pub const TOOL_OUTCOME_UNKNOWN_METADATA_KEY: &str = "sc.tool_outcome_unknown";Expand description
Reserved ChatMessage.metadata key marking a Role::Tool result whose
success/failure outcome is UNKNOWN. Codex v1 function_call_output and
custom_tool_call_output records carry only free-form output text, so
inferring success from that text would be brittle. Importers stamp this
marker instead and reduction candidates fail closed until a harness gives
us a structured outcome.