diff --git a/.opencode/skills/molecular-cot-logging/SKILL.md b/.opencode/skills/molecular-cot-logging/SKILL.md
index 4172090d..f9569672 100644
--- a/.opencode/skills/molecular-cot-logging/SKILL.md
+++ b/.opencode/skills/molecular-cot-logging/SKILL.md
@@ -9,7 +9,7 @@ description: Structured logging protocol for agent-driven development, based on
 @RELATION DISPATCHES -> [Std.Semantics.Python]
 @RELATION DISPATCHES -> [Std.Semantics.Svelte]
 @RATIONALE Long CoT chains need stabilisation through explicit reasoning bonds. The three-marker system (REASON/REFLECT/EXPLORE) maps directly to the molecular CoT paper and produces machine-readable execution traces that LLM agents can parse, analyse, and use for fine-tuning (MoLE-Syn bond distributions). Without structured markers, agent-generated code exhibits invisible failures: a function returns `None` instead of raising — the agent's attention never sees it because there's no log; a fallback path activates silently — no EXPLORE marker, no trace. JSON-line format ensures every log entry is a self-contained, parseable unit that survives log rotation, aggregation, and agent parsing — unlike plain-text logs that require regex heuristics.
-@REJECTED Legacy Entry/Exit/Action/Coherence markers rejected — they are too generic, do not map to reasoning structure, and prevent traceability graph analysis. Plain-text logging rejected — JSON lines are mandatory for agent parsing. Unstructured printf-style logging rejected — agents cannot reliably extract structured fields (trace_id, marker, intent) from free-form text, making automated diagnosis impossible.
+@REJECTED Legacy Entry/Exit/Action/Coherence markers rejected — they are too generic, do not map to reasoning structure, and prevent traceability graph analysis. Plain-text logging rejected — JSON lines are mandatory for agent parsing. Unstructured printf-style logging rejected — agents cannot reliably extract structured fields (trace_id, marker, intent) from free-form text, making automated diagnosis impossible. cot_span decorator rejected — replaced by belief_scope context manager + logger.reason/reflect/explore which gives more granular intent control per logical branch.
 @DATA_CONTRACT LogEntry -> { ts: str, level: str, trace_id: str, span_id?: str, src: str, marker: REASON|REFLECT|EXPLORE, intent: str, payload?: object, error?: str }
 @INVARIANT Every log line MUST carry exactly one valid marker (REASON | REFLECT | EXPLORE). No markerless log lines in C4/C5 code.
 @INVARIANT trace_id MUST propagate via ContextVar across async boundaries. Every incoming request or background job seeds a new trace_id.
@@ -207,58 +207,7 @@ class TraceMiddleware(BaseHTTPMiddleware):
         return response
 ```
 
-## IV. Python Decorator (Span + Marker)
-
-For C4/C5 functions, a decorator that auto-emits REASON / REFLECT markers:
-
-```python
-import asyncio
-from functools import wraps
-
-def cot_span(marker: str = "REASON", intent: str | None = None):
-    """Wrap a function in a CoT span.  On enter → REASON, on success → REFLECT,
-    on exception → EXPLORE."""
-    def decorator(func):
-        @wraps(func)
-        async def async_wrapper(*args, **kwargs):
-            src = f"{func.__module__}.{func.__qualname__}"
-            prev_span = push_span(func.__qualname__)
-            default_intent = intent or f"Execute {func.__qualname__}"
-            try:
-                log(src, marker, default_intent, payload=_summarise_args(args, kwargs))
-                result = await func(*args, **kwargs)
-                log(src, "REFLECT", f"{func.__qualname__} completed",
-                    payload={"result": _summarise_value(result)})
-                return result
-            except Exception as e:
-                log(src, "EXPLORE", f"{func.__qualname__} failed",
-                    error=str(e), payload={"args": _summarise_args(args, kwargs)})
-                raise
-            finally:
-                pop_span(prev_span)
-
-        @wraps(func)
-        def sync_wrapper(*args, **kwargs):
-            ...  # same logic, sync variant
-        return async_wrapper if asyncio.iscoroutinefunction(func) else sync_wrapper
-    return decorator
-
-
-def _summarise_value(val, max_len: int = 200) -> str:
-    s = str(val)
-    return s[:max_len] + "..." if len(s) > max_len else s
-
-def _summarise_args(args, kwargs) -> dict:
-    # Skip 'self', 'cls', 'db', 'request' — too verbose
-    skip = {"self", "cls", "db", "request", "session"}
-    result = {}
-    for k, v in kwargs.items():
-        if k not in skip:
-            result[k] = _summarise_value(v)
-    return result
-```
-
-## V. Svelte / Frontend Pattern
+## IV. Svelte / Frontend Pattern
 
 The frontend implementation lives at `frontend/src/lib/cot-logger.ts` (installed as `$lib/cot-logger`).
