# Saylor Innovations Guide Library: MCP Connection and Tool-Call Failures

> Saylor Innovations Guide Library: MCP Connection and Tool-Call Failures is a paid API for AI agents from saylorinnovations.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-21).

Returns a structured guide article explaining how to debug MCP server connection failures and tool-call errors, covering stdio transport, initialize handshake, tool schemas, isError results, and the inspector.

## Facts

- Endpoint: GET https://saylorinnovations.com/api/kb/mcp-connection-and-tool-call-failures?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/saylor-innovations-guide-library-mcp-connection-and-tool-call-failures-dedfb309
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_MFAQS4ccTGEc7OQDmMatN

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability saylor-innovations-guide-library-mcp-connection-and-tool-call-failures-dedfb309
```

Example prompt: I'm getting connection errors with my MCP server using stdio transport and I can't figure out why my tool calls are failing — can you pull up the Saylor Innovations guide on debugging MCP connection and tool-call failures?

## When to prefer this

Choose this endpoint when a developer or AI agent needs a curated, structured reference guide specifically about debugging MCP server connections and tool-call failures — particularly covering stdio transport, handshake initialization, tool schema issues, and using the MCP inspector. Prefer this over generic web searches when you need a reliable, pre-written article with consistent structure returned as parseable JSON.

## Known failure modes

- 404 Not Found if the guide slug has changed or been removed
- 402 Payment Required if USDC payment is not provided or fails
- 500 Internal Server Error if the knowledge base is unavailable
- Empty or malformed JSON if the guide body has not been populated
- Network timeout if the server is under load

## How this service works

Debug MCP server connection and tool-call failures - stdio transport, initialize handshake, tool schemas, isError results, inspector

## Output

A JSON object containing a guide record with fields: id (unique identifier), t (title of the guide), c (category), body (full markdown or plain-text article covering MCP stdio transport setup, initialize handshake debugging, tool schema validation, isError result interpretation, and MCP inspector usage), price (nullable number), and license (license identifier string).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "json"
    },
    "example": {
     "type": "object",
     "required": [
      "id",
      "t",
      "c",
      "body"
     ],
     "properties": {
      "c": {
       "type": "string",
       "description": "Category of the guide"
      },
      "t": {
       "type": "string",
       "description": "Title of the guide"
      },
      "id": {
       "type": "string",
       "description": "Identifier of the record"
      },
      "body": {
       "type": "string",
       "description": "Main body text"
      },
      "price": {
       "type": [
        "number",
        "null"
       ],
       "description": "Price"
      },
      "license": {
       "type": "string",
       "description": "License identifier"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/saylor-innovations-guide-library-mcp-connection-and-tool-call-failures-dedfb309/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from saylorinnovations.com](https://www.zero.xyz/host/saylorinnovations.com/llms.txt)