Oracle ADB Server

How the tunnel works

This server connects to Oracle ADB through your existing ossh tunnel. Two modes are supported — pick whichever suits your workflow:

Mode	What you do	What the server does
manual (default)	Run your ossh command in a terminal before calling connect	Checks localhost:1522 is reachable, then connects
auto	Nothing — just call connect	Spawns the ossh command itself, then connects, kills it on disconnect

Your ossh command (for reference):

ssh -o 'ProxyCommand=ossh proxy -V -U%r --overlay-bastion --region us-ashburn-1
  --compartment <ocid.compartment> -- ssh stb-internal.bastion<region>.oci.oracleiaas.com
  -p 22 -A -s proxy:ocid.bastion.oc1.iad.<key> 192.168.111.2
  -L 1522:ocidwdata.adb.<region>.oraclecloud.com:1522
  -t watch -n 90 date'

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Prerequisites

• Python 3.11+ ✅ (you have 3.14)
• ossh in your system PATH ✅
• Wallet zip at C:\scripts\oci_01.zip ✅

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Step 1 — Install dependencies

Open PowerShell and run:

cd C:\scripts
python -m venv mcp-oracle-env
mcp-oracle-env\Scripts\activate
pip install -r oracle-mcp\requirements.txt

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Step 2 — Edit config.py

Open C:\scripts\oracle-mcp\config.py and fill in:

# "manual" or "auto" — see table above
TUNNEL_MODE = "manual"

# Only needed if TUNNEL_MODE = "auto"
OCI_REGION          = "us-ashburn-1"
COMPARTMENT_OCID    = "ocid1.compartment.oc1..<your-compartment-ocid>"
BASTION_SESSION_OCID = "ocid1.bastion.oc1.iad.<your-static-session-key>"
ADB_PRIVATE_IP      = "192.168.111.2"
ADB_HOSTNAME        = "<your-adb-hostname>.adb.us-ashburn-1.oraclecloud.com"

# Always required
ADB_SERVICE_NAME = "<your_db_name>_medium"   # see Step 3 below
DB_USERNAME      = "<your_db_username>"
DB_PASSWORD      = "<your_db_password>"

# Leave as "" if you didn't set a password when downloading the wallet
WALLET_PASSWORD  = ""

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Step 3 — Find your ADB service name

The service name is inside your wallet zip:

Expand-Archive C:\scripts\oci_01.zip -DestinationPath C:\scripts\wallet_preview -Force
type C:\scripts\wallet_preview\tnsnames.ora

You'll see entries like mydb_high, mydb_medium, mydb_low, mydb_tp. Use mydb_medium for general use — good balance of speed and concurrency.

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Step 4 — Register with Cline (VS Code)

1. Open VS Code with the Cline extension installed
2. Click the Cline icon in the sidebar → MCP Servers → Edit Config
3. Add the following:

{
  "mcpServers": {
    "oracle-adb": {
      "command": "C:\\scripts\\mcp-oracle-env\\Scripts\\python.exe",
      "args": ["C:\\scripts\\oracle-mcp\\server.py"]
    }
  }
}

4. Save the file — Cline will pick up the server automatically.

Also works with Claude Desktop. Config file is at: C:\Users\mh026488\AppData\Roaming\Claude\claude_desktop_config.json Use the same JSON block above.

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Step 5 — Connect and use

Manual tunnel mode (default)

1. Open a PowerShell terminal and run your ossh command — leave it running
2. In Cline, say: Connect to the Oracle database
3. The server verifies the tunnel is up and connects

Auto tunnel mode

1. Set TUNNEL_MODE = "auto" in config.py
2. In Cline, say: Connect to the Oracle database
3. The server launches ossh, waits for the tunnel, then connects
4. When you say disconnect, the tunnel is killed cleanly

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Example prompts once connected

Show me all tables starting with AP_

Generate an ERD for the AP invoicing tables

Explain the AP_INVOICES table — row count, columns, sample data

Search for all columns containing EMPLOYEE across the schema

Query the top 10 suppliers by invoice count

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Troubleshooting

Problem	Fix
No listener on localhost:1522	You're in manual mode but haven't run your ossh command yet
ossh tunnel exited unexpectedly	Check BASTION_SESSION_OCID and COMPARTMENT_OCID in config.py match your command
ORA-01017 invalid credentials	Check DB_USERNAME / DB_PASSWORD in config.py
Wallet error / SSL error	Verify WALLET_ZIP_PATH is C:\scripts\oci_01.zip and WALLET_PASSWORD is correct
Service name not found	Check ADB_SERVICE_NAME matches an entry in tnsnames.ora (Step 3)
Tunnel drops after a while	Normal — the watch -n 90 date keepalive in your ossh command handles this; in auto mode it's included automatically

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File layout

C:\scripts\
├── oracle-mcp\
│   ├── server.py          # MCP entrypoint
│   ├── connection.py      # ossh tunnel + wallet + DB connection
│   ├── schema.py          # Table/column introspection
│   ├── relationships.py   # Heuristic FK inference
│   ├── diagram.py         # Mermaid ERD generation
│   ├── query.py           # Read-only SQL executor
│   ├── config.py          # ← EDIT THIS
│   └── requirements.txt
├── oci_01.zip             # Your wallet ✅
└── mcp-oracle-env\        # Python venv (created in Step 1)