Infracost MCP Server

MCP server that lets Claude interact with Infracost for Terraform cost estimation and cloud governance. Works with Claude Desktop and Claude Code.

What it does

• Generate cost breakdowns for Terraform configurations

• Compare costs between different configs or branches

• Create and manage tagging policies in Infracost Cloud

• Set up cost guardrails that block expensive PRs

• Post cost comments to GitHub/GitLab/Azure/Bitbucket PRs

• Upload custom properties for resource classification

• Access predefined usage YAML files for cost estimation

Prerequisites

• Node.js >= 18

• Infracost CLI (for cost estimation tools)

• Infracost service token from Infracost Cloud > Org Settings > API tokens

Installation

Configuration

Create a .env file in the project root:

Get your service token from the Infracost Cloud dashboard under Org Settings > API tokens.

Usage

With Claude Code

The repo includes .mcp.json and .claude/agents/ so it works out of the box - just open the project in Claude Code and the Infracost tools will be available.

With Claude Desktop

Add to your Claude Desktop config file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

• Linux: ~/.config/Claude/claude_desktop_config.json

• Windows: %APPDATA%/Claude/claude_desktop_config.json

Restart Claude Desktop after updating the config.

Examples

Natural Language Queries

Ask Claude things like:

Cost Estimation:

• "What's the monthly cost of my Terraform in ./infrastructure?"

• "Show me a cost breakdown for ./terraform/prod in table format"

• "Generate an HTML cost report and save it to report.html"

• "Upload the cost estimate from infracost.json to Infracost Cloud"

Cost Comparison:

• "Compare costs between ./staging and ./prod configs"

• "What's the cost difference if I switch from t3.medium to t3.large?"

• "Show me cost changes between the current branch and main"

Tagging Policies:

• "Create a tagging policy that requires Environment and Owner tags"

• "List all tagging policies for my organization"

• "Add a tagging policy that allows only 'dev', 'staging', 'prod' for Environment tags"

• "Update the tagging policy to also require a CostCenter tag"

Cost Guardrails:

• "Set up a guardrail that blocks PRs adding more than $200/month"

• "Create a guardrail that warns when total infrastructure cost exceeds $10k/month"

• "Block PRs with cost increases over 25% for my production repo"

• "List all active guardrails"

Pull Request Integration:

• "Post the cost estimate from infracost.json to GitHub PR #123 in owner/repo"

• "Add a cost comment to the current GitLab merge request"

JSON Examples

Generate cost breakdown:

Compare configurations:

Create tagging policy:

Create cost guardrail:

See docs/EXAMPLES.md for more detailed examples.

Available Tools

CLI Tools (require Infracost CLI)

• infracost_breakdown - Generate cost breakdown for Terraform infrastructure

• infracost_diff - Show cost differences between two configurations

• infracost_output - Combine and format Infracost JSON files

• infracost_upload - Upload cost estimates to Infracost Cloud

• infracost_comment - Post cost comments to pull requests

Cloud API Tools (require service token)

Tagging Policies:

• infracost_cloud_list_tagging_policies - List all tagging policies

• infracost_cloud_get_tagging_policy - Get a specific tagging policy

• infracost_cloud_create_tagging_policy - Create a new tagging policy

• infracost_cloud_update_tagging_policy - Update an existing tagging policy

• infracost_cloud_delete_tagging_policy - Delete a tagging policy

Guardrails:

• infracost_cloud_list_guardrails - List all guardrails

• infracost_cloud_get_guardrail - Get a specific guardrail

• infracost_cloud_create_guardrail - Create a cost guardrail

• infracost_cloud_update_guardrail - Update an existing guardrail

• infracost_cloud_delete_guardrail - Delete a guardrail

Custom Properties:

• infracost_cloud_upload_custom_properties - Upload custom property values via CSV

MCP Resources

The server provides predefined Infracost usage YAML files as MCP resources:

• infracost://usage/small - Small usage defaults ($5/month) for development environments

• infracost://usage/medium - Medium usage defaults ($10/month) for staging environments

• infracost://usage/large - Large usage defaults ($20/month) for production environments

• infracost://usage/example - Example template showing how to customize usage values

These resources can be used to understand Infracost usage files or as templates for creating custom usage configurations. Claude can access these resources directly to help you set up cost estimation with realistic usage patterns.

Project Structure

• src/ - TypeScript source code

• dist/ - Compiled JavaScript output (created by npm run build)

• resources/ - Predefined Infracost usage YAML files

• docs/ - Additional documentation and examples

• .claude/ - Claude Code agent configuration

Development

Troubleshooting

CLI tools not working:

• Verify Infracost CLI is installed: infracost --version

• Ensure INFRACOST_SERVICE_TOKEN is set correctly

Cloud API errors:

• Check that your service token has the necessary permissions

• Verify the organization slug is correct

Server not connecting:

• Ensure the path to dist/index.js is absolute in your MCP config

• Restart Claude Desktop after making config changes

• Check that npm run build completed successfully

No resources found:

• Run terraform init in your Terraform directory first

• Verify the path to your Terraform files is correct

Resources

• Infracost Documentation

• Infracost Cloud API

• Model Context Protocol

License

MIT