feat(logging): structured TRACE events and end-to-end request correlation

Add core/trace.py with trace_event, traced_async_stream, and payload snapshots.
Merge TRACE fields into JSON logs; promote claude_session_id, http path/method.
Instrument API, messaging/CLI, and OpenAI-compat/native provider paths.
Harden log sink with enqueue and stdlib intercept re-entrancy guard.
Document behavior in .env.example and README; extend tests.

.env.example

@@ -136,6 +136,11 @@ WEB_FETCH_ALLOWED_SCHEMES=http,https
 WEB_FETCH_ALLOW_PRIVATE_NETWORKS=false
 
 
+# Structured TRACE logs: lines with `"trace": true` merge ingress/routing/cli/provider/egress
+# stages. Conversation text is logged in those payloads (verbatim). Values under keys named
+# like ``api_key`` / ``authorization`` are redacted. Raw transport payloads still require
+# the LOG_RAW_* toggles below.
+#
 # Verbose diagnostics (avoid logging raw prompts / SSE bodies in production)
 DEBUG_PLATFORM_EDITS=false
 DEBUG_SUBAGENT_STACK=false
@@ -144,7 +149,7 @@ LOG_RAW_API_PAYLOADS=false
 LOG_RAW_SSE_EVENTS=false
 # When true, log full exception text and tracebacks for unhandled errors (may leak request-derived data).
 LOG_API_ERROR_TRACEBACKS=false
-# When true, log message/transcription text previews in messaging adapters (may leak user content).
+# When true, log message/transcription text previews in messaging adapters only (handler ingress always TRACEs verbatim text separately).
 LOG_RAW_MESSAGING_CONTENT=false
 # When true, log full Claude CLI stderr, non-JSON stdout lines, and parser error text.
 LOG_RAW_CLI_DIAGNOSTICS=false

README.md

@@ -406,6 +406,8 @@ LOG_MESSAGING_ERROR_DETAILS=false
 
 Raw logging flags can expose prompts, tool arguments, paths, and model output. Keep them off unless you are debugging locally.
 
+Structured TRACE rows append fields such as `"trace": true`, `stage`, `event`, and `source` and include conversation context needed to follow Claude Code flows end-to-end. Dictionary keys resembling credentials (for example `api_key` / `authorization` values nested in structured payloads) are redacted; arbitrary prose you type into prompts may still appear verbatim.
+
 ### 6. Local Web Tools
 
 ```dotenv

api/app.py

@@ -13,6 +13,7 @@ from starlette.types import Receive, Scope, Send
 
 from config.logging_config import configure_logging
 from config.settings import get_settings
+from core.trace import extract_claude_session_id_from_headers, trace_event
 from providers.exceptions import ProviderError
 
 from .admin_routes import router as admin_router
@@ -95,6 +96,18 @@ def create_app(*, lifespan_enabled: bool = True) -> FastAPI:
         app_kwargs["lifespan"] = lifespan
     app = FastAPI(**app_kwargs)
 
+    @app.middleware("http")
+    async def trace_http_correlation(request: Request, call_next):
+        """Attach HTTP identifiers and optional Claude session id to logs."""
+        claude_sid = extract_claude_session_id_from_headers(request.headers)
+        with logger.contextualize(
+            http_method=request.method,
+            http_path=request.url.path,
+            claude_session_id=claude_sid,
+        ):
+            response = await call_next(request)
+        return response
+
     # Register routes
     app.include_router(admin_router)
     app.include_router(router)
@@ -111,14 +124,16 @@ def create_app(*, lifespan_enabled: bool = True) -> FastAPI:
 
         message_summary, tool_names = summarize_request_validation_body(body)
 
-        logger.debug(
-            "Request validation failed: path={} query={} error_locs={} error_types={} message_summary={} tool_names={}",
-            request.url.path,
-            str(request.url.query),
-            [list(error.get("loc", ())) for error in exc.errors()],
-            [str(error.get("type", "")) for error in exc.errors()],
-            message_summary,
-            tool_names,
+        trace_event(
+            stage="ingress",
+            event="server.request.validation_failed",
+            source="api",
+            path=request.url.path,
+            query=dict(request.query_params),
+            error_locs=[list(error.get("loc", ())) for error in exc.errors()],
+            error_types=[str(error.get("type", "")) for error in exc.errors()],
+            message_summary=message_summary,
+            tool_names=tool_names,
         )
         return await request_validation_exception_handler(request, exc)
 

api/routes.py

@@ -5,6 +5,7 @@ from loguru import logger
 
 from config.settings import Settings
 from core.anthropic import get_token_count
+from core.trace import trace_event
 from providers.registry import ProviderRegistry
 
 from . import dependencies
@@ -231,6 +232,7 @@ async def list_models(
     _auth=Depends(require_api_key),
 ):
     """List the model ids this proxy advertises to Claude-compatible clients."""
