add config (#494)

* add config

* improvements

* cleaner flags

* fixes

* fixes

skills/agent-browser/SKILL.md

@@ -300,6 +300,20 @@ agent-browser eval -b "$(echo -n 'Array.from(document.querySelectorAll("a")).map
 - Nested quotes, arrow functions, template literals, or multiline -> use `eval --stdin <<'EVALEOF'`
 - Programmatic/generated scripts -> use `eval -b` with base64
 
+## Configuration File
+
+Create `agent-browser.json` in the project root for persistent settings:
+
+```json
+{
+  "headed": true,
+  "proxy": "http://localhost:8080",
+  "profile": "./browser-data"
+}
+```
+
+Priority (lowest to highest): `~/.agent-browser/config.json` < `./agent-browser.json` < env vars < CLI flags. Use `--config <path>` or `AGENT_BROWSER_CONFIG` env var for a custom config file (exits with error if missing/invalid). All CLI options map to camelCase keys (e.g., `--executable-path` -> `"executablePath"`). Boolean flags accept `true`/`false` values (e.g., `--headed false` overrides config). Extensions from user and project configs are merged, not replaced.
+
 ## Deep-Dive Documentation
 
 | Reference | When to Use |