diff --git a/ariadne/services/hermes_code_defects.py b/ariadne/services/hermes_code_defects.py
index d52896f..d1d6fb3 100644
--- a/ariadne/services/hermes_code_defects.py
+++ b/ariadne/services/hermes_code_defects.py
@@ -241,20 +241,47 @@ def _is_writable(path: str, cfg: dict) -> bool:
     return bool(prefixes) and any(path.startswith(p) for p in prefixes)
 
 
-def extract_defects(bundle: dict, cfg: dict) -> list[dict[str, Any]]:
-    """Return every mechanically-fixable defect the evidence names.
+ALL_CATEGORIES: tuple[str, ...] = (LINT_VIOLATION, UNDEFINED_NAME, FAILING_ASSERTION)
 
-    Inputs: the evidence bundle and the per-job code cfg. Outputs: the lint,
-    undefined-name and failing-assertion defects together, most precisely
-    located first, so the instruction leads with the defect whose fix is least
-    open to interpretation.
+
+def enabled_categories(cfg: dict) -> tuple[str, ...]:
+    """Return the defect categories this deployment allows Hermes to be asked about.
+
+    Inputs: the per-job code cfg, whose `fix_categories` names the enabled
+    ones. Outputs: the recognised subset, in declaration order.
+
+    This is the operator's control over what Hermes may be pointed at. It is
+    deliberately separate from the action allowlist: that gates what Ariadne
+    executes on its own, whereas everything here becomes a pull request a
+    person reads. An unrecognised name is ignored rather than trusted, and an
+    empty setting means every category, so the default stays obvious.
     """
 
-    return (
-        extract_lint_defects(bundle, cfg)
-        + extract_name_defects(bundle, cfg)
-        + extract_assertion_defects(bundle, cfg)
-    )
+    raw = cfg.get("fix_categories") if isinstance(cfg, dict) else None
+    names = {str(item).strip() for item in (raw or []) if str(item).strip()}
+    if not names:
+        return ALL_CATEGORIES
+    return tuple(category for category in ALL_CATEGORIES if category in names)
+
+
+def extract_defects(bundle: dict, cfg: dict) -> list[dict[str, Any]]:
+    """Return every enabled mechanically-fixable defect the evidence names.
+
+    Inputs: the evidence bundle and the per-job code cfg. Outputs: the enabled
+    categories' defects together, most precisely located first, so the
+    instruction leads with the defect whose fix is least open to
+    interpretation.
+    """
+
+    enabled = enabled_categories(cfg)
+    found: list[dict[str, Any]] = []
+    if LINT_VIOLATION in enabled:
+        found += extract_lint_defects(bundle, cfg)
+    if UNDEFINED_NAME in enabled:
+        found += extract_name_defects(bundle, cfg)
+    if FAILING_ASSERTION in enabled:
+        found += extract_assertion_defects(bundle, cfg)
+    return found
 
