Update compass: add Global Skills section

- Document synthetic-search skill as globally available
- Location: ~/.letta/skills/
- Functions: synthetic_search(), search(), web_search()
- Zero data retention web search

system/compass.md

@@ -50,6 +50,15 @@ These live in `system/` — always in context, always present, the irreducible A
 
 **Note:** These files must be kept current. They are always in context—stale data is worse than no data. Update when specs change, APIs shift, infrastructure evolves.
 
+## Global Skills (Available to All Agents)
+
+**Location:** `~/.letta/skills/`
+
+- `synthetic-search/` — Web search via Synthetic API (zero data retention)
+  - Functions: `synthetic_search()`, `search()`, `web_search()`
+  - Returns formatted results with URL, title, snippet, published date
+  - Requires: `SYNTHETIC_API_KEY` environment variable
+
 ---
 
 ## Part 2: Active Context (Requires Read)