The Complete Production SOP: How to Deploy and Run MCP Tool Definitions with Strict Input JSON Schemas in Autonomous AI Agents

---
name: "mcp-tool-definition-json-schema"
description: "Design robust, self-describing MCP tools with strict parameter schemas and constraints."
metadata:
  author: "Model Context Protocol"
  version: "1.0.0"
  runtime_compatibility:
    - "codex"
    - "claude-code"
    - "cursor"
    - "windsurf"
triggers:
  - "define mcp tool schema"
  - "format mcp tool return"
  - "validate mcp tool input"
permissions:
  fs_read: true
  fs_write: "workspace"
  shell_exec: false
  net_access: false
---

# MCP Tool Definitions with Strict Input JSON Schemas
Authors tool manifests for Model Context Protocol: inputSchema with required arrays, property descriptions, enum constraints, and comprehensive return content formatting.

import { Tool } from '@modelcontextprotocol/sdk/types.js';

export const databaseQueryTool: Tool = {
  name: 'execute_sql_query',
  description: 'Executes a read-only parameterized SQL query against the read-replica database. Use this tool only for SELECT queries.',
  inputSchema: {
    type: 'object',
    properties: {
      query: {
        type: 'string',
        description: 'The SQL SELECT statement to execute. Must not contain mutative operations (INSERT, UPDATE, DELETE).'
      },
      timeoutMs: {
        type: 'integer',
        description: 'Maximum query execution timeout in milliseconds.',
        minimum: 100,
        maximum: 30000,
        default: 5000
      },
      isolationLevel: {
        type: 'string',
        enum: ['READ_COMMITTED', 'REPEATABLE_READ'],
        description: 'Transaction isolation level.'
      }
    },
    required: ['query'],
    additionalProperties: false
  }
};