+    trace_event(stage="ingress", event="api.models.list", source="api")
     registry = getattr(request.app.state, "provider_registry", None)
     provider_registry = registry if isinstance(registry, ProviderRegistry) else None
     return _build_models_list_response(settings, provider_registry)
@@ -250,5 +252,11 @@ async def stop_cli(request: Request, _auth=Depends(require_api_key)):
         raise HTTPException(status_code=503, detail="Messaging system not initialized")
 
     count = await handler.stop_all_tasks()
+    trace_event(
+        stage="ingress",
+        event="api.cli.stop_via_handler",
+        source="api",
+        cancelled_nodes=count,
+    )
     logger.info("STOP_CLI: source=handler cancelled_count={}", count)
     return {"status": "stopped", "cancelled_count": count}

api/services.py

@@ -14,6 +14,7 @@ from loguru import logger
 from config.settings import Settings
 from core.anthropic import get_token_count, get_user_facing_error_message
 from core.anthropic.sse import ANTHROPIC_SSE_RESPONSE_HEADERS
+from core.trace import api_messages_request_snapshot, trace_event, traced_async_stream
 from providers.base import BaseProvider
 from providers.exceptions import InvalidRequestError, ProviderError
 
@@ -118,7 +119,12 @@ class ClaudeProxyService:
                 input_tokens = self._token_counter(
                     routed.request.messages, routed.request.system, routed.request.tools
                 )
-                logger.info("Optimization: Handling Anthropic web server tool")
+                trace_event(
+                    stage="routing",
+                    event="api.optimization.web_server_tool",
+                    source="api",
+                    model=routed.request.model,
+                )
                 egress = WebFetchEgressPolicy(
                     allow_private_network_targets=self._settings.web_fetch_allow_private_networks,
                     allowed_schemes=self._settings.web_fetch_allowed_scheme_set(),
@@ -134,6 +140,12 @@ class ClaudeProxyService:
 
             optimized = try_optimizations(routed.request, self._settings)
             if optimized is not None:
+                trace_event(
+                    stage="routing",
+                    event="api.optimization.short_circuit",
+                    source="api",
+                    model=routed.request.model,
+                )
                 return optimized
             logger.debug("No optimization matched, routing to provider")
 
@@ -143,29 +155,57 @@ class ClaudeProxyService:
                 thinking_enabled=routed.resolved.thinking_enabled,
             )
 
-            request_id = f"req_{uuid.uuid4().hex[:12]}"
-            logger.info(
-                "API_REQUEST: request_id={} model={} messages={}",
-                request_id,
-                routed.request.model,
-                len(routed.request.messages),
+            trace_event(
+                stage="routing",
+                event="api.route.resolved",
+                source="api",
+                provider_id=routed.resolved.provider_id,
+                provider_model=routed.resolved.provider_model,
+                provider_model_ref=routed.resolved.provider_model_ref,
+                gateway_model=routed.request.model,
+                thinking_enabled=routed.resolved.thinking_enabled,
             )
-            if self._settings.log_raw_api_payloads:
-                logger.debug(
-                    "FULL_PAYLOAD [{}]: {}", request_id, routed.request.model_dump()
+
+            request_id = f"req_{uuid.uuid4().hex[:12]}"
+            with logger.contextualize(request_id=request_id):
+                trace_event(
+                    stage="ingress",
+                    event="api.request.received",
+                    source="api",
+                    message_count=len(routed.request.messages),
+                    snapshot=api_messages_request_snapshot(routed.request),
                 )
 
-            input_tokens = self._token_counter(
-                routed.request.messages, routed.request.system, routed.request.tools
-            )
-            return anthropic_sse_streaming_response(
-                provider.stream_response(
-                    routed.request,
-                    input_tokens=input_tokens,
-                    request_id=request_id,
-                    thinking_enabled=routed.resolved.thinking_enabled,
-                ),
-            )
+                if self._settings.log_raw_api_payloads:
+                    logger.debug(
+                        "FULL_PAYLOAD [{}]: {}", request_id, routed.request.model_dump()
+                    )
+
+                input_tokens = self._token_counter(
+                    routed.request.messages,
+                    routed.request.system,
+                    routed.request.tools,
+                )
+
+                streamed = traced_async_stream(
+                    provider.stream_response(
+                        routed.request,
+                        input_tokens=input_tokens,
+                        request_id=request_id,
+                        thinking_enabled=routed.resolved.thinking_enabled,
+                    ),
+                    stage="egress",
+                    source="api",
+                    complete_event="api.response.stream_completed",
+                    interrupted_event="api.response.stream_interrupted",
+                    chunk_event=None,
+                    extra={
+                        "request_id": request_id,
+                        "provider_id": routed.resolved.provider_id,
+                        "gateway_model": routed.request.model,
+                    },
+                )
+                return anthropic_sse_streaming_response(streamed)
 
         except ProviderError:
             raise
@@ -188,12 +228,23 @@ class ClaudeProxyService:
                 tokens = self._token_counter(
                     routed.request.messages, routed.request.system, routed.request.tools
                 )
-                logger.info(
-                    "COUNT_TOKENS: request_id={} model={} messages={} input_tokens={}",
-                    request_id,
-                    routed.request.model,
-                    len(routed.request.messages),
-                    tokens,
+                trace_event(
+                    stage="routing",
+                    event="api.route.resolved",
+                    source="api",
+                    kind="count_tokens",
+                    provider_id=routed.resolved.provider_id,
+                    provider_model=routed.resolved.provider_model,
+                    provider_model_ref=routed.resolved.provider_model_ref,
+                    gateway_model=routed.request.model,
+                )
+                trace_event(
+                    stage="ingress",
+                    event="api.count_tokens.completed",
+                    source="api",
+                    message_count=len(routed.request.messages),
+                    input_tokens=tokens,
+                    snapshot=api_messages_request_snapshot(routed.request),
                 )
                 return TokenCountResponse(input_tokens=tokens)
             except ProviderError:

cli/manager.py

@@ -56,8 +56,6 @@ class CLISessionManager:
         self._real_to_temp: dict[str, str] = {}
         self._lock = asyncio.Lock()
 
-        logger.info("CLISessionManager initialized")
-
     async def get_or_create_session(
         self, session_id: str | None = None
     ) -> tuple[CLISession, str, bool]:
@@ -87,7 +85,6 @@ class CLISessionManager:
                 log_raw_cli_diagnostics=self._log_raw_cli_diagnostics,
             )
             self._pending_sessions[temp_id] = new_session
-            logger.info(f"Created new session: {temp_id}")
 
             return new_session, temp_id, True
 

cli/session.py

@@ -9,6 +9,8 @@ from typing import Any
 
 from loguru import logger
 
+from core.trace import trace_event
+
 from .process_registry import register_pid, unregister_pid
 