 
 def defect_instruction(defects: list[dict[str, Any]]) -> str:
diff --git a/ariadne/services/hermes_code_repos.py b/ariadne/services/hermes_code_repos.py
index 98c2e04..0f9be48 100644
--- a/ariadne/services/hermes_code_repos.py
+++ b/ariadne/services/hermes_code_repos.py
@@ -48,6 +48,7 @@ def build_config(config: Any) -> dict[str, Any]:
         "owner": config.hermes_code_owner,
         "repo": config.hermes_code_repo,
         "max_open_proposals": getattr(config, "hermes_code_max_open_proposals", 0),
+        "fix_categories": list(getattr(config, "hermes_fix_categories", None) or []),
         "base_branch": config.hermes_code_base_branch,
         "timeout_seconds": _GITEA_TIMEOUT_SECONDS,
         "legacy_job": str(getattr(config, "hermes_code_job", "") or ""),
diff --git a/ariadne/settings.py b/ariadne/settings.py
index ca649aa..75f2bf3 100644
--- a/ariadne/settings.py
+++ b/ariadne/settings.py
@@ -193,6 +193,7 @@ class Settings:
     hermes_max_branches: int
     hermes_job_namespaces: dict
     hermes_code_max_open_proposals: int
+    hermes_fix_categories: list
     hermes_max_actions_per_incident: int
     hermes_api_url: str
     hermes_api_key: str
diff --git a/ariadne/settings_hermes.py b/ariadne/settings_hermes.py
index 0f83f78..be63138 100644
--- a/ariadne/settings_hermes.py
+++ b/ariadne/settings_hermes.py
@@ -41,6 +41,9 @@ def _hermes_autotriage_config() -> dict[str, Any]:
         "hermes_max_branches": _env_int("ARIADNE_HERMES_MAX_BRANCHES", 5),
         "hermes_job_namespaces": _pair_map(_env("ARIADNE_HERMES_JOB_NAMESPACES", "")),
         "hermes_code_max_open_proposals": _env_int("ARIADNE_HERMES_CODE_MAX_OPEN_PROPOSALS", 64),
+        "hermes_fix_categories": [
+            item.strip() for item in _env("ARIADNE_HERMES_FIX_CATEGORIES", "").split(",") if item.strip()
+        ],
         "hermes_max_actions_per_incident": _env_int("ARIADNE_HERMES_MAX_ACTIONS_PER_INCIDENT", 1),
         "hermes_api_url": _env(
             "ARIADNE_HERMES_API_URL",
diff --git a/tests/test_hermes_code_defects.py b/tests/test_hermes_code_defects.py
index 7a50071..e97f6bf 100644
--- a/tests/test_hermes_code_defects.py
+++ b/tests/test_hermes_code_defects.py
@@ -271,3 +271,39 @@ def test_a_lint_defect_with_a_disallowed_suffix_is_dropped() -> None:
 
     cfg = {"allowed_path_prefixes": ["ariadne/"], "allowed_suffixes": [".go"]}
     assert module.extract_lint_defects(_bundle("ariadne/app.py:1:1: E501 Long"), cfg) == []
+
+
+# --- the operator's control over what Hermes may be asked to fix ---------------
+
+
+def test_no_setting_means_every_category() -> None:
+    """The default must be obvious rather than silently empty."""
+
+    assert module.enabled_categories({}) == module.ALL_CATEGORIES
+    assert module.enabled_categories({"fix_categories": []}) == module.ALL_CATEGORIES
+    assert module.enabled_categories(None) == module.ALL_CATEGORIES
+
+
+def test_a_category_can_be_switched_off() -> None:
+    cfg = {**CFG, "fix_categories": [module.LINT_VIOLATION]}
+    assert module.enabled_categories(cfg) == (module.LINT_VIOLATION,)
+
+    bundle = {
+        "jenkins": {
+            "console_failures": [{"text": "ariadne/app.py:12:5: E501 Line too long"}],
+            "console_tail": "",
+            "failed_tests": [{"name": "t", "className": "c", "errorDetails": "boom"}],
+        }
+    }
+    cats = {d["category"] for d in module.extract_defects(bundle, cfg)}
+    assert cats == {module.LINT_VIOLATION}
+
+
+def test_an_unrecognised_category_is_ignored_not_trusted() -> None:
+    cfg = {"fix_categories": ["lint_violation", "rewrite_everything"]}
+    assert module.enabled_categories(cfg) == (module.LINT_VIOLATION,)
+
+
+def test_categories_keep_their_declared_order() -> None:
+    cfg = {"fix_categories": [module.FAILING_ASSERTION, module.LINT_VIOLATION]}
+    assert module.enabled_categories(cfg) == (module.LINT_VIOLATION, module.FAILING_ASSERTION)
diff --git a/tests/test_hermes_code_flow.py b/tests/test_hermes_code_flow.py
index dbd8259..454768f 100644
--- a/tests/test_hermes_code_flow.py
+++ b/tests/test_hermes_code_flow.py
@@ -46,6 +46,7 @@ def _code_cfg(**overrides) -> dict:  # type: ignore[no-untyped-def]
         "owner": "bstein",
         "repo": "hermes-code-demo",
         "max_open_proposals": 0,
+        "fix_categories": [],
         "base_branch": "master",
         "timeout_seconds": 15.0,
         "legacy_job": JOB,