Forge

AI-native build orchestration that replaces Makefiles with declarative YAML and makes every tool an MCP server.

What problem does Forge solve?

Teams build Go services with Makefiles, shell scripts, and ad-hoc tooling. These scripts break silently, produce unreproducible builds, and are invisible to AI coding agents that communicate through structured protocols. Test environment setup -- Kind clusters, TLS registries, Helm charts -- requires manual steps that differ per developer machine. Forge replaces this with a single forge.yaml configuration file where every component is an MCP server speaking JSON-RPC 2.0 over stdio. AI agents invoke builds, create test environments, and run test suites directly through the MCP protocol.

Quick Start

go install github.com/alexandremahdhaoui/forge/cmd/forge@latest

# forge.yaml
name: my-project
artifactStorePath: .forge/artifact-store.yaml

build:
  - name: my-app
    src: ./cmd/my-app
    dest: ./build/bin
    engine: forge://go-build

test:
  - name: unit
    runner: forge://go-test

forge build       # Build all artifacts
forge test-all    # Build + run all test stages (fail-fast)

How does it work?

+-------------------+
| AI Agent / User   |
+---------+---------+
          |
     forge.yaml
          |
+---------+---------+
|    forge CLI      |  MCP server + orchestrator
|                   |  Reads config, resolves engines,
|                   |  tracks artifacts, runs tests
+---------+---------+
          | MCP over stdio (JSON-RPC 2.0)
          |
  +-------+--------+--------------+
  |                |              |
+-+--------+ +-----+------+ +----+--------+
| Build    | | Test       | | TestEnv     |
| Engines  | | Runners    | | Managers    |
|          | |            | |             |
| go-build | | go-test    | | testenv     |
| container| | go-lint    | |  +--kind    |
| generic  | | generic    | |  +--lcr     |
| parallel | | parallel   | |  +--helm    |
+----------+ +------------+ +-------------+

Forge starts each engine as a child process communicating over stdio. The parallel-builder and parallel-test-runner engines wrap multiple sub-engines for concurrent execution. Engine URIs (forge://engine-name, alias://custom-name) resolve to MCP servers at runtime. See DESIGN.md for the full architecture.

Table of Contents

• How do I configure Forge?
• How do I build and test?
• What tools are included?
• How do I extend Forge?
• FAQ
• Documentation

How do I configure Forge?

name: my-project
artifactStorePath: .forge/artifact-store.yaml

build:
  - name: my-app            # Artifact name
    src: ./cmd/my-app        # Source directory
    dest: ./build/bin        # Output directory
    engine: forge://go-build    # Engine URI

  - name: ws-controller-image
    src: ./containers/ws-controller/Containerfile
    context: git@github.com:user/other-repo.git  # Build from sibling repo
    engine: forge://container-build

test:
  - name: unit
    runner: forge://go-test     # Test runner engine

  - name: integration
    runner: forge://go-test
    testenv: alias://setup-integration  # Testenv chain alias

engines:
  - alias: setup-integration
    type: testenv
    testenv:                 # Testenv chain: engines run sequentially,
      - engine: forge://testenv-kind      # each propagating env vars to the next
      - engine: forge://testenv-lcr
        spec:
          enabled: true
      - engine: forge://testenv-helm-install
        spec:
          charts:
            - name: my-chart
              sourceType: helm-repo
              url: https://charts.example.com
              chartName: my-chart
              namespace: default

See forge-yaml-schema.md for the complete field reference.

How do I build and test?

# Build
forge build                          # Build all artifacts
forge build my-app                   # Build one artifact
# There is no force flag: a build is skipped only when every recorded input
# and output still has the digest it was built with, so an edit rebuilds
# and a touch does not. To rebuild anyway, delete the output.

# Test
forge test-all                       # Build + run all test stages
forge test unit run                  # Run one test stage
forge test integration run           # Run with auto-created environment

# Working directory override
forge --cwd /path/to/project build   # Run from a different directory
forge --cwd ./subproject test-all    # Relative paths allowed

# Test environment management
forge test integration create        # Create environment
forge test integration list          # List environments
forge test integration get <id>      # Get environment details
forge test integration delete <id>   # Delete environment

See forge-cli.md for the full command reference.

What tools are included?

Forge ships 28 CLI tools, all implemented as MCP servers.

How do I extend Forge?

All engines implement JSON-RPC 2.0 over stdio. To create a new engine:

1. Define the engine's MCP tool schema (OpenAPI spec)
2. Run forge-dev to generate the server scaffolding
3. Implement the tool handler
4. Reference the engine in forge.yaml with a forge:// URI

See Engine Development and forge-dev for step-by-step guides.

FAQ

Does Forge only work with Go? No. generic-builder wraps any shell command as a build step. generic-test-runner wraps any command as a test. Native engines exist for Go, but the architecture is language-agnostic.

How does lazy rebuild work? go-dependency-detector scans Go AST to record file paths, modification timestamps, and go.mod package versions. On subsequent builds, Forge compares current state against stored dependencies and skips unchanged artifacts. See lazy-rebuild.md.

Can AI agents use Forge directly? Yes. Run forge --mcp to start Forge as an MCP server. All 28 engines speak MCP natively. AI agents invoke builds, tests, and environment operations through JSON-RPC 2.0 without wrapper scripts.

How do test environments work? Testenv sub-engines compose into sequential chains. Each sub-engine (Kind cluster, TLS registry, Helm charts) propagates environment variables to the next via envPropagation config. Template expansion ({{.Env.KUBECONFIG}}) enables dynamic configuration. See testing.md.

How do I build from a different repository? Set the context field in forge.yaml to a git URL. Forge parses the module path, checks go.work for a local match, and resolves to the local directory if found. Otherwise, it clones to a temp directory. The src path resolves relative to the context directory.

build:
  - name: controller-image
    src: ./containers/controller/Containerfile
    context: git@github.com:user/other-repo.git
    engine: forge://container-build

How do I run Forge from a Go workspace? Forge auto-detects Go workspaces. When the go.work above CWD lists the forge module, every builtin engine resolves to go run github.com/alexandremahdhaoui/forge/cmd/<name> with no version, from the caller's directory, so the workspace checkout runs. When it does not, the engine runs at the pinned forge version. No environment variable is needed. FORGE_RUN_LOCAL_ENABLED=true remains a forced override that builds engines from the checkout named by FORGE_RUN_LOCAL_BASEDIR. If CWD is the workspace root or not inside a use directive member, forge changes to the forge repo member directory. Use --skip-workspace-resolution to disable auto-detection. See workspace-development.md.

How do MCP clients set the working directory? All 12 MCP tool inputs accept a cwd field (JSON key "cwd") that overrides the server's working directory for the request. This replaces the previous projectDir field.

What is the test stage execution order? forge test-all runs stages in the order defined in forge.yaml with fail-fast behavior: lint-tags, lint-license, lint, unit, integration, e2e, e2e-stub. Each stage creates and tears down its own test environment if one is configured.

Documentation

User guides: getting-started | forge-cli | forge-yaml-schema | testing | generic-builder | generic-test-runner | lazy-rebuild | migrating-from-makefile

Engine development: getting-started | forge-dev | creating-build-engine | creating-test-runner | creating-testenv-subengine

Design: DESIGN.md | testenv-architecture

Contributing

See CONTRIBUTING.md for commit conventions, testing workflow, project structure, and development patterns.

License

Apache 2.0