 # Cap stderr capture so a runaway child cannot exhaust memory; pipe is still drained.
@@ -136,7 +138,6 @@ class CLISession:
                     "--dangerously-skip-permissions",
                     "--verbose",
                 ]
-                logger.info(f"Resuming Claude session {session_id}")
             else:
                 cmd = [
                     self.claude_bin,
@@ -147,7 +148,6 @@ class CLISession:
                     "--dangerously-skip-permissions",
                     "--verbose",
                 ]
-                logger.info("Starting new Claude session")
 
             if self.allowed_dirs:
                 for d in self.allowed_dirs:
@@ -157,6 +157,22 @@ class CLISession:
                 settings_json = json.dumps({"plansDirectory": self.plans_directory})
                 cmd.extend(["--settings", settings_json])
 
+            trace_event(
+                stage="claude_cli",
+                event="claude_cli.process.launch",
+                source="claude_cli",
+                resume_session_id=(
+                    session_id
+                    if session_id and not session_id.startswith("pending_")
+                    else None
+                ),
+                fork_session=fork_session,
+                prompt=prompt,
+                cwd=self.workspace,
+                claude_binary=self.claude_bin,
+                cli_argv=cmd,
+            )
+
             try:
                 self.process = await asyncio.create_subprocess_exec(
                     *cmd,

config/logging_config.py

@@ -9,14 +9,26 @@ included at top level for easy grep/filter.
 import json
 import logging
 import re
+import threading
 from pathlib import Path
 
 from loguru import logger
 
 _configured = False
 
-# Context keys we promote to top-level JSON for traceability
-_CONTEXT_KEYS = ("request_id", "node_id", "chat_id")
+# Loguru ``logger.bind()`` key used by structured TRACE payloads; ``core/trace.py``
+# uses the identical string constant ``TRACE_PAYLOAD_BINDING``.
+_TRACE_PAYLOAD_BINDING = "trace_payload"
+
+# Context keys we promote to top-level JSON for traceability / grep
+_CONTEXT_KEYS = (
+    "request_id",
+    "node_id",
+    "chat_id",
+    "claude_session_id",
+    "http_method",
+    "http_path",
+)
 
 _TELEGRAM_BOT_RE = re.compile(
     r"(https?://api\.telegram\.org/)bot([0-9]+:[A-Za-z0-9_-]+)(/?)",
@@ -48,9 +60,16 @@ def _serialize_with_context(record) -> str:
         "function": record["function"],
         "line": record["line"],
     }
+    trace_payload = extra.get(_TRACE_PAYLOAD_BINDING)
     for key in _CONTEXT_KEYS:
         if key in extra and extra[key] is not None:
             out[key] = extra[key]
+    if isinstance(trace_payload, dict):
+        for tk, tv in trace_payload.items():
+            if tk in out:
+                continue
+            out[tk] = tv
+        out["trace"] = True
     record["_json"] = json.dumps(out, default=str)
     return "{_json}\n"
 
@@ -58,20 +77,31 @@ def _serialize_with_context(record) -> str:
 class InterceptHandler(logging.Handler):
     """Redirect stdlib logging to loguru."""
 
+    def __init__(self) -> None:
+        super().__init__()
+        self._local = threading.local()
+
     def emit(self, record: logging.LogRecord) -> None:
+        if getattr(self._local, "active", False):
+            # Avoid deadlock when nested stdlib records fire during a loguru emit.
+            return
+        self._local.active = True
         try:
-            level = logger.level(record.levelname).name
-        except ValueError:
-            level = record.levelno
+            try:
+                level = logger.level(record.levelname).name
+            except ValueError:
+                level = record.levelno
 
-        frame, depth = logging.currentframe(), 2
-        while frame is not None and frame.f_code.co_filename == logging.__file__:
-            frame = frame.f_back
-            depth += 1
+            frame, depth = logging.currentframe(), 2
+            while frame is not None and frame.f_code.co_filename == logging.__file__:
+                frame = frame.f_back
+                depth += 1
 
-        logger.opt(depth=depth, exception=record.exc_info).log(
-            level, record.getMessage()
-        )
+            logger.opt(depth=depth, exception=record.exc_info).log(
+                level, record.getMessage()
+            )
+        finally:
+            self._local.active = False
 
 
 def configure_logging(
@@ -104,6 +134,7 @@ def configure_logging(
         encoding="utf-8",
         mode="a",
         rotation="50 MB",
+        enqueue=True,
     )
 
     # Intercept stdlib logging: route all root logger output to loguru

core/anthropic/sse.py

@@ -187,12 +187,6 @@ class SSEBuilder:
         event_str = format_sse_event(event_type, data)
         if self._log_raw_events:
             logger.debug("SSE_EVENT: {} - {}", event_type, event_str.strip())
-        else:
-            logger.debug(
-                "SSE_EVENT: event_type={} serialized_bytes={}",
-                event_type,
-                len(event_str.encode("utf-8")),
-            )
         return event_str
 
     def message_start(self) -> str:

core/trace.py

@@ -0,0 +1,214 @@
+"""Structured TRACE events for end-to-end request / CLI / provider logging.