 
@@ -321,7 +270,7 @@ const res = await requestApi("/api/endpoint");
 if (res.trace_id) setTraceId(res.trace_id);
 ```
 
-## VI. CLI / Stdout Reader (for humans)
+## V. CLI / Stdout Reader (for humans)
 
 To make JSON lines readable in development:
 
@@ -341,7 +290,7 @@ for line in sys.stdin:
 "
 ```
 
-## VII. Anti-patterns
+## VI. Anti-patterns
 
 | ❌ Don't | ✅ Do |
 |----------|-------|
diff --git a/backend/src/agent/_confirmation.py b/backend/src/agent/_confirmation.py
index bf01bb5b..661a6e35 100644
--- a/backend/src/agent/_confirmation.py
+++ b/backend/src/agent/_confirmation.py
@@ -122,7 +122,7 @@ async def handle_resume(
     user_jwt: str = "", env_id: str | None = None,
 ) -> AsyncGenerator[str]:
     from src.agent.context import set_user_jwt
-    from src.core.cot_logger import log
+    from src.core.logger import logger
 
     set_user_jwt(user_jwt)
     pending = _pending_confirmations.pop(conversation_id, None)
@@ -134,7 +134,11 @@ async def handle_resume(
             })
             return
         if action == "confirm":
-            log("AgentChat.Confirmation", "REASON", "Fast-path confirmation resume", {"tool": pending.get("tool_name"), "conv_id": conversation_id})
+            logger.reason(
+                "Fast-path confirmation resume",
+                payload={"tool": pending.get("tool_name"), "conv_id": conversation_id},
+                extra={"src": "AgentChat.Confirmation"},
+            )
             tool_name = str(pending.get("tool_name") or "unknown_action")
             tool_args = normalize_tool_args(pending.get("tool_args"))
             yield json.dumps({
@@ -148,7 +152,11 @@ async def handle_resume(
             tool_obj = find_tool(tool_name)
             if tool_obj is None:
                 error = f"Unknown tool: {tool_name}"
-                log("AgentChat.Confirmation", "EXPLORE", "Unknown tool in resume", {"tool": tool_name}, error=error)
+                logger.explore(
+                    "Unknown tool in resume",
+                    payload={"tool": tool_name}, error=error,
+                    extra={"src": "AgentChat.Confirmation"},
+                )
                 yield json.dumps({
                     "content": f"❌ {tool_name} — {error}",
                     "metadata": {"type": "tool_error", "tool": tool_name, "error": error},
@@ -157,7 +165,11 @@ async def handle_resume(
             try:
                 output = await tool_obj.ainvoke(tool_args)
             except Exception as exc:
-                log("AgentChat.Confirmation", "EXPLORE", "Tool invocation failed in resume", {"tool": tool_name}, error=str(exc))
+                logger.explore(
+                    "Tool invocation failed in resume",
+                    payload={"tool": tool_name}, error=str(exc),
+                    extra={"src": "AgentChat.Confirmation"},
+                )
                 yield json.dumps({
                     "content": f"❌ {tool_name} — {exc}",
                     "metadata": {"type": "tool_error", "tool": tool_name, "error": str(exc)},
@@ -171,10 +183,18 @@ async def handle_resume(
                 "content": str(output),
                 "metadata": {"type": "stream_token", "token": str(output)},
             })
-            log("AgentChat.Confirmation", "REFLECT", "Fast-path confirmation completed", {"tool": tool_name})
+            logger.reflect(
+                "Fast-path confirmation completed",
+                payload={"tool": tool_name},
+                extra={"src": "AgentChat.Confirmation"},
+            )
             return
 
-    log("AgentChat.Confirmation", "REASON", "LangGraph checkpoint resume", {"conv_id": conversation_id, "action": action})
+    logger.reason(
+        "LangGraph checkpoint resume",
+        payload={"conv_id": conversation_id, "action": action},
+        extra={"src": "AgentChat.Confirmation"},
+    )
     agent = await create_agent(get_all_tools(), env_id, interrupt_before=[])
     if action == "confirm":
         config = {"configurable": {"thread_id": conversation_id}}
@@ -205,7 +225,11 @@ async def handle_resume(
                     "metadata": {"type": "tool_end", "tool": tool_name, "output": {"result": str(output)[:500]}},
                 })
     elif action == "deny":
-        log("AgentChat.Confirmation", "REFLECT", "Checkpoint resume denied", {"conv_id": conversation_id})
+        logger.reflect(
+            "Checkpoint resume denied",
+            payload={"conv_id": conversation_id},
+            extra={"src": "AgentChat.Confirmation"},
+        )
         yield json.dumps({
             "content": "⏹️ Операция отменена",
             "metadata": {"type": "confirm_resolved", "result": "denied"},
diff --git a/backend/src/agent/_persistence.py b/backend/src/agent/_persistence.py
index ebb80689..4d2cdd05 100644
--- a/backend/src/agent/_persistence.py
+++ b/backend/src/agent/_persistence.py
@@ -15,7 +15,7 @@ from typing import Any
 
 import httpx
 
-from src.core.cot_logger import log
+from src.core.logger import logger
 
 SAVE_API_URL = os.getenv("FASTAPI_URL", "http://localhost:8000") + "/api/agent/conversations/save"
 TITLE_MAX_LENGTH = 80
@@ -170,13 +170,13 @@ def _get_llm_config() -> dict[str, Any] | None:
 
 async def _call_llm_for_title(user_text: str) -> str | None:
     """Call LLM to generate a 3-5 word Russian title. Returns title or None on failure."""
-    from src.core.cot_logger import log as _log
+    from src.core.logger import logger as _logger
 
     try:
         import asyncio as _asyncio
         config = await _asyncio.to_thread(_get_llm_config)
         if not config or not config.get("configured"):
-            _log("AgentChat.Persistence", "EXPLORE", "LLM title: no provider configured", {})
+            _logger.explore("LLM title: no provider configured", extra={"src": "AgentChat.Persistence"})
             return None
 
         clean_text = clean_title(user_text)[:200]
@@ -211,8 +211,11 @@ async def _call_llm_for_title(user_text: str) -> str | None:
         async with httpx.AsyncClient(timeout=10) as client:
             resp = await client.post(api_url, json=payload, headers=headers)
             if resp.status_code != 200:
-                _log("AgentChat.Persistence", "EXPLORE", "LLM title: API error",
-                     {"status": resp.status_code}, error=resp.text[:200])
+                _logger.explore(
+                    "LLM title: API error",
+                    payload={"status": resp.status_code}, error=resp.text[:200],
+                    extra={"src": "AgentChat.Persistence"},
+                )
                 return None
             data = resp.json()
             title = data.get("choices", [{}])[0].get("message", {}).get("content", "")
@@ -223,7 +226,7 @@ async def _call_llm_for_title(user_text: str) -> str | None:
                 if title:
                     return title
     except Exception as e:
-        _log("AgentChat.Persistence", "EXPLORE", "LLM title generation failed", {}, error=str(e))
+        _logger.explore("LLM title generation failed", error=str(e), extra={"src": "AgentChat.Persistence"})
     return None
 
 
@@ -263,11 +266,17 @@ async def generate_llm_title(conv_id: str, user_text: str) -> None:
             }
             async with httpx.AsyncClient(timeout=5) as client:
                 await client.post(SAVE_API_URL, json=payload, headers=headers)
-            log("AgentChat.Persistence", "REFLECT", "LLM title updated",
-                {"conv_id": conv_id, "title": title[:40]})
+            logger.reflect(
+                "LLM title updated",
+                payload={"conv_id": conv_id, "title": title[:40]},
+                extra={"src": "AgentChat.Persistence"},
+            )
         except Exception as e:
-            log("AgentChat.Persistence", "EXPLORE", "LLM title save failed",
-                {"conv_id": conv_id}, error=str(e))
+            logger.explore(
+                "LLM title save failed",
+                payload={"conv_id": conv_id}, error=str(e),
+                extra={"src": "AgentChat.Persistence"},
+            )
         finally:
             _title_locks.pop(conv_id, None)
 # #endregion AgentChat.Persistence.GenerateLlmTitle
@@ -314,7 +323,12 @@ async def prefetch_dashboards(env_id: str) -> str:
             if total > limit:
                 suffix = f"\n... {total - limit} more dashboards omitted. Ask for a narrower search if needed."
