Accept raw control characters inside JSON strings in model replies

doc/architecture/SPEC/kb_service.md

@@ -298,3 +298,6 @@ diff 时保留原摘录（证据不会因此变得更"好过"）。只扩展带
 `CALIBRATION_KEYS` = `knowledge_lifecycle.calibration_set`。`check_flip_to_shadow` 另要求 head 为
 `enabled: true` 且 `mode` 为 shadow（缺省即 shadow）。知识 L1 的白名单只含 `knowledge/`，adapter 这一处改动由它单独校验；
 调用方还需在 head adapter 上跑 `config.parse_lifecycle`。测试：`test_kb_lifecycle_flip.py`。
+
+## 2026-09-30 模型回复解析
+`models.parse_json_object` 取裸 JSON 对象或最后一个 ```json 围栏块，用 `json.loads(strict=False)`：字符串里的原始控制字符（多行值里的换行、制表符，例如图示）按数据接受，不再把结构正确的回答判为 `ModelUnavailable`。测试：`test_kb_intake_gate.py`。

src/infermatrix_copilot/kb_service/models.py

@@ -64,12 +64,15 @@ class ModelReply:
 
 
 def parse_json_object(text: str) -> dict:
-    """The reply's JSON object: a bare object, or the last fenced ```json block."""
+    """The reply's JSON object: a bare object, or the last fenced ```json block.
+    Raw control characters inside strings (a newline in a multi-line value,
+    e.g. a diagram) are accepted: models write them, and they are data, not
+    structure (``strict=False``)."""
     text = text.strip()
     candidates = [text] + [m.group(1) for m in _JSON_FENCE.finditer(text)][::-1]
     for candidate in candidates:
         try:
-            value = json.loads(candidate)
+            value = json.loads(candidate, strict=False)
         except ValueError:
             continue
         if isinstance(value, dict):

test/test_kb_intake_gate.py

@@ -92,6 +92,17 @@ def test_default_roles_are_pinned_and_cross_family(monkeypatch):
         roles_from_env()
 
 
+def test_parse_json_object_accepts_raw_newlines_inside_strings():
+    """Regression (kb init pilot, 2026-09-30): the generator wrote an ASCII
+    diagram with literal newlines inside a JSON string; strict parsing
+    rejected a well-formed answer and the stage stopped."""
+    fenced = '```json\n{"architecture_md": "A\n  -> B\n\tC", "n": 1}\n```'
+    assert parse_json_object(fenced) == {"architecture_md": "A\n  -> B\n\tC", "n": 1}
+    assert parse_json_object('{"a": "x\ny"}') == {"a": "x\ny"}
+    with pytest.raises(ModelUnavailable):
+        parse_json_object('{"a": "unterminated\n')
+
+
 def test_parse_json_object_and_unavailable():
     assert parse_json_object('text\n```json\n{"a": 1}\n```') == {"a": 1}
     with pytest.raises(ModelUnavailable):