this derivation will be built:
  /nix/store/106idc5q9n8qfz2cxy3qzy8vhqnkdksm-treefmt-check.drv
building '/nix/store/106idc5q9n8qfz2cxy3qzy8vhqnkdksm-treefmt-check.drv'
treefmt-check> treefmt v2.5.0traversed 44 files
treefmt-check> emitted 29 files for processing
treefmt-check> formatted 29 files (1 changed) in 40ms
treefmt-check>  M crates/ssync-core/src/cleanup.rs
treefmt-check> diff --git a/crates/ssync-core/src/cleanup.rs b/crates/ssync-core/src/cleanup.rs
treefmt-check> index 7b9ed1a..f5aaa05 100644
treefmt-check> --- a/crates/ssync-core/src/cleanup.rs
treefmt-check> +++ b/crates/ssync-core/src/cleanup.rs
treefmt-check> @@ -62,7 +62,11 @@ pub fn plan(adapters: &[Box<dyn Adapter>], filter: &Filter) -> Result<Vec<Victim
treefmt-check>      }
treefmt-check>      let mut victims = Vec::new();
treefmt-check>      for adapter in adapters {
treefmt-check> -        if filter.agent.as_deref().is_some_and(|a| a != adapter.agent()) {
treefmt-check> +        if filter
treefmt-check> +            .agent
treefmt-check> +            .as_deref()
treefmt-check> +            .is_some_and(|a| a != adapter.agent())
treefmt-check> +        {
treefmt-check>              continue;
treefmt-check>          }
treefmt-check>          let files = crate::session_files(adapter.session_root(), adapter.as_ref());
treefmt-check> @@ -164,14 +168,18 @@ mod tests {
treefmt-check>              "{\"type\":\"title\",\"v\":1,\"title\":\"\",\"pad\":\" \"}\n",
treefmt-check>          );
treefmt-check>          // named: kept
treefmt-check> -        let named = root.join("--p--").join(
treefmt-check> -            "2026-01-02T00-00-00-000Z_019e539d-f6ab-71ac-be20-d3ae2b23ea4b.jsonl",
treefmt-check> -        );
treefmt-check> -        std::fs::write(&named, "{\"type\":\"title\",\"v\":1,\"title\":\"keep me\"}\n").unwrap();
treefmt-check> +        let named = root
treefmt-check> +            .join("--p--")
treefmt-check> +            .join("2026-01-02T00-00-00-000Z_019e539d-f6ab-71ac-be20-d3ae2b23ea4b.jsonl");
treefmt-check> +        std::fs::write(
treefmt-check> +            &named,
treefmt-check> +            "{\"type\":\"title\",\"v\":1,\"title\":\"keep me\"}\n",
treefmt-check> +        )
treefmt-check> +        .unwrap();
treefmt-check>          // no title record at all (plain pi): kept
treefmt-check> -        let plain = root.join("--p--").join(
treefmt-check> -            "2026-01-03T00-00-00-000Z_019e539d-f6ab-71ac-be20-d3ae2b23ea4c.jsonl",
treefmt-check> -        );
treefmt-check> +        let plain = root
treefmt-check> +            .join("--p--")
treefmt-check> +            .join("2026-01-03T00-00-00-000Z_019e539d-f6ab-71ac-be20-d3ae2b23ea4c.jsonl");
treefmt-check>          std::fs::write(&plain, "{\"type\":\"session\",\"version\":3}\n").unwrap();
treefmt-check>  
treefmt-check>          let victims = plan(
treefmt-check> @@ -214,7 +222,13 @@ mod tests {
treefmt-check>              unnamed: false,
treefmt-check>          };
treefmt-check>          assert!(plan(&adapters(&root), &filter(None, None)).is_err());
treefmt-check> -        assert!(plan(&adapters(&root), &filter(Some("codex"), Some(SystemTime::now()))).is_err());
treefmt-check> +        assert!(
treefmt-check> +            plan(
treefmt-check> +                &adapters(&root),
treefmt-check> +                &filter(Some("codex"), Some(SystemTime::now()))
treefmt-check> +            )
treefmt-check> +            .is_err()
treefmt-check> +        );
treefmt-check>          // agent-restricted: selects only from that agent
treefmt-check>          let victims = plan(
treefmt-check>              &adapters(&root),
error: Cannot build '/nix/store/106idc5q9n8qfz2cxy3qzy8vhqnkdksm-treefmt-check.drv'.
       Reason: builder failed with exit code 1.
       Output paths:
         /nix/store/6phxvzrqag2k0rby2j3cb3v9lsszqpb9-treefmt-check
       Last 25 log lines:
       >          // no title record at all (plain pi): kept
       > -        let plain = root.join("--p--").join(
       > -            "2026-01-03T00-00-00-000Z_019e539d-f6ab-71ac-be20-d3ae2b23ea4c.jsonl",
       > -        );
       > +        let plain = root
       > +            .join("--p--")
       > +            .join("2026-01-03T00-00-00-000Z_019e539d-f6ab-71ac-be20-d3ae2b23ea4c.jsonl");
       >          std::fs::write(&plain, "{\"type\":\"session\",\"version\":3}\n").unwrap();
       >  
       >          let victims = plan(
       > @@ -214,7 +222,13 @@ mod tests {
       >              unnamed: false,
       >          };
       >          assert!(plan(&adapters(&root), &filter(None, None)).is_err());
       > -        assert!(plan(&adapters(&root), &filter(Some("codex"), Some(SystemTime::now()))).is_err());
       > +        assert!(
       > +            plan(
       > +                &adapters(&root),
       > +                &filter(Some("codex"), Some(SystemTime::now()))
       > +            )
       > +            .is_err()
       > +        );
       >          // agent-restricted: selects only from that agent
       >          let victims = plan(
       >              &adapters(&root),
       For full logs, run:
         nix log /nix/store/106idc5q9n8qfz2cxy3qzy8vhqnkdksm-treefmt-check.drv