diff --git a/headroom/transforms/content_detector.py b/headroom/transforms/content_detector.py
index 5e364fed6..bb8325e42 100644
--- a/headroom/transforms/content_detector.py
+++ b/headroom/transforms/content_detector.py
@@ -457,6 +457,23 @@ def _try_detect_html(content: str) -> DetectionResult | None:
     )
 
 
+def _is_search_result_line(line: str) -> bool:
+    """True when a line looks like ``path:line:content`` grep output.
+
+    The bare ``^[^\\s:]+:\\d+:`` shape also matches ISO-8601 timestamps
+    (``…T09:57:59…``) and XML-ish wrappers harnesses prepend to user turns
+    (Copilot CLI's ``<current_datetime>…`` line), which misroutes prose to
+    the SearchCompressor — and that compressor keeps only matching lines,
+    deleting the rest. So the pre-colon segment must additionally look like
+    a file path: no angle brackets and no ``=`` (rules out markup tags and
+    ``key=value:12:`` log lines).
+    """
+    if not _SEARCH_RESULT_PATTERN.match(line):
+        return False
+    prefix = line.split(":", 1)[0]
+    return "<" not in prefix and ">" not in prefix and "=" not in prefix
+
+
 def _try_detect_search(content: str) -> DetectionResult | None:
     """Try to detect grep/ripgrep search results."""
     lines = content.split("\n")[:100]  # Check first 100 lines
@@ -465,10 +482,16 @@ def _try_detect_search(content: str) -> DetectionResult | None:
 
     matching_lines = 0
     for line in lines:
-        if line.strip() and _SEARCH_RESULT_PATTERN.match(line):
+        if line.strip() and _is_search_result_line(line):
             matching_lines += 1
 
-    if matching_lines == 0:
+    # Absolute floor: a single coincidental `word:digits:` line (a timestamp,
+    # a URL, a time literal inside prose) must not classify a whole payload as
+    # search results — the SearchCompressor drops every non-matching line, so
+    # a false positive is data loss. A genuine one-line grep result loses
+    # nothing by staying uncompressed: all of its lines match, so the
+    # compressor would have kept it verbatim anyway.
+    if matching_lines < 2:
         return None
 
     # Calculate confidence based on proportion of matching lines
diff --git a/tests/test_transforms_content_detection.py b/tests/test_transforms_content_detection.py
index 1201c2a60..e74776292 100644
--- a/tests/test_transforms_content_detection.py
+++ b/tests/test_transforms_content_detection.py
@@ -170,6 +170,49 @@ def test_search_detection_uses_match_ratio() -> None:
     assert _try_detect_search("\n\n") is None
 
 
+def test_search_detection_rejects_datetime_prefixed_user_message() -> None:
+    """Regression: wrap-copilot ate one-line interactive prompts (2026-08-23).
+
+    Copilot CLI prepends ``<current_datetime>…</current_datetime>`` to every
+    interactive user turn. The ISO-8601 ``T09:57:59`` matched the grep
+    ``file:line:`` pattern, so a datetime + one-line prompt classified as
+    SEARCH_RESULTS (1 match / 2 lines = 50% ≥ 30%) and the SearchCompressor
+    deleted the prompt line — the model received only the timestamp.
+    """
+    incident = (
+        "<current_datetime>2026-08-23T09:57:59.792+02:00</current_datetime>\n"
+        "\n"
+        "Please update the PR desc and check .overlay/ for hints."
+    )
+    assert _try_detect_search(incident) is None
+    assert detect_content_type(incident).content_type is not ContentType.SEARCH_RESULTS
+
+
+def test_search_detection_requires_two_matching_lines() -> None:
+    """A single coincidental ``word:digits:`` line must not classify prose."""
+    assert _try_detect_search("src/foo.py:12:def foo():") is None
+    assert (
+        _try_detect_search(
+            "Meeting at 09:30:00 tomorrow.\nBring the reports.\nDo not forget coffee."
+        )
+        is None
+    )
+    # Two genuine grep lines still classify.
+    two = "src/foo.py:12:def foo():\nsrc/bar.py:34:    foo()"
+    result = _try_detect_search(two)
+    assert result is not None
+    assert result.content_type is ContentType.SEARCH_RESULTS
+
+
+def test_search_detection_rejects_tag_like_and_key_value_prefixes() -> None:
+    """Markup / key=value lines are not file paths even with ``:\\d+:`` inside."""
+    assert (
+        _try_detect_search('<log time="10:00:00">started</log>\n<log time="10:00:01">stopped</log>')
+        is None
+    )
+    assert _try_detect_search("timeout=30:12:retried\ntimeout=31:12:retried") is None
+
+
 def test_log_detection_prefers_build_output_patterns() -> None:
     log_output = "\n".join(
         [
diff --git a/tests/test_transforms_content_router.py b/tests/test_transforms_content_router.py
index 4f76c6386..74ce9b5c9 100644
--- a/tests/test_transforms_content_router.py
+++ b/tests/test_transforms_content_router.py
@@ -1785,3 +1785,23 @@ def test_detect_content_overrides_html_misroute_for_grep_and_logs(
         "</section></main></body></html>"
     )
     assert _detect_content(html).content_type is ContentType.HTML
+
+
+def test_datetime_prefixed_user_prompt_survives_router() -> None:
+    """Regression (2026-08-23): interactive wrap-copilot prompts were deleted.
+
+    Copilot CLI prepends ``<current_datetime>…</current_datetime>`` to every
+    interactive user turn; the ISO timestamp matched the grep ``file:line:``
+    detector, the one-line prompt classified as SEARCH_RESULTS, and
+    SearchCompressor kept only the datetime line — the model received no
+    request and answered "How can I help you today?". The router must never
+    route this shape to the search line-filter and must keep the prose.
+    """
+    prompt = (
+        "<current_datetime>2026-08-23T09:57:59.792+02:00</current_datetime>\n"
+        "\n"
+        "Please update the PR desc and check .overlay/ for hints."
+    )
+    result = ContentRouter().compress(prompt)
+    assert result.strategy_used is not CompressionStrategy.SEARCH
+    assert "Please update the PR desc" in result.compressed