             return f"Available dashboards in environment '{env_id or 'default'}' ({total} total):\n" + "\n".join(lines) + suffix
-    except Exception:
+    except Exception as e:
+        logger.explore(
+            "Prefetch dashboards failed",
+            payload={"env_id": env_id}, error=str(e),
+            extra={"src": "AgentChat.Persistence.PrefetchDashboards"},
+        )
         return ""
 # #endregion AgentChat.Persistence.PrefetchDashboards
 
@@ -369,8 +383,16 @@ async def save_conversation(conv_id: str, user_text: str, user_id: str = "admin"
 
         async with httpx.AsyncClient(timeout=10) as client:
             await client.post(SAVE_API_URL, json=payload, headers=headers)
+        logger.reflect(
+            "Conversation saved",
+            payload={"conv_id": conv_id, "msg_count": len(messages), "title": title[:40]},
+            extra={"src": "AgentChat.Persistence.SaveConversation"},
+        )
     except Exception as e:
-        log("AgentChat.Persistence", "EXPLORE", "Failed to save conversation",
-            {"conv_id": conv_id}, error=str(e))
+        logger.explore(
+            "Failed to save conversation",
+            payload={"conv_id": conv_id}, error=str(e),
+            extra={"src": "AgentChat.Persistence"},
+        )
 # #endregion AgentChat.Persistence.SaveConversation
 # #endregion AgentChat.Persistence
diff --git a/backend/src/agent/_tool_resolver.py b/backend/src/agent/_tool_resolver.py
index c1fe75b0..dea52317 100644
--- a/backend/src/agent/_tool_resolver.py
+++ b/backend/src/agent/_tool_resolver.py
@@ -9,7 +9,7 @@
 from typing import Any
 
 from src.agent.tools import get_all_tools
-from src.core.cot_logger import log
+from src.core.logger import logger
 
 # #region AgentChat.ToolResolver.Sets [C:1] [TYPE Constants] [SEMANTICS agent-chat,tools,sets]
 # @ingroup AgentChat
@@ -56,7 +56,11 @@ def known_agent_tool_names() -> set[str]:
     try:
         return {str(tool_obj.name) for tool_obj in get_all_tools() if getattr(tool_obj, "name", None)}
     except Exception as exc:
-        log("AgentChat.ToolResolver", "EXPLORE", "tool catalog lookup failed", {"error": str(exc)})
+        logger.explore(
+            "tool catalog lookup failed",
+            payload={"error": str(exc)},
+            extra={"src": "AgentChat.ToolResolver"},
+        )
         return _SAFE_AGENT_TOOLS | _GUARDED_AGENT_TOOLS | _DANGEROUS_AGENT_TOOLS
 # #endregion AgentChat.ToolResolver.KnownNames
 
@@ -105,39 +109,46 @@ def coerce_tool_call(tool_call: Any) -> tuple[str | None, dict[str, Any]]:
 #            uses keyword matching to guess the user's intent and auto-trigger HITL.
 def infer_tool_from_text(text: str) -> str | None:
     lowered = (text or "").lower()
+    inferred: str | None = None
     if any(word in lowered for word in ["окруж", "environment", "env"]):
-        return "list_environments"
-    if any(word in lowered for word in ["maintenance", "обслуж", "баннер"]):
+        inferred = "list_environments"
+    elif any(word in lowered for word in ["maintenance", "обслуж", "баннер"]):
         if any(word in lowered for word in ["start", "созда", "запусти", "начни"]):
-            return "start_maintenance"
-        if any(word in lowered for word in ["end", "закрой", "заверши", "останов"]):
-            return "end_maintenance"
-        return "list_maintenance_events"
-    if any(word in lowered for word in ["дашборд", "dashboard", "dashboards", "дашборды"]):
-        return "search_dashboards"
-    if any(word in lowered for word in ["здоров", "health", "статус системы", "system status"]):
-        return "get_health_summary"
-    if any(word in lowered for word in ["задач", "task", "таск"]):
-        return "get_task_status"
-    if any(word in lowered for word in ["llm", "provider", "провайдер", "модель"]):
-        return "list_llm_providers"
-    if any(word in lowered for word in ["branch", "ветк"]):
-        return "create_branch"
-    if any(word in lowered for word in ["commit", "коммит"]):
-        return "commit_changes"
-    if any(word in lowered for word in ["deploy", "депло", "разверн"]):
-        return "deploy_dashboard"
-    if any(word in lowered for word in ["миграц", "migration", "migrate"]):
-        return "execute_migration"
-    if any(word in lowered for word in ["backup", "бэкап", "резерв"]):
-        return "run_backup"
-    if any(word in lowered for word in ["валидац", "validation", "validate"]):
-        return "run_llm_validation"
-    if any(word in lowered for word in ["документ", "documentation", "docs"]):
-        return "run_llm_documentation"
-    if any(word in lowered for word in ["инструмент", "tool", "capabilit", "умеешь", "можешь"]):
-        return "show_capabilities"
-    return None
+            inferred = "start_maintenance"
+        elif any(word in lowered for word in ["end", "закрой", "заверши", "останов"]):
+            inferred = "end_maintenance"
+        else:
+            inferred = "list_maintenance_events"
+    elif any(word in lowered for word in ["дашборд", "dashboard", "dashboards", "дашборды"]):
+        inferred = "search_dashboards"
+    elif any(word in lowered for word in ["здоров", "health", "статус системы", "system status"]):
+        inferred = "get_health_summary"
+    elif any(word in lowered for word in ["задач", "task", "таск"]):
+        inferred = "get_task_status"
+    elif any(word in lowered for word in ["llm", "provider", "провайдер", "модель"]):
+        inferred = "list_llm_providers"
+    elif any(word in lowered for word in ["branch", "ветк"]):
+        inferred = "create_branch"
+    elif any(word in lowered for word in ["commit", "коммит"]):
+        inferred = "commit_changes"
+    elif any(word in lowered for word in ["deploy", "депло", "разверн"]):
+        inferred = "deploy_dashboard"
+    elif any(word in lowered for word in ["миграц", "migration", "migrate"]):
+        inferred = "execute_migration"
+    elif any(word in lowered for word in ["backup", "бэкап", "резерв"]):
+        inferred = "run_backup"
+    elif any(word in lowered for word in ["валидац", "validation", "validate"]):
+        inferred = "run_llm_validation"
