diff --git a/CLAUDE.md b/CLAUDE.md
index cf4efff..ff80e46 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -70,7 +70,8 @@ BATTERIES (opt-in siblings, each nil-safe + a default):
   audit/     run.Audit Sink + Writer + queryable Memory  [P4 ✓]
              default (skillaudit Storage iface; GORM stays in mort)
   critic/    two-tier timeout state machine + Escalator  [P4]
-  schedule/  cron runner cores                           [P4]
+  schedule/  generic cron Runner (Tick/Loop over a wired  [P4 ✓]
+             Due/Run/Mark/Next; no cron grammar of its own)
   checkpoint/ CheckpointStore + run.Checkpointer handle  [P4 ✓]
              (throttled Save/Complete/Fail) + Memory (exec wiring=P2 follow-up)
   budget/    DBBudget rolling-7d + NoOp (run.Budget);    [P4 ✓]
diff --git a/schedule/runner.go b/schedule/runner.go
new file mode 100644
index 0000000..2a7d8b4
--- /dev/null
+++ b/schedule/runner.go
@@ -0,0 +1,103 @@
+// Package schedule is the cron-runner battery: a generic ticker that, each
+// interval, asks a store for the jobs whose next-run time has passed, runs each
+// one, and stamps its next fire time. It is host-agnostic orchestration — the
+// host wires the store (skill.SkillStore.ListDueScheduled /
+// persona.Storage.ListScheduledAgents), the run (run.Executor), and the cron
+// "next fire" function (a cron library, or skill's schedule parser). The
+// battery owns no cron grammar of its own, so it never duplicates the parser.
+package schedule
+
+import (
+	"context"
+	"log/slog"
+	"time"
+)
+
+// Due is one schedulable job: its id and its cron expression.
+type Due struct {
+	ID   string
+	Cron string
+}
+
+// Runner periodically fires due jobs. Every func field is required except Now
+// (defaults to time.Now) and Logger (defaults to slog.Default). Construct the
+// struct directly and call Loop (or Tick for a single pass / tests).
+type Runner struct {
+	// Interval is how often Loop checks for due jobs. <= 0 defaults to 1m.
+	Interval time.Duration
+	// Due lists the jobs due at now.
+	Due func(ctx context.Context, now time.Time) ([]Due, error)
+	// Run executes one job by id.
+	Run func(ctx context.Context, id string) error
+	// Mark records that a job ran at ranAt and is next due at nextAt.
+	Mark func(ctx context.Context, id string, ranAt, nextAt time.Time) error
+	// Next computes a cron expression's next fire after a given time.
+	Next func(cron string, after time.Time) (time.Time, error)
+
+	Now    func() time.Time
+	Logger *slog.Logger
+}
+
+func (r *Runner) now() time.Time {
+	if r.Now != nil {
+		return r.Now()
+	}
+	return time.Now()
+}
+
+func (r *Runner) log() *slog.Logger {
+	if r.Logger != nil {
+		return r.Logger
+	}
+	return slog.Default()
+}
+
+// Tick runs one pass: every currently-due job is run, then stamped with its
+// next fire time. A job whose Run or Next errors is logged and skipped (its
+// next-run time is left unchanged so it stays due and retries next tick) — one
+// bad job never stalls the others. Returns the error from Due (the only
+// pass-fatal step).
+func (r *Runner) Tick(ctx context.Context) error {
+	now := r.now()
+	due, err := r.Due(ctx, now)
+	if err != nil {
+		return err
+	}
+	for _, j := range due {
+		if err := r.Run(ctx, j.ID); err != nil {
+			r.log().Warn("scheduled job failed; will retry next tick", "job", j.ID, "error", err)
+			continue
+		}
+		next, err := r.Next(j.Cron, now)
+		if err != nil {
+			r.log().Warn("scheduled job has an unparseable cron; not rescheduling", "job", j.ID, "cron", j.Cron, "error", err)
+			continue
+		}
+		if err := r.Mark(ctx, j.ID, now, next); err != nil {
+			r.log().Warn("failed to stamp scheduled job's next run", "job", j.ID, "error", err)
+		}
+	}
+	return nil
+}
+
+// Loop ticks every Interval until ctx is cancelled. A Tick error (the Due
+// lister failing) is logged and the loop continues — a transient store hiccup
+// shouldn't kill the scheduler.
