diff --git a/bridge/frontier.py b/bridge/frontier.py
new file mode 100644
index 0000000..2be7c4c
--- /dev/null
+++ b/bridge/frontier.py
@@ -0,0 +1,89 @@
+"""Next-frontier suggestions — PRD acceptance criterion #19.
+
+'Every play session ends with at least one visible unresolved next-step
+frontier.'
+
+next_frontier(state) inspects the current SessionState and returns a
+single short, in-character medieval-voice string that tells the player
+what's worth returning for. The function is pure: same state → same
+suggestion. Order of evaluation prefers the most actionable signal
+(an active session needing attention beats a generic 'come back later').
+
+Returned string is always non-empty — even an empty kingdom gets a
+'found your first city' onboarding nudge so the player has a frontier.
+"""
+
+from __future__ import annotations
+
+from typing import Optional
+
+from bridge.session_state import Session, SessionState, SessionStatus
+
+
+def next_frontier(state: SessionState) -> str:
+    """Return one short medieval-voice 'come back to do X' string."""
+    sessions = state.sessions
+
+    if not sessions:
+        return "Found your first city — open a Claude Code session and the realm begins."
+
+    # Priority order: redirected (acute, transient) > waiting (input expected)
+    # > inactive (registered but quiet) > momentum-buildup > momentum-tier-up
+    # > goal-pending > generic come-back.
+
+    # 1) Any redirected session — surface that first; momentum is on the line.
+    redirected = [s for s in sessions if s.status == SessionStatus.REDIRECTED]
+    if redirected:
+        s = redirected[0]
+        return f"'{s.name}' is redirected — return to rebuild momentum."
+
+    # 2) Waiting sessions — the agent expects input, this is the warmest re-entry.
+    waiting = [s for s in sessions if s.status == SessionStatus.WAITING]
+    if waiting:
+        s = waiting[0]
+        return f"'{s.name}' awaits your council. The next charter starts with you."
+
+    # 3) Inactive sessions — registered but never engaged.
+    inactive = [s for s in sessions if s.status == SessionStatus.INACTIVE]
+    if inactive:
+        s = inactive[0]
+        return f"'{s.name}' is registered but quiet — open the session to begin."
+
+    # 4) Active session about to tier up its momentum (next +1 culture).
+    actives = [s for s in sessions if s.status == SessionStatus.ACTIVE]
+    if actives:
+        s = max(actives, key=lambda x: x.momentum)
+        next_tier = ((s.momentum // 10) + 1) * 10
+        gap = next_tier - s.momentum
+        if 0 < gap <= 3:
+            return f"'{s.name}' is {gap} from the next culture tier."
+        # 5) Generic come-back for active sessions.
+        return f"'{s.name}' is at work; return to claim the next charter."
+
+    # 6) All suspended (game-closed) — give a return invite.
+    return "The chronicles preserve your work. Return when you're ready."
+
+
+def frontier_priority_kind(state: SessionState) -> str:
+    """Return a stable identifier for which frontier kind fired.
+
+    Useful for testing + telemetry. Mirrors next_frontier's branches.
+    """
+    sessions = state.sessions
+    if not sessions:
+        return "first_city"
+    if any(s.status == SessionStatus.REDIRECTED for s in sessions):
+        return "redirected"
+    if any(s.status == SessionStatus.WAITING for s in sessions):
+        return "waiting"
+    if any(s.status == SessionStatus.INACTIVE for s in sessions):
+        return "inactive"
+    actives = [s for s in sessions if s.status == SessionStatus.ACTIVE]
+    if actives:
+        s = max(actives, key=lambda x: x.momentum)
+        next_tier = ((s.momentum // 10) + 1) * 10
+        gap = next_tier - s.momentum
+        if 0 < gap <= 3:
+            return "momentum_tier_up_imminent"
+        return "active_general"
+    return "all_suspended"
diff --git a/bridge/tests/test_frontier.py b/bridge/tests/test_frontier.py
new file mode 100644
index 0000000..4b0d963
--- /dev/null
+++ b/bridge/tests/test_frontier.py
@@ -0,0 +1,127 @@
+"""Tests for the next-frontier helper (PRD acceptance #19)."""
+
+import pytest
+
+from bridge.frontier import frontier_priority_kind, next_frontier
+from bridge.session_state import SessionState, SessionStatus
+
+
+def _state_with_session(name: str, status: SessionStatus, **kwargs) -> SessionState:
+    state = SessionState(kingdom_name="Camelot")
+    s = state.add_session(name)
+    s.status = status
+    for k, v in kwargs.items():
+        setattr(s, k, v)
+    return state
+
+
+# ────────────────────────────────────────────────────────────────────────
+# Always non-empty — acceptance criterion guarantee
+# ────────────────────────────────────────────────────────────────────────
+
+def test_empty_state_yields_first_city_frontier():
+    state = SessionState()
+    out = next_frontier(state)
+    assert out  # non-empty
+    assert "first city" in out.lower()
+    assert frontier_priority_kind(state) == "first_city"
+
+
+def test_all_suspended_state_yields_chronicles_invite():
+    state = SessionState()
+    s1 = state.add_session("X")
+    s1.status = SessionStatus.SUSPENDED
+    s2 = state.add_session("Y")
+    s2.status = SessionStatus.SUSPENDED
+    out = next_frontier(state)
+    assert "chronicles" in out.lower() or "return" in out.lower()
+    assert frontier_priority_kind(state) == "all_suspended"
+
+
+# ────────────────────────────────────────────────────────────────────────
+# Priority ordering
+# ────────────────────────────────────────────────────────────────────────
+
+def test_redirected_takes_priority_over_active():
+    state = SessionState()
+    a = state.add_session("Active")
+    a.status = SessionStatus.ACTIVE
+    a.momentum = 8
+    r = state.add_session("Redirected")
+    r.status = SessionStatus.REDIRECTED
+    assert frontier_priority_kind(state) == "redirected"
+    assert "Redirected" in next_frontier(state)
+
+
+def test_waiting_beats_inactive_and_active_idle():
+    state = SessionState()
+    state.add_session("Inactive").status = SessionStatus.INACTIVE
+    state.add_session("Waiting").status = SessionStatus.WAITING
+    state.add_session("Active").status = SessionStatus.ACTIVE
+    assert frontier_priority_kind(state) == "waiting"
+    assert "Waiting" in next_frontier(state)
+
+
+def test_inactive_beats_active_when_no_redirect_or_waiting():
+    state = SessionState()
+    state.add_session("Inactive").status = SessionStatus.INACTIVE
+    a = state.add_session("Active")
+    a.status = SessionStatus.ACTIVE
+    a.momentum = 4
+    assert frontier_priority_kind(state) == "inactive"
+
+
+# ────────────────────────────────────────────────────────────────────────
+# Active-session frontiers
+# ────────────────────────────────────────────────────────────────────────
+
+def test_active_session_near_culture_tier_calls_out_the_gap():
+    state = _state_with_session("Court", SessionStatus.ACTIVE, momentum=8)
+    out = next_frontier(state)
+    assert frontier_priority_kind(state) == "momentum_tier_up_imminent"
+    assert "2 from" in out  # 10 - 8 = 2
+    assert "culture" in out
+
+
+def test_active_session_far_from_tier_uses_generic_message():
+    state = _state_with_session("Court", SessionStatus.ACTIVE, momentum=4)
+    out = next_frontier(state)
+    assert frontier_priority_kind(state) == "active_general"
+    assert "claim" in out.lower() or "charter" in out.lower()
+
+
+def test_active_at_exact_tier_uses_generic():
+    """At momentum=10 the gap is 10 (next tier 20-10), so generic message."""
+    state = _state_with_session("Court", SessionStatus.ACTIVE, momentum=10)
+    assert frontier_priority_kind(state) == "active_general"
+
+
+def test_active_with_highest_momentum_chosen():
+    """If multiple actives, the one with highest momentum is the frontier."""
+    state = SessionState()
+    a = state.add_session("Low")
+    a.status = SessionStatus.ACTIVE
+    a.momentum = 1
+    b = state.add_session("High")
+    b.status = SessionStatus.ACTIVE
+    b.momentum = 9
+    out = next_frontier(state)
+    assert "High" in out
+    assert "1 from" in out  # 10 - 9 = 1
+
+
+# ────────────────────────────────────────────────────────────────────────
+# String quality — always non-empty, never crashes
+# ────────────────────────────────────────────────────────────────────────
+
+@pytest.mark.parametrize("status", list(SessionStatus))
+def test_every_status_yields_nonempty_frontier(status):
+    state = _state_with_session("X", status, momentum=5)
+    out = next_frontier(state)
+    assert out  # always non-empty
+    assert isinstance(out, str)
+
+
+def test_session_name_in_output_when_session_exists():
+    state = _state_with_session("Funky Royal Court", SessionStatus.WAITING)
+    assert "Funky Royal Court" in next_frontier(state)
diff --git a/docs/audit-2026-05-08.md b/docs/audit-2026-05-08.md
index 0472a42..27e835b 100644
--- a/docs/audit-2026-05-08.md
+++ b/docs/audit-2026-05-08.md
@@ -1,9 +1,15 @@
 # Claude Kingdoms — CTO-Style Audit Against PRD v1.5
 
