diff --git a/b454-nixos-module-execstartpre-datadir.md b/b454-nixos-module-execstartpre-datadir.md
index 58fba22..49d50b8 100644
--- a/b454-nixos-module-execstartpre-datadir.md
+++ b/b454-nixos-module-execstartpre-datadir.md
@@ -15,11 +15,13 @@ Root cause: The NixOS module creates tmpfiles rules for the data directory, but
 
 ## Plan
 
-- [ ] Phase 1: Add `ExecStartPre` to systemd service configuration in `nix/module.nix`
-- [ ] Phase 2: Create directories before service starts (dataDir, dataDir/git, dataDir/relay)
-- [ ] Phase 3: Set proper ownership and permissions
-- [ ] Phase 4: Investigate if there are specific custom path options for git and relay data directories
-- [ ] Phase 5: Update ExecStartPre logic to handle those paths if they exist
+- [x] Phase 1: Add `ExecStartPre` to systemd service configuration in `nix/module.nix`
+- [x] Phase 2: Create directories before service starts (dataDir, dataDir/git, dataDir/relay)
+- [x] Phase 3: Set proper ownership and permissions
+- [x] Phase 4: Investigate if there are specific custom path options for git and relay data directories
+  - Confirmed: No separate options exist; git/relay paths are derived from dataDir
+- [x] Phase 5: Update ExecStartPre logic to handle those paths if they exist
+  - N/A: Paths are always `${dataDir}/git` and `${dataDir}/relay`
 
 ## Implementation
 
@@ -52,6 +54,16 @@ serviceConfig = {
 
 ## Progress
 
+### 2026-01-20 [Session 08:15]
+- Completed: Implemented ExecStartPre directives in nix/module.nix
+- Implementation details:
+  - Added 7 ExecStartPre commands with `+` prefix (runs as root)
+  - Creates dataDir, dataDir/git, dataDir/relay with mkdir -p
+  - Sets ownership with chown -R to cfg.user:cfg.group
+  - Sets permissions 750 on all three directories
+- Decision: Kept existing tmpfiles.rules for boot-time setup and consistency
+- Verified: No separate git/relay path options exist; they're always derived from dataDir
+
 ### 2026-01-20 [Session 07:41]
 - Started work: Created worktree for implementation