wayfinder: recheck claims before showing the frontier in Handoff

Add a gate at the top of the Handoff section that rereads the session's
assertions — the resolution answer, the appended Decisions-so-far line,
and facts later tickets depend on — against the actual tracker state and
linked assets, fixing whatever doesn't hold, before the Next steps block
reveals the available sessions and new frontier.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

skills/in-progress/README.md

@@ -8,3 +8,4 @@ Skills that are still being developed. They're not ready to ship — expect roug
 - **[writing-beats](./writing-beats/SKILL.md)** — Shape an article as a journey of beats, choose-your-own-adventure style. Pick a starting beat, write only that beat, then pivot to the next, until the article reaches a natural end.
 - **[writing-fragments](./writing-fragments/SKILL.md)** — Grilling session that mines you for fragments — heterogeneous nuggets of writing — and appends them to a single document as raw material for a future article.
 - **[writing-shape](./writing-shape/SKILL.md)** — Take a markdown file of raw material and shape it into an article paragraph by paragraph, arguing format choices at each step.
+- **[claude-handoff](./claude-handoff/SKILL.md)** — Hand the current conversation off to a fresh background agent that picks up the work immediately, seeded with a handoff summary via `claude --bg`. User-invoked.

skills/in-progress/claude-handoff/SKILL.md

@@ -0,0 +1,18 @@
+---
+name: claude-handoff
+description: Hand the current conversation off to a fresh background agent that picks up the work immediately.
+argument-hint: "What will the next session be used for?"
+disable-model-invocation: true
+---
+
+Write a handoff summary of the current conversation so a fresh agent can continue the work. Instead of saving it, launch a background agent seeded with the summary as its prompt: `claude --bg --name "<descriptive name>" "<handoff summary>"`. It starts in the current working directory and returns immediately; the user manages it with `claude agents`.
+
+Always pass `-n`/`--name` with a descriptive name (e.g. `--name "Fix login bug"`) — it sets the display name shown in the job list, session picker, and terminal title.
+
+Include a "suggested skills" section in the summary, which suggests skills that the agent should invoke.
+
+Do not duplicate content already captured in other artifacts (PRDs, plans, ADRs, issues, commits, diffs). Reference them by path or URL instead.
+
+Redact any sensitive information, such as API keys, passwords, or personally identifiable information — the summary becomes the agent's prompt.
+
+If the user passed arguments, treat them as a description of what the next session will focus on and tailor the summary accordingly.

skills/in-progress/wayfinder/SKILL.md

@@ -104,7 +104,9 @@ The user may run unblocked tickets in parallel, so expect other sessions to be e
 
 ## Handoff
 
-End every session with a **Next steps** block the user can copy-paste. Two cases:
+**Recheck your claims first.** Before you show the frontier, reread every assertion you're about to hand off — the resolution answer, the Decisions-so-far line you appended, any facts later tickets will depend on — against the actual tracker state and the assets you linked, and fix whatever doesn't hold. The available sessions and the new frontier the human is about to act on are only as sound as the claims underneath them.
+
+Then end every session with a **Next steps** block the user can copy-paste. Two cases:
 
 **Open tickets remain.** Query the map for the currently-unblocked children, then give two copy-paste options: a bare command for one session (you pick the next ticket), and one pinned command per unblocked ticket for running them in parallel. Paste one line per fresh window — opening one, some, or all of them.