hoangnguyen0403/agent-skills-standard/common-subagent-driven-development

Subagent-Driven Development (SDD)

Priority: P1 (HIGH)

Execute a multi-task plan with one implementation owner per slice, independent review after each task, and whole-branch review before completion.

1. Placement Decision

Choose placement before any edit. Delegate only when at least one named benefit applies: independent parallel work over disjoint owned paths that are verifiable alone; measured context pressure such as observed truncation, lost constraints, or replay cost; a required independent verification gate that must be a separate owner from the implementer; or real host-enforced permission isolation, meaning the host enforces the boundary because prompt text is not enforcement. A specialist label, another workflow stage, file count, plan length, or "more thorough" fan-out is not a named benefit.

Precedence, first match wins: controlling host authority, then required independence or isolation, then coupling and verifiability, then economical eligible capability (common-task-complexity-routing).

One implementation context is not one actor for the lifecycle: main-loop implementation still requires a separate reviewer, and a single worker still requires independent review.

• Record the decision with its named benefit, or the host requirement that forced it. Reuse an approach the plan already records; do not re-ask.
• Missing required approval, packet, standards, or isolation stops only the affected operation. Report the exact missing item; do not infer permission or silently change the execution path.
• Plan approval authorizes neither merge, deployment, premium spend, nor a different execution mode.

2. Lifecycle

Host instructions bind these operations to native invocation; canonical text names semantics only. If a required operation or permission control is unavailable on the host surface, report the affected operation unsupported; do not claim success. Dispatch, sequencing and recovery detail: Methodology.

3. Task Loop

1. Select placement and prepare: Apply Section 1 and record the decision. Record BASE=$(git rev-parse HEAD). Generate the packet with task_brief.py <PLAN_FILE> <TASK_NUMBER> --assignment <ASSIGNMENT_JSON> --out <BRIEF_FILE>. The assignment manifest is required; never dispatch a bare task section.
2. Execute or dispatch: One implementer per task when the placement decision requires it; otherwise execute the slice in the recorded single context. The packet, not repeated prose, carries authority and acceptance.
3. Yield: Wait for a completion notification; never poll status in a loop.
4. Review: Generate the scoped cumulative package from $BASE and the owned paths. Dispatch an independent reviewer with brief, report and package. Implementer self-review never satisfies this gate.
5. Fix: Re-prompt the same worker with concrete failed ACs; regenerate the cumulative package and re-review against cumulative state.
6. Integrate: Orchestrator verifies the diff, runs required covering checks, and commits.

4. Failure-Specific Recovery

Retry count alone never authorizes premium. Timeout and cancellation are not completion. Required human approvals remain external to agent verdicts.

5. Final Review and Evidence

Run whole-branch review on a capable host hint, then complete the branch. Before deleting the workspace, archive packets, reports, immutable review snapshots and verification receipts at durable references; cleanup must not invalidate handoff links.

Anti-Patterns

• No worker commits: workers leave changes; the orchestrator commits.
• No recursive delegation: workers do not spawn agents.
• No self-approval: implementer verdicts do not satisfy independent review.
• No agent per stage: a workflow stage, specialist label, or file count never justifies a new agent; no named benefit, no dispatch.
• No polling loops: yield until a completion event.
• No fabricated savings or enforcement claims: prompt text is not a sandbox, and savings need complete measured coverage.

References

Methodology & Gates · Prompt Templates · Progress Receipts · Capability & Effort Resolution