+func (r *Runner) Loop(ctx context.Context) {
+	interval := r.Interval
+	if interval <= 0 {
+		interval = time.Minute
+	}
+	t := time.NewTicker(interval)
+	defer t.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-t.C:
+			if err := r.Tick(ctx); err != nil {
+				r.log().Warn("schedule tick failed", "error", err)
+			}
+		}
+	}
+}
diff --git a/schedule/runner_test.go b/schedule/runner_test.go
new file mode 100644
index 0000000..bbde4fc
--- /dev/null
+++ b/schedule/runner_test.go
@@ -0,0 +1,82 @@
+package schedule
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+)
+
+func TestTickRunsDueAndStampsNext(t *testing.T) {
+	ctx := context.Background()
+	now := time.Date(2026, 1, 1, 12, 0, 0, 0, time.UTC)
+	var ran []string
+	marked := map[string]time.Time{}
+
+	r := &Runner{
+		Now: func() time.Time { return now },
+		Due: func(_ context.Context, _ time.Time) ([]Due, error) {
+			return []Due{{ID: "a", Cron: "hourly"}, {ID: "b", Cron: "bad"}}, nil
+		},
+		Run:  func(_ context.Context, id string) error { ran = append(ran, id); return nil },
+		Mark: func(_ context.Context, id string, _, next time.Time) error { marked[id] = next; return nil },
+		Next: func(cron string, after time.Time) (time.Time, error) {
+			if cron == "bad" {
+				return time.Time{}, errors.New("unparseable")
+			}
+			return after.Add(time.Hour), nil
+		},
+	}
+	if err := r.Tick(ctx); err != nil {
+		t.Fatal(err)
+	}
+	// Both ran; only the parseable one got a next stamp.
+	if len(ran) != 2 {
+		t.Errorf("ran = %v, want both", ran)
+	}
+	if marked["a"] != now.Add(time.Hour) {
+		t.Errorf("a next = %v, want +1h", marked["a"])
+	}
+	if _, ok := marked["b"]; ok {
+		t.Errorf("b should not be stamped (bad cron), got %v", marked["b"])
+	}
+}
+
+func TestTickRunFailureDoesNotStampOrStall(t *testing.T) {
+	ctx := context.Background()
+	var ran []string
+	marked := map[string]bool{}
+	r := &Runner{
+		Due: func(_ context.Context, _ time.Time) ([]Due, error) {
+			return []Due{{ID: "x", Cron: "h"}, {ID: "y", Cron: "h"}}, nil
+		},
+		Run: func(_ context.Context, id string) error {
+			ran = append(ran, id)
+			if id == "x" {
+				return errors.New("boom")
+			}
+			return nil
+		},
+		Mark: func(_ context.Context, id string, _, _ time.Time) error { marked[id] = true; return nil },
+		Next: func(string, time.Time) (time.Time, error) { return time.Now(), nil },
+	}
+	if err := r.Tick(ctx); err != nil {
+		t.Fatal(err)
+	}
+	if len(ran) != 2 { // y still runs despite x failing
+		t.Errorf("ran = %v, want both attempted", ran)
+	}
+	if marked["x"] { // failed job NOT stamped -> stays due, retries
+		t.Error("failed job x should not be stamped")
+	}
+	if !marked["y"] {
+		t.Error("y should be stamped")
+	}
+}
+
+func TestTickDueErrorIsFatalToPass(t *testing.T) {
+	r := &Runner{Due: func(context.Context, time.Time) ([]Due, error) { return nil, errors.New("store down") }}
+	if err := r.Tick(context.Background()); err == nil {
+		t.Error("Tick should surface the Due lister error")
+	}
+}