diff --git a/CLAUDE.md b/CLAUDE.md
index 4c0cc0b..5c11207 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -33,7 +33,7 @@ becwright/
 ├── README.md                 # public conceptual document (English; README.es.md = Spanish)
 ├── pyproject.toml            # packaging + `becwright` command (setuptools)
 ├── src/becwright/            # packaged ENGINE (installable, not copied into each repo)
-│   ├── cli.py                # argparse: check / install / uninstall / export / import
+│   ├── cli.py                # argparse: init / check / install / uninstall / export / import
 │   ├── engine.py             # path matching + runs checks + decides pass/fail
 │   ├── rules.py              # Rule model + loading of .bec/rules.yaml
 │   ├── bundle.py             # export/import of BECs (the portable bundle)
@@ -54,7 +54,7 @@ engine comes from the installed package.
 (Portability, C)** done: `becwright export` / `import` move a BEC between repos
 as a single self-contained `.bec.yaml` (a custom check's code travels embedded),
 with a trust gate that shows the code before installing. Commands:
-`check / install / uninstall / export / import`. **Multi-language:** the engine
+`init / check / install / uninstall / export / import`. **Multi-language:** the engine
 is agnostic (runs any check on any file); the generic `forbid` check (regex via
 `--pattern`) lets you write rules for any language without code, and the catalog
 includes Python and JS/TS BECs. Included checks: `forbid` (any language),
diff --git a/README.es.md b/README.es.md
index ca41b55..681ee52 100644
--- a/README.es.md
+++ b/README.es.md
@@ -54,17 +54,17 @@ becwright se instala una vez como herramienta; cada repo solo aporta su propio
 # 1. Instalar el motor (una vez, global)
 pipx install becwright              # o: pip install becwright
 
-# 2. En el repo donde querés las reglas, instalar el hook de git
-becwright install                   # escribe .git/hooks/pre-commit
+# 2. En tu repo, generar reglas + instalar el hook
+becwright init                      # detecta tu lenguaje, escribe .bec/rules.yaml, instala el hook
 
-# 3. Escribir tus reglas en .bec/rules.yaml (ver ejemplos abajo)
-# 4. Listo: cada commit corre los chequeos; si una regla blocking falla, frena.
+# 3. Listo: cada commit corre los chequeos; si una regla blocking falla, frena.
 ```
 
 Comandos disponibles:
 
 | Comando | Qué hace |
 |---|---|
+| `becwright init` | Genera un `.bec/rules.yaml` de arranque e instala el hook |
 | `becwright check` | Corre las reglas sobre los archivos en staging |
 | `becwright install` | Instala el hook `pre-commit` nativo |
 | `becwright uninstall` | Quita el hook |
diff --git a/README.md b/README.md
index 9ddda0d..23aab59 100644
--- a/README.md
+++ b/README.md
@@ -53,17 +53,17 @@ becwright is installed once as a tool; each repo only contributes its own
 # 1. Install the engine (once, global)
 pipx install becwright              # or: pip install becwright
 
-# 2. In the repo where you want the rules, install the git hook
-becwright install                   # writes .git/hooks/pre-commit
+# 2. In your repo, scaffold rules + install the hook
+becwright init                      # detects your language, writes .bec/rules.yaml, installs the hook
 
-# 3. Write your rules in .bec/rules.yaml (see examples below)
-# 4. Done: each commit runs the checks; if a blocking rule fails, it stops.
+# 3. Done: each commit runs the checks; if a blocking rule fails, it stops.
 ```
 
 Available commands:
 
 | Command | What it does |
 |---|---|
+| `becwright init` | Scaffold a starter `.bec/rules.yaml` and install the hook |
 | `becwright check` | Runs the rules over the staged files |
 | `becwright install` | Installs the native `pre-commit` hook |
 | `becwright uninstall` | Removes the hook |
diff --git a/documentation/architecture.es.md b/documentation/architecture.es.md
index 5a1e57f..62c3eb3 100644
--- a/documentation/architecture.es.md
+++ b/documentation/architecture.es.md
@@ -10,7 +10,7 @@ filtra archivos por su ruta y corre un comando.
 
 | Módulo | Responsabilidad |
 |---|---|
-| `cli.py` | CLI con argparse: `check / install / uninstall / export / import` |
+| `cli.py` | CLI con argparse: `init / check / install / uninstall / export / import` |
 | `rules.py` | El modelo `Rule` y la carga de `.bec/rules.yaml` |
 | `engine.py` | Matching de rutas por glob, corre los checks, decide pasa/no-pasa |
 | `git.py` | Raíz del repo, archivos en staging, el hook pre-commit nativo |
diff --git a/documentation/architecture.md b/documentation/architecture.md
index 3940aa1..4510de2 100644
--- a/documentation/architecture.md
+++ b/documentation/architecture.md
@@ -10,7 +10,7 @@ itself — it matches files by path and runs a command.
 
