Infracost MCP Server

Note: This is a community-maintained MCP server. It is not an official Model Context Protocol server from Infracost.

A Model Context Protocol (MCP) server for running the Infracost CLI to estimate, compare, and publish infrastructure cost changes from Terraform and other Infrastructure as Code projects.

Overview

This server provides eight MCP tools across estimation, reporting, collaboration, and operations workflows:

• infracost_breakdown to generate baseline cost estimates.
• infracost_diff to compare planned cost changes.
• infracost_output to render existing Infracost JSON in different formats.
• infracost_comment to post PR comments on supported SCM platforms.
• infracost_upload to upload reports to Infracost Cloud.
• infracost_configure to get or set CLI configuration.
• infracost_auth to run authentication flow.
• infracost_generate_usage to generate usage files with sensible defaults.

Platform Compatibility

This MCP server is platform-agnostic and works in local and CI environments:

• Local development
• GitHub Actions
• GitLab CI/CD
• Azure DevOps
• CircleCI, Jenkins, and Bitbucket Pipelines
• AI Agents and Copilot workflows

The primary requirements are Node.js and the Infracost CLI binary.

Tool Matrix

Tools

infracost_breakdown

Runs infracost breakdown.

Inputs:

• workingDirectory (string, optional): Command working directory.
• path (string, optional): Path to Terraform/IaC directory or plan JSON.
• configFile (string, optional): Path to Infracost config file.
• usageFile (string, optional): Path to usage file.
• format (string, optional): Output format. Default: table.
• fields (string[], optional): Fields to include in output.
• showSkus (boolean, optional): Include SKU details.
• syncUsageFile (boolean, optional): Sync usage file with detected resources.
• compareTo (string, optional): Baseline Infracost JSON path.
• terraformWorkspace (string, optional): Terraform workspace.
• terraformPlanFlags (string, optional): Flags for terraform plan.
• timeoutSeconds (number, optional): Timeout in seconds.
• extraArgs (string[], optional): Additional CLI arguments.

infracost_diff

Runs infracost diff.

Inputs:

• workingDirectory (string, optional): Command working directory.
• path (string, optional): Path to Terraform/IaC directory or plan JSON.
• configFile (string, optional): Path to Infracost config file.
• usageFile (string, optional): Path to usage file.
• format (string, optional): Output format. Default: table.
• compareTo (string, optional): Baseline Infracost JSON path.
• showSkus (boolean, optional): Include SKU details.
• syncUsageFile (boolean, optional): Sync usage file with detected resources.
• terraformWorkspace (string, optional): Terraform workspace.
• terraformPlanFlags (string, optional): Flags for terraform plan.
• timeoutSeconds (number, optional): Timeout in seconds.
• extraArgs (string[], optional): Additional CLI arguments.

infracost_output

Runs infracost output.

Inputs:

• workingDirectory (string, optional): Command working directory.
• path (string, optional): Infracost JSON file path. Auto-detected when omitted.
• format (string, optional): Output format. Default: table.
• fields (string[], optional): Fields to include in output.
• showSkus (boolean, optional): Include SKU details.
• timeoutSeconds (number, optional): Timeout in seconds.
• extraArgs (string[], optional): Additional CLI arguments.

infracost_comment

Runs infracost comment.

Inputs:

• workingDirectory (string, optional): Command working directory.
• platform (string, optional): Platform (github, gitlab, azure-repos, bitbucket). Default: github.
• path (string, optional): Infracost JSON file path. Auto-detected when omitted.
• repo (string, optional): Repository (owner/repo).
• pullRequest (string, optional): Pull request number.
• commit (string, optional): Commit SHA.
• token (string, optional): Platform token.
• tag (string, optional): Comment tag.
• behavior (string, optional): Comment update behavior.
• dryRun (boolean, optional): Generate without posting.
• timeoutSeconds (number, optional): Timeout in seconds.
• extraArgs (string[], optional): Additional CLI arguments.

infracost_upload

Runs infracost upload.

