API Reference

Complete API documentation for MCP-RS v0.16.0+ - Multi-database support with MySQL and PostgreSQL.

📚 API Documentation Sections

1. Database Engine API

Comprehensive reference for database engine implementations:

📄 Database Engine API
- Core types (Value, DatabaseError, QueryResult, ExecuteResult)
- DatabaseEngine trait
- DatabaseConnection trait
- PreparedStatement trait
- Transaction trait with ACID support
- Isolation levels
- Error handling

2. MCP Protocol API

Standard JSON-RPC 2.0 protocol methods:

Initialization
Tools (list, call)
Resources (list, read)
Prompts (list, get)
Error codes

3. Integration Guides

Step-by-step guides for each database:

PostgreSQL Integration Guide
MySQL Integration Guide (coming soon)
Performance Tuning Guide

🗄️ Supported Database Engines

Database	Status	Features	Driver	Version
MySQL	✅ Phase 1 Complete	Transactions, Prepared Statements, JSON	sqlx 0.8	5.7+
PostgreSQL	✅ Phase 2 Complete	Transactions, Prepared Statements, JSON, UUID	sqlx 0.8	12+

Core Data Types Quick Reference

Value Enum

pub enum Value {
    Null,                                    // SQL NULL
    Bool(bool),                              // Boolean
    Int(i64),                                // 64-bit integer
    Float(f64),                              // 64-bit float
    String(String),                          // UTF-8 text
    Binary(Vec<u8>),                         // Raw binary
    Json(serde_json::Value),                 // JSON objects/arrays
    DateTime(chrono::DateTime<Utc>),         // UTC timestamp
}

DatabaseError Enum

pub enum DatabaseError {
    ConnectionFailed(String),
    QueryFailed(String),
    TransactionFailed(String),
    SecurityViolation(String),
    ConfigurationError(String),
    ConfigValidationError(String),
    PoolError(String),
    TimeoutError(String),
    UnsupportedOperation(String),
    ValidationError(String),
}

IsolationLevel Enum

pub enum IsolationLevel {
    Serializable,       // Highest isolation
    RepeatableRead,     // Prevents dirty/non-repeatable reads
    ReadCommitted,      // Prevents dirty reads
    ReadUncommitted,    // Lowest isolation, fastest
}

MCP Protocol Methods

Initialization

`initialize`

Establishes connection and negotiates capabilities.

Request:

{
  "jsonrpc": "2.0",
  "method": "initialize",
  "params": {
    "protocolVersion": "2024-11-05",
    "capabilities": {
      "roots": { "listChanged": true },
      "sampling": {}
    },
    "clientInfo": {
      "name": "client-name",
      "version": "1.0.0"
    }
  },
  "id": 1
}

Response:

{
  "jsonrpc": "2.0",
  "result": {
    "protocolVersion": "2024-11-05",
    "capabilities": {
      "logging": {},
      "tools": { "listChanged": true },
      "resources": { "subscribe": true, "listChanged": true },
      "prompts": { "listChanged": true }
    },
    "serverInfo": {
      "name": "mcp-rs",
      "version": "0.16.0"
    }
  },
  "id": 1
}

Tools

`tools/list`

Lists available tools.

Request:

{
  "jsonrpc": "2.0",
  "method": "tools/list",
  "id": 2
}

Response:

{
  "jsonrpc": "2.0",
  "result": {
    "tools": [
      {
        "name": "get_posts",
        "description": "Retrieve WordPress posts",
        "inputSchema": {
          "type": "object",
          "properties": {},
          "required": []
        }
      }
    ]
  },
  "id": 2
}

`tools/call`

Executes a tool.

Request:

{
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "name": "create_post",
    "arguments": {
      "title": "My New Post",
      "content": "This is the post content."
    }
  },
  "id": 3
}

Response:

{
  "jsonrpc": "2.0",
  "result": {
    "content": [
      {
        "type": "text",
        "text": "Created post with ID: 123"
      }
    ],
    "isError": false
  },
  "id": 3
}

Resources (MCP)

`resources/list`

Lists available resources.