+    elif any(word in lowered for word in ["документ", "documentation", "docs"]):
+        inferred = "run_llm_documentation"
+    elif any(word in lowered for word in ["инструмент", "tool", "capabilit", "умеешь", "можешь"]):
+        inferred = "show_capabilities"
+
+    if inferred:
+        logger.reason("Tool inferred from user text",
+                      payload={"tool": inferred, "text_preview": (text or "")[:80]},
+                      extra={"src": "AgentChat.ToolResolver.InferFromText"})
+    return inferred
 # #endregion AgentChat.ToolResolver.InferFromText
 
 
@@ -155,7 +166,11 @@ def extract_tool_call_from_state(state, user_text: str = "") -> tuple[str | None
                 if tool_name:
                     return (str(tool_name), tool_args)
     except Exception as exc:
-        log("AgentChat.ToolResolver", "EXPLORE", "tool_call extraction failed", {"error": str(exc)})
+        logger.explore(
+            "tool_call extraction failed",
+            payload={"error": str(exc)},
+            extra={"src": "AgentChat.ToolResolver"},
+        )
 
     if getattr(state, "next", None):
         node_or_tool = str(state.next[0])
@@ -164,7 +179,11 @@ def extract_tool_call_from_state(state, user_text: str = "") -> tuple[str | None
 
     inferred_tool = infer_tool_from_text(user_text)
     if inferred_tool:
-        log("AgentChat.ToolResolver", "EXPLORE", "tool_call inferred from user text", {"tool": inferred_tool})
+        logger.explore(
+            "tool_call inferred from user text",
+            payload={"tool": inferred_tool},
+            extra={"src": "AgentChat.ToolResolver"},
+        )
         return (inferred_tool, {})
     return (None, {})
 # #endregion AgentChat.ToolResolver.ExtractFromState
diff --git a/backend/src/agent/app.py b/backend/src/agent/app.py
index 48d77dc4..da7f73ca 100644
--- a/backend/src/agent/app.py
+++ b/backend/src/agent/app.py
@@ -49,7 +49,7 @@ from src.agent.langgraph_setup import create_agent
 from src.agent.middleware import log_tool_event
 from src.agent.tools import get_tools_for_query
 from src.core.auth.jwt import decode_token
-from src.core.cot_logger import log
+from src.core.logger import logger
 
 JWT_SECRET = os.getenv("JWT_SECRET", "super-secret-key")
 MAX_FILE_SIZE_BYTES = 10 * 1024 * 1024  # 10 MB
@@ -96,8 +96,11 @@ def _persist_chat_file(file_path: str, conv_id: str) -> str | None:
 
     shutil.copy2(str(src), str(dest_file))
     rel_path = str(dest_file.relative_to(Path(storage_root)))
-    log("AgentChat.PersistFile", "REFLECT", "Chat file persisted to storage",
-        {"original": src.name, "rel_path": rel_path, "size": dest_file.stat().st_size})
+    logger.reflect(
+        "Chat file persisted to storage",
+        payload={"original": src.name, "rel_path": rel_path, "size": dest_file.stat().st_size},
+        extra={"src": "AgentChat.PersistFile"},
+    )
     return rel_path
 # #endregion AgentChat.GradioApp.PersistFile
 # Per-conversation mutex for HITL resume (FR-026): keyed by conversation_id
@@ -159,6 +162,13 @@ async def agent_handler(  # noqa: C901 — intentionally complex C4 orchestratio
     try:
         # ── Resolve conversation ID early (needed for file persistence) ──
         conv_id = conversation_id or str(uuid.uuid4())
+        is_resume = action in ("confirm", "deny")
+        logger.reason(
+            "Agent handler invoked",
+            payload={"user_id": user_id, "conv_id": conv_id, "action": action, "env_id": env_id,
+                     "is_resume": is_resume, "msg_len": len(str(message))},
+            extra={"src": "AgentChat.GradioApp.Handler"},
+        )
 
         # ── Parse message ──
         text = message.get("text", "") if isinstance(message, dict) else str(message)
@@ -335,12 +345,24 @@ async def agent_handler(  # noqa: C901 — intentionally complex C4 orchestratio
                     if attempt < max_attempts - 1:
                         text = "Respond with valid JSON only. Previous response was malformed.\n\n" + text
                         continue
+                    logger.explore(
+                        "LLM malformed output",
+                        payload={"conv_id": conv_id, "attempt": attempt},
+                        error=str(e),
+                        extra={"src": "AgentChat.GradioApp.Handler"},
+                    )
                     yield json.dumps({
                         "content": "❌ Ошибка обработки ответа LLM. Пожалуйста, уточните запрос.",
                         "metadata": {"type": "error", "code": "LLM_MALFORMED_OUTPUT", "detail": str(e)},
                     })
 
         except Exception as exc:
+            logger.explore(
+                "Agent handler failed",
+                payload={"conv_id": conv_id, "user_id": user_id},
+                error=str(exc),
+                extra={"src": "AgentChat.GradioApp.Handler"},
+            )
             try:
                 state = await agent.aget_state(config)
                 if getattr(state, "next", None):
@@ -358,6 +380,11 @@ async def agent_handler(  # noqa: C901 — intentionally complex C4 orchestratio
         await save_conversation(conv_id, text, user_id, assistant_text="".join(assistant_parts))
         # Fire-and-forget: generate LLM title in background (best-effort)
         asyncio.create_task(generate_llm_title(conv_id, text))
+        logger.reflect(
+            "Agent handler completed",
+            payload={"conv_id": conv_id, "assistant_len": len("".join(assistant_parts))},
+            extra={"src": "AgentChat.GradioApp.Handler"},
+        )
 
     finally:
         _user_locks[user_id] = False
diff --git a/backend/src/agent/langgraph_setup.py b/backend/src/agent/langgraph_setup.py
index 88a0ef34..1d8bd615 100644
--- a/backend/src/agent/langgraph_setup.py
+++ b/backend/src/agent/langgraph_setup.py
@@ -20,6 +20,8 @@ from langgraph.checkpoint.postgres.aio import AsyncPostgresSaver
 from langgraph.prebuilt import create_react_agent
 from psycopg.rows import dict_row
 
+from src.core.logger import logger
+
