ask-matt: give wayfinder real routing help

Wayfinder is the heaviest, most cognitively demanding flow, and the
wiki shows people misusing it two ways: over-reaching for it on
well-scoped work (it's slower and denser than a single grill), and
losing the way at the handoff after the map (looping straight into
/implement and skipping /to-spec). Sharpen the router's wayfinder
on-ramp to steer both.

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

.changeset/ask-matt-wayfinder-guidance.md

@@ -0,0 +1,10 @@
+---
+"mattpocock-skills": patch
+---
+
+Make `/ask-matt` clued-up about `/wayfinder` — the heaviest, most cognitively demanding flow.
+
+The router now sharpens the two routing mistakes people most often make with wayfinder:
+
+- **Over-reaching for it.** It's slower and denser than a single grill, so it's flagged as the heaviest flow and reserved for the idea that genuinely won't fit one session — a well-scoped feature belongs on `/grill-with-docs`, not here.
+- **Losing the way at the handoff.** When the map clears, wayfinder hands off, it doesn't build: merge onto the main flow at `/to-spec` (which collapses the map's linked decisions into a buildable plan) rather than looping the map straight into `/implement`. Straight-to-`/implement` is only for efforts that turned out genuinely small.

skills/engineering/ask-matt/SKILL.md

@@ -41,7 +41,9 @@ A starting situation that generates work, then merges onto the main flow.
 
 - **Something's broken** → **`/diagnosing-bugs`**. For the hard ones: the bug that resists a first glance, the intermittent flake, the regression that crept in between two known-good states. It refuses to theorise until it has a **tight feedback loop** — one command that already goes red on *this* bug — then fixes with a regression test. Its post-mortem hands off to **`/improve-codebase-architecture`** when the real finding is that there's no good seam to lock the bug down.
 
-- **A huge, foggy effort — a greenfield project or a huge feature build, too big for one session** → **`/wayfinder`**. When the way from here to the destination isn't visible yet, it charts a **shared map** of investigation tickets on the issue tracker and resolves them one at a time — producing **decisions, not deliverables** — until the fog is pushed back and the way is clear. Then it merges onto the main flow at **`/to-spec`** (or, if the effort turned out small enough, straight to **`/implement`**). Where **`/grill-with-docs`** sharpens an idea you can hold in one session, wayfinder is for the idea you can't.
+- **A huge, foggy effort — a greenfield project or a huge feature build, too big for one session** → **`/wayfinder`**, the most cognitively demanding flow here. When the way from here to the destination isn't visible yet, it charts a **shared map** of investigation tickets on the issue tracker and resolves them one at a time — producing **decisions, not deliverables** — until the fog is pushed back and the way is clear. Where **`/grill-with-docs`** sharpens an idea you can hold in one session, wayfinder is for the idea you can't — and it's slower and denser, so save it for exactly that, never a well-scoped feature.
+
+  When the map clears, **it hands off, it doesn't build**: merge onto the main flow at **`/to-spec`**, which collapses the map's linked decisions into a buildable plan, then `/to-tickets` and `/implement` as usual. Looping the map straight into `/implement` skips that collapse and throws the linked detail away — go straight to `/implement` only when the effort turned out genuinely small.
 
 ## Codebase health