Execution Mode Selector

Execution Mode Selector

Purpose

Use this skill before execution starts to choose the minimum sufficient execution shape for a coding task. The output is a mode verdict plus rationale, and when needed, a coarse sprint topology that explains why the task should not be run as one continuous solo rollout. This skill works at task level: it decides how the whole task should run, not what counts as done for one chosen sprint or slice.

Activation Gate

Activate when any condition is true:

• The task spans multiple modules, interfaces, or execution stages.
• Verification cost is high enough that failure would be discovered late.
• Core requirements, architecture, or feasibility are still uncertain.
• The user asks whether the task should be split into sprints, done in one shot, or discussed first.
• The host agent is about to start a long-running task and needs an execution-shape decision first.

Do not activate when any condition is true:

• The request is a tiny, obvious edit with local verification and low rollback cost.
• The work is already inside managed execution with a confirmed sprint/checkpoint structure.
• The user is asking to update plan lifecycle state, run checkpoint validation, or perform final acceptance review.

Scope Limit

This skill does:

• execution-shape selection before implementation starts
• coarse sprint topology for sprint-required cases
• rationale for why one-shot execution is safe or unsafe
• handoff recommendation to the next owner skill

This skill does not:

• own docs/plans/PLAN_INDEX.json lifecycle state
• produce checkpoint verdict artifacts
• perform plan execution or runtime orchestration
• replace task-specific acceptance review
• emit low-level execution checklists

Ownership Boundary

• sdd-plan-maintainer owns plan lifecycle truth and managed plan state.
• checkpoint-gatekeeper owns checkpoint verdicts and bounded remediation loops.
• multi-agent-discussion-advisor owns discussion-phase multi-role synthesis when discussion is required.
• execution-mode-selector owns only the pre-execution decision surface: which execution mode to use, and why.

Boundary rule:

• Keep sprint topology coarse and strategy-level.
• If the next step is planning, hand off to sdd-plan-maintainer.
• If the next step is discussion, hand off to multi-agent-discussion-advisor.
• If a sprint or work slice already exists and only its completion contract is missing, route to execution-contract-designer instead of re-running execution-shape selection.

Script Decision

Use the skill-bundled scripts/smoke.sh for structure and contract checks only. No business runtime script is required in v1.

Workflow Contract

1. Frame the task: goal, scope, constraints, unknowns, and verification burden.
2. Check complexity signals, uncertainty signals, and rollback cost.
3. Select one verdict:

• one-shot
• research-first
• discussion-first
• sprint-required

1. Explain why the chosen mode is safer than the main alternatives.
2. If the verdict is sprint-required, provide a coarse sprint topology:

• sprint title
• what this sprint closes
• why this boundary exists

1. Point to the next owner skill:

• sdd-plan-maintainer for managed planning
• multi-agent-discussion-advisor for pre-execution discussion

Hard Rules

• Do not create or mutate plan lifecycle state.
• Do not emit checkpoint or acceptance verdicts.
• Do not decompose into low-level implementation tasks.
• When choosing anything other than one-shot, explain why one-shot execution is unsafe.
• Prefer the minimum sufficient harness: do not recommend sprints or discussion when a one-shot path is clearly safe.
• Keep trigger logic cue-based and explainable; do not build a hidden scoring engine into the skill contract.

Resource Map

• Read references/positioning-boundary.md for layer split and non-goals.
• Read references/trigger-rules.md for activation and anti-trigger rules.
• Read references/execution-modes.md for mode definitions and comparison guidance.
• Read references/process-protocol.md for the decision sequence.
• Read references/output-contract.md for output fields and verdict schema.
• Read references/regression-cases.md for trigger-boundary regression expectations.
• Read references/examples/README.md for positive and negative examples.
• Use the skill-bundled scripts/smoke.sh for deterministic smoke checks.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: ChristopheZhao
• Source: ChristopheZhao/vibe-coding-skills
• License: MIT

Install and usage instructions live in the source repository linked above.