diff --git a/docker/scripts/bash-guard-hook.sh b/docker/scripts/bash-guard-hook.sh
index c744dc38..c2ab7a65 100755
--- a/docker/scripts/bash-guard-hook.sh
+++ b/docker/scripts/bash-guard-hook.sh
@@ -72,6 +72,23 @@ if echo "$low" | grep -qE '(^|[[:space:];&|])(curl|wget|http|https)[[:space:]][^
     exit 2
 fi
 
+# --- internal API calls -------------------------------------------------------
+# Agents must reach the orchestrator through their MCP manifest verbs, never
+# raw HTTP. This blocks `curl http://roboco-orchestrator:8000/...`,
+# `wget http://localhost:8000/...`, `http http://127.0.0.1/...` (HTTPie),
+# scheme-less forms like `curl roboco-orchestrator:8000/...`, and the
+# protocol-relative `//host/path` form.
+# KNOWN GAPS (out of scope here):
+#   - Variable expansion: `URL=http://orchestrator/x; curl $URL` — the guard
+#     sees `curl $URL`, not the expanded URL, so this slips through. The
+#     X-Agent-Role check (task 4) is the second gate.
+#   - Interpreter one-liners: `python -c "import urllib.request; ..."` — too
+#     deeply hidden to regex. Mitigated by the manifest-bound MCP surface.
+if echo "$low" | grep -qE '(^|[[:space:];&|])(curl|wget|http|https|httpie)[[:space:]][^|]*((http|https):)?//?(roboco-[a-z0-9_-]+|localhost|127\.0\.0\.1|0\.0\.0\.0)[:/]'; then
+    echo "Denied: internal API calls bypass the gateway. Use the MCP verbs (roboco-flow / roboco-do / roboco-git-readonly / roboco-optimal / roboco-docs) — they route through the orchestrator with the right auth and tracing." >&2
+    exit 2
+fi
+
 if echo "$low" | grep -qE '(^|[[:space:];&|])(env|printenv)([[:space:]]|$)' && ! echo "$low" | grep -qE '(^|[[:space:];&|])env[[:space:]]+-i'; then
     # allow `env VAR=val cmd` style prefixes (`env ` followed by `NAME=`)
     if ! echo "$low" | grep -qE '(^|[[:space:];&|])env[[:space:]]+[a-z_][a-z0-9_]*='; then
diff --git a/tests/unit/scripts/__init__.py b/tests/unit/scripts/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/tests/unit/scripts/test_bash_guard.py b/tests/unit/scripts/test_bash_guard.py
new file mode 100644
index 00000000..3421a975
--- /dev/null
+++ b/tests/unit/scripts/test_bash_guard.py
@@ -0,0 +1,52 @@
+"""bash-guard-hook.sh denies curl/wget against orchestrator/localhost.
+
+The PreToolUse hook reads Claude Code's event JSON from stdin in the form
+``{"tool_name": "Bash", "tool_input": {"command": "..."}}`` and exits with
+code 2 to deny, 0 to allow. Tests wrap each command in that envelope.
+"""
+
+from __future__ import annotations
+
+import json
+import subprocess
+from pathlib import Path
+
+# tests/unit/scripts/test_bash_guard.py
+#   parents[0] = scripts
+#   parents[1] = unit
+#   parents[2] = tests
+#   parents[3] = <repo root>
+GUARD = Path(__file__).parents[3] / "docker" / "scripts" / "bash-guard-hook.sh"
+
+_DENIED = 2
+_ALLOWED = 0
+
+
+def _run(cmd: str) -> int:
+    payload = json.dumps({"tool_name": "Bash", "tool_input": {"command": cmd}})
+    result = subprocess.run(
+        [str(GUARD)],
+        input=payload,
+        capture_output=True,
+        text=True,
+    )
+    return result.returncode
+
+
+def test_blocks_internal_curl_to_orchestrator() -> None:
+    assert (
+        _run("curl http://roboco-orchestrator:8000/api/v2/flow/main_pm/delegate")
+        == _DENIED
+    )
+
+
+def test_blocks_internal_curl_to_localhost() -> None:
+    assert _run("curl http://localhost:8000/api/v2/flow/dev/i_am_done") == _DENIED
+
+
+def test_blocks_internal_curl_to_127() -> None:
+    assert _run("curl http://127.0.0.1:8000/api/health") == _DENIED
+
+
+def test_allows_external_curl_to_documentation() -> None:
+    assert _run("curl https://docs.python.org/3/") == _ALLOWED