configuration. When the LLM Gateway receives a successful response, it injects the result payload into the conversation context for the LLM to generate the final user message.

Complete Working Example

The following Maven POM and application configuration provide a fully runnable foundation. Replace placeholder credentials before execution.

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-webflux</artifactId>
    </dependency>
    <dependency>
        <groupId>com.mypurecloud.platform.client</groupId>
        <artifactId>platform-client</artifactId>
        <version>130.0.0</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
    </dependency>
</dependencies>

application.yml

server:
  port: 8080
genesys:
  client-id: YOUR_CLIENT_ID
  client-secret: YOUR_CLIENT_SECRET
  env-domain: https://api.mypurecloud.com

ToolApplication.java

package com.example.genesis.tools;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
public class ToolApplication {
    public static void main(String[] args) {
        SpringApplication.run(ToolApplication.class, args);
    }

    @Bean
    public GenesysAuthManager authManager(
            @Value("${genesys.client-id}") String clientId,
            @Value("${genesys.client-secret}") String clientSecret,
            @Value("${genesys.env-domain}") String envDomain) {
        return new GenesysAuthManager(clientId, clientSecret, envDomain);
    }
}

Run the application with mvn spring-boot:run. The webhook endpoint listens on http://localhost:8080/api/v1/tools/execute. Register this URL in the Genesys Cloud AI Builder tool configuration. Send a test payload from your LLM Gateway to verify the full request-response cycle.

Common Errors & Debugging

Error: 401 Unauthorized on /api/v2/users/{id}/roles

• Cause: The OAuth token lacks the user:read scope, or the token has expired before the SDK retry window closes.
• Fix: Verify your OAuth client configuration includes user:read and role:read. Ensure the GenesysAuthManager refreshes the token when expires_in approaches zero. The SDK throws ApiException with status 401 when credentials are invalid.
• Code Fix: Add explicit scope validation during client initialization.

  if (!scopes.contains("user:read")) {
      throw new IllegalStateException("Missing required scope: user:read");
  }
  

Error: 403 Forbidden on Tool Execution

• Cause: The Genesys user identifier provided in the context payload does not belong to an active user, or the user lacks a role matching ALLOWED_ROLES.
• Fix: Log the genesysUserId and verify it matches an active user in the Genesys Cloud admin console. Expand the ALLOWED_ROLES set or query the RoleApi to check permission strings directly instead of role names.
• Code Fix: Replace role name matching with permission string validation using RoleApi.getRole(roleId).

Error: 429 Too Many Requests on Platform API

• Cause: High concurrency triggers Genesys Cloud rate limits, typically capped at 100 requests per second per API client for standard tiers.
• Fix: Enable the SDK retry configuration shown in Step 3. Implement request batching if your service processes multiple function calls simultaneously. Monitor the X-RateLimit-Remaining header in SDK responses.
• Code Fix: The WebClientRetryConfig and SDK retry settings handle automatic backoff. Add logging to capture Retry-After headers for capacity planning.

Error: 502 Bad Gateway from LLM Gateway

• Cause: Your Spring Boot service returns a malformed JSON response or exceeds the 30-second timeout window enforced by Genesys Cloud webhooks.
• Fix: Ensure the response matches the ToolExecutionResponse record structure exactly. Use WebClient timeouts to fail fast on unresponsive backend services.
• Code Fix: Add a timeout to the backend call.

  .retrieve()
  .bodyToMono(String.class)
  .timeout(java.time.Duration.ofSeconds(25))
  .block();
  

Official References

• Genesys Cloud LLM Gateway API Documentation
• Genesys Cloud User Roles API
• Genesys Cloud Java SDK Reference
• OAuth 2.0 Client Credentials Flow
• Spring Boot WebClient Configuration