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Documentation Index

Fetch the complete documentation index at: https://docs.universalbench.dev/llms.txt

Use this file to discover all available pages before exploring further.

UniversalBench is a single endpoint, single tool API. The endpoint is your personal MCP URL, the tool is called execute, and it accepts 20+ optional input fields organised into seven domains: compute, web, files, database, GitHub, code authoring, and state. Mix and match fields per call.

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Base URL

Every customer gets a personal URL with their identity baked in: 
https://universalbench-mcp.penantiaglobal.workers.dev/u/ubk_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Copy yours from the dashboard at universalbench.dev. Treat it like a password.

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Protocol

UniversalBench speaks the standard MCP protocol over HTTP using the Streamable HTTP transport. Most users connect via an MCP client (Claude Desktop, Cursor, Claude Code, custom agents on the MCP SDKs) and never see the wire format. If you want to call the API directly without an MCP SDK, post JSON RPC envelopes to your URL: 
curl -X POST https://universalbench-mcp.penantiaglobal.workers.dev/u/ubk_your_key \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
      "name": "execute",
      "arguments": {
        "code": "print(2 + 2)"
      }
    }
  }'

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Discovery

To list the single available tool and its full schema: 
{ "jsonrpc": "2.0", "id": 1, "method": "tools/list" }
The response returns one tool named execute with the full input schema. The schema is dynamic and reflects the live capability set, so new capabilities appear in your AI’s tool description automatically when we ship them. See Tools for current field documentation.

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Errors

Errors follow standard JSON RPC error semantics:
CodeMeaning
-32001Authentication failed (URL token invalid or revoked)
-32002Monthly free tier exhausted and wallet is empty
-32601Tool name not recognized (only execute is supported)
-32700Request body is not valid JSON
Tool execution failures (Python exceptions, bash non zero exit codes, network errors) are returned as successful JSON RPC responses with the error captured in the content field. This lets your AI see and reason about the error rather than failing the entire call.