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"))

---

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

OS	Path
macOS	~/.claude/settings.json
Windows	%APPDATA%\Claude\settings.json
Linux	~/.claude/settings.json

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

Variable	Default	Description
TRANSPORT	http	stdio for local dev, http for Docker
PORT	8182	HTTP port (only used when TRANSPORT=http)

Health check

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