diff --git a/src/agentex/lib/core/tracing/obs_ids.py b/src/agentex/lib/core/tracing/obs_ids.py
deleted file mode 100644
index 1be803a84..000000000
--- a/src/agentex/lib/core/tracing/obs_ids.py
+++ /dev/null
@@ -1,83 +0,0 @@
-"""Correlate adk business spans with the active observability trace.
-
-The adk business ``trace_id`` is the agent **task id** (run-level: it spans the
-whole agent run across many requests -- task/create, then each message/send turn),
-so we must NOT overwrite it with a per-request observability trace_id. Doing so
-would collapse the run-level grouping.
-
-Instead, each business span is *tagged* with the active observability
-trace_id/span_id (this is the OpenTelemetry "span link" pattern -- correlate
-across trace granularities rather than merging them). You can then pivot from a
-persisted business span to the Tempo/Datadog trace for the turn that produced it,
-while the business trace still groups the entire run by task id.
-
-Source selection follows SGP_OBS_MODE, matching egp-api-backend:
-  - unset / "dd_only": ddtrace context (current stack)
-  - "dual":            OTel/LGTM preferred, ddtrace fallback
-  - "lgtm":            OTel/LGTM only
-
-This never fabricates ids -- if no observability context is active, it returns
-an empty dict and the span is simply not tagged.
-"""
-from __future__ import annotations
-
-import os
-from typing import Dict, Optional, Tuple
-
-__all__ = ("get_obs_mode", "obs_correlation")
-
-DD_ONLY = "dd_only"
-DUAL = "dual"
-LGTM = "lgtm"
-_DEFAULT_MODE = DD_ONLY
-_VALID_MODES = (DD_ONLY, DUAL, LGTM)
-
-
-def get_obs_mode() -> str:
-    """Unset/empty/unrecognized -> ``dd_only`` (current behavior)."""
-    raw = os.getenv("SGP_OBS_MODE")
-    if not raw:
-        return _DEFAULT_MODE
-    mode = raw.strip().lower()
-    return mode if mode in _VALID_MODES else _DEFAULT_MODE
-
-
-def _lgtm_ids() -> Optional[Tuple[str, str]]:
-    try:
-        from opentelemetry import trace
-    except ImportError:
-        return None
-    ctx = trace.get_current_span().get_span_context()
-    if ctx and ctx.is_valid:
-        return format(ctx.trace_id, "032x"), format(ctx.span_id, "016x")
-    return None
-
-
-def _ddtrace_ids() -> Optional[Tuple[str, str]]:
-    try:
-        from ddtrace import tracer
-    except ImportError:
-        return None
-    ctx = tracer.current_trace_context()
-    if ctx and ctx.trace_id:
-        return format(ctx.trace_id, "032x"), format(ctx.span_id or 0, "016x")
-    return None
-
-
-def obs_correlation() -> Dict[str, str]:
-    """Return ``{"obs.trace_id": ..., "obs.span_id": ...}`` for the active
-    observability context, or ``{}`` if none is active.
-
-    Never fabricates ids -- this is a correlation tag, not the span's id.
-    """
-    mode = get_obs_mode()
-    if mode == LGTM:
-        ids = _lgtm_ids()
-    elif mode == DUAL:
-        ids = _lgtm_ids() or _ddtrace_ids()
-    else:  # dd_only
-        ids = _ddtrace_ids()
-
-    if not ids:
-        return {}
-    return {"obs.trace_id": ids[0], "obs.span_id": ids[1]}
diff --git a/src/agentex/lib/core/tracing/trace.py b/src/agentex/lib/core/tracing/trace.py
index c3ec91bc3..a22bfd658 100644
--- a/src/agentex/lib/core/tracing/trace.py
+++ b/src/agentex/lib/core/tracing/trace.py
@@ -11,7 +11,6 @@
 from agentex.types.span import Span
 from agentex.lib.utils.logging import make_logger
 from agentex.lib.utils.model_utils import recursive_model_dump
-from agentex.lib.core.tracing.obs_ids import obs_correlation
 from agentex.lib.core.tracing.span_error import set_span_error
 from agentex.lib.core.tracing.span_queue import (
     SpanEventType,
@@ -80,12 +79,6 @@ def start_span(
 
         serialized_input = recursive_model_dump(input) if input else None
         serialized_data = recursive_model_dump(data) if data else None
-        # Tag the business span with the active observability trace_id/span_id
-        # (OTel/ddtrace) so it can be correlated to the per-turn obs trace. The
-        # business trace_id stays the run-level task id -- see obs_ids.py.
-        obs = obs_correlation()
-        if obs:
-            serialized_data = {**(serialized_data or {}), **obs}
         id = str(uuid.uuid4())
 
         span = Span(
@@ -236,12 +229,6 @@ async def start_span(
 
         serialized_input = recursive_model_dump(input) if input else None
         serialized_data = recursive_model_dump(data) if data else None
-        # Tag the business span with the active observability trace_id/span_id
-        # (OTel/ddtrace) so it can be correlated to the per-turn obs trace. The
-        # business trace_id stays the run-level task id -- see obs_ids.py.
-        obs = obs_correlation()
-        if obs:
-            serialized_data = {**(serialized_data or {}), **obs}
         id = str(uuid.uuid4())
 
         span = Span(