Function reads_output_format 

pub fn reads_output_format(agent_output_format: &str) -> bool

Whether a block’s output can be read as a digest: Claude Code’s stream-json shape, which Qwen’s stream also has. Any other provider’s file reads as no conversation at all, so a caller that has only the file skips such a block instead of reading 96 KB of it to find nothing. A pane sends its own translated activity instead (activity_from_entries). agentOutputFormat is empty on blocks created before it was recorded, which were all Claude.