• Blog
  • Docs
  • Pricing
  • We’re hiring!
Log inSign up
dcm31

dcm31

mcp-tester

Test any MCP server - list tools and call them
Public
Like
mcp-tester
Home
Code
3
README.md
H
main.ts
test.ts
Branches
1
Pull requests
Remixes
History
Environment variables
Val Town is a collaborative website to build and scale JavaScript apps.
Deploy APIs, crons, & store data – all from the browser, and deployed in milliseconds.
Sign up now
Code
/
README.md
Code
/
README.md
Search
…
Viewing readonly version of main branch: v4
View latest version
README.md

MCP Tester

Test any MCP server - discover tools and call them interactively.

URL: https://dcm31-mcp-tester.web.val.run

What this does

  1. Enter any MCP server URL
  2. Discover available tools via the MCP protocol
  3. Call tools with custom arguments
  4. See raw JSON-RPC responses

Usage

Interactive UI

Visit the endpoint and enter an MCP server URL to test.

Programmatic API

# Discover tools curl -X POST "https://dcm31-mcp-tester.web.val.run/?url=https://dicemcp.val.run" \ -H "Content-Type: application/json" \ -d '{"method": "discover"}' # Call a tool curl -X POST "https://dcm31-mcp-tester.web.val.run/?url=https://dicemcp.val.run" \ -H "Content-Type: application/json" \ -d '{"method": "call", "tool": "roll_dice", "args": {"count": 3}}' # Quick connectivity test curl "https://dcm31-mcp-tester.web.val.run/api/test?url=https://dicemcp.val.run"

From Another Val

const TESTER = "https://dcm31-mcp-tester.web.val.run"; const MCP_URL = "https://your-mcp.val.run"; // Discover tools const discovery = await fetch(`${TESTER}/?url=${encodeURIComponent(MCP_URL)}`, { method: "POST", headers: { "Content-Type": "application/json" }, body: JSON.stringify({ method: "discover" }), }).then(r => r.json()); console.log(discovery.tools); // Call a tool const result = await fetch(`${TESTER}/?url=${encodeURIComponent(MCP_URL)}`, { method: "POST", headers: { "Content-Type": "application/json" }, body: JSON.stringify({ method: "call", tool: "your_tool_name", args: { foo: "bar" } }), }).then(r => r.json()); console.log(result);

API Reference

EndpointMethodDescription
/?url=<mcp-url>POSTRun MCP operations (see body params below)
/api/test?url=<mcp-url>GETQuick discovery test
/GETInteractive UI

POST Body Parameters

FieldDescription
method"discover" or "call" (or raw MCP method like "tools/list")
toolTool name (required for "call")
argsTool arguments object (optional for "call")
paramsRaw params for passthrough MCP methods

See Also

  • mcp-dice - Minimal MCP server example
  • MCP Specification
FeaturesVersion controlCode intelligenceCLIMCP
Use cases
TeamsAI agentsSlackGTM
DocsShowcaseTemplatesNewestTrendingAPI examplesNPM packages
PricingNewsletterBlogAboutCareers
We’re hiring!
Brandhi@val.townStatus
X (Twitter)
Discord community
GitHub discussions
YouTube channel
Bluesky
Open Source Pledge
Terms of usePrivacy policyAbuse contact
© 2026 Val Town, Inc.