terraform-tools-mcp-server

An HTTP MCP server that exposes Terraform/Terragrunt tooling as Claude Code tools, eliminating the need for Python scripts in the repository.

Tools

terraform_generate_variables

Generates a valid variables.tf HCL file for a Terraform module by inferring types from *.auto.tfvars.json input files.

Claude Code workflow:

1. Find all <unit>.auto.tfvars.json files across terragrunt environment directories

2. Read their contents and call terraform_generate_variables

3. Write the returned variables_tf string to src/<project>/modules/<unit>/variables.tf

terragrunt_generate_mock_outputs

Generates a Terragrunt mock_outputs JSON document from a unit's outputs.tf.

Claude Code workflow:

1. Read src/<project>/modules/<unit>/outputs.tf

2. Call terragrunt_generate_mock_outputs

3. Write the returned mock_outputs_json to src/<project>/terragrunt/common/mock_outputs/<unit>.json

4. Update HCL dependency blocks to reference the file via jsondecode(file("mock_outputs/<unit>.json"))

Related MCP server: DriftHound MCP Server

Deployment: Synology DS1019+ via Container Manager

This is the primary deployment target. The server runs as a persistent container and is reachable from any machine on the network at http://<diskstation-ip>:8182/mcp.

Prerequisites

• Docker image built and pushed to a registry accessible from the NAS, or the source copied directly onto the NAS and built there (see below).

• Container Manager installed on the DS1019+ (DSM 7.2+).

Option A — Build on the NAS

1. Copy the project to the NAS (e.g. via File Station or scp):

   scp -r terraform-tools-mcp-server/ admin@<diskstation-ip>:/volume1/docker/terraform-tools-mcp-server/

2. SSH into the NAS and build:

   ssh admin@<diskstation-ip>
   cd /volume1/docker/terraform-tools-mcp-server
   docker compose build

3. Start the container:

   docker compose up -d

Option B — Build locally, push to registry, pull on NAS

1. Build and tag:

   docker build -t terraform-tools-mcp-server:latest .
   docker tag terraform-tools-mcp-server:latest <your-registry>/terraform-tools-mcp-server:latest
   docker push <your-registry>/terraform-tools-mcp-server:latest

2. On the NAS, update docker-compose.yml to reference the registry image (replace build: . with image: <your-registry>/terraform-tools-mcp-server:latest), then:

   docker compose pull
   docker compose up -d

Option C — Container Manager GUI (DSM)

1. Open Container Manager → Project → Create.

2. Set the project path to the folder containing docker-compose.yml.

3. Container Manager will build and start the container automatically.

4. Port 8182 will be exposed on the NAS's LAN IP.

Verify the container is running

curl http://<diskstation-ip>:8182/health
# Expected: {"status":"ok","server":"terraform-tools-mcp-server","version":"1.0.0"}

Claude Code MCP configuration (VS Code)

Add the remote MCP server to your Claude Code settings so it's available in every project.

Location of settings file

You can also open it from VS Code via the command palette: Claude: Open Settings.

settings.json entry

{
  "mcpServers": {
    "terraform-tools": {
      "type": "http",
      "url": "http://<diskstation-ip>:8182/mcp"
    }
  }
}

Replace <diskstation-ip> with your NAS's LAN IP address (e.g. 192.168.1.50) or hostname (e.g. diskstation.local).

Per-project override (optional)

To scope the server to a specific project only, add the same block to .claude/settings.json in the project root instead of the global file.

Verify Claude Code sees the tools

In VS Code with Claude Code, run:

/mcp

You should see terraform-tools listed with tools terraform_generate_variables and terragrunt_generate_mock_outputs.

Local development (stdio — no Docker)

npm install
npm run build
TRANSPORT=stdio node dist/index.js

Tip — reproducible Docker builds: Once you've run npm install locally, a package-lock.json will be generated. Commit that file alongside the project and the Dockerfile can be changed back to npm ci / npm ci --omit=dev for fully reproducible, faster image builds.

Local Claude Code config for stdio:

{
  "mcpServers": {
    "terraform-tools": {
      "command": "node",
      "args": ["/absolute/path/to/terraform-tools-mcp-server/dist/index.js"],
      "env": { "TRANSPORT": "stdio" }
    }
  }
}

Environment variables

Health check

GET http://<host>:8182/health
→ {"status":"ok","server":"terraform-tools-mcp-server","version":"1.0.0"}