Merge pull request #56 from dazzaji/fix/handoff-regex-truncation

Fix handoff_request extractor truncating nested payloads at the first `}`
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Tobin South 2026-05-28 17:48:21 -07:00 committed by GitHub
commit 248331e0fe
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@ -138,9 +138,15 @@ HANDOFF_PAYLOAD_SCHEMA = {
},
}
HANDOFF_RE = re.compile(
r'\{"type":\s*"handoff_request".*?\}', re.DOTALL
)
# Matches the START of a handoff_request object only. The full object —
# which always contains nested objects (`payload`, and `payload.params`) —
# is then extracted with json.JSONDecoder().raw_decode in extract_handoff.
# A plain regex cannot do this safely: a non-greedy `.*?\}` stops at the
# first `}` and truncates every real payload, while a greedy `.*\}`
# over-captures across any later `}` in the stream. raw_decode is string-
# and nesting-aware, so it returns exactly one complete JSON value.
HANDOFF_START_RE = re.compile(r'\{\s*"type"\s*:\s*"handoff_request"')
_JSON_DECODER = json.JSONDecoder()
# Denylist for instruction-like phrasing. Low-assurance; see docstring.
_DENY_PREFIX = ("#", ">", "---", "System:", "Assistant:", "Human:",
@ -242,30 +248,34 @@ def extract_handoff(text: str, source_agent: str = "unknown") -> dict | None:
Returns a dict with target_agent, intent, params, and pre-rendered
steering_input, or None if any gate fails. Every attempt is logged.
"""
m = HANDOFF_RE.search(text)
m = HANDOFF_START_RE.search(text)
if not m:
return None
raw = m.group(0)
try:
obj = json.loads(raw)
obj, end = _JSON_DECODER.raw_decode(text, m.start())
except json.JSONDecodeError:
audit_log({"source": source_agent, "result": "reject",
"reason": "invalid_json", "raw_len": len(raw)})
"reason": "invalid_json",
"raw_len": len(text) - m.start()})
return None
# Length of the decoded handoff object, for the audit log on any
# later rejection. raw_decode returns the end offset of the parsed
# value; the old m.group(0) string no longer exists.
raw_len = end - m.start()
target = obj.get("target_agent")
payload = obj.get("payload")
if target not in ALLOWED_TARGETS:
audit_log({"source": source_agent, "target": target,
"result": "reject", "reason": "target_not_allowlisted",
"raw_len": len(raw)})
"raw_len": raw_len})
return None
try:
jsonschema.validate(instance=payload, schema=HANDOFF_PAYLOAD_SCHEMA)
except jsonschema.ValidationError as e:
audit_log({"source": source_agent, "target": target,
"result": "reject", "reason": f"schema: {e.message}",
"raw_len": len(raw)})
"raw_len": raw_len})
return None
intent = payload["intent"]
@ -273,7 +283,7 @@ def extract_handoff(text: str, source_agent: str = "unknown") -> dict | None:
if not _validate_params(intent, params):
audit_log({"source": source_agent, "target": target, "intent": intent,
"result": "reject", "reason": "params_schema",
"raw_len": len(raw)})
"raw_len": raw_len})
return None
raw_event = payload.get("event", "") or ""