 | Module | Responsibility |
 |---|---|
-| `cli.py` | Argparse CLI: `check / install / uninstall / export / import` |
+| `cli.py` | Argparse CLI: `init / check / install / uninstall / export / import` |
 | `rules.py` | The `Rule` model and loading of `.bec/rules.yaml` |
 | `engine.py` | Glob path matching, running checks, deciding pass/fail |
 | `git.py` | Repo root, staged files, the native pre-commit hook |
diff --git a/documentation/usage.es.md b/documentation/usage.es.md
index 5015598..0fe62e1 100644
--- a/documentation/usage.es.md
+++ b/documentation/usage.es.md
@@ -12,16 +12,22 @@ pipx install becwright      # o: pip install becwright
 
 ```bash
 cd tu-repo
-becwright install           # escribe .git/hooks/pre-commit
-# creá .bec/rules.yaml (ver abajo)
+becwright init              # genera .bec/rules.yaml (según el lenguaje) e instala el hook
 ```
 
-A partir de ahí, cada `git commit` corre los checks.
+`init` detecta si el repo tiene archivos Python o JS/TS y escribe un
+`.bec/rules.yaml` de arranque con reglas acordes, y luego instala el hook
+pre-commit. Revisá las reglas generadas y corré `becwright check --all` para ver
+el estado actual.
+
+A partir de ahí, cada `git commit` corre los checks. (También podés configurarlo
+a mano: `becwright install` más un `.bec/rules.yaml` que escribas vos.)
 
 ## Comandos
 
 | Comando | Descripción |
 |---|---|
+| `becwright init` | Genera un `.bec/rules.yaml` de arranque e instala el hook |
 | `becwright check` | Corre las reglas sobre los archivos en staging |
 | `becwright check --all` | Corre las reglas sobre todo el repo (`git ls-files`) |
 | `becwright install` | Instala el hook pre-commit |
diff --git a/documentation/usage.md b/documentation/usage.md
index f820108..e40830d 100644
--- a/documentation/usage.md
+++ b/documentation/usage.md
@@ -12,16 +12,21 @@ pipx install becwright      # or: pip install becwright
 
 ```bash
 cd your-repo
-becwright install           # writes .git/hooks/pre-commit
-# create .bec/rules.yaml (see below)
+becwright init              # scaffolds .bec/rules.yaml (language-aware) and installs the hook
 ```
 
-From then on, every `git commit` runs the checks.
+`init` detects whether the repo has Python or JS/TS files and writes a starter
+`.bec/rules.yaml` with matching rules, then installs the pre-commit hook. Review
+the generated rules and run `becwright check --all` to see the current state.
+
+From then on, every `git commit` runs the checks. (You can also set up by hand:
+`becwright install` plus a `.bec/rules.yaml` you write yourself.)
 
 ## Commands
 
 | Command | Description |
 |---|---|
+| `becwright init` | Scaffold a starter `.bec/rules.yaml` and install the hook |
 | `becwright check` | Run rules over the staged files |
 | `becwright check --all` | Run rules over the whole repo (`git ls-files`) |
 | `becwright install` | Install the pre-commit hook |
diff --git a/src/becwright/cli.py b/src/becwright/cli.py
index ffc2f0f..127aa78 100644
--- a/src/becwright/cli.py
+++ b/src/becwright/cli.py
@@ -70,6 +70,99 @@ def _cmd_uninstall(_: argparse.Namespace) -> int:
     return 0
 
