> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hasmcp.com/llms.txt
> Use this file to discover all available pages before exploring further.

# How does the Payload Inspector help me debug before-and-after data transformations?

> Visualizing Javascript Interception and JMESPath results interactively.

# The Payload Inspector

When explicitly designing complex data transformation layers, developers frequently need to observe how raw HTTP outputs change into pruned contextual strings in real-time. HasMCP offers a native **Payload Inspector** to facilitate exactly this.

### Real-time Diffs

Within the Streaming Debug Console or the standard Analytics Request Viewer, you can click on any individual tool execution record to launch the inspector.

1. **The Origin View**: The inspector displays the exact raw response received by the HasMCP Execution Proxy directly from the `upstream` database or provider. This typically includes massive unneeded arrays, redundant metadata, and unsanitized HTML bodies.
2. **The Transform Pipeline**: The UI visually displays which exact transformation pipelines were executed sequentially (e.g., "JMESPath Block #1" followed by "JS Interceptor: Strip HTML").
3. **The Final Output**: The right panel displays the strict, finalized JSON object emitted back down the SSE (MCP Streamable HTTP) connection directly into Claude's operational context window.

This side-by-side comparative UI allows developers to immediately identify logic flaws. If your customized Goja script accidentally returns `undefined`, the Payload Inspector highlights the catastrophic final payload diff so you can quickly rewrite the script dynamically in the browser without deploying code.