 # ── Monkey-patch: OpenAI SDK for Pydantic BaseModel classes ──
 # LangChain BaseTool objects carry an ``args_schema`` field that is a Pydantic
 # BaseModel *class* reference (not an instance). When the OpenAI SDK recursively
@@ -111,8 +113,9 @@ async def _fetch_llm_config() -> dict | None:
                 if config.get("configured"):
                     _llm_config = config
                     return config
-    except Exception:
-        pass  # Keep existing config on failure
+    except Exception as e:
+        logger.explore("Failed to fetch LLM config from FastAPI", error=str(e),
+                       extra={"src": "AgentChat.LangGraph.Setup"})
     return _llm_config
 
 
@@ -151,10 +154,24 @@ async def create_agent(
         api_key = config["api_key"]
         base_url = config.get("base_url") or "https://api.openai.com/v1"
         model = config.get("default_model") or "gpt-4o-mini"
+        config_source = "FastAPI"
     else:
         api_key = os.getenv("LLM_API_KEY")
         base_url = os.getenv("LLM_BASE_URL", "https://api.openai.com/v1")
         model = os.getenv("LLM_MODEL", "gpt-4o")
+        config_source = "env vars"
+        logger.explore(
+            "LLM config not found in FastAPI, falling back to env vars",
+            payload={"model": model, "provider_type": config.get("provider_type") if config else None},
+            error="No configured LLM provider in FastAPI",
+            extra={"src": "AgentChat.LangGraph.Setup"},
+        )
+
+    logger.reason(
+        "Creating LangGraph agent",
+        payload={"model": model, "config_source": config_source, "tools_count": len(tools), "env_id": env_id},
+        extra={"src": "AgentChat.LangGraph.Setup"},
+    )
 
     llm = ChatOpenAI(
         model=model,
@@ -179,6 +196,11 @@ async def create_agent(
         checkpointer = _CHECKPOINTER
     else:
         checkpointer = InMemorySaver()
+        logger.explore(
+            "Postgres checkpointer unavailable, falling back to InMemorySaver",
+            error="_CHECKPOINTER is None — checkpoints will be lost on restart",
+            extra={"src": "AgentChat.LangGraph.Setup"},
+        )
 
     graph = create_react_agent(
         model=llm,
@@ -189,5 +211,10 @@ async def create_agent(
         interrupt_before=_interrupt_before_from_env() if interrupt_before is None else interrupt_before,
     )
 
+    logger.reflect(
+        "LangGraph agent created",
+        payload={"model": model, "checkpointer_type": type(checkpointer).__name__, "tools_count": len(tools)},
+        extra={"src": "AgentChat.LangGraph.Setup"},
+    )
     return graph
 # #endregion AgentChat.LangGraph.Setup
diff --git a/backend/src/agent/middleware.py b/backend/src/agent/middleware.py
index b4df238b..5bfdfb98 100644
--- a/backend/src/agent/middleware.py
+++ b/backend/src/agent/middleware.py
@@ -7,11 +7,9 @@
 # @REJECTED ConfirmationRiskMiddleware rejected — LangGraph interrupt_before=DANGEROUS_TOOLS handles HITL natively.
 
 from datetime import UTC, datetime
-import logging
 
 from src.agent.context import get_user_jwt
-
-logger = logging.getLogger("cot")
+from src.core.logger import logger
 
 
 # #region AgentChat.Middleware.LoggingMiddleware [C:3] [TYPE Function] [SEMANTICS audit,tool,logging]
@@ -48,9 +46,10 @@ async def log_tool_event(event: dict, conversation_id: str) -> None:
         elif kind == "on_tool_error":
             audit_payload["error"] = str(data.get("error", ""))[:500]
 
-    logger.info(
-        "Tool audit: %(event_type)s — %(tool)s — conv=%(conversation_id)s",
-        audit_payload,
+    logger.reason(
+        "Tool audit event",
+        payload=audit_payload,
+        extra={"src": "AgentChat.Middleware.LoggingMiddleware"},
     )
 
     # TODO: Async write to assistant_audit table via REST call to FastAPI
diff --git a/backend/src/agent/run.py b/backend/src/agent/run.py
index 03c7c132..485dd173 100644
--- a/backend/src/agent/run.py
+++ b/backend/src/agent/run.py
@@ -11,9 +11,8 @@
 import os
 import socket
 import httpx
-import logging
 
-logger = logging.getLogger("cot")
+from src.core.logger import logger
 
 FASTAPI_URL = os.getenv("FASTAPI_URL", "http://localhost:8000")
 
@@ -46,16 +45,37 @@ def _fetch_llm_config() -> dict | None:
             resp.raise_for_status()
             config = resp.json()
             if config.get("configured"):
-                logger.info("LLM config fetched from FastAPI: %s (%s)", config.get("provider_type"), config.get("default_model"))
+                logger.reason(
+                    "LLM config fetched from FastAPI",
+                    payload={"provider_type": config.get("provider_type"), "model": config.get("default_model")},
+                    extra={"src": "AgentChat.Run.FetchLlmConfig"},
+                )
                 return config
-            logger.warning("FastAPI returned no active LLM provider: %s", config.get("reason"))
+            logger.explore(
+                "FastAPI returned no active LLM provider",
+                payload={"reason": config.get("reason")},
+                error="No configured LLM provider",
+                extra={"src": "AgentChat.Run.FetchLlmConfig"},
+            )
         except Exception as e:
             if attempt < 5:
-                logger.info("Waiting for FastAPI (attempt %d/6): %s", attempt + 1, e)
+                logger.reason(
+                    f"Waiting for FastAPI (attempt {attempt + 1}/6)",
+                    payload={"error": str(e)},
+                    extra={"src": "AgentChat.Run.FetchLlmConfig"},
+                )
                 time.sleep(5)
             else:
-                logger.warning("Failed to fetch LLM config from FastAPI after 6 attempts: %s", e)
-                logger.info("Falling back to env vars for LLM config")
+                logger.explore(
+                    "Failed to fetch LLM config after 6 attempts",
+                    error=str(e),
+                    extra={"src": "AgentChat.Run.FetchLlmConfig"},
+                )
+                logger.explore(
+                    "Falling back to env vars for LLM config",
+                    error="FastAPI unreachable",
+                    extra={"src": "AgentChat.Run.FetchLlmConfig"},