Inputs:

• workingDirectory (string, optional): Command working directory.
• path (string, optional): Infracost JSON file path. Auto-detected when omitted.
• timeoutSeconds (number, optional): Timeout in seconds.
• extraArgs (string[], optional): Additional CLI arguments.

infracost_configure

Runs infracost configure.

Inputs:

• workingDirectory (string, optional): Command working directory.
• set (string, optional): Set configuration value.
• get (string, optional): Read configuration value.
• timeoutSeconds (number, optional): Timeout in seconds.
• extraArgs (string[], optional): Additional CLI arguments.

infracost_auth

Runs infracost auth login.

Inputs:

• workingDirectory (string, optional): Command working directory.
• timeoutSeconds (number, optional): Timeout in seconds.
• extraArgs (string[], optional): Additional CLI arguments.

infracost_generate_usage

Generates an Infracost usage file with sensible defaults for specified resource types. This is a utility tool that complements infracost_configure by providing pre-filled templates you can customize for your workloads. Returns both raw JSON and formatted guidance.

Inputs:

• resourceTypes (string[], required): Resource types to include (e.g., ["aws_lambda_function", "aws_s3_bucket"]).
• outputFilePath (string, optional): Path where usage file should be saved (for guidance only).
• includeGuidance (boolean, optional): Include formatted guidance. Default: true.
• onlyJson (boolean, optional): Return only raw JSON (no guidance). Default: false.

Supported resource types: aws_lambda_function, aws_instance, aws_db_instance, aws_s3_bucket, aws_dynamodb_table, aws_ebs_volume, aws_cloudfront_distribution, aws_lb, aws_nat_gateway, google_compute_instance, google_storage_bucket, azurerm_windows_virtual_machine, azurerm_linux_virtual_machine, azurerm_storage_account, azurerm_mssql_database.

Prompt Cookbook

Use these minimal prompts in Copilot Chat with @infracost. CLI tools default to the current workspace root when no path is given. If you add a file or folder as Copilot context (#file or #folder), reference it in your prompt and the tool will target that path. The server auto-detects common report files (infracost-diff.json, infracost-base.json, infracost.json), so you usually do not need to pass path for infracost_output, infracost_comment, or infracost_upload.

Quick prompts

@infracost run infracost_breakdown
@infracost run infracost_diff
@infracost run infracost_output
@infracost run infracost_comment with dryRun true
@infracost run infracost_upload

Run breakdown (infracost_breakdown)

@infracost run infracost_breakdown

Expected output: Baseline cost estimate with command output, exit code, stdout, and stderr.

Run diff (infracost_diff)

@infracost run infracost_diff

Expected output: Cost delta from the planned change compared to current baseline.

Render output (infracost_output)

@infracost run infracost_output with format html

Expected output: Formatted output from existing Infracost JSON (auto-detected when possible).

Post PR comment (infracost_comment)

@infracost run infracost_comment with repo owner/repo and pullRequest 123 and dryRun true

Expected output: Generated comment payload, or posted comment when not in dry-run mode. Platform defaults to github.

Upload report (infracost_upload)

@infracost run infracost_upload

Expected output: Upload confirmation for Infracost Cloud ingestion.

Configure CLI (infracost_configure)

@infracost run infracost_configure with:
- set: currency=USD

Expected output: Configuration update confirmation from the CLI.

Authenticate (infracost_auth)

@infracost run infracost_auth

Expected output: Authentication flow prompt or login success details.

Generate usage file (infracost_generate_usage)

@infracost run infracost_generate_usage with:
- resourceTypes: ["aws_lambda_function", "aws_s3_bucket", "aws_dynamodb_table"]
- outputFilePath: ./infracost-usage.json
- includeGuidance: true

Expected output: Pre-filled usage file JSON with sensible defaults, plus guidance on customization and usage. Use onlyJson: true to return only the JSON for programmatic handling.

