fix(agent-challenge): stop public log redaction from wedging the event loop

packages/challenges/agent-challenge/src/agent_challenge/api/routes.py

@@ -5049,16 +5049,38 @@ def _is_sensitive_task_event_metadata_key(key: str) -> bool:
 
 
 # Whole-segment secret markers (not substrings of longer words like "tokens").
-_PUBLIC_SECRET_SEGMENT_RE = re.compile(
-    r"(?<![A-Za-z0-9_.-])"
-    r"(?:"
-    r"(?:[A-Za-z0-9_.]+[-_.])*(?:secret|raw-ref|broker-ref|pod-)[A-Za-z0-9_.-]*"
-    r"|"
-    r"(?:[A-Za-z0-9_.]+[-_.])*token(?:[-_.][A-Za-z0-9_.]+)*"
-    r")"
-    r"(?![A-Za-z0-9_.-])",
+#
+# Redaction is a single linear pass: grab each delimited word, then decide with
+# two bounded checks. The previous single-regex form nested
+# ``(?:[A-Za-z0-9_.]+[-_.])*`` over a class that also contains the separators
+# ``_`` and ``.``, so every dotted/underscored run that never reached
+# ``secret``/``token`` had exponentially many ways to split: 37 chars took 23ms,
+# 61 chars took 91s. pip output has exactly that shape, and the endpoint that
+# replays it is public, so a single log line pinned the event loop at 100% CPU
+# and starved every evaluation running on the validator.
+_PUBLIC_SECRET_WORD_RE = re.compile(r"(?<![A-Za-z0-9_.-])[A-Za-z0-9_.-]+(?![A-Za-z0-9_.-])")
+_PUBLIC_SECRET_MARKER_RE = re.compile(
+    r"(?:^|[-_.])(?:secret|raw-ref|broker-ref|pod-)",
     flags=re.IGNORECASE,
 )
+_PUBLIC_TOKEN_SEGMENT_RE = re.compile(
+    r"(?:^|[-_.])token(?:[-_.]|$)",
+    flags=re.IGNORECASE,
+)
+
+
+def _redact_public_secret_segments(value: str) -> str:
+    """Redact whole words that carry a secret marker on a segment boundary."""
+
+    def _replace(match: re.Match[str]) -> str:
+        word = match.group(0)
+        if _PUBLIC_SECRET_MARKER_RE.search(word):
+            return "[REDACTED_SECRET]"
+        if _PUBLIC_TOKEN_SEGMENT_RE.search(word):
+            return "[REDACTED_SECRET]"
+        return word
+
+    return _PUBLIC_SECRET_WORD_RE.sub(_replace, value)
 
 
 def _terminal_bench_task_id_shield_pattern() -> re.Pattern[str]:
@@ -5105,7 +5127,7 @@ def _shield(match: re.Match[str]) -> str:
     # Segment-boundary redaction: match secret/token/raw-ref/broker-ref/pod- as
     # whole hyphen/underscore/dot-delimited segments, not as substrings of a
     # longer word (``tokens`` must not match ``token``).
-    sanitized = _PUBLIC_SECRET_SEGMENT_RE.sub("[REDACTED_SECRET]", sanitized)
+    sanitized = _redact_public_secret_segments(sanitized)
     for index, original in enumerate(shields):
         sanitized = sanitized.replace(f"\x00TBSAFE{index}\x00", original)
     return sanitized

packages/challenges/agent-challenge/tests/test_public_task_event_redaction.py

@@ -39,3 +39,40 @@ def test_public_task_event_text_still_redacts_genuine_secrets() -> None:
     for secret in _GENUINE_SECRET_SHAPES:
         assert secret not in out, f"secret still visible: {secret!r} in {out!r}"
     assert "[REDACTED_SECRET]" in out
+
+
+def test_secret_redaction_is_linear_on_dotted_runs() -> None:
+    """A public log line must never wedge the event loop.
+
+    ``_PUBLIC_SECRET_SEGMENT_RE`` nested ``(?:[A-Za-z0-9_.]+[-_.])*`` over a class
+    that also contains the separators, so a dotted/underscored run that never
+    reaches ``secret``/``token`` backtracked exponentially: 37 chars took 23ms and
+    61 chars took 91s. pip output carries exactly that shape
+    ("Successfully installed agent-challenge-1.0.1 aiohappyeyeballs-2.7.1 ..."),
+    and the endpoint serving it is public, so one log line pinned the validator
+    at 100% CPU and starved every evaluation.
+    """
+    import time
+
+    from agent_challenge.api.routes import _public_task_event_text
+
+    payload = "a.b_c." * 40 + "!"
+    started = time.perf_counter()
+    _public_task_event_text(payload)
+    elapsed = time.perf_counter() - started
+    assert elapsed < 1.0, f"redaction took {elapsed:.1f}s on {len(payload)} chars"
+
+
+def test_realistic_pip_output_is_fast_and_unredacted() -> None:
+    from agent_challenge.api.routes import _public_task_event_text
+
+    line = (
+        "Successfully installed agent-challenge-1.0.1 aiohappyeyeballs-2.7.1 "
+        "aiohttp-3.14.3 aiosignal-1.4.0 async-substrate-interface-2.2.1 "
+    ) * 6
+    import time
+
+    started = time.perf_counter()
+    out = _public_task_event_text(line)
+    assert time.perf_counter() - started < 1.0
+    assert "agent-challenge-1.0.1" in out