fix(cli): make project cleanup safe

cmd/engram/main.go

@@ -95,7 +95,8 @@ var (
 	storeDeleteProject     = func(s *store.Store, name string, hard bool) (*store.DeleteProjectResult, error) {
 		return s.DeleteProject(name, hard)
 	}
-	storeTimeline = func(s *store.Store, observationID int64, before, after int) (*store.TimelineResult, error) {
+	storePruneProject = func(s *store.Store, name string) (*store.PruneResult, error) { return s.PruneProject(name) }
+	storeTimeline     = func(s *store.Store, observationID int64, before, after int) (*store.TimelineResult, error) {
 		return s.Timeline(observationID, before, after)
 	}
 	storeFormatContext = func(s *store.Store, project, scope string) (string, error) { return s.FormatContext(project, scope) }
@@ -1861,7 +1862,7 @@ func cmdProjects(cfg store.Config) {
 		fmt.Fprintf(os.Stderr, "unknown projects subcommand: %s\n", subCmd)
 		fmt.Fprintln(os.Stderr, "usage: engram projects list")
 		fmt.Fprintln(os.Stderr, "       engram projects consolidate [--all] [--dry-run]")
-		fmt.Fprintln(os.Stderr, "       engram projects prune [--dry-run]")
+		fmt.Fprintln(os.Stderr, "       engram projects prune [--dry-run] [--paths-only]")
 		exitFunc(1)
 	}
 }
@@ -1962,6 +1963,47 @@ func findNormalizationEquivalentProjects(name string, existing []string) []proje
 	return matches
 }
 
+// mergedRecordCount reports how many records a merge actually moved. The store
+// validates every source against the canonical name and fail-closes on the ones
+// it cannot prove normalization-equivalent, so a merge can succeed while moving
+// nothing at all. Callers must report that outcome honestly instead of
+// announcing a completed merge.
+func mergedRecordCount(result *store.MergeResult) int64 {
+	if result == nil {
+		return 0
+	}
+	return result.ObservationsUpdated + result.SessionsUpdated + result.PromptsUpdated
+}
+
+// reportUnmergedSources names the selected sources the store left untouched, so
+// a partially applied merge never reads as a complete one.
+func reportUnmergedSources(sources []string, result *store.MergeResult) {
+	merged := make(map[string]bool, len(result.SourcesMerged))
+	for _, name := range result.SourcesMerged {
+		merged[name] = true
+	}
+
+	// SourcesMerged holds the trimmed spelling the store actually rewrote, while
+	// sources holds the raw spellings the operator selected. Only a source that
+	// is literally the canonical name was a no-op by request.
+	var skipped []string
+	seen := make(map[string]bool, len(sources))
+	for _, source := range sources {
+		if strings.TrimSpace(source) == "" || source == result.Canonical {
+			continue
+		}
+		if merged[strings.TrimSpace(source)] || seen[source] {
+			continue
+		}
+		seen[source] = true
+		skipped = append(skipped, source)
+	}
+	if len(skipped) == 0 {
+		return
+	}
+	fmt.Printf("  Not merged (no records moved): %s\n", strings.Join(skipped, ", "))
+}
+
 func cmdProjectsConsolidate(cfg store.Config) {
 	doAll := false
 	dryRun := false
@@ -2073,10 +2115,17 @@ func cmdProjectsConsolidate(cfg store.Config) {
 			fatal(err)
 		}
 
-		fmt.Printf("Done! Merged into %q:\n", result.Canonical)
+		if mergedRecordCount(result) == 0 {
+			fmt.Printf("Nothing merged into %q: the store moved no records for the %d selected project(s).\n",
+				result.Canonical, len(sources))
+			return
+		}
+
+		fmt.Printf("Done! Merged %d project(s) into %q:\n", len(result.SourcesMerged), result.Canonical)
 		fmt.Printf("  Observations: %d\n", result.ObservationsUpdated)
 		fmt.Printf("  Sessions:     %d\n", result.SessionsUpdated)
 		fmt.Printf("  Prompts:      %d\n", result.PromptsUpdated)
+		reportUnmergedSources(sources, result)
 		return
 	}
 
