Workspace Layout

Fabric Harness uses .fabricharness/ as the embedded workspace directory. The CLI walks up from your current working directory to find the nearest workspace root.

Directory shape

.fabricharness/
  agents/                # TypeScript agent definitions (one per file)
    ask.ts
    issue-triage.ts

  roles/                 # Markdown role overlays
    engineer.md
    reviewer.md

  skills/                # Reusable Markdown procedures
    triage-issue/
      SKILL.md
    fix-tests/
      SKILL.md

  policies/              # Optional capability/security policies
    default.ts
    production.ts

  sandboxes/             # Project-specific sandbox factories
    local.ts
    docker.ts

  sessions/              # Persisted session state (gitignore-friendly)
  build/                 # Emitted build artifacts (gitignored)

  config.ts              # Optional central config (model, target, temporal, ...)

AGENTS.md                # Repo-level agent guidelines (cross-tool standard)

Each .ts file in this directory must default-export agent({...}) from @fabric-harness/sdk. Agent definitions declare typed input/output, model defaults, and triggers, and surface in fh describe.

See Agent anatomy.

`roles/`

Markdown files with optional YAML frontmatter. Roles are system-prompt overlays, not user messages. Precedence is call role → session role → agent role.

`skills/`

Each skill lives in its own directory with a SKILL.md. Frontmatter declares name, description, and (optionally) model. The body is the instructional prompt.

`policies/`

Optional. Capability policies that scope filesystem reads/writes, allowed commands, network egress, and required approvals.

`sandboxes/`

Project-specific factories that return a SandboxEnv. Use this when the built-in local/docker/empty sandboxes don't cover your needs.

`sessions/`

Session history, tasks, approvals, checkpoints, and artifacts persisted by the file-backed session store. SQLite and Postgres stores are also available — see Session stores.

`build/`

Output of fh build. Each target produces its own subdirectory:

.fabricharness/build/
  node/
  docker/
  temporal-worker/
  cloudflare/
  foundry-hosted-agent/

`config.ts`

Optional. See Configuration.

`AGENTS.md`

A repo-level Markdown file that tools across the agent ecosystem look for. Use it to capture project-wide guidelines (preferred libraries, security expectations, never-do's).