-**Date:** 2026-05-08
+**Date:** 2026-05-08 (updated 14:00 PDT after the 5-hour supervision sprint)
 **Reviewer:** claude-code
-**Repo HEAD:** `4b4b119` (PR #21 merged)
-**Test count on `main`:** 149 passing
+**Repo HEAD:** `ea739ba` (PR #30 merged) → see closure status below for live state
+**Test count on `main`:** 234+ passing (was 149 at audit time)
+
+> **Closure update — every P0 and P1 line item identified in this audit
+> is now closed.** PR refs: #23 (P0 #1 enum), #24 (P0 #3 Stop→COMPLETED),
+> #25 (P0 #2 schema), #26 (BR-9), #27 (#11 + #12), #28 (GM-8), #29
+> (GM-5), #30 (#9 + #20). The original audit grid below is preserved
+> as the historical baseline.
 
 This is a hard-eyed alignment review against `ClaudeKingdomsPRD.md` v1.5.
 It calls out what's truly shipped, where the implementation diverges
diff --git a/tui/app.py b/tui/app.py
index 61a5f7c..2b10801 100644
--- a/tui/app.py
+++ b/tui/app.py
@@ -27,6 +27,7 @@
 
 from bridge.session_state import SessionState, Session, SessionStatus
 from bridge.scoring import ScoringEngine, SimpleScoringStrategy
+from bridge.frontier import next_frontier
 from tui.medieval_voice import MedievalVoice, voice_for_change
 
 # Forward-only import for type hints; BridgeLoop is optional at runtime.
@@ -49,6 +50,10 @@ def render_state(self, state: SessionState) -> str:
                 f"goals={s.goals_completed} momentum={s.momentum} "
                 f"tokens={s.tokens} plans={len(s.plans)}"
             )
+        # PRD acceptance #19: every play session ends with a visible
+        # unresolved frontier — so always show one.
+        lines.append("")
+        lines.append(f"Next: {next_frontier(state)}")
         return "\n".join(lines)