Architecture Overview

Architectural stance

Ultimate Harness is a control plane for agentic software work. It should own durable artifacts and lifecycle semantics while delegating execution to runtime adapters.

Issue / Spec / Request
        |
        v
Workflow Profile  ---> Skills
        |
        v
Mission Packet
        |
        v
Runtime Adapter  ---> Runtime Session (Codex, Claude Code, Pi, Hermes, ...)
        |
        v
Sandbox Backend  ---> Git worktree / AgentFS / future backend
        |
        v
Verification Result
        |
        v
Human Review + Promotion
        |
        v
Canonical Project State + Audit Trail

Major components

1. Artifact store

The .harness/ directory stores project metadata, specs, workflow profiles, mission packets, adapter manifests, sandbox records, verification results, and audit records.

2. Workflow engine

Initially this can be a documented procedure or small CLI commands. It maps work types to required artifacts, skills, checks, and approval gates.

3. Mission compiler

Transforms a request/spec/plan into a mission packet suitable for runtime execution.

4. Runtime registry

Knows which adapters are available, what capabilities they support, and how to invoke them.

5. Runtime adapter

Translates a mission packet into runtime-specific execution while reporting structured status and outputs back to the harness.

6. Sandbox manager

Creates, identifies, inspects, and disposes of isolated workspaces.

7. Verification manager

Runs checks, captures results, and prepares review gates.

8. Promotion manager

Moves approved outputs into canonical project state and writes audit records.

Design constraints

• Runtime adapters must not define product semantics; they implement the contract.
• Sandboxes are not optional for agent-generated changes in MVP workflows.
• Human-readable artifacts should remain useful without the CLI.
• Machine-readable schemas should be versioned and introduced incrementally.