wayfinder → to-spec: no size check when the cleared map is bigger than one spec

## What happened I ran `/wayfinder` on a greenfield product redesign. I named the map's destination as: "One new spec replaces every old spec. Together with `GLOSSARY.md` and the ADRs, it's ready to split into build issues." The map worked. When it cleared, its output was a full product spec of about 68k characters, covering 15 feature areas. Next I followed the handoff in `/ask-matt`: when the map clears, go to `/to-spec`, then `/to-tickets`. I ran `/to-spec` on the map. Nothing in that step said the input was too big for one spec, and the agent went on to treat the whole product spec as a single buildable spec. I only found out it needed splitting by asking `/ask-matt` directly. Its answer was one `/to-spec` per feature area, in the order the areas depend on each other, because one spec plus its tickets has to fit in one context window. ## What I expected At some point the flow would tell me that the map's output was bigger than one `/to-spec`, and that I should split it into one spec per area first. ## Where the gap is - `/ask-matt` says `/to-spec` "collapses the map's linked decisions into a buildable plan". That reads as one plan, whatever size the map is. - `/to-spec` has no size check. It writes a spec from whatever it's given. - `/to-tickets` checks that each ticket fits in one context window, but nothing checks whether the spec does. - `/wayfinder` names the destination in Chart step 1, but nothing asks whether that destination is bigger than one spec. ## Suggested fixes (either or both) 1. **`/wayfinder`, Chart step 1 (Name the destination):** if the destination is a spec too big for one `/to-spec`, make the destination "a product spec plus a build order of areas, each small enough for one `/to-spec`". The split then gets planned as part of the map. 2. **`/to-spec`, a check before step 1:** "If the input covers more than one feature area, or reading and exploring it won't fit in one context window along with the spec and tickets, stop. Propose one spec per area, in the order they depend on each other, and have the user pick the first." A line in `/ask-matt`'s wayfinder on-ramp would also help: "If the cleared map holds more than one feature, run `/to-spec` once per feature, not once for the map." --- Drafted with Claude Code from a retro on the session.