+
+Emitted lines are merged into JSON log rows by ``config.logging_config``.
+Conversation and Claude Code prompts are logged verbatim unless values live under
+sanitized credential keys (e.g. ``api_key``, ``authorization``).
+"""
+
+from __future__ import annotations
+
+import asyncio
+from collections.abc import AsyncIterator, Mapping
+from typing import Any
+
+from loguru import logger
+
+TRACE_PAYLOAD_BINDING = "trace_payload"
+
+_SECRET_VALUE_KEYS = frozenset(
+    k.lower()
+    for k in (
+        "authorization",
+        "x-api-key",
+        "anthropic-auth-token",
+        "api_key",
+        "password",
+        "secret",
+        "token",
+        "bearer_token",
+        "openapi_token",
+        "nvidia-api-key",
+    )
+)
+
+
+def _sanitize_trace_value(obj: Any) -> Any:
+    """Recursively copy JSON-like structures redacting credential-shaped keys."""
+    if isinstance(obj, Mapping):
+        out: dict[str, Any] = {}
+        for k, v in obj.items():
+            if str(k).lower() in _SECRET_VALUE_KEYS:
+                out[str(k)] = "<redacted>"
+            else:
+                out[str(k)] = _sanitize_trace_value(v)
+        return out
+    if isinstance(obj, tuple | list):
+        return [_sanitize_trace_value(x) for x in obj]
+    return obj
+
+
+def trace_event(*, stage: str, event: str, source: str, **fields: Any) -> None:
+    """Emit one structured TRACE row (merged into JSON by the log sink)."""
+    payload = _sanitize_trace_value(
+        {
+            "stage": stage,
+            "event": event,
+            "source": source,
+            **fields,
+        },
+    )
+    logger.bind(trace_payload=payload).info("TRACE {}", event)
+
+
+def api_messages_request_snapshot(req: Any) -> dict[str, Any]:
+    """Return a sanitized snapshot of an Anthropic ``MessagesRequest``-like body."""
+    if hasattr(req, "model_dump"):
+        data = req.model_dump(mode="python")
+    elif isinstance(req, Mapping):
+        data = dict(req)
+    else:
+        data = {}
+
+    snapshot: dict[str, Any] = {}
+    for key in (
+        "model",
+        "messages",
+        "system",
+        "tools",
+        "tool_choice",
+        "max_tokens",
+        "thinking",
+        "temperature",
+        "top_p",
+        "top_k",
+        "stop_sequences",
+        "metadata",
+        "stream",
+        "thinking_enabled",
+    ):
+        if key in data and data[key] is not None:
+            snapshot[key] = data[key]
+    return _sanitize_trace_value(snapshot)
+
+
+def extract_claude_session_id_from_headers(headers: Mapping[str, str]) -> str | None:
+    """Best-effort session id forwarded by Claude Code / SDK via HTTP."""
+    lowered = {str(k).lower(): v for k, v in headers.items() if isinstance(v, str)}
+    for key in (
+        "anthropic-session-id",
+        "x-anthropic-session-id",
+        "claude-session-id",
+        "x-claude-session-id",
+    ):
+        candidate = lowered.get(key)
+        if candidate:
+            return candidate
+    return None
+
+
+async def traced_async_stream(
+    agen: AsyncIterator[str],
+    *,
+    stage: str,
+    source: str,
+    complete_event: str,
+    interrupted_event: str,
+    chunk_event: str | None = None,
+    chunk_interval: int = 250,
+    extra: Mapping[str, Any] | None = None,
+) -> AsyncIterator[str]:
+    """Emit TRACE rows when a text stream completes, fails, cancels, or periodically."""
+    common = dict(extra or {})
+    count = 0
+    nbytes = 0
+    interrupted = False
+    try:
+        async for chunk in agen:
+            count += 1
+            nbytes += len(chunk.encode("utf-8", errors="replace"))
+            if chunk_event and chunk_interval > 0 and count % chunk_interval == 0:
+                trace_event(
+                    stage=stage,
+                    event=chunk_event,
+                    source=source,
+                    stream_chunks_so_far=count,
+                    stream_bytes_so_far=nbytes,
+                    **common,
+                )
+            yield chunk
+    except asyncio.CancelledError:
+        interrupted = True
+        trace_event(
+            stage=stage,
+            event=interrupted_event,
+            source=source,
+            stream_chunks=count,
+            stream_bytes=nbytes,
+            outcome="cancelled",
+            **common,
+        )
+        raise
+    except BaseExceptionGroup as grp:
+        interrupted = True
+        trace_event(
+            stage=stage,
+            event=interrupted_event,
+            source=source,
+            stream_chunks=count,
+            stream_bytes=nbytes,
+            outcome="exception_group",
+            note=str(grp),
+            **common,
+        )
+        raise
+    except BaseException as exc:
+        interrupted = True
+        trace_event(
+            stage=stage,
+            event=interrupted_event,
+            source=source,
+            stream_chunks=count,
+            stream_bytes=nbytes,
+            outcome="error",
+            exc_type=type(exc).__name__,
+            **common,
+        )
+        raise
+
+    if not interrupted:
+        trace_event(
+            stage=stage,
+            event=complete_event,
+            source=source,
+            stream_chunks=count,
+            stream_bytes=nbytes,
+            outcome="ok",
+            **common,
+        )
+
+
+def provider_chat_body_snapshot(body: Mapping[str, Any]) -> dict[str, Any]:
+    """Sanitized OpenAI-compat chat body subset for traces (conversation text verbatim)."""
