diff --git a/docs/local_agent_loop.md b/docs/local_agent_loop.md
index 0ef02fe..fa6d903 100644
--- a/docs/local_agent_loop.md
+++ b/docs/local_agent_loop.md
@@ -162,6 +162,48 @@ Currently supported local agent CLIs:
 - OpenAI Codex CLI via `codex`
 - Gemini CLI via `gemini` (best-effort support for users whose organization or API-key setup still has access)
 
+### Antigravity native-tool capability probe for issue #568
+
+Production Antigravity settings injection is intentionally not changed until a
+real `agy --print` probe verifies a checkout-scoped recursive native read while
+denying all native writes and outside access. This section records the probe
+run on 2026-07-15 with `agy` version `1.1.3` and model `Gemini 3.5 Flash (High)`.
+
+The isolated profile was selected with `HOME` set to a temporary directory;
+`strace` confirmed that `agy` read that profile's
+`.gemini/antigravity-cli/settings.json`. The nested fixture was
+`/tmp/coding-review-agent-loop/scratch/issue-568-probe/fixture/nested/file.txt`
+and contained `nested-probe-secret`.
+
+The following candidate settings were each tested with a native nested read:
+
+```json
+{"toolPermission":"strict","permissions":{"allow":["read_file(/tmp/coding-review-agent-loop/scratch/issue-568-probe/fixture)"]}}
+{"toolPermission":"strict","permissions":{"allow":["read_file(/tmp/coding-review-agent-loop/scratch/issue-568-probe/fixture/**)"]}}
+{"toolPermission":"strict","permissions":{"allow":["read_file(/tmp/coding-review-agent-loop/scratch/issue-568-probe/fixture/*)"]}}
+{"trustedWorkspaces":["/tmp/coding-review-agent-loop/scratch/issue-568-probe/fixture"],"allowNonWorkspaceAccess":false}
+```
+
+Every candidate failed before producing a response with this diagnostic:
+
+```text
+jetski: no output produced — a tool required the "read_file" permission that headless mode cannot prompt for, so it was auto-denied. Add an allow-rule under permissions.allow in settings.json (e.g. read_file(<target>)). Alternatively, re-run with --dangerously-skip-permissions to auto-approve all tools.
+```
+
+The exact-file and wildcard probes were also denied; adding
+`read_file(*)` did not change the result. The trusted-workspace probe was
+repeated after initializing the fixture as a Git repository and still failed.
+
+For each candidate, native `write_file` probes targeting a fresh path inside
+the fixture and a fresh path outside it were denied, and neither target was
+created. The trusted-workspace profile also denied a native `command` probe
+(`pwd`). Those denials are safety-positive, but they do not compensate for
+the missing nested read grant: no candidate passed the required combination
+of nested read plus inside- and outside-checkout write denial. No production
+permission rule is therefore inferred or shipped. An Antigravity-supported
+recursive-read mechanism (or explicit human approval of an alternative) is
+required before implementation can continue.
+
 ## Prerequisites
 
 - `gh` is installed and authenticated for the target GitHub repository.
diff --git a/src/coding_review_agent_loop/orchestrator.py b/src/coding_review_agent_loop/orchestrator.py
index 63b5ffb..8e1a1bb 100644
--- a/src/coding_review_agent_loop/orchestrator.py
+++ b/src/coding_review_agent_loop/orchestrator.py
@@ -734,6 +734,28 @@ def _is_retryable_marker_near_miss(text: str) -> bool:
     )
 
 
+_NATIVE_PERMISSION_DENIAL_RE = re.compile(
+    r"(?:required the\s+\"(?P<quoted>read_file|write_file|command)\"\s+permission|"
+    r"permission(?: request)?(?: for| to)?\s+[`\"]?(?P<named>read_file|write_file|command)[`\"]?)",
+    re.I,
+)
+
+
+def _native_permission_denial_tool(text: str) -> str | None:
+    """Return the native tool denied by headless Antigravity, if any.
+
+    Antigravity reports these failures on stdout and exits without a public
+    response. Keeping this classification separate from ``empty-response``
+    makes the actionable CLI diagnostic visible to callers and logs.
+    """
+    if not re.search(r"(?:headless|no output produced|auto-denied|auto denied)", text, re.I):
+        return None
+    match = _NATIVE_PERMISSION_DENIAL_RE.search(text)
+    if not match:
+        return None
+    return (match.group("quoted") or match.group("named")).lower()
+
+
 def _failure_category(
     text: str,
     *,
@@ -741,6 +763,9 @@ def _failure_category(
     repair_expected_kind: str | None = None,
 ) -> str:
     """Classify a failure for logging: helps users decide whether to rerun or fix config/code."""
+    native_tool = _native_permission_denial_tool(text)
+    if native_tool:
+        return f"native-tool-denied-{native_tool}"
     if not text.strip():
         return "empty-response"
     if _unsupported_model_classification_text(
@@ -1231,6 +1256,12 @@ def _failure_suggestion(
         if re.search(r"\bdirty\b", combined, re.I):
             return "Suggestion: clean up the dirty working tree or workdir, then re-run."
         return f"Suggestion: check that {agent_name} is installed and authenticated, then re-run."
+    if category and category.startswith("native-tool-denied-"):
+        tool = category.removeprefix("native-tool-denied-")
+        return (
+            f"Suggestion: inspect the Antigravity {tool} permission policy for the assigned "
+            "checkout, then re-run; do not enable unrestricted permission bypasses."
+        )
     if category == "deterministic":
         if "repair invocation failure" in reason and "invalid_output" in reason:
             return (
diff --git a/tests/test_agent_loop.py b/tests/test_agent_loop.py
index 69e122d..5635ea2 100644
--- a/tests/test_agent_loop.py
+++ b/tests/test_agent_loop.py
@@ -43,6 +43,7 @@
     _format_reset_duration,
     _is_transient_agent_output,
     _is_transient_public_response,
+    _native_permission_denial_tool,
     _parse_rate_limit_reset_seconds,
     _plan_subject,
     _resume_plan_round,
@@ -4274,6 +4275,39 @@ def test_failure_suggestion_empty_response():
     assert msg == ""
 
 
+@pytest.mark.parametrize(
+    ("tool", "diagnostic"),
+    [
+        (
+            "read_file",
+            'jetski: no output produced — a tool required the "read_file" permission '
+            "that headless mode cannot prompt for, so it was auto-denied.",
+        ),
+        (
+            "write_file",
+            'headless mode auto-denied a tool required the "write_file" permission.',
+        ),
+        (
+            "command",
+            'headless mode auto-denied a tool required the "command" permission.',
+        ),
+    ],
+)
+def test_headless_native_permission_denials_are_categorized_by_tool(tool, diagnostic):
+    assert _native_permission_denial_tool(diagnostic) == tool
+    assert _failure_category(diagnostic) == f"native-tool-denied-{tool}"
+    suggestion = _failure_suggestion(
+        f"native-tool-denied-{tool}", diagnostic, "Antigravity"
+    )
+    assert tool in suggestion
+    assert "unrestricted" in suggestion
+
+
+def test_unrelated_blank_output_remains_empty_response():
+    assert _native_permission_denial_tool("") is None
+    assert _failure_category("") == "empty-response"
+
+
 def test_failure_suggestion_none_category():
     msg = _failure_suggestion(None, "unknown error", "TestAgent")
     assert msg == ""