fix: resolve stale session, ref resolution and cursor-ref collision bugs (#427)

skills/agent-browser/SKILL.md

@@ -191,6 +191,35 @@ agent-browser find placeholder "Search" type "query"
 agent-browser find testid "submit-btn" click
 ```
 
+## JavaScript Evaluation (eval)
+
+Use `eval` to run JavaScript in the browser context. **Shell quoting can corrupt complex expressions** -- use `--stdin` or `-b` to avoid issues.
+
+```bash
+# Simple expressions work with regular quoting
+agent-browser eval 'document.title'
+agent-browser eval 'document.querySelectorAll("img").length'
+
+# Complex JS: use --stdin with heredoc (RECOMMENDED)
+agent-browser eval --stdin <<'EVALEOF'
+JSON.stringify(
+  Array.from(document.querySelectorAll("img"))
+    .filter(i => !i.alt)
+    .map(i => ({ src: i.src.split("/").pop(), width: i.width }))
+)
+EVALEOF
+
+# Alternative: base64 encoding (avoids all shell escaping issues)
+agent-browser eval -b "$(echo -n 'Array.from(document.querySelectorAll("a")).map(a => a.href)' | base64)"
+```
+
+**Why this matters:** When the shell processes your command, inner double quotes, `!` characters (history expansion), backticks, and `$()` can all corrupt the JavaScript before it reaches agent-browser. The `--stdin` and `-b` flags bypass shell interpretation entirely.
+
+**Rules of thumb:**
+- Single-line, no nested quotes -> regular `eval 'expression'` with single quotes is fine
+- Nested quotes, arrow functions, template literals, or multiline -> use `eval --stdin <<'EVALEOF'`
+- Programmatic/generated scripts -> use `eval -b` with base64
+
 ## Deep-Dive Documentation
 
 | Reference | When to Use |