+    keys = ("model", "messages", "tools", "tool_choice", "temperature", "max_tokens")
+    snap = {k: body[k] for k in keys if k in body and body[k] is not None}
+    return _sanitize_trace_value(snap)
+
+
+def provider_native_messages_body_snapshot(body: Mapping[str, Any]) -> dict[str, Any]:
+    """Sanitized Anthropic Messages API body subset for traces."""
+    keys = (
+        "model",
+        "messages",
+        "system",
+        "tools",
+        "tool_choice",
+        "max_tokens",
+        "thinking",
+        "metadata",
+        "temperature",
+        "top_p",
+        "top_k",
+        "stop_sequences",
+    )
+    snap = {k: body[k] for k in keys if k in body and body[k] is not None}
+    return _sanitize_trace_value(snap)

messaging/handler.py

@@ -11,6 +11,7 @@ import asyncio
 from loguru import logger
 
 from core.anthropic import format_user_error_preview, get_user_facing_error_message
+from core.trace import trace_event
 
 from .cli_event_constants import STATUS_MESSAGE_PREFIXES
 from .command_dispatcher import (
@@ -102,26 +103,17 @@ class ClaudeMessageHandler:
         Determines if this is a new conversation or reply,
         creates/extends the message tree, and queues for processing.
         """
-        raw = incoming.text or ""
-        if self._log_raw_messaging_content:
-            text_preview = raw[:80]
-            if len(raw) > 80:
-                text_preview += "..."
-            logger.info(
-                "HANDLER_ENTRY: chat_id={} message_id={} reply_to={} text_preview={!r}",
-                incoming.chat_id,
-                incoming.message_id,
-                incoming.reply_to_message_id,
-                text_preview,
-            )
-        else:
-            logger.info(
-                "HANDLER_ENTRY: chat_id={} message_id={} reply_to={} text_len={}",
-                incoming.chat_id,
-                incoming.message_id,
-                incoming.reply_to_message_id,
-                len(raw),
-            )
+        platform_name = getattr(self.platform, "name", "messaging")
+        trace_event(
+            stage="ingress",
+            event="turn.received",
+            source=platform_name,
+            chat_id=incoming.chat_id,
+            platform_message_id=incoming.message_id,
+            reply_to_message_id=incoming.reply_to_message_id,
+            thread_id=getattr(incoming, "message_thread_id", None),
+            message_text=incoming.text or "",
+        )
 
         with logger.contextualize(
             chat_id=incoming.chat_id, node_id=incoming.message_id
@@ -240,8 +232,16 @@ class ClaudeMessageHandler:
         )
 
         if was_queued and status_msg_id:
-            # Update status to show queue position
             queue_size = self.tree_queue.get_queue_size(node_id)
+            trace_event(
+                stage="routing",
+                event="turn.queued",
+                source=getattr(self.platform, "name", "messaging"),
+                chat_id=incoming.chat_id,
+                platform_message_id=node_id,
+                status_message_id=status_msg_id,
+                queue_size=queue_size,
+            )
             await self.platform.queue_edit_message(
                 incoming.chat_id,
                 status_msg_id,
@@ -343,10 +343,18 @@ class ClaudeMessageHandler:
         last_status: str | None = None
 
         parent_session_id = None
+        platform_nm = getattr(self.platform, "name", "messaging")
         if tree and node.parent_id:
             parent_session_id = tree.get_parent_session_id(node_id)
             if parent_session_id:
-                logger.info(f"Will fork from parent session: {parent_session_id}")
+                trace_event(
+                    stage="claude_cli",
+                    event="claude_cli.fork.from_parent_session",
+                    source=platform_nm,
+                    chat_id=chat_id,
+                    node_id=node_id,
+                    parent_session_id=parent_session_id,
+                )
 
         editor = ThrottledTranscriptEditor(
             platform=self.platform,
@@ -377,6 +385,33 @@ class ClaudeMessageHandler:
                     temp_session_id = session_or_temp_id
                 else:
                     captured_session_id = session_or_temp_id
+
+                sess_evt = (
+                    "claude_cli.session.pending_created"
+                    if is_new
+                    else "claude_cli.session.reused"
+                )
+                trace_event(
+                    stage="claude_cli",
+                    event=sess_evt,
+                    source=platform_nm,
+                    chat_id=chat_id,
+                    node_id=node_id,
+                    status_message_id=status_msg_id,
+                    session_handle=str(session_or_temp_id),
+                    parent_resume_session_id=parent_session_id,
+                    fork_requested=bool(parent_session_id),
+                )
+                trace_event(
+                    stage="claude_cli",
+                    event="claude_cli.request.sent",
+                    source=platform_nm,
+                    chat_id=chat_id,
+                    node_id=node_id,
+                    prompt=incoming.text,
+                    fork_session_arg=bool(parent_session_id),
+                    resume_session_arg=parent_session_id,
+                )
             except RuntimeError as e:
                 error_message = get_user_facing_error_message(e)
                 transcript.apply({"type": "error", "message": error_message})
@@ -390,10 +425,15 @@ class ClaudeMessageHandler:
                         MessageState.ERROR,
                         error_message=error_message,
                     )
+                trace_event(
+                    stage="claude_cli",
+                    event="claude_cli.session.limit_reached",
+                    source=platform_nm,
+                    chat_id=chat_id,
+                    node_id=node_id,
+                )
                 return
 
-            logger.info(f"HANDLER: Starting CLI task processing for node {node_id}")
