Oracle MCP Server (Go)

This is a Model Context Protocol (MCP) server for Oracle databases, written in Go. It allows LLMs (like Claude) to interact with your Oracle database to inspect schemas, view PL/SQL source code, and execute read-only queries.

It uses the standard Stdio transport, meaning it is designed to be run directly by an MCP client (like Claude Desktop or an MCP-enabled IDE extension).

🔒 Security Note

This server is strictly READ-ONLY. It is designed with data safety as the top priority.

✅ What This Server CAN Do:

• Execute SELECT queries against your data
• Read Oracle's data dictionary views (ALL_*, DBA_*, V$*)
• View PL/SQL source code from ALL_SOURCE
• Retrieve DDL scripts using DBMS_METADATA.GET_DDL
• Generate execution plans (stores temporary data in PLAN_TABLE, then cleans up)

❌ What This Server CANNOT Do:

• No INSERT, UPDATE, DELETE — Cannot modify any table data
• No CREATE, ALTER, DROP — Cannot change database schema
• No EXECUTE — Cannot run stored procedures or functions
• No GRANT, REVOKE — Cannot change privileges
• No TRUNCATE, MERGE — Cannot perform any data manipulation

🛡️ How We Ensure Read-Only Safety:

1. Query Validation: The sql-select tool explicitly validates that queries start with SELECT or WITH before execution
2. Dictionary Views Only: All other tools query Oracle's read-only data dictionary views
3. No DDL Execution: DDL is only retrieved as text, never executed
4. Temporary Data Cleanup: Any temporary data (like execution plans) is immediately deleted after use

Note: For additional security, you can connect with a database user that only has SELECT privileges on the required dictionary views. This provides defense-in-depth at the database level.

Features

📊 Table & Schema Tools

Tool	Description
sql-select	Execute arbitrary SELECT or WITH queries (limited to 1000 rows)
list-tables	List all accessible tables (excluding system schemas)
get-table-schema	Get column definitions for a specific table
list-constraints	List all constraints for a table (PK, FK, Unique, Check)
get-constraint-columns	Get the columns that make up a constraint

🔧 PL/SQL Objects Tools

Tool	Description
list-objects	List Oracle objects by type (PROCEDURE, FUNCTION, PACKAGE, TYPE, etc.)
get-object-source	Get PL/SQL source code for procedures, functions, packages, types, triggers
describe-object	Get comprehensive info about any Oracle object (like SQL*Plus DESCRIBE)

📅 Scheduler Jobs Tools

Tool	Description
list-jobs	List all Oracle Scheduler jobs
get-job-details	Get detailed information about a specific job

🔗 Dependencies Tools

Tool	Description
list-dependencies	List what objects depend on or are used by a given object

👁️ Views Tools

Tool	Description
list-views	List all views accessible to the current user
get-view-definition	Get the SQL definition of a view

📇 Index Tools

Tool	Description
list-indexes	List all indexes, optionally filtered by table
get-index-columns	Get the columns that make up an index

🔢 Sequence Tools

Tool	Description
list-sequences	List all sequences accessible to the current user

⚡ Trigger Tools

Tool	Description
list-triggers	List all triggers, optionally filtered by table

🏷️ Type Tools

Tool	Description
list-types	List all user-defined types (object types, collection types)
get-type-attributes	Get the attributes (fields) of a user-defined type

🔄 Synonym Tools

Tool	Description
list-synonyms	List all synonyms accessible to the current user

🔍 Search & Analysis Tools

Tool	Description
search-source	Search for text within PL/SQL source code to find where tables, columns, or variables are used
search-columns	Search for column names across all tables (find all tables with a specific column)
get-ddl	Get the full SQL CREATE script (DDL) for any object using DBMS_METADATA
explain-plan	Get the execution plan for a SQL query to analyze performance
get-table-stats	Get optimizer statistics for a table (row count, last analyzed, size)
list-invalid-objects	List all database objects with INVALID status that need recompilation

📝 Documentation Tools

Tool	Description
get-table-comments	Get comments/documentation for a table and its columns
get-table-relationships	Get all foreign key relationships for a table (incoming and outgoing)

📊 Monitoring Tools

Tool	Description
list-sessions	List active database sessions (requires V$SESSION privilege)
get-job-run-history	Get execution history of a scheduler job (status, duration, errors)

Prerequisites

• Go (1.18+): To build the application.
• Oracle Database: Access to an Oracle instance.
• No Instant Client Required: Uses go-ora, a pure Go driver.

