fix(config): decode saved JSON-object settings when loading

persist_current() saves env values verbatim, so LLM_EXTRA_HEADERS,
LLM_EXTRA_BODY and their DEDUPE_ variants land in cli-config.json as JSON
text. The loader passed that text unchanged to the dict fields, so a later
launch without the env var failed validation. Decode saved strings for
dict fields, as pydantic-settings does for env vars.

strix/config/loader.py

@@ -6,7 +6,8 @@ import json
 import logging
 import os
 from pathlib import Path
-from typing import TYPE_CHECKING, Any
+from types import UnionType
+from typing import TYPE_CHECKING, Any, Union, get_args, get_origin
 
 from pydantic import AliasChoices, BaseModel
 
@@ -126,13 +127,36 @@ def _read_json_overrides(path: Path) -> dict[str, dict[str, Any]]:
                 continue  # env wins under some alias; skip the JSON file for this field
             for alias in aliases:
                 if alias in env_block_upper:
-                    sub_data[fname] = env_block_upper[alias]
+                    sub_data[fname] = _decode_saved_value(finfo, env_block_upper[alias])
                     break
         if sub_data:
             nested[sub_name] = sub_data
     return nested
 
 
+def _decode_saved_value(finfo: FieldInfo, value: Any) -> Any:
+    """Decode a JSON string saved for a dict field, as pydantic does for env vars.
+
+    ``persist_current`` saves env values verbatim, so a dict setting such as
+    ``LLM_EXTRA_HEADERS`` lands in the file as JSON text. Values that are
+    already objects, or aren't valid JSON, are left for validation to judge.
+    """
+    if not isinstance(value, str) or not _is_dict_field(finfo):
+        return value
+    try:
+        return json.loads(value)
+    except ValueError:
+        return value
+
+
+def _is_dict_field(finfo: FieldInfo) -> bool:
+    annotation = finfo.annotation
+    candidates = (
+        get_args(annotation) if get_origin(annotation) in (Union, UnionType) else (annotation,)
+    )
+    return any(c is dict or get_origin(c) is dict for c in candidates)
+
+
 def _first_alias_value(aliases: list[str], source: Mapping[str, Any]) -> Any | None:
     return next((source[alias] for alias in aliases if alias in source), None)
 

tests/test_config_loader.py

@@ -37,6 +37,12 @@ _LLM_ENV_KEYS = [
     "STRIX_RUNTIME_BACKEND",
     # TelemetrySettings
     "STRIX_TELEMETRY",
+    # JSON-object settings
+    "LLM_EXTRA_HEADERS",
+    "LLM_EXTRA_BODY",
+    "STRIX_DEDUPE_MODEL",
+    "DEDUPE_LLM_EXTRA_HEADERS",
+    "DEDUPE_LLM_EXTRA_BODY",
 ]
 
 
@@ -406,6 +412,57 @@ def test_persist_current_replaces_corrupt_file(
     assert json.loads(target.read_text(encoding="utf-8")) == {"env": {"STRIX_LLM": "env-model"}}
 
 
+@pytest.mark.parametrize(
+    ("env_var", "section", "field"),
+    [
+        ("LLM_EXTRA_HEADERS", "llm", "extra_headers"),
+        ("LLM_EXTRA_BODY", "llm", "extra_body"),
+        ("DEDUPE_LLM_EXTRA_HEADERS", "dedupe", "extra_headers"),
+        ("DEDUPE_LLM_EXTRA_BODY", "dedupe", "extra_body"),
+    ],
+)
+def test_persisted_json_object_setting_reloads_without_env(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch, env_var: str, section: str, field: str
+) -> None:
+    loader.apply_config_override(tmp_path / "cli-config.json")
+    monkeypatch.setenv(env_var, '{"X-Tenant": "acme"}')
+    loader.load_settings()
+    loader.persist_current()
+    monkeypatch.delenv(env_var)
+    loader.apply_config_override(tmp_path / "cli-config.json")
+
+    settings = loader.load_settings()
+
+    assert getattr(getattr(settings, section), field) == {"X-Tenant": "acme"}
+
+
+def test_json_object_setting_saved_as_object_still_loads(tmp_path: Path) -> None:
+    target = tmp_path / "cli-config.json"
+    target.write_text(
+        json.dumps({"env": {"LLM_EXTRA_BODY": {"service_tier": "flex"}}}), encoding="utf-8"
+    )
+    loader.apply_config_override(target)
+
+    assert loader.load_settings().llm.extra_body == {"service_tier": "flex"}
+
+
+def test_invalid_saved_json_object_setting_is_rejected(tmp_path: Path) -> None:
+    target = tmp_path / "cli-config.json"
+    target.write_text(json.dumps({"env": {"LLM_EXTRA_BODY": "not json"}}), encoding="utf-8")
+    loader.apply_config_override(target)
+
+    with pytest.raises(ValidationError):
+        loader.load_settings()
+
+
+def test_saved_string_setting_is_not_json_decoded(tmp_path: Path) -> None:
+    target = tmp_path / "cli-config.json"
+    target.write_text(json.dumps({"env": {"STRIX_LLM": '{"not": "decoded"}'}}), encoding="utf-8")
+    loader.apply_config_override(target)
+
+    assert loader.load_settings().llm.model == '{"not": "decoded"}'
+
+
 def test_persist_current_sets_0600_mode(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setenv("STRIX_LLM", "persisted-model")
     target = tmp_path / "cli-config.json"