 
+_SKIP_DIRS = {".git", "node_modules", ".venv", "venv", "__pycache__", "dist", "build", ".tox"}
+_EXT_LANG = {".py": "python", ".js": "js", ".ts": "ts"}
+
+
+def _detect_languages(root: Path) -> list[str]:
+    found: set[str] = set()
+    for path in root.rglob("*"):
+        if not path.is_file():
+            continue
+        if any(part in _SKIP_DIRS for part in path.relative_to(root).parts):
+            continue
+        lang = _EXT_LANG.get(path.suffix)
+        if lang:
+            found.add(lang)
+    return [lang for lang in ("python", "js", "ts") if lang in found]
+
+
+def _starter_rules(langs: list[str]) -> list[dict]:
+    source_globs = [g for lang, g in (("python", "**/*.py"), ("js", "**/*.js"), ("ts", "**/*.ts")) if lang in langs]
+    rules: list[dict] = []
+    if source_globs:
+        rules.append(dict(
+            id="no-hardcoded-secrets", paths=source_globs, severity="blocking",
+            check="python3 -m becwright.checks.hardcoded_secrets",
+            intent="No secret (key, token, password) should be hardcoded in the code.",
+            why="A secret in the repo stays in git history forever and is visible to anyone with access to the code."))
+    if "python" in langs:
+        rules.append(dict(
+            id="no-debug-remnants", paths=["**/*.py"], severity="blocking",
+            check="python3 -m becwright.checks.debug_remnants",
+            intent="Debug code (breakpoints, pdb) must not be committed.",
+            why="A forgotten breakpoint hangs the process in production or CI."))
+        rules.append(dict(
+            id="no-dangerous-eval", paths=["**/*.py"], severity="blocking",
+            check="python3 -m becwright.checks.dangerous_eval",
+            intent="Avoid eval and exec, which run arbitrary code.",
+            why="Dynamic eval/exec on untrusted input is remote code execution."))
+    if "js" in langs or "ts" in langs:
+        js_globs = [g for g in source_globs if g.endswith((".js", ".ts"))]
+        rules.append(dict(
+            id="no-debugger-js", paths=js_globs, severity="blocking",
+            check="python3 -m becwright.checks.forbid --pattern '\\bdebugger\\b'",
+            intent="Do not leave 'debugger;' in JavaScript/TypeScript code.",
+            why="A forgotten 'debugger' halts execution and should not reach production."))
+        rules.append(dict(
+            id="no-console-log-js", paths=js_globs, severity="warning",
+            check="python3 -m becwright.checks.forbid --pattern 'console\\.log\\s*\\('",
+            intent="Avoid 'console.log(...)' in JavaScript/TypeScript code.",
+            why="Debug console.log statements clutter production output."))
+    return rules
+
+
+def _render_rules_yaml(rules: list[dict]) -> str:
+    header = (
+        "# becwright rules - generated by `becwright init`. Tune them to your repo.\n"
+        "# Catalog: https://github.com/DataDave-Dev/becwright/tree/main/becs\n"
+        "# Docs: https://github.com/DataDave-Dev/becwright/tree/main/documentation\n"
+    )
+    if not rules:
+        return header + "rules: []\n"
+    blocks = []
+    for r in rules:
+        paths = "\n".join(f'      - "{p}"' for p in r["paths"])
+        blocks.append(
+            f"  - id: {r['id']}\n"
+            f"    intent: >\n      {r['intent']}\n"
+            f"    why_it_matters: >\n      {r['why']}\n"
+            f"    paths:\n{paths}\n"
+            f"    check: {r['check']}\n"
+            f"    severity: {r['severity']}\n"
+        )
+    return header + "rules:\n" + "\n".join(blocks)
+
+
+def _cmd_init(args: argparse.Namespace) -> int:
+    root = git.repo_root()
+    rules_path = root / ".bec" / "rules.yaml"
+    if rules_path.exists() and not args.force:
+        print(f"{YELLOW}{rules_path} already exists. Use --force to overwrite.{RESET}")
+        return 1
+    langs = _detect_languages(root)
+    rules = _starter_rules(langs)
+    rules_path.parent.mkdir(parents=True, exist_ok=True)
+    rules_path.write_text(_render_rules_yaml(rules), encoding="utf-8")
+
+    detected = ", ".join(langs) if langs else "none"
+    print(f"{GREEN}Created {rules_path}{RESET} {DIM}({len(rules)} starter rule(s); languages: {detected}){RESET}")
+    ok, msg = git.install_hook(root)
+    print((GREEN if ok else YELLOW) + msg + RESET)
+    print(f"{DIM}Review your rules, then run `becwright check --all` to see the current state.{RESET}")
+    return 0
+
+
 def _cmd_export(args: argparse.Namespace) -> int:
     root = git.repo_root()
     rule = next((r for r in load_rules(root / ".bec" / "rules.yaml") if r.id == args.rule_id), None)
@@ -151,6 +244,10 @@ def _build_parser() -> argparse.ArgumentParser:
     p_check.add_argument("--all", action="store_true", help="check the whole repo, not just staging")
     p_check.set_defaults(func=_cmd_check)
 