-            event_count = 0
             async for event_data in cli_session.start_task(
                 incoming.text,
                 session_id=parent_session_id,
@@ -404,9 +444,6 @@ class ClaudeMessageHandler:
                         f"HANDLER: Non-dict event received: {type(event_data)}"
                     )
                     continue
-                event_count += 1
-                if event_count % 10 == 0:
-                    logger.debug(f"HANDLER: Processed {event_count} events so far")
 
                 (
                     captured_session_id,
@@ -426,7 +463,6 @@ class ClaudeMessageHandler:
                 parsed_list = parse_cli_event(
                     event_data, log_raw_cli=self._log_raw_cli_diagnostics
                 )
-                logger.debug(f"HANDLER: Parsed {len(parsed_list)} events from CLI")
 
                 for parsed in parsed_list:
                     (
@@ -448,6 +484,13 @@ class ClaudeMessageHandler:
                     )
 
         except asyncio.CancelledError:
+            trace_event(
+                stage="claude_cli",
+                event="turn.processor.cancelled",
+                source=platform_nm,
+                chat_id=chat_id,
+                node_id=node_id,
+            )
             logger.warning(f"HANDLER: Task cancelled for node {node_id}")
             cancel_reason = None
             if isinstance(node.context, dict):
@@ -466,6 +509,14 @@ class ClaudeMessageHandler:
                     node_id, MessageState.ERROR, error_message="Cancelled by user"
                 )
         except Exception as e:
+            trace_event(
+                stage="claude_cli",
+                event="turn.processor.exception",
+                source=platform_nm,
+                chat_id=chat_id,
+                node_id=node_id,
+                exc_type=type(e).__name__,
+            )
             logger.error(
                 "HANDLER: Task failed with exception: {}",
                 format_exception_for_log(
@@ -480,7 +531,14 @@ class ClaudeMessageHandler:
                     node_id, error_msg, "Parent task failed"
                 )
         finally:
-            logger.info(f"HANDLER: _process_node completed for node {node_id}")
+            trace_event(
+                stage="routing",
+                event="turn.processor.finished",
+                source=platform_nm,
+                chat_id=chat_id,
+                node_id=node_id,
+                claude_session_id=captured_session_id or temp_session_id,
+            )
             # Free the session-manager slot. Session IDs are persisted in the tree and
             # can be resumed later by ID; we don't need to keep a CLISession instance
             # around after this node completes.

messaging/node_event_pipeline.py

@@ -7,6 +7,8 @@ from typing import Any
 
 from loguru import logger
 
+from core.trace import trace_event
+
 from .cli_event_constants import TRANSCRIPT_EVENT_TYPES, get_status_for_event
 from .platforms.base import SessionManagerInterface
 from .safe_diagnostics import text_len_hint
@@ -34,6 +36,15 @@ async def handle_session_info_event(
         return captured_session_id, temp_session_id
 
     await cli_manager.register_real_session_id(temp_session_id, real_session_id)
+    trace_event(
+        stage="claude_cli",
+        event="claude_cli.session.registered",
+        source="claude_cli",
+        node_id=node_id,
+        temp_session_id=temp_session_id,
+        real_session_id=real_session_id,
+        tree_root_id=tree.root_id if tree else None,
+    )
     if tree and real_session_id:
         await tree.update_state(
             node_id,
@@ -76,7 +87,13 @@ async def process_parsed_cli_event(
     elif ptype == "complete":
         if not had_transcript_events:
             transcript.apply({"type": "text_chunk", "text": "Done."})
-        logger.info("HANDLER: Task complete, updating UI")
+        trace_event(
+            stage="claude_cli",
+            event="turn.completed",
+            source="cli_event",
+            node_id=node_id,
+            claude_session_id=captured_session_id,
+        )
         await update_ui(format_status("✅", "Complete"), force=True)
         if tree and captured_session_id:
             await tree.update_state(
@@ -87,15 +104,22 @@ async def process_parsed_cli_event(
             session_store.save_tree(tree.root_id, tree.to_dict())
     elif ptype == "error":
         error_msg = parsed.get("message", "Unknown error")
+        em = error_msg if isinstance(error_msg, str) else str(error_msg)
+        trace_event(
+            stage="claude_cli",
+            event="turn.failed",
+            source="cli_event",
+            node_id=node_id,
+            claude_session_id=captured_session_id,
+            cli_error_message=em,
+        )
         if log_messaging_error_details:
             logger.error("HANDLER: Error event received: {}", error_msg)
         else:
-            em = error_msg if isinstance(error_msg, str) else str(error_msg)
             logger.error(
                 "HANDLER: Error event received: message_chars={}",
                 text_len_hint(em),
             )
-        logger.info("HANDLER: Updating UI with error status")
         await update_ui(format_status("❌", "Error"), force=True)
         if tree:
             await propagate_error_to_children(node_id, error_msg, "Parent task failed")

providers/anthropic_messages.py

@@ -21,6 +21,7 @@ from core.anthropic.native_sse_block_policy import (
     NativeSseBlockPolicyState,
     transform_native_sse_block_event,
 )
+from core.trace import provider_native_messages_body_snapshot, trace_event
 from providers.base import BaseProvider, ProviderConfig
 from providers.error_mapping import (
     map_error,
@@ -338,13 +339,16 @@ class AnthropicMessagesTransport(BaseProvider):
         body = self._build_request_body(request, thinking_enabled=thinking_enabled)
         thinking_enabled = self._is_thinking_enabled(request, thinking_enabled)
 
-        logger.info(
-            "{}_STREAM:{} natively passing Anthropic request model={} msgs={} tools={}",
