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Connect LangChain4j’s native McpClient to Magic Hour and download an image you already created. This Java example calls tools directly without a language model, provider API key, new generation, or additional Magic Hour generation credits.

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Install and configure

Requires Java 17+ and Maven. Download pom.xml and MagicHour.java, preserving this layout:
The example pins langchain4j-mcp to 1.22.0-beta32 and uses its native DefaultMcpClient and StreamableHttpMcpTransport. Jackson 2.22.1 parses the native tool result’s JSON text; it matches the released SDK’s own dependency version. Provide a Magic Hour API key through your server-side secret manager as MAGIC_HOUR_API_KEY. Keep the key, account data, saved project IDs, and temporary download URLs private.

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Verify access

From the example directory:
Discovery is public. The account command checks actual API authorization and prints only an authorization flag and discovered tool count, without exposing account fields.

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Retrieve and download a saved image

Use an image project ID returned by a previously accepted Magic Hour creation:
The retrieval command reports the project’s ID, status, and charged credits. Downloading requires complete status. If it is still queued or rendering, retry retrieval later with that same ID. Neither command creates a replacement project. The download command preserves the exact signed URL and its query string. Its separate storage request does not receive your Magic Hour authorization header. It writes through a temporary file, preserves an existing output, and removes its temporary file after failure.

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Native client behavior

The example uses McpClient.listTools() and McpClient.executeTool(ToolExecutionRequest). It checks the native ToolExecutionResult.isError() flag and parses resultText(). A try-with-resources block closes the MCP client. HTTP request/response logging and automatic health checks are disabled. The MCP transport uses the fixed Magic Hour endpoint, a Bearer header, and no redirects. The example pins protocol 2025-11-25, which the hosted endpoint supports, rather than probing a newer unsupported protocol. This example intentionally exposes only read-only account and image-recovery operations. In this SDK release, the legacy HTTP transport can reinitialize and replay a request once after a session-expired HTTP 404. The modern multiRoundTripMaxRetries setting does not disable that legacy behavior. Consequently, this guide does not use that client path for a paid create operation or claim that it guarantees one submission. Create media through another verified Magic Hour integration or the REST API, save its accepted ID, then recover it here. See Magic Hour MCP for the wider tool inventory and our privacy policy for external processing details. Native validation on October 24, 2026 discovered 48 tools, authenticated the account read, retrieved an existing completed image project, and downloaded its usable 640×640 PNG. The 310,597-byte file passed full image decoding, and the Maven processes exited successfully. These account, retrieval, and download commands created no new project or generation charge. No model-backed agent run or marketplace listing was part of this validation.