+                )
     return None
 
 
@@ -85,9 +105,18 @@ if __name__ == "__main__":
         try:
             port = _find_free_port(configured_port)
             if port != configured_port:
-                logger.warning("Port %d is in use, falling back to port %d", configured_port, port)
+                logger.explore(
+                    "Port in use, falling back",
+                    payload={"configured_port": configured_port, "actual_port": port},
+                    error=f"Port {configured_port} is in use",
+                    extra={"src": "AgentChat.Run.PortBinding"},
+                )
         except OSError as e:
-            logger.error("Failed to find a free port: %s", e)
+            logger.explore(
+                "Failed to find a free port",
+                error=str(e),
+                extra={"src": "AgentChat.Run.PortBinding"},
+            )
             raise
     else:
         port = configured_port
diff --git a/backend/src/agent/tools.py b/backend/src/agent/tools.py
index 3346977e..a7348363 100644
--- a/backend/src/agent/tools.py
+++ b/backend/src/agent/tools.py
@@ -14,6 +14,7 @@ from langchain_core.tools import tool
 from pydantic import BaseModel, Field
 
 from src.agent.context import get_service_jwt, get_user_jwt
+from src.core.logger import logger
 
 FASTAPI_URL = os.getenv("FASTAPI_URL", "http://localhost:8000")
 TOOL_RESPONSE_LIMIT = 4000
@@ -178,9 +179,15 @@ class SearchDashboardsInput(BaseModel):
 @tool(args_schema=SearchDashboardsInput)
 async def search_dashboards(query: str, env_id: str | None = None) -> str:
     """Search and list dashboards by name, with optional environment filter."""
+    logger.reason("Search dashboards", payload={"query": query, "env_id": env_id},
+                  extra={"src": "AgentChat.Tools.SearchDashboards"})
     params = {"q": query, "env_id": env_id or ""}
     resp = await _get("/api/dashboards", params=params)
     if resp.status_code != 200:
+        logger.explore("Dashboard search failed",
+                       payload={"status": resp.status_code, "query": query},
+                       error=resp.text[:200],
+                       extra={"src": "AgentChat.Tools.SearchDashboards"})
         return f"Error {resp.status_code}: Unable to fetch dashboards. {resp.text}"
 
     try:
@@ -189,6 +196,9 @@ async def search_dashboards(query: str, env_id: str | None = None) -> str:
         total = data.get("total", 0)
 
         if total == 0:
+            logger.reflect("No dashboards found",
+                           payload={"query": query, "total": 0},
+                           extra={"src": "AgentChat.Tools.SearchDashboards"})
             return f"No dashboards found matching '{query}' in environment '{env_id or 'default'}'."
 
         lines = [f"Found {total} dashboard(s) in environment '{env_id or 'default'}':"]
@@ -199,8 +209,14 @@ async def search_dashboards(query: str, env_id: str | None = None) -> str:
             lines.append(f"  - {title}")
             lines.append(f"    Owners: {owners}")
             lines.append(f"    Last modified: {modified}")
+        logger.reflect("Dashboards listed",
+                       payload={"query": query, "total": total},
+                       extra={"src": "AgentChat.Tools.SearchDashboards"})
         return "\n".join(lines)
     except (json.JSONDecodeError, KeyError) as e:
+        logger.explore("Failed to parse dashboards response",
+                       payload={"query": query}, error=str(e),
+                       extra={"src": "AgentChat.Tools.SearchDashboards"})
         return f"Could not parse dashboards response: {e}"
 # #endregion AgentChat.Tools.SearchDashboards
 
@@ -220,9 +236,18 @@ class HealthSummaryInput(BaseModel):
 @tool(args_schema=HealthSummaryInput)
 async def get_health_summary(env_id: str | None = None) -> str:
     """Get system health summary — dashboard validation status, recent failures."""
+    logger.reason("Get health summary", payload={"env_id": env_id},
+                  extra={"src": "AgentChat.Tools.HealthSummary"})
     resp = await _get("/api/health/summary", params={"environment_id": env_id or ""})
     if resp.status_code != 200:
+        logger.explore("Health check failed",
+                       payload={"status": resp.status_code},
+                       error=resp.text[:200],
+                       extra={"src": "AgentChat.Tools.HealthSummary"})
         return f"Health check failed: HTTP {resp.status_code}"
+    logger.reflect("Health summary retrieved",
+                   payload={"status": resp.status_code},
+                   extra={"src": "AgentChat.Tools.HealthSummary"})
     return _trim_response(resp.text, 2000)
 # #endregion AgentChat.Tools.HealthSummary
 
@@ -236,8 +261,11 @@ async def get_health_summary(env_id: str | None = None) -> str:
 @tool
 async def list_environments() -> str:
     """List configured deployment environments."""
+    logger.reason("List environments", extra={"src": "AgentChat.Tools.ListEnvironments"})
     resp = await _get("/api/settings/environments")
     result = _api_result(resp)
+    logger.reflect("Environments listed", payload={"status": resp.status_code},
+                   extra={"src": "AgentChat.Tools.ListEnvironments"})
     return _trim_response(_safe_json_text(result))
 # #endregion AgentChat.Tools.ListEnvironments
 
@@ -251,8 +279,13 @@ async def list_environments() -> str:
 @tool
 async def get_task_status(task_id: str) -> str:
     """Check the status of a background task by its task_id."""
+    logger.reason("Get task status", payload={"task_id": task_id},
+                  extra={"src": "AgentChat.Tools.TaskStatus"})
     resp = await _get(f"/api/tasks/{task_id}")
-    return _api_result(resp)
+    result = _api_result(resp)
+    logger.reflect("Task status retrieved", payload={"task_id": task_id, "status": resp.status_code},
+                   extra={"src": "AgentChat.Tools.TaskStatus"})
+    return result
 # #endregion AgentChat.Tools.TaskStatus
 
 
@@ -278,8 +311,12 @@ async def show_capabilities() -> str:
 @tool
 async def list_llm_providers() -> str:
     """List configured LLM providers."""