-            tag,
-            req_tag,
-            body.get("model"),
-            len(body.get("messages", [])),
-            len(body.get("tools", [])),
+        trace_event(
+            stage="provider",
+            event="provider.request.sent",
+            source="provider",
+            provider=self._provider_name,
+            gateway_model=request.model,
+            downstream_model=body.get("model"),
+            message_count=len(body.get("messages", [])),
+            tool_count=len(body.get("tools", [])),
+            body=provider_native_messages_body_snapshot(body),
         )
 
         response: httpx.Response | None = None
@@ -373,28 +377,48 @@ class AnthropicMessagesTransport(BaseProvider):
                     _validated_stream_send
                 )
 
+                chunk_count = 0
+                chunk_bytes = 0
+
                 async for chunk in self._iter_stream_chunks(
                     response,
                     state=state,
                     thinking_enabled=thinking_enabled,
                 ):
+                    chunk_count += 1
+                    chunk_bytes += len(chunk.encode("utf-8", errors="replace"))
                     sent_any_event = True
                     emitted_tracker.feed(chunk)
                     yield chunk
 
+                trace_event(
+                    stage="provider",
+                    event="provider.response.completed",
+                    source="provider",
+                    provider=self._provider_name,
+                    gateway_model=request.model,
+                    sse_chunks_out=chunk_count,
+                    sse_bytes_out=chunk_bytes,
+                )
+
             except Exception as error:
                 if not isinstance(error, httpx.HTTPStatusError):
-                    self._log_stream_transport_error(tag, req_tag, error)
+                    self._log_stream_transport_error(
+                        tag, req_tag, error, request_id=request_id
+                    )
                 error_message = self._get_error_message(error, request_id)
 
                 if response is not None and not response.is_closed:
                     await response.aclose()
 
-                logger.info(
-                    "{}_STREAM: Emitting native SSE error event for {}{}",
-                    tag,
-                    type(error).__name__,
-                    req_tag,
+                trace_event(
+                    stage="provider",
+                    event="provider.response.error",
+                    source="provider",
+                    provider=self._provider_name,
+                    error_message=error_message,
+                    exc_type=type(error).__name__,
+                    mid_stream=sent_any_event,
                 )
                 if sent_any_event:
                     for event in emitted_tracker.iter_close_unclosed_blocks():

providers/base.py

@@ -80,26 +80,43 @@ class BaseProvider(ABC):
         build(request, thinking_enabled=thinking_enabled)
 
     def _log_stream_transport_error(
-        self, tag: str, req_tag: str, error: Exception
+        self,
+        tag: str,
+        req_tag: str,
+        error: Exception,
+        *,
+        request_id: str | None = None,
     ) -> None:
         """Log streaming transport failures (metadata-only unless verbose is enabled)."""
         from loguru import logger
 
+        from core.trace import trace_event
+
+        response = getattr(error, "response", None)
+        http_status = (
+            getattr(response, "status_code", None) if response is not None else None
+        )
+        trace_event(
+            stage="provider",
+            event="provider.response.transport_error",
+            source="provider",
+            provider=tag,
+            request_id=request_id,
+            exc_type=type(error).__name__,
+            http_status=http_status,
+        )
+
         if self._config.log_api_error_tracebacks:
             logger.error(
                 "{}_ERROR:{} {}: {}", tag, req_tag, type(error).__name__, error
             )
             return
-        response = getattr(error, "response", None)
-        status_code = (
-            getattr(response, "status_code", None) if response is not None else None
-        )
         logger.error(
             "{}_ERROR:{} exc_type={} http_status={}",
             tag,
             req_tag,
             type(error).__name__,
-            status_code,
+            http_status,
         )
 
     @abstractmethod

providers/openai_compat.py

@@ -23,6 +23,7 @@ from core.anthropic import (
     append_request_id,
     map_stop_reason,
 )
+from core.trace import provider_chat_body_snapshot, trace_event
 from providers.base import BaseProvider, ProviderConfig
 from providers.error_mapping import (
     map_error,
@@ -353,13 +354,16 @@ class OpenAIChatTransport(BaseProvider):
         body = self._build_request_body(request, thinking_enabled=thinking_enabled)
         thinking_enabled = self._is_thinking_enabled(request, thinking_enabled)
         req_tag = f" request_id={request_id}" if request_id else ""
-        logger.info(
-            "{}_STREAM:{} model={} msgs={} tools={}",
-            tag,
-            req_tag,
-            body.get("model"),
-            len(body.get("messages", [])),
-            len(body.get("tools", [])),
+        trace_event(
+            stage="provider",
+            event="provider.request.sent",
+            source="provider",
+            provider=self._provider_name,
+            gateway_model=request.model,
+            downstream_model=body.get("model"),
+            message_count=len(body.get("messages", [])),
+            tool_count=len(body.get("tools", [])),
+            body=provider_chat_body_snapshot(body),
         )
 
         yield sse.message_start()
@@ -455,7 +459,7 @@ class OpenAIChatTransport(BaseProvider):
             except asyncio.CancelledError, GeneratorExit:
                 raise
             except Exception as e:
-                self._log_stream_transport_error(tag, req_tag, e)
