Checkpoint

Checkpoint

checkpoint 保存、恢復、列出長 session 的工作狀態，讓 context compression 或換 session 後能接回 branch、ticket、phase、next action。

Contract

Checkpoint 是 session continuity tool，不是 planning、triage、或 implementation skill。 它只寫 workspace memory / timeline 類的 local state，不替下游 skill 決定 scope，也不自動切 branch。

Mode Routing

User says	Mode	Reference
checkpoint, 存檔, save checkpoint, save state	save	checkpoint-save-flow.md
resume, 恢復, resume checkpoint, 接回去	resume	checkpoint-resume-list-flow.md
list checkpoints, 列出存檔, show checkpoints	list	checkpoint-resume-list-flow.md

Ambiguous input defaults to save.

Reference Loading

Situation	Load
Any run	polaris-project-dir.md, session-timeline.md, shared-defaults.md
Save	checkpoint-save-flow.md, checkpoint-carry-forward-flow.md
Resume / list	checkpoint-resume-list-flow.md

Hard Rules

• Save must capture branch, git status summary, ticket, todo disposition, phase, next action, and recent timeline context.
• 回報 checkpoint saved 前，carry-forward validation 必須通過。
• Resume verifies the checkpoint branch exists before suggesting a switch.
• 未取得使用者明確指示前，不切 branch、不 stash、不 rewrite memory。
• 不可默默丟掉 pending items；每項都要標記 done、carry-forward、或 dropped。

Completion

Save 回傳 branch、ticket、phase、next action、resume phrase。Resume 回傳 checkpoint timestamp、branch、ticket、可取得時的 current status、next action。List 回傳 recent checkpoint rows。

Step 2.5 — L2 Deterministic Check: cross-session-carry-forward

Save mode 的 carry-forward gate 由 checkpoint-carry-forward-flow.md 執行；必須呼叫 scripts/check-carry-forward.sh，通過後才可回報 checkpoint saved。

Post-Task Reflection (required)

Execute post-task-reflection-checkpoint.md before reporting completion.