Dependencies

System Dependencies

• Node.js >=24.14.0
• npm (bundled with Node.js)
• Infracost CLI installed and available in PATH (or via INFRACOST_BINARY_PATH)

npm Dependencies

Runtime:

• @modelcontextprotocol/sdk (MCP server SDK)

Development:

• typescript (build/compile)
• tsx (development runner)
• vitest (unit test runner)
• @types/node (Node.js typings)

Environment Variables

• INFRACOST_API_KEY: Infracost API key for cloud-backed features.
• INFRACOST_BINARY_PATH: Override path to Infracost binary.

Installation

npm install
npm run build

Configuration

Usage with VS Code Copilot Chat

This workspace is preconfigured in .vscode/mcp.json:

{
  "servers": {
    "infracost": {
      "type": "stdio",
      "command": "node",
      "args": ["./dist/index.js"]
    }
  }
}

Reload VS Code (Cmd+Shift+P -> Developer: Reload Window) after changing MCP configuration.

Then query the server from Copilot Chat with @infracost, for example:

@infracost run infracost_breakdown
@infracost run infracost_diff

Usage with Other MCP Clients

Use stdio transport with the built entrypoint:

{
  "name": "infracost-mcp-server",
  "type": "stdio",
  "command": "node",
  "args": ["/absolute/path/to/infracost-mcp/dist/index.js"]
}

Build first with npm run build, then start your MCP client.

Running

npm start

Development mode:

npm run dev

Built mode:

npm run start

Debugging

Use .vscode/launch.json:

• Debug MCP Server (runs npm run dev)
• Debug MCP Server (Built) (runs dist/index.js after build)

Set breakpoints in src/index.ts, then press F5.

Testing

See docs/TESTING.md for Copilot Chat scenarios, manual JSON-RPC checks, and troubleshooting guidance.

Quick validation prompt in Copilot Chat:

@infracost run infracost_breakdown

Interactive VS Code Workflows

1. PR Cost Impact Review

1. Generate a baseline:

@infracost run infracost_breakdown with:
- path: .
- format: json

1. Generate a diff:

@infracost run infracost_diff with:
- path: .
- format: diff

1. Draft a PR comment:

@infracost run infracost_comment with:
- platform: github
- path: infracost-diff.json
- repo: owner/repo
- pullRequest: 123
- dryRun: true

2. Reporting Pipeline Setup

1. Render a report for humans:

@infracost run infracost_output with:
- path: infracost-diff.json
- format: html

1. Upload for centralized tracking:

@infracost run infracost_upload with:
- path: infracost-diff.json

3. Environment Bootstrap

1. Configure defaults:

@infracost run infracost_configure with:
- set: currency=USD

1. Authenticate:

@infracost run infracost_auth

Best Practices

• Keep workingDirectory explicit when running inside monorepos.
• Use --format json for machine processing and --format table for human triage.
• Keep timeoutSeconds high enough for large Terraform plans.
• Prefer infracost_comment with dryRun=true before posting to production PR threads.
• Use infracost_upload for historical visibility in Infracost Cloud.

Additional Use Cases

• Pre-merge cost gates in pull requests.
• Scheduled baseline cost snapshots in CI.
• Cost delta reporting for release trains.
• Team-level FinOps dashboards based on uploaded reports.

Related Projects

Infracost Resources

• Infracost website
• Infracost documentation
• Infracost CLI repository

Model Context Protocol

• MCP official documentation
• MCP TypeScript SDK
• MCP servers registry

Community and Contributing

• Contributing Guide
• Code of Conduct
• Security Policy
• Testing Guide
• Maintainer Guide

Attribution and License

Maintained by Carl Dawson under the Down At The Bottom Of The Mole Hole organization.

Development

npm run lint
npm test
npm run build

License

Licensed under the MIT License.