Request:

{
  "jsonrpc": "2.0",
  "method": "resources/list",
  "id": 4
}

Response:

{
  "jsonrpc": "2.0",
  "result": {
    "resources": [
      {
        "uri": "wordpress://posts",
        "name": "WordPress Posts",
        "description": "All published WordPress posts",
        "mimeType": "application/json"
      },
      {
        "uri": "wordpress://pages",
        "name": "WordPress Pages",
        "description": "All published WordPress pages",
        "mimeType": "application/json"
      }
    ]
  },
  "id": 4
}

`resources/read`

Reads a resource.

Request:

{
  "jsonrpc": "2.0",
  "method": "resources/read",
  "params": {
    "uri": "wordpress://posts"
  },
  "id": 5
}

Response:

{
  "jsonrpc": "2.0",
  "result": {
    "contents": [
      {
        "uri": "wordpress://posts",
        "mimeType": "application/json",
        "text": "[{\"id\":1,\"title\":\"Sample Post\",\"content\":\"...\"}]"
      }
    ]
  },
  "id": 5
}

Prompts

`prompts/list`

Lists available prompts.

Request:

{
  "jsonrpc": "2.0",
  "method": "prompts/list",
  "id": 6
}

Response:

{
  "jsonrpc": "2.0",
  "result": {
    "prompts": [
      {
        "name": "wordpress_content_analysis",
        "description": "Analyze WordPress content for SEO and readability",
        "arguments": [
          {
            "name": "post_id",
            "description": "WordPress post ID to analyze",
            "required": true
          }
        ]
      }
    ]
  },
  "id": 6
}

`prompts/get`

Retrieves a prompt.

Request:

{
  "jsonrpc": "2.0",
  "method": "prompts/get",
  "params": {
    "name": "wordpress_content_analysis",
    "arguments": { "post_id": "123" }
  },
  "id": 7
}

Response:

{
  "jsonrpc": "2.0",
  "result": {
    "description": "WordPress content analysis prompt",
    "messages": [
      {
        "role": "user",
        "content": {
          "type": "text",
          "text": "Please analyze the following WordPress post..."
        }
      }
    ]
  },
  "id": 7
}

Error Codes

Code	Message	Description
-32700	Parse error	Invalid JSON
-32600	Invalid Request	Invalid JSON-RPC request
-32601	Method not found	Method doesn’t exist
-32602	Invalid params	Invalid method parameters
-32603	Internal error	Internal JSON-RPC error
-32000	Server error	Generic server error
-32001	Invalid tool	Tool not found or invalid
-32002	Tool execution failed	Tool execution error
-32003	Resource not found	Resource URI not found
-32004	Resource read failed	Resource read error
-32005	Configuration error	Configuration validation error

WordPress Handler API

Available Tools

`get_posts`

Retrieves WordPress posts.

`create_post`

Creates a new WordPress post.

title (string, required)
content (string, required)

`get_comments`

Retrieves WordPress comments.

post_id (number, optional)

Resources

wordpress://posts - All published posts
wordpress://pages - All published pages
wordpress://media - Media library items
wordpress://categories - Post categories
wordpress://tags - Post tags
wordpress://users - Site users

Version Information

Current Version: v0.16.0
Phase 1: MySQL (Complete)
Phase 2: PostgreSQL (Complete)
Last Updated: 2025-11-23

Quick Start

Database Connection Example

use mcp_rs::handlers::database::engines::postgresql::PostgreSqlEngine;
use mcp_rs::handlers::database::types::{DatabaseConfig, DatabaseEngine};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let config = DatabaseConfig {
        engine_type: "postgresql".to_string(),
        host: "localhost".to_string(),
        port: 5432,
        username: "postgres".to_string(),
        password: "password".to_string(),
        database: "myapp".to_string(),
        ..Default::default()
    };

    let engine = PostgreSqlEngine::new(config)?;
    let conn = engine.connect().await?;

    // Execute query
    let stmt = conn.prepare(
        "SELECT * FROM users WHERE age > $1"
    ).await?;

    let result = stmt.query(&[
        Value::Int(18)
    ]).await?;

    for row in result.rows {
        println!("{:?}", row);
    }

    conn.close().await?;
    Ok(())
}

For more details, see:

📄 Database Engine API - Complete API reference
📖 PostgreSQL Integration Guide - Setup and usage
📖 Implementation Guides - All guides