+    p_init = sub.add_parser("init", help="scaffold a starter .bec/rules.yaml and install the hook")
+    p_init.add_argument("--force", action="store_true", help="overwrite an existing .bec/rules.yaml")
+    p_init.set_defaults(func=_cmd_init)
+
     sub.add_parser("install", help="install the pre-commit hook").set_defaults(func=_cmd_install)
     sub.add_parser("uninstall", help="remove the pre-commit hook").set_defaults(func=_cmd_uninstall)
 
diff --git a/tests/test_init.py b/tests/test_init.py
new file mode 100644
index 0000000..7d75737
--- /dev/null
+++ b/tests/test_init.py
@@ -0,0 +1,108 @@
+import subprocess
+from pathlib import Path
+
+from becwright import cli
+from becwright.rules import load_rules
+
+_SRC = Path(__file__).resolve().parents[1] / "src"
+
+
+def _git(root, *args):
+    subprocess.run(["git", *args], cwd=root, check=True, capture_output=True, text=True)
+
+
+def _init_repo(path):
+    _git(path, "init")
+    _git(path, "config", "user.email", "t@t.t")
+    _git(path, "config", "user.name", "t")
+    return path
+
+
+# --- detection ---
+
+def test_detect_languages_skips_noise_dirs(tmp_path):
+    (tmp_path / "a.py").write_text("x = 1\n", encoding="utf-8")
+    (tmp_path / "b.ts").write_text("const x = 1\n", encoding="utf-8")
+    (tmp_path / "node_modules").mkdir()
+    (tmp_path / "node_modules" / "c.js").write_text("//\n", encoding="utf-8")
+    assert cli._detect_languages(tmp_path) == ["python", "ts"]
+
+
+def test_detect_languages_none(tmp_path):
+    (tmp_path / "README.md").write_text("# hi\n", encoding="utf-8")
+    assert cli._detect_languages(tmp_path) == []
+
+
+# --- starter rules ---
+
+def test_starter_rules_python():
+    ids = [r["id"] for r in cli._starter_rules(["python"])]
+    assert ids == ["no-hardcoded-secrets", "no-debug-remnants", "no-dangerous-eval"]
+
+
+def test_starter_rules_js():
+    ids = [r["id"] for r in cli._starter_rules(["js"])]
+    assert ids == ["no-hardcoded-secrets", "no-debugger-js", "no-console-log-js"]
+
+
+def test_starter_rules_empty():
+    assert cli._starter_rules([]) == []
+
+
+# --- rendering ---
+
+def test_render_yaml_parses_and_keeps_forbid(tmp_path):
+    p = tmp_path / "rules.yaml"
+    p.write_text(cli._render_rules_yaml(cli._starter_rules(["js"])), encoding="utf-8")
+    rules = load_rules(p)
+    assert {r.id for r in rules} == {"no-hardcoded-secrets", "no-debugger-js", "no-console-log-js"}
+    dbg = next(r for r in rules if r.id == "no-debugger-js")
+    assert r"--pattern '\bdebugger\b'" in dbg.check
+
+
+def test_render_empty_is_valid(tmp_path):
+    p = tmp_path / "rules.yaml"
+    p.write_text(cli._render_rules_yaml([]), encoding="utf-8")
+    assert load_rules(p) == []
+
+
+# --- the init command ---
+
+def test_init_creates_rules_and_hook(tmp_path, monkeypatch):
+    _init_repo(tmp_path)
+    (tmp_path / "a.py").write_text("x = 1\n", encoding="utf-8")
+    monkeypatch.chdir(tmp_path)
+    assert cli.main(["init"]) == 0
+    rules_path = tmp_path / ".bec" / "rules.yaml"
+    assert "no-debug-remnants" in {r.id for r in load_rules(rules_path)}
+    assert (tmp_path / ".git" / "hooks" / "pre-commit").exists()
+
+
+def test_init_refuses_existing(tmp_path, monkeypatch):
+    _init_repo(tmp_path)
+    (tmp_path / ".bec").mkdir()
+    rules_path = tmp_path / ".bec" / "rules.yaml"
+    rules_path.write_text("rules: []\n", encoding="utf-8")
+    monkeypatch.chdir(tmp_path)
+    assert cli.main(["init"]) == 1
+    assert rules_path.read_text(encoding="utf-8") == "rules: []\n"
+
+
+def test_init_force_overwrites(tmp_path, monkeypatch):
+    _init_repo(tmp_path)
+    (tmp_path / "a.py").write_text("x = 1\n", encoding="utf-8")
+    (tmp_path / ".bec").mkdir()
+    (tmp_path / ".bec" / "rules.yaml").write_text("rules: []\n", encoding="utf-8")
+    monkeypatch.chdir(tmp_path)
+    assert cli.main(["init", "--force"]) == 0
+    assert load_rules(tmp_path / ".bec" / "rules.yaml")
+
+
+def test_init_generated_rule_blocks_via_check(tmp_path, monkeypatch):
+    monkeypatch.setenv("PYTHONPATH", str(_SRC))
+    _init_repo(tmp_path)
+    (tmp_path / "app.js").write_text("function f(){ debugger; }\n", encoding="utf-8")
+    monkeypatch.chdir(tmp_path)
+    assert cli.main(["init"]) == 0
+    _git(tmp_path, "add", "app.js")
+    assert cli.main(["check", "--all"]) == 1