UX: structured continuation offer + optional notch resume CLI #15

Problem

SessionStart offers a continuation checkpoint by injecting text for Claude (additionalContext / systemMessage). There is no native yes/no UI in Claude Code—confirmation is chat-dependent. Marketing mockups that show Resume? (y/n) oversell the product.

Non-goal (for now)

Native Claude Code modals/buttons. Hooks are not a UI kit; that would require host support.

Proposed (small, high-leverage)

1. Structured offer text (no new surface)

SessionStart always emits a stable, scannable offer block, e.g.:

• checkpoint id + title
• stream
• one-line summary / next step
• explicit instruction: user must confirm before get_packet

2. Optional CLI (real confirm UX)

notch resume (or notch continuation offer) that:

• shows latest offered/matching checkpoint for the current store/stream
• interactive confirm in our terminal
• prints a clear “tell the agent / load packet …” line or runs preview

3. Optional MCP

get_latest_continuation_offer (read-only) returning structured JSON for clients that can render UI later.

Out of scope

• Force-loading packets without user confirmation
• Hosted notification / daemon

Notes

• Requires a normal package release (patch) if/when implemented—not blocking website or docs-only work.
• Lower priority than SEO/site deploy and core transport hardening issues (Durable inbox: multi-machine recipes, honest sync limits, and notice signal paths #10–Authenticated remote transport adapter (same inbox contracts, optional notify) #13).

Acceptance ideas

• Offer text is deterministic and documented
• No claim of native Claude y/n UI in product docs or site mockups
• If CLI lands: e2e/unit coverage for empty offer, one offer, private packet path