[rudycelekli]

What type of PR is this? (check all applicable)

• Refactor
• Feature
• Bug Fix
• Optimization
• Documentation Update

Related issue: N/A (found by reading the code; reproduced on main at 6b33dff)

What changed?
New _normalize_tool_error returns the (truncated) message when the error is an object with a non-empty string message; anything else goes through the old path, so the existing string-error test still passes.

Why?
Copilot's schema defines tool.execution_complete error as ToolExecutionCompleteError {"message": str, "code"?: str} (github/copilot-sdk session_events.py). CopilotParser passes it to _normalize_tool_result (Sensor/adr_sensor/parsers/copilot_parser.py:302), which only knows result objects (detailedContent/content) and falls back to json.dumps, so a rejected tool gets error '{"message": "The user rejected this tool call.", "code": "denied"}'.

How did you test it?

• Reproduction: new TestCopilotParser::test_tool_failure_uses_message_of_error_object. main parser: FAILED ('{"message": ...e": "denied"}' == 'The user rej...is tool call.'); branch: passed.
• Test suite: Sensor pytest tests/ -q (py3.14) 609 passed; Python 3.9.6 parser test files 245 passed.
• Not tested: real Copilot logs (none locally). Low-to-moderate impact: the message was already inside the JSON blob; the fix makes the field the plain message other parsers emit. The error code is dropped (still not exported elsewhere).

Potential risks
The change only affects the input described above; other paths go through the same code as before, and the component's existing tests pass.

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