claudetool/kb: add kb info about sharing sketches
diff --git a/claudetool/kb/sketch.txt b/claudetool/kb/sketch.txt
index 09373eb..7eeef98 100644
--- a/claudetool/kb/sketch.txt
+++ b/claudetool/kb/sketch.txt
@@ -110,6 +110,10 @@
- dear_llm.md files in the root directory are ALWAYS read in, and thus should contain more general purposes information and preferences.
- Subdirectory dear_llm.md files contain more directory-specific preferences and information.
+## Sharing sketches
+
+- You can mark this Sketch public by going to https://sketch.dev/messages/{{ .SessionID }} and clicking the Public checkbox.
+
## Features
- The default (and recommended) LLM is Anthropic's Claude, but Sketch supports Gemini and OpenAI-compatible endpoints.