When retainToolCalls is enabled (new default), the retention transcript
is output as JSON with full message structure including tool_use blocks
(Edit, Read, Bash, Grep, etc.) and their complete input dicts, plus
tool_result blocks (truncated at 2k chars). This preserves the context
of what actions the assistant actually took, not just its narration.
Hindsight MCP tools (recall/retain/reflect) are excluded to prevent
feedback loops. Channel message tools still get their text extracted
inline. Setting retainToolCalls=false falls back to the legacy text
format.
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