@@ -2194,8 +2243,14 @@ func cmdProjectsConsolidate(cfg store.Config) {
 			fmt.Println()
 			continue
 		}
-		fmt.Printf("  Merged: %d obs, %d sessions, %d prompts\n",
-			result.ObservationsUpdated, result.SessionsUpdated, result.PromptsUpdated)
+		if mergedRecordCount(result) == 0 {
+			fmt.Printf("  Nothing merged into %q: the store moved no records for the %d selected project(s).\n",
+				mergeCanonical, len(sources))
+		} else {
+			fmt.Printf("  Merged: %d obs, %d sessions, %d prompts\n",
+				result.ObservationsUpdated, result.SessionsUpdated, result.PromptsUpdated)
+			reportUnmergedSources(sources, result)
+		}
 
 		if renameTarget != "" && renameTarget != mergeCanonical {
 			migrateResult, err := s.MigrateProject(mergeCanonical, renameTarget)
@@ -2214,9 +2269,13 @@ func cmdProjectsConsolidate(cfg store.Config) {
 
 func cmdProjectsPrune(cfg store.Config) {
 	dryRun := false
+	pathsOnly := false
 	for i := 3; i < len(os.Args); i++ {
-		if os.Args[i] == "--dry-run" {
+		switch os.Args[i] {
+		case "--dry-run":
 			dryRun = true
+		case "--paths-only":
+			pathsOnly = true
 		}
 	}
 
@@ -2231,15 +2290,21 @@ func cmdProjectsPrune(cfg store.Config) {
 		fatal(err)
 	}
 
-	// Find projects with 0 observations
+	// Find projects with 0 observations.
 	var candidates []store.ProjectStats
 	for _, ps := range allStats {
-		if ps.ObservationCount == 0 {
-			candidates = append(candidates, ps)
+		if ps.ObservationCount != 0 || (pathsOnly && !isPathLikeProjectName(ps.Name)) {
+			continue
 		}
+		candidates = append(candidates, ps)
 	}
+	sort.Slice(candidates, func(i, j int) bool { return candidates[i].Name < candidates[j].Name })
 
 	if len(candidates) == 0 {
+		if pathsOnly {
+			fmt.Println("No path-named projects to prune.")
+			return
+		}
 		fmt.Println("No empty projects to prune.")
 		return
 	}
@@ -2286,17 +2351,23 @@ func cmdProjectsPrune(cfg store.Config) {
 
 	totalSessions := int64(0)
 	totalPrompts := int64(0)
+	successful := 0
 	for _, ps := range selected {
-		result, err := s.PruneProject(ps.Name)
+		result, err := storePruneProject(s, ps.Name)
 		if err != nil {
 			fmt.Fprintf(os.Stderr, "Error pruning %q: %v\n", ps.Name, err)
 			continue
 		}
+		successful++
 		totalSessions += result.SessionsDeleted
 		totalPrompts += result.PromptsDeleted
 	}
 
-	fmt.Printf("\nPruned %d project(s): %d sessions, %d prompts removed.\n", len(selected), totalSessions, totalPrompts)
+	fmt.Printf("\nPruned %d project(s): %d sessions, %d prompts removed.\n", successful, totalSessions, totalPrompts)
+}
+
+func isPathLikeProjectName(name string) bool {
+	return strings.ContainsAny(name, `/\`)
 }
 
 // cmdSetup classifies os.Args[2:] with a two-pass, order-independent
@@ -2645,6 +2716,10 @@ Commands:
                      Merge similar project names into one canonical name
                        --all      Scan ALL projects for similar name groups
                        --dry-run  Preview what would be merged (no changes)
+  projects prune [--dry-run] [--paths-only]
+                     Remove projects with no observations
+                       --dry-run     Preview projects without removing data
+                       --paths-only  Limit pruning to project names containing / or \
   setup [agent]      Install/setup agent integration (opencode, pi, claude-code,
                      gemini-cli, codex, antigravity-cli, windsurf, qwen, kiro,
                      cursor, vscode-copilot, kilocode)