Add 'handoff' skill to improve workflow documentation and agent transitions

skills/productivity/README.md

@@ -4,4 +4,5 @@ General workflow tools, not code-specific.
 
 - **[caveman](./caveman/SKILL.md)** — Ultra-compressed communication mode. Cuts token usage ~75% by dropping filler while keeping full technical accuracy.
 - **[grill-me](./grill-me/SKILL.md)** — Get relentlessly interviewed about a plan or design until every branch of the decision tree is resolved.
+- **[handoff](./handoff/SKILL.md)** — Compact the current conversation into a handoff document so another agent can continue the work.
 - **[write-a-skill](./write-a-skill/SKILL.md)** — Create new skills with proper structure, progressive disclosure, and bundled resources.

skills/productivity/handoff/SKILL.md

@@ -0,0 +1,13 @@
+---
+name: handoff
+description: Compact the current conversation into a handoff document for another agent to pick up.
+argument-hint: "What will the next session be used for?"
+---
+
+Write a handoff document summarising the current conversation so a fresh agent can continue the work. Save it to a path produced by `mktemp -t handoff-XXXXXX.md` (read the file before you write to it).
+
+Suggest the skills to be used, if any, by the next session.
+
+Do not duplicate content already captured in other artifacts (PRDs, plans, ADRs, issues, commits, diffs). Reference them by path or URL instead.
+
+If the user passed arguments, treat them as a description of what the next session will focus on and tailor the doc accordingly.