Somewhat related, I built ccrider [1], which indexes the session transcripts that agents already write to disk (Claude Code, Codex, Copilot) into a local SQLite FTS database. It has a TUI, CLI, and an MCP server so the agent can search past sessions itself. Same local-first idea, based the raw logs rather than a maintained digest. Should work nicely with recall as well.
[1] https://github.com/neilberkman/ccrider