# MCP Contract Compatibility Checker

> MCP Contract Compatibility Checker is a paid API for AI agents from www.mahastrategies.com, paid per call via x402, $0.015/call, status unknown (last checked 2026-09-14).

Validates declared MCP tool contracts against a server snapshot by comparing required tool names and exact input/output schema digests without contacting the server

## Facts

- Endpoint: POST https://www.mahastrategies.com/api/v1/micro/mcp-contract-compatibility
- Price: $0.015/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/mcp-contract-compatibility-checker-e3d97e8e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_x62DlPLQi7KBl6BirsvU7

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 mcp-contract-compatibility-checker-e3d97e8e -d '<json body>'
```

Example prompt: Before I upgrade my MCP server, check if the declared tool contracts are still compatible — here's my server snapshot with the required tool names and schema digests, using HTTP transport and POST method with JSON body, with public data class.

## When to prefer this

Choose this endpoint when you need offline, deterministic MCP tool contract validation — i.e., comparing declared required tool names and schema digests against a server snapshot without making live server requests. It is ideal for CI/CD pipelines, pre-upgrade audits, and protocol version bumps where you want a reproducible, receipt-backed compatibility check. Do not use it if you need semantic schema subtyping proofs or official conformance certification.

## Known failure modes

- Schema digest mismatch if the offered snapshot uses incompatible schema formats
- Missing required tool names in the offered snapshot cause boundary violations
- Unsupported protocol version or transport type returns an error
- Malformed body or missing required fields (dataClass, required, offered) cause a 400-level rejection
- Incompatible bodyType enum value (must be json, form-data, or text) causes rejection

## How this service works

Check declared MCP tool contracts before an upgrade. Compare required names and exact input/output schema digests with a supplied server snapshot, protocol version and transport. No server contact, semantic schema-subtyping proof or official conformance certification.

## Output

Returns a structured result including the offer ID ('mcp-contract-compatibility'), protocol version, compatibility result object, an array of boundary violations (0–128 items), an input digest, a receipt digest, and the amount charged in base units (15000). No live server is contacted during validation.

## 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",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "required": [
      "dataClass",
      "required",
      "offered"
     ],
     "properties": {
      "offered": {
       "type": "object"
      },
      "required": {
       "type": "object"
      },
      "dataClass": {
       "enum": [
        "public",
        "synthetic"
       ],
       "type": "string"
      }
     },
     "additionalProperties": false
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "version",
      "offerId",
      "amountBaseUnits",
      "inputDigest",
      "result",
      "boundaries",
      "receiptDigest"
     ],
     "properties": {
      "result": {
       "type": "object"
      },
      "offerId": {
       "enum": [
        "mcp-contract-compatibility"
       ],
       "type": "string"
      },
      "version": {
       "enum": [
        "maha-microproducts/0.1"
       ],
       "type": "string"
      },
      "boundaries": {
       "type": "array",
       "maxItems": 128,
       "minItems": 0
      },
      "inputDigest": {
       "type": "string",
       "maxLength": 71
      },
      "receiptDigest": {
       "type": "string",
       "maxLength": 71
      },
      "amountBaseUnits": {
       "enum": [
        "15000"
       ],
       "type": "string"
      }
     },
     "additionalProperties": false
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/mcp-contract-compatibility-checker-e3d97e8e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from www.mahastrategies.com](https://www.zero.xyz/host/www.mahastrategies.com/llms.txt)