Scaffolding

The scaffold package generates new Go projects with stub implementations of the harness runner interfaces. Generated projects compile immediately and include provider-specific guidance in comments.

Usage

# From the harness module
go run ./scaffold -name myagent -out /path/to/output

What Gets Generated

myagent/
├── go.mod
├── main.go            # Entry point with runner.Run()
├── developer.go       # Developer interface stubs (Execute, Refactor)
├── reviewer.go        # Reviewer interface stub (Review)
├── planner.go         # Planner interface stub (Plan) [optional]
├── tester.go          # Tester interface stub (RunTests) [optional]
└── README.md          # Getting started instructions

Generated Stubs

Each file contains a working implementation with TODO comments indicating where to add your LLM-specific logic:

// developer.go
type MyDeveloper struct{}
 
func (d *MyDeveloper) Execute(ctx context.Context, plan string) error {
    // TODO: Call your LLM to generate code based on the plan.
    // Example with Claude:
    //   resp, err := claude.Complete(ctx, plan)
    //   writeFiles(resp.Files)
    return nil
}
 
func (d *MyDeveloper) Refactor(ctx context.Context, issues []review.Issue, guidance string) error {
    // TODO: Call your LLM to fix the reported issues.
    return nil
}

Integration

The generated project imports the harness module and wires up the runner:

func main() {
    cfg := runner.Config{
        Developer:     &MyDeveloper{},
        Reviewer:      &MyReviewer{},
        MaxIterations: 3,
    }
 
    result, err := runner.Run(context.Background(), cfg)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("Result: %s (%d iterations)\n", result.Status, result.Iterations)
}

Add checkpoint, cost, memory, or any other primitives as needed. See Primitives for the full list.

Model Routing

Generated harnesses read the same model-routing environment variables that the desktop Harness runner sends:

Variable	Purpose
`HARNESS_MODEL`	Default model for every phase
`HARNESS_PLAN_MODEL`	Model for planner work
`HARNESS_IMPLEMENTATION_MODEL`	Model for execute/refactor work
`HARNESS_SKILLS_MODEL`	Model for review or skill execution

If a phase variable is empty, the generated config falls back to HARNESS_MODEL.

Primitives Storage & Persistence