+    logger.reason("List LLM providers", extra={"src": "AgentChat.Tools.ListLlmProviders"})
     resp = await _get("/api/llm/providers")
-    return _api_result(resp)
+    result = _api_result(resp)
+    logger.reflect("LLM providers listed", payload={"status": resp.status_code},
+                   extra={"src": "AgentChat.Tools.ListLlmProviders"})
+    return result
 # #endregion AgentChat.Tools.ListLlmProviders
 
 
@@ -292,8 +329,12 @@ async def list_llm_providers() -> str:
 @tool
 async def get_llm_status() -> str:
     """Check whether the LLM runtime is configured and usable."""
+    logger.reason("Get LLM status", extra={"src": "AgentChat.Tools.LlmStatus"})
     resp = await _get("/api/llm/status")
-    return _api_result(resp)
+    result = _api_result(resp)
+    logger.reflect("LLM status retrieved", payload={"status": resp.status_code},
+                   extra={"src": "AgentChat.Tools.LlmStatus"})
+    return result
 # #endregion AgentChat.Tools.LlmStatus
 
 
@@ -318,12 +359,17 @@ async def run_backup(
     dashboard_ids: list[int] | None = None,
 ) -> str:
     """Run a Superset backup for an environment, optionally scoped to dashboard IDs."""
+    vars = {"env_id": environment_id, "dashboard_id": dashboard_id, "dashboard_ids": dashboard_ids}
+    logger.reason("Run backup", payload=vars, extra={"src": "AgentChat.Tools.RunBackup"})
     params: dict[str, Any] = {"environment_id": environment_id}
-    ids = _dashboard_ids(dashboard_id, dashboard_ids)
-    if ids:
-        params["dashboard_ids"] = ids
+    ids_l = _dashboard_ids(dashboard_id, dashboard_ids)
+    if ids_l:
+        params["dashboard_ids"] = ids_l
     resp = await _post("/api/tasks", {"plugin_id": "superset-backup", "params": params})
-    return _api_result(resp, {201})
+    result = _api_result(resp, {201})
+    logger.reflect("Backup task created", payload={"status": resp.status_code},
+                   extra={"src": "AgentChat.Tools.RunBackup"})
+    return result
 # #endregion AgentChat.Tools.RunBackup
 
 
@@ -352,6 +398,9 @@ async def execute_migration(
     fix_cross_filters: bool = True,
 ) -> str:
     """Execute dashboard migration between two environments."""
+    logger.reason("Execute migration",
+                  payload={"source": source_env_id, "target": target_env_id, "ids_count": len(selected_ids)},
+                  extra={"src": "AgentChat.Tools.ExecuteMigration"})
     payload = {
         "source_env_id": source_env_id,
         "target_env_id": target_env_id,
@@ -360,7 +409,10 @@ async def execute_migration(
         "fix_cross_filters": fix_cross_filters,
     }
     resp = await _post("/api/migration/execute", payload)
-    return _api_result(resp)
+    result = _api_result(resp)
+    logger.reflect("Migration executed", payload={"status": resp.status_code},
+                   extra={"src": "AgentChat.Tools.ExecuteMigration"})
+    return result
 # #endregion AgentChat.Tools.ExecuteMigration
 
 
@@ -394,12 +446,18 @@ async def create_branch(
     env_id: str | None = None,
 ) -> str:
     """Create a branch in a dashboard Git repository."""
+    logger.reason("Create branch",
+                  payload={"dashboard_ref": dashboard_ref, "branch_name": branch_name, "from_branch": from_branch},
+                  extra={"src": "AgentChat.Tools.CreateBranch"})
     resp = await _post(
         f"/api/git/repositories/{dashboard_ref}/branches",
         {"name": branch_name, "from_branch": from_branch},
         params={"env_id": env_id} if env_id else None,
     )
-    return _api_result(resp)
+    result = _api_result(resp)
+    logger.reflect("Branch created", payload={"status": resp.status_code},
+                   extra={"src": "AgentChat.Tools.CreateBranch"})
+    return result
 # #endregion AgentChat.Tools.CreateBranch
 
 
@@ -424,12 +482,18 @@ async def commit_changes(
     env_id: str | None = None,
 ) -> str:
     """Stage and commit changes in a dashboard Git repository."""
+    logger.reason("Commit changes",
+                  payload={"dashboard_ref": dashboard_ref, "message": message[:80]},
+                  extra={"src": "AgentChat.Tools.CommitChanges"})
     resp = await _post(
         f"/api/git/repositories/{dashboard_ref}/commit",
         {"message": message, "files": files or []},
         params={"env_id": env_id} if env_id else None,
     )
-    return _api_result(resp)
+    result = _api_result(resp)
+    logger.reflect("Changes committed", payload={"status": resp.status_code},
+                   extra={"src": "AgentChat.Tools.CommitChanges"})
+    return result
 # #endregion AgentChat.Tools.CommitChanges
 
 
@@ -452,12 +516,18 @@ async def deploy_dashboard(
     env_id: str | None = None,
 ) -> str:
     """Deploy a dashboard from Git to a target environment."""
+    logger.reason("Deploy dashboard",
+                  payload={"dashboard_ref": dashboard_ref, "target_env": environment_id},
+                  extra={"src": "AgentChat.Tools.DeployDashboard"})
     resp = await _post(
         f"/api/git/repositories/{dashboard_ref}/deploy",
         {"environment_id": environment_id},
         params={"env_id": env_id} if env_id else None,
     )
-    return _api_result(resp)
+    result = _api_result(resp)
+    logger.reflect("Dashboard deployed", payload={"status": resp.status_code},
+                   extra={"src": "AgentChat.Tools.DeployDashboard"})
+    return result
 # #endregion AgentChat.Tools.DeployDashboard
 
 
@@ -482,6 +552,9 @@ async def run_llm_documentation(
     provider_id: str | None = None,
 ) -> str:
     """Generate dataset documentation via the LLM documentation task."""
