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0157ac7 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 | """Heuristic parser for text-emitted tool calls."""
import json
import re
import uuid
from enum import Enum
from typing import Any
from loguru import logger
_CONTROL_TOKEN_RE = re.compile(r"<\|[^|>]{1,80}\|>")
_CONTROL_TOKEN_START = "<|"
_CONTROL_TOKEN_END = "|>"
class ParserState(Enum):
TEXT = 1
MATCHING_FUNCTION = 2
PARSING_PARAMETERS = 3
class HeuristicToolParser:
"""
Stateful parser for raw text tool calls.
Some OpenAI-compatible models emit tool calls as text rather than structured
chunks. This parser converts the common ``● <function=...>`` form into
Anthropic-style ``tool_use`` blocks.
"""
_FUNC_START_PATTERN = re.compile(r"●\s*<function=([^>]+)>")
_PARAM_PATTERN = re.compile(
r"<parameter=([^>]+)>(.*?)(?:</parameter>|$)", re.DOTALL
)
_WEB_TOOL_JSON_PATTERN = re.compile(
r"(?is)\b(?:use\s+)?(?P<tool>WebFetch|WebSearch)\b.*?(?P<json>\{.*?\})"
)
def __init__(self):
self._state = ParserState.TEXT
self._buffer = ""
self._current_tool_id = None
self._current_function_name = None
self._current_parameters = {}
def _extract_web_tool_json_calls(self) -> tuple[str, list[dict[str, Any]]]:
detected_tools: list[dict[str, Any]] = []
for match in self._WEB_TOOL_JSON_PATTERN.finditer(self._buffer):
try:
tool_input = json.loads(match.group("json"))
except json.JSONDecodeError:
continue
if not isinstance(tool_input, dict):
continue
tool_name = match.group("tool")
if tool_name == "WebFetch" and "url" not in tool_input:
continue
if tool_name == "WebSearch" and "query" not in tool_input:
continue
detected_tools.append(
{
"type": "tool_use",
"id": f"toolu_heuristic_{uuid.uuid4().hex[:8]}",
"name": tool_name,
"input": tool_input,
}
)
logger.debug(
"Heuristic bypass: Detected JSON-style tool call '{}'",
tool_name,
)
if not detected_tools:
return self._buffer, []
return "", detected_tools
def _strip_control_tokens(self, text: str) -> str:
return _CONTROL_TOKEN_RE.sub("", text)
def _split_incomplete_control_token_tail(self) -> str:
start = self._buffer.rfind(_CONTROL_TOKEN_START)
if start == -1:
return ""
end = self._buffer.find(_CONTROL_TOKEN_END, start)
if end != -1:
return ""
prefix = self._buffer[:start]
self._buffer = self._buffer[start:]
return prefix
def feed(self, text: str) -> tuple[str, list[dict[str, Any]]]:
"""Feed text and return safe text plus detected tool calls."""
self._buffer += text
self._buffer = self._strip_control_tokens(self._buffer)
self._buffer, detected_tools = self._extract_web_tool_json_calls()
filtered_output_parts: list[str] = []
while True:
if self._state == ParserState.TEXT:
if "●" in self._buffer:
idx = self._buffer.find("●")
filtered_output_parts.append(self._buffer[:idx])
self._buffer = self._buffer[idx:]
self._state = ParserState.MATCHING_FUNCTION
else:
safe_prefix = self._split_incomplete_control_token_tail()
if safe_prefix:
filtered_output_parts.append(safe_prefix)
break
filtered_output_parts.append(self._buffer)
self._buffer = ""
break
if self._state == ParserState.MATCHING_FUNCTION:
match = self._FUNC_START_PATTERN.search(self._buffer)
if match:
self._current_function_name = match.group(1).strip()
self._current_tool_id = f"toolu_heuristic_{uuid.uuid4().hex[:8]}"
self._current_parameters = {}
self._buffer = self._buffer[match.end() :]
self._state = ParserState.PARSING_PARAMETERS
logger.debug(
"Heuristic bypass: Detected start of tool call '{}'",
self._current_function_name,
)
elif len(self._buffer) > 100:
filtered_output_parts.append(self._buffer[0])
self._buffer = self._buffer[1:]
self._state = ParserState.TEXT
else:
break
if self._state == ParserState.PARSING_PARAMETERS:
finished_tool_call = False
while True:
param_match = self._PARAM_PATTERN.search(self._buffer)
if param_match and "</parameter>" in param_match.group(0):
pre_match_text = self._buffer[: param_match.start()]
if pre_match_text:
filtered_output_parts.append(pre_match_text)
key = param_match.group(1).strip()
val = param_match.group(2).strip()
self._current_parameters[key] = val
self._buffer = self._buffer[param_match.end() :]
else:
break
if "●" in self._buffer:
idx = self._buffer.find("●")
if idx > 0:
filtered_output_parts.append(self._buffer[:idx])
self._buffer = self._buffer[idx:]
finished_tool_call = True
elif len(self._buffer) > 0 and not self._buffer.strip().startswith("<"):
if "<parameter=" not in self._buffer:
filtered_output_parts.append(self._buffer)
self._buffer = ""
finished_tool_call = True
if finished_tool_call:
detected_tools.append(
{
"type": "tool_use",
"id": self._current_tool_id,
"name": self._current_function_name,
"input": self._current_parameters,
}
)
logger.debug(
"Heuristic bypass: Emitting tool call '{}' with {} params",
self._current_function_name,
len(self._current_parameters),
)
self._state = ParserState.TEXT
else:
break
return "".join(filtered_output_parts), detected_tools
def flush(self) -> list[dict[str, Any]]:
"""Flush any remaining tool call in the buffer."""
self._buffer = self._strip_control_tokens(self._buffer)
detected_tools = []
if self._state == ParserState.PARSING_PARAMETERS:
partial_matches = re.finditer(
r"<parameter=([^>]+)>(.*)$", self._buffer, re.DOTALL
)
for match in partial_matches:
key = match.group(1).strip()
val = match.group(2).strip()
self._current_parameters[key] = val
detected_tools.append(
{
"type": "tool_use",
"id": self._current_tool_id,
"name": self._current_function_name,
"input": self._current_parameters,
}
)
self._state = ParserState.TEXT
self._buffer = ""
return detected_tools
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