Loop Primitives Reference

Use this after loop-discovery.md proves a loop candidate but the durable building blocks are still unclear. Keep the decision owner-focused: primitives are ingredients, not answers by themselves.

Primitive Map

Primitive	Use when	Better Harness owner
Automation	The trigger is scheduled or event-like and each run can start from stable input	automation-readiness.md, then host automation
Worktree	More than one agent or run may write files, or background work must not touch active local edits	Git/worktree policy plus selected loop owner
Skill	The durable asset is procedural knowledge, examples, references, scripts, or validation steps	../agent-customize/skill-discovery.md
Plugin / Connector	The loop must be installed across repos or access external systems	Plugin packaging or MCP-backed access after an owner exists
Subagent	Independent exploration, maker/checker review, or parallel evidence collection is valuable	Custom Agent/Subagent route
State	The loop spans turns, days, runs, worktrees, or external systems	loop-state-ledger.md

Selection Rules

• Prefer one primary owner and only the primitives needed to make it reliable.
• Use automation for the heartbeat, not for broad judgment.
• Use worktrees when file isolation is the main risk; do not use them as a substitute for review.
• Use Skills for reusable procedure; do not use them as runtime memory, scheduling, approval, or tracing infrastructure.
• Use plugins only after the canonical Skill, hook, script, agent, or reference is stable enough to distribute.
• Use MCP/connectors as access layers. The workflow owner still needs trigger, input, validation, stop, and safety contracts.
• Use subagents when the split improves evidence quality, not merely to make a task sound more autonomous.
• Use state ledgers when the next run must know what already happened.

Output Addendum

When Loop Discovery needs primitive detail, add this compact line to the result:

Primitives: primary=<owner>; support=<automation|worktree|skill|plugin|connector|subagent|state>; why=<one sentence>

If no primitive is needed beyond the selected owner, say so explicitly.