+    logger.reason("Run LLM documentation",
+                  payload={"dataset_id": dataset_id, "environment_id": environment_id},
+                  extra={"src": "AgentChat.Tools.LlmDocumentation"})
     resolved_provider = await _resolve_active_provider_id(provider_id)
     params = {
         "dataset_id": str(dataset_id),
@@ -490,7 +563,11 @@ async def run_llm_documentation(
     if resolved_provider:
         params["provider_id"] = resolved_provider
     resp = await _post("/api/tasks", {"plugin_id": "llm_documentation", "params": params})
-    return _api_result(resp, {201})
+    result = _api_result(resp, {201})
+    logger.reflect("LLM documentation task created",
+                   payload={"status": resp.status_code, "provider_id": resolved_provider},
+                   extra={"src": "AgentChat.Tools.LlmDocumentation"})
+    return result
 # #endregion AgentChat.Tools.LlmDocumentation
 
 
@@ -524,10 +601,19 @@ async def run_llm_validation(
 ) -> str:
     """Create and immediately run an LLM dashboard validation policy, or run an existing policy."""
     if policy_id:
+        logger.reason("Run existing validation policy",
+                      payload={"policy_id": policy_id},
+                      extra={"src": "AgentChat.Tools.LlmValidation"})
         resp = await _post(f"/api/validation-tasks/{policy_id}/run")
-        return _api_result(resp)
+        result = _api_result(resp)
+        logger.reflect("Validation policy run", payload={"policy_id": policy_id, "status": resp.status_code},
+                       extra={"src": "AgentChat.Tools.LlmValidation"})
+        return result
 
     ids = _dashboard_ids(dashboard_id, dashboard_ids)
+    logger.reason("Create LLM validation policy",
+                  payload={"environment_id": environment_id, "dashboard_count": len(ids)},
+                  extra={"src": "AgentChat.Tools.LlmValidation"})
     sources = []
     if dashboard_url:
         sources.append({"type": "dashboard_url", "value": dashboard_url})
@@ -560,7 +646,11 @@ async def run_llm_validation(
     except (json.JSONDecodeError, KeyError) as exc:
         return f"Validation policy created but response could not be parsed: {exc}. Raw: {create_resp.text}"
     run_resp = await _post(f"/api/validation-tasks/{created_id}/run")
-    return _api_result(run_resp)
+    result = _api_result(run_resp)
+    logger.reflect("Validation policy created and run",
+                   payload={"policy_id": created_id, "status": run_resp.status_code},
+                   extra={"src": "AgentChat.Tools.LlmValidation"})
+    return result
 # #endregion AgentChat.Tools.LlmValidation
 
 
@@ -573,8 +663,12 @@ async def run_llm_validation(
 @tool
 async def list_maintenance_events() -> str:
     """List active and completed maintenance events."""
+    logger.reason("List maintenance events", extra={"src": "AgentChat.Tools.ListMaintenance"})
     resp = await _get("/api/maintenance/events")
-    return _api_result(resp)
+    result = _api_result(resp)
+    logger.reflect("Maintenance events listed", payload={"status": resp.status_code},
+                   extra={"src": "AgentChat.Tools.ListMaintenance"})
+    return result
 # #endregion AgentChat.Tools.ListMaintenance
 
 
@@ -603,6 +697,9 @@ async def start_maintenance(
     message: str | None = None,
 ) -> str:
     """Start a maintenance event and apply banners to affected dashboards."""
+    logger.reason("Start maintenance",
+                  payload={"environment_id": environment_id, "tables": tables},
+                  extra={"src": "AgentChat.Tools.StartMaintenance"})
     payload = {
         "tables": tables,
         "environment_id": environment_id,
@@ -611,7 +708,10 @@ async def start_maintenance(
         "message": message,
     }
     resp = await _post("/api/maintenance/start", payload)
-    return _api_result(resp, {200, 202})
+    result = _api_result(resp, {200, 202})
+    logger.reflect("Maintenance started", payload={"status": resp.status_code},
+                   extra={"src": "AgentChat.Tools.StartMaintenance"})
+    return result
 # #endregion AgentChat.Tools.StartMaintenance
 
 
@@ -637,13 +737,25 @@ async def end_maintenance(
 ) -> str:
     """End one maintenance event, or end all active events when end_all is true."""
     if end_all:
+        logger.reason("End all maintenance events",
+                      payload={"environment_id": environment_id},
+                      extra={"src": "AgentChat.Tools.EndMaintenance"})
         payload = {"environment_id": environment_id} if environment_id else {}
         resp = await _post("/api/maintenance/end-all", payload)
-        return _api_result(resp, {202})
+        result = _api_result(resp, {202})
+        logger.reflect("All maintenance ended", payload={"status": resp.status_code},
+                       extra={"src": "AgentChat.Tools.EndMaintenance"})
+        return result
     if not maintenance_id:
         return "Error: maintenance_id is required unless end_all=true."
+    logger.reason("End maintenance event",
+                  payload={"maintenance_id": maintenance_id},
+                  extra={"src": "AgentChat.Tools.EndMaintenance"})
     resp = await _post(f"/api/maintenance/{maintenance_id}/end")
-    return _api_result(resp, {202})
+    result = _api_result(resp, {202})
+    logger.reflect("Maintenance ended", payload={"status": resp.status_code, "maintenance_id": maintenance_id},
+                   extra={"src": "AgentChat.Tools.EndMaintenance"})
+    return result
 # #endregion AgentChat.Tools.EndMaintenance
 
 
diff --git a/backend/src/core/cot_logger.py b/backend/src/core/cot_logger.py
index b832c95f..5a4854b3 100644
--- a/backend/src/core/cot_logger.py
+++ b/backend/src/core/cot_logger.py
@@ -170,6 +170,9 @@ def log(
 # #region MarkerLogger [C:2] [TYPE Class] [SEMANTICS logger, proxy, marker, syntactic-sugar]
 # @ingroup Core
 # @BRIEF Thin proxy class providing .reason(), .reflect(), .explore() convenience methods.
+# @DEPRECATED Use logger.reason/reflect/explore from src.core.logger instead — MarkerLogger has
+#             zero usages in the codebase and adds a redundant abstraction layer.
+# @REPLACED_BY logger.reason/reflect/explore (monkey-patched on superset_tools_app logger)
 class MarkerLogger:
     """Thin proxy over the cot_logger.log() function.