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fix(mcp): chain JSON decode errors during tool invocation #3576

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mshsheikh wants to merge 2 commits into from
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fix(mcp): chain JSON decode errors during tool invocation #3576

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fix(mcp): chain JSON decode errors during tool invocation
mshsheikh Jun 4, 2026
f247c38
fix(mcp): preserve JSON decode causes without exposing redacted input
mshsheikh Jun 4, 2026
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4 changes: 2 additions & 2 deletions src/agents/mcp/util.py
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Original file line number Diff line number Diff line change
Expand Up @@ -592,11 +592,11 @@ async def invoke_mcp_tool(
error_message = f"Invalid JSON input for tool {tool_name_for_display}"
if _debug.DONT_LOG_TOOL_DATA:
logger.debug(error_message)
Comment on lines 593 to 594

@chatgpt-codex-connector chatgpt-codex-connector Bot Jun 4, 2026

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P1 Badge Avoid chaining raw tool input in the redaction path

When _debug.DONT_LOG_TOOL_DATA is true, this branch now falls through to raise ... from json_decode_error, but json.JSONDecodeError retains the original payload in its .doc attribute. For malformed MCP tool arguments containing secrets, any caller or error reporter that inspects chained exceptions can recover the redacted input; this also contradicts the existing redaction regression in tests/mcp/test_mcp_util.py that expects __cause__ and __context__ to be absent in this mode.

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raise ModelBehaviorError(error_message)
raise ModelBehaviorError(error_message) from None
else:
error_message = f"{error_message}: {input_json}"
logger.debug(error_message)
raise ModelBehaviorError(error_message) from json_decode_error
raise ModelBehaviorError(error_message) from json_decode_error

if not isinstance(json_data, dict):
raise ModelBehaviorError(
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