Intermediate · ~30 minutes

Deep Dive: Task Board

Build a complete Task Board application with multiple modules, entities, workflows, screens, tests, and governance policies.

ℹ️
This tutorial assumes you've completed the Quick Start. If not, start there first.

1 Project Setup

Start with a fresh project:

prodara init task-board --template minimal
cd task-board

We'll evolve this minimal project into a full multi-file Task Board with 4 specification files.

2 Product Declaration

Replace app.prd with the product declaration:

app.prd
product task_board {
  title: "Task Board"
  version: "1.0.0"
  modules: [board, platform]
}

This declares a product with two modules: board for the core task management domain, and platform for cross-cutting concerns.

3 Domain Model

Create board.prd with entities and enums:

board.prd
module board {
  actor member {
    title: "Team Member"
  }

  actor admin {
    title: "Board Admin"
  }

  entity task {
    task_id: uuid
    title: string
    description: optional<string>
    status: task_status = backlog
    assignee: optional
    created_at: datetime
  }

  enum task_status {
    backlog
    todo
    in_progress
    review
    done
  }

  enum task_error {
    invalid_title
    unauthorized
    task_not_found
  }
}

4 Workflows

Add workflows to board.prd:

board.prd (continued)
  capability task_management {
    title: "Task Management"
  }

  workflow create_task {
    capability: task_management
    authorization { member: [task.create] }
    writes { task }
    returns { ok: task; error: task_error }
  }

  workflow move_task {
    capability: task_management
    authorization { member: [task.update] }
    reads { task }
    writes { task }
    transitions {
      task.status: backlog -> todo
      task.status: todo -> in_progress
      task.status: in_progress -> review
      task.status: review -> done
    }
    returns { ok: task; error: task_error }
  }

  workflow delete_task {
    capability: task_management
    authorization { admin: [task.delete] }
    writes { task }
    returns { ok: task; error: task_error }
  }

5 Surfaces

Add screens to board.prd:

board.prd (continued)
  surface board_view {
    kind: dashboard
    title: "Task Board"
    binds: task
    actions: [do_create_task, do_move_task]
    hooks { load: load_tasks }
  }

  surface task_detail {
    kind: view
    title: "Task Detail"
    binds: task
    actions: [do_move_task, do_delete_task]
  }

  action do_create_task { workflow: create_task }
  action do_move_task { workflow: move_task }
  action do_delete_task { workflow: delete_task }

6 Governance

Create platform.prd with a constitution:

platform.prd
module platform {
  constitution board_policies {
    policies {
      security {
        authentication: required
        authorization: required
      }
      testing {
        tests_required: true
      }
      style {
        indentation: 2
        naming: camelCase
      }
    }
  }
}

7 Specification Tests

Add tests at the end of board.prd:

board.prd (continued)
  test create_task_auth {
    target: create_task
    expect {
      authorization {
        member: allowed
      }
    }
  }

  test move_task_transitions {
    target: move_task
    given { task.status: todo }
    expect {
      transition: "task.status: todo -> in_progress"
      returns: ok
    }
  }

8 Compile & Test

Run the full pipeline:

# Validate
prodara validate .

# Compile to Product Graph
prodara graph --output product-graph.json .

# Run tests
prodara test .

# Full build pipeline
prodara build .

9 Semantic Diffing

Now make a change - add a priority field to the task entity - and see the incremental plan: 

# First, compile to establish a baseline
prodara build .

# Now edit board.prd - add: priority: integer = 0
# Then generate the incremental plan
prodara plan --format json .

The plan shows which nodes changed and which downstream artifacts are impacted, including the depth of impact propagation through the graph.

What's Next?