User GuidesProtocol Tester

Using the Protocol Tester

Test MCP, A2A, and REST endpoints directly inside the Agentic Asset Designer platform with the built-in Protocol Tester—no external tools required.

Overview

The Protocol Tester is an in-app, Postman-like component that lets you:

  • Discover capabilities — Connect to an MCP or A2A URL and see tools, resources, prompts, or skills automatically.
  • Run requests — Fill in parameters using schema-based forms (no raw JSON), then view status, headers, and response body.
  • Copy cURL — Generate a cURL command from any request for use in scripts or external tools.
  • Replay history — Recent requests are saved so you can replay or compare results.

Protocol is auto-detected from the URL (e.g. paths containing /mcp or /a2a), and all requests go through the platform’s proxy so CORS and browser security are handled for you.

Where to Find It

Standalone page

  • Open the sidebar and click Protocol Tester (flask icon).
  • You’ll see the full tester with URL bar, optional auth and headers, and a history drawer.
  • Use this when you want to test any MCP, A2A, or REST URL (including servers not yet registered in the platform).

MCP Server detail — Test tab

  • Open an MCP server from the Servers list, then select the Test tab.
  • The tester is pre-filled with that server’s MCP endpoint URL and auth (if configured).
  • Protocol is locked to MCP; after you click Send, tools, resources, and prompts appear as cards you can run.

Agent Card detail — Test tab

  • Open an agent card from the Agent Cards list, then select the Test tab.
  • The tester is pre-filled with the card’s A2A endpoint; discovered skills are shown.
  • Protocol is locked to A2A so you can send messages and test skills.

How It Works

  1. Enter or use the pre-filled URL (e.g. https://your-domain.com/api/platform/SERVER_ID/mcp).
  2. Click Send — The tester detects the protocol, calls the appropriate discovery (e.g. initialize, tools/list, resources/list, prompts/list for MCP), and displays the results.
  3. Use the discovery cards — Each tool, resource, or prompt has a Test button. Click it to open a form built from the schema (text, number, select, etc.).
  4. Submit and view the response — Status, timing, and body are shown; you can switch between formatted JSON, raw text, and headers, and copy the request as cURL.

MCP HTTP-Streamable and SSE

Many MCP servers use the HTTP-Streamable transport. The Protocol Tester is built to work with them:

  • Headers — It sends Accept: application/json, text/event-stream and User-Agent: ProtocolTester/1.0 (MCP-HTTP) on every MCP request, so servers that expect these headers will respond correctly.
  • SSE responses — If the server returns Server-Sent Events (e.g. event: message and data: {"result":{...}}), the tester automatically extracts the JSON from the data: line and displays tools and results. No extra configuration is needed.

If discovery finds no tools, resources, or prompts, the UI shows the raw tools/list response (status and body) so you can see exactly what the server returned and debug connection or protocol issues.

Security and Limits

  • Proxy — All outbound requests are sent through the platform’s proxy. Private and internal IPs are blocked (SSRF protection).
  • Auth — Credentials you enter (Bearer token, basic auth, etc.) are used only for the request; they are not stored on the server.
  • Limits — Request body size and timeouts are enforced by the proxy to keep the service stable.

Related Guides

Creating Your First MCP ServerTesting MCP Endpoints