Module task 

AI Task Definition

A Task is a unit of work to be performed by an AI agent. It is step ④ in the end-to-end flow described in mod.rs — the stable identity for a piece of work, independent of how many times it is attempted (Runs) or how the strategy evolves (Plan revisions).

Position in Lifecycle

 ③  Plan ──steps──▶ [PlanStep₀, PlanStep₁, ...]
                         │
                         ├─ inline (no task)
                         └─ task ──▶ ④ Task
                                       │
                                       ├──▶ Run₀ ──plan──▶ Plan_v1
                                       ├──▶ Run₁ ──plan──▶ Plan_v2
                                       │
                                       ▼
                                   ⑤  Run (execution)

Status Transitions

Draft ──▶ Running ──▶ Done
  │          │
  ├──────────┴──▶ Failed
  └──────────────▶ Cancelled

Relationships

Field	Target	Cardinality	Notes
parent	Task	0..1	Back-reference to parent Task for sub-Tasks
intent	Intent	0..1	Originating user request
runs	Run	0..N	Chronological execution history
dependencies	Task	0..N	Must complete before this Task starts

Reverse references:

• PlanStep.task → this Task (forward link from Plan)
• Run.task → this Task (each Run knows its owner)

Replanning

When a Run fails or the agent determines the plan needs revision, a new Plan revision is created. The Task stays the same — it is the stable identity for the work. Only the strategy (Plan) evolves:

Task (constant)                Intent (constant, plan updated)
  │                              └─ plan ──▶ Plan_v2 (latest)
  └─ runs:
       Run₀ ──plan──▶ Plan_v1   (snapshot: original plan)
       Run₁ ──plan──▶ Plan_v2   (snapshot: revised plan)

Purpose

• Stable Identity: The Task persists across retries and replanning. All Runs, regardless of which Plan version they executed, belong to the same Task.
• Scope Definition: constraints and acceptance_criteria define what the agent must and must not do, and how success is measured.
• Hierarchy: parent enables recursive decomposition — a PlanStep can spawn a sub-Task, which in turn has its own Plan and Runs.
• Dependency Management: dependencies enables ordering between sibling Tasks (e.g. “implement API before writing tests”).

Structs

Task

A unit of work with constraints and success criteria.

Enums

GoalType

Classification of the work a Task aims to accomplish.

TaskStatus

Lifecycle status of a Task.