Configuration

The application requires the following environment variables:

• ORACLE_USER: Database username.
• ORACLE_PASSWORD: Database password.
• ORACLE_CONNECT_STRING: host:port/service_name.

Building

Quick Build

go build -o mcp_oracle.exe .

Build & Release to GitHub

To create a new release with the executable uploaded to GitHub:

# Interactive mode - prompts for version
.\release.ps1

# Specify version directly
.\release.ps1 -Version "v1.2.0"

# Create as draft release
.\release.ps1 -Version "v1.2.0" -Draft

Prerequisites for releasing:

• GitHub CLI (gh) installed and authenticated
• Run gh auth login if not already authenticated

Usage with Claude Desktop

To use this with the Claude Desktop app, add the following to your configuration file (typically %APPDATA%\Claude\claude_desktop_config.json on Windows):

{
  "mcpServers": {
    "oracle-db": {
      "command": "c:/path/to/your/mcp_oracle.exe",
      "args": [],
      "env": {
        "ORACLE_USER": "your_user",
        "ORACLE_PASSWORD": "your_password",
        "ORACLE_CONNECT_STRING": "localhost:1521/XEPDB1"
      },
      "disabled": false,
      "autoApprove": [
        "sql-select",
        "list-tables",
        "get-table-schema",
        "list-constraints",
        "get-constraint-columns",
        "list-objects",
        "get-object-source",
        "describe-object",
        "list-jobs",
        "get-job-details",
        "list-dependencies",
        "list-views",
        "get-view-definition",
        "list-indexes",
        "get-index-columns",
        "list-sequences",
        "list-triggers",
        "list-types",
        "get-type-attributes",
        "list-synonyms",
        "search-source",
        "search-columns",
        "get-ddl",
        "explain-plan",
        "get-table-stats",
        "list-invalid-objects",
        "get-table-comments",
        "get-table-relationships",
        "list-sessions",
        "get-job-run-history"
      ]
    }
  }
}

Make sure to replace the paths and credentials with your actual values.

Usage with VS Code (Extension)

If you are developing a VS Code extension that acts as an MCP client:

1. Spawn the mcp_oracle.exe process.
2. Set the environment variables in the process options.
3. Communicate via stdin and stdout using the MCP JSON-RPC protocol.

Tool Examples

Query Data

Tool: sql-select
Arguments: {"query": "SELECT * FROM employees WHERE department_id = 10"}

List All Procedures

Tool: list-objects
Arguments: {"object_type": "PROCEDURE", "owner": "HR"}

Get Source Code

Tool: get-object-source
Arguments: {"object_name": "CALCULATE_SALARY", "object_type": "PROCEDURE", "owner": "HR"}

List Jobs

Tool: list-jobs
Arguments: {"owner": "MYSCHEMA"}

Find Dependencies

Tool: list-dependencies
Arguments: {"object_name": "MY_PACKAGE", "direction": "used_by"}

Get Table Constraints

Tool: list-constraints
Arguments: {"table_name": "EMPLOYEES", "owner": "HR"}

Manual Testing (CLI)

You can verify the server starts by running it, but it will hang waiting for JSON-RPC input on stdin.

$env:ORACLE_USER="user"
$env:ORACLE_PASSWORD="password"
$env:ORACLE_CONNECT_STRING="localhost:1521/xe"
.\mcp_oracle.exe

MCP Protocol

This server implements the Model Context Protocol (MCP) specification:

• Transport: Stdio (stdin/stdout)
• Protocol: JSON-RPC 2.0
• Discovery: Supports tools/list for automatic tool discovery
• Execution: Supports tools/call for tool execution

When an AI agent connects, it will automatically discover all available tools via the tools/list method.