+                self._log_stream_transport_error(tag, req_tag, e, request_id=request_id)
                 mapped_e = map_error(e, rate_limiter=self._global_rate_limiter)
                 base_message = user_visible_message_for_mapped_provider_error(
                     mapped_e,
@@ -463,11 +467,13 @@ class OpenAIChatTransport(BaseProvider):
                     read_timeout_s=self._config.http_read_timeout,
                 )
                 error_message = append_request_id(base_message, request_id)
-                logger.info(
-                    "{}_STREAM: Emitting SSE error event for {}{}",
-                    tag,
-                    type(e).__name__,
-                    req_tag,
+                trace_event(
+                    stage="provider",
+                    event="provider.response.error",
+                    source="provider",
+                    provider=tag,
+                    error_message=error_message,
+                    mapped_error_type=type(mapped_e).__name__,
                 )
                 for event in sse.close_all_blocks():
                     yield event
@@ -552,5 +558,14 @@ class OpenAIChatTransport(BaseProvider):
                     provider_input,
                     provider_input - input_tokens,
                 )
+        trace_event(
+            stage="provider",
+            event="provider.response.completed",
+            source="provider",
+            provider=self._provider_name,
+            finish_reason=(None if finish_reason is None else str(finish_reason)),
+            output_tokens=output_tokens,
+            prompt_tokens_estimate=input_tokens,
+        )
         yield sse.message_delta(map_stop_reason(finish_reason), output_tokens)
         yield sse.message_stop()

tests/api/test_safe_logging.py

@@ -70,11 +70,7 @@ def test_sse_builder_default_debug_has_no_serialized_json_content():
         sse = SSEBuilder("msg_x", "m", 1, log_raw_events=False)
         sse.message_start()
 
-    assert mock_debug.call_count == 1
-    message = str(mock_debug.call_args)
-    assert "serialized_bytes=" in message
-    assert "role" not in message
-    assert "assistant" not in message
+    assert mock_debug.call_count == 0
 
 
 def test_sse_builder_raw_logging_includes_event_body_when_enabled():

tests/core/test_trace.py

@@ -0,0 +1,38 @@
+"""Structured TRACE logging assertions."""
+
+from __future__ import annotations
+
+import json
+from pathlib import Path
+
+from loguru import logger
+
+from config.logging_config import configure_logging
+from core.trace import TRACE_PAYLOAD_BINDING, trace_event
+
+
+def test_trace_payload_merged_into_json_line(tmp_path) -> None:
+    log_file = str(tmp_path / "t.log")
+    configure_logging(log_file, force=True)
+    trace_event(stage="s", event="e.v1", source="unit", hello="world", n=42)
+    logger.complete()
+    text = Path(log_file).read_text(encoding="utf-8").strip().split("\n")[-1]
+    row = json.loads(text)
+    assert row["trace"] is True
+    assert row["stage"] == "s"
+    assert row["event"] == "e.v1"
+    assert row["source"] == "unit"
+    assert row["hello"] == "world"
+    assert row["n"] == 42
+    assert TRACE_PAYLOAD_BINDING == "trace_payload"
+
+
+def test_sanitize_masks_nested_api_key_strings() -> None:
+    """Credential-shaped keys redact without touching normal message text."""
+    from core.trace import _sanitize_trace_value
+
+    out = _sanitize_trace_value(
+        {"outer": {"api_key": "secret", "text": "visible"}},
+    )
+    assert out["outer"]["api_key"] == "<redacted>"
+    assert out["outer"]["text"] == "visible"

tests/messaging/test_handler.py

@@ -14,10 +14,11 @@ def handler(mock_platform, mock_cli_manager, mock_session_store):
 
 
 @pytest.mark.asyncio
-async def test_handle_message_default_logs_text_len_not_content(
+async def test_handle_message_turn_trace_includes_full_message_text(
     mock_platform, mock_cli_manager, mock_session_store, incoming_message_factory
 ):
-    secret = "user-secret-content-never-log-default"
+    """turn.received always records the verbatim user message (local debugging)."""
+    secret = "user-message-content-visible-in-trace"
     handler = ClaudeMessageHandler(
         mock_platform,
         mock_cli_manager,
@@ -27,33 +28,33 @@ async def test_handle_message_default_logs_text_len_not_content(
     incoming = incoming_message_factory(text=secret)
     with (
         patch.object(handler, "_handle_message_impl", new_callable=AsyncMock),
-        patch("messaging.handler.logger.info") as log_info,
+        patch("messaging.handler.trace_event") as trace_mock,
     ):
         await handler.handle_message(incoming)
-    blob = " ".join(str(c) for c in log_info.call_args_list)
-    assert secret not in blob
-    assert "text_len=" in blob
+    kwargs = trace_mock.call_args.kwargs
+    assert kwargs["event"] == "turn.received"
+    assert kwargs["message_text"] == secret
 
 
 @pytest.mark.asyncio
-async def test_handle_message_raw_content_logging_includes_preview(
+async def test_handle_message_log_raw_messaging_does_not_change_turn_received_shape(
     mock_platform, mock_cli_manager, mock_session_store, incoming_message_factory
 ):
-    secret = "visible-preview-xyz"
+    """LOG_RAW_MESSAGING_CONTENT is adapter-only; ingress TRACE always includes text."""
+    text = "visible-either-way"
     handler = ClaudeMessageHandler(
         mock_platform,
         mock_cli_manager,
         mock_session_store,
         log_raw_messaging_content=True,
     )
-    incoming = incoming_message_factory(text=secret)
+    incoming = incoming_message_factory(text=text)
     with (
         patch.object(handler, "_handle_message_impl", new_callable=AsyncMock),
-        patch("messaging.handler.logger.info") as log_info,
+        patch("messaging.handler.trace_event") as trace_mock,
     ):
         await handler.handle_message(incoming)
-    blob = " ".join(str(c) for c in log_info.call_args_list)
-    assert secret in blob
+    assert trace_mock.call_args.kwargs["message_text"] == text
 
 
 def test_get_initial_status_new_conversation(handler):