diff --git a/.codex/DELEGATION.md b/.codex/DELEGATION.md
index 52ff3c8..4f5f049 100644
--- a/.codex/DELEGATION.md
+++ b/.codex/DELEGATION.md
@@ -42,7 +42,7 @@ codex exec --json --sandbox read-only \
 
 ```bash
 codex exec --json --sandbox workspace-write \
-  --ask-for-approval on-request \
+  -c approval_policy="on-request" \
   -c approvals_reviewer=auto_review \
   -c sandbox_workspace_write.network_access=false \
   -c model="$CODEX_MODEL" \
diff --git a/.gitignore b/.gitignore
index 7a28f25..9906785 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,3 +11,6 @@ inspect/
 
 # Codex exec run packets (external-subagent transcripts)
 .codex-runs/
+
+# TypeScript incremental build cache
+*.tsbuildinfo
diff --git a/scripts/codex-run.sh b/scripts/codex-run.sh
index d580941..5b260aa 100755
--- a/scripts/codex-run.sh
+++ b/scripts/codex-run.sh
@@ -44,8 +44,11 @@ if [ "$ROLE" = "explorer" ]; then
     -c model="$CODEX_MODEL" \
     --output-schema "$SCHEMA" -o "$RUN/result.json" "$(cat "$RUN/task.md")"
 else
+  # codex-cli `exec` has no --ask-for-approval flag; approval policy is a
+  # config override. on-request + auto_review lets it self-unblock without
+  # an interactive approver. Sandbox stays workspace-write, network off.
   set -- codex exec --json --sandbox workspace-write \
-    --ask-for-approval on-request \
+    -c approval_policy="on-request" \
     -c approvals_reviewer=auto_review \
     -c sandbox_workspace_write.network_access=false \
     -c model="$CODEX_MODEL" \
diff --git a/src/sim/phylogeny.test.ts b/src/sim/phylogeny.test.ts
new file mode 100644
index 0000000..9984c20
--- /dev/null
+++ b/src/sim/phylogeny.test.ts
@@ -0,0 +1,122 @@
+import { describe, expect, it } from "vitest";
+import { computePhylogeny } from "./phylogeny";
+import type { Species } from "./types";
+
+describe("computePhylogeny", () => {
+  const species = (values: Partial<Species>): Species => ({
+    id: values.id ?? 1,
+    parentId: values.parentId ?? null,
+    color: values.color ?? "#000000",
+    centroid: values.centroid ?? ({} as any),
+    bornTick: values.bornTick ?? 0,
+    population: values.population ?? 10,
+    peakPopulation: values.peakPopulation ?? 10,
+    ...values,
+  });
+
+  it("returns empty layout for empty input", () => {
+    const result = computePhylogeny({}, 1234);
+
+    expect(result.nodes).toEqual([]);
+    expect(result.links).toEqual([]);
+    expect(result.rows).toBe(1);
+    expect(result.t0).toBe(0);
+  });
+
+  it("filters out species with peakPopulation below minPeak", () => {
+    const speciesById: Record<number, Species> = {
+      1: species({ id: 1, parentId: null, peakPopulation: 5 }),
+      2: species({ id: 2, parentId: 1, peakPopulation: 9 }),
+      3: species({ id: 3, parentId: 1, peakPopulation: 11 }),
+    };
+
+    const result = computePhylogeny(speciesById, 100, { minPeak: 10 });
+
+    const ids = result.nodes.map((n) => n.id);
+    expect(ids).toEqual([3]);
+  });
+
+  it("relinks through pruned intermediates to nearest kept ancestor", () => {
+    const speciesById: Record<number, Species> = {
+      1: species({ id: 1, parentId: null, peakPopulation: 20 }),
+      2: species({ id: 2, parentId: 1, peakPopulation: 4 }),
+      3: species({ id: 3, parentId: 2, peakPopulation: 30 }),
+    };
+
+    const result = computePhylogeny(speciesById, 100, { minPeak: 10 });
+    const keptNode = result.nodes.find((n) => n.id === 3);
+
+    expect(keptNode?.parentId).toBe(1);
+
+    const linksForNode = result.links.filter((l) => l.child.id === 3);
+    expect(linksForNode).toHaveLength(1);
+    expect(linksForNode[0]?.parent.id).toBe(1);
+  });
+
+  it("sets alive false when extinctTick is present", () => {
+    const speciesById: Record<number, Species> = {
+      1: species({
+        id: 1,
+        parentId: null,
+        peakPopulation: 20,
+        extinctTick: 3,
+        population: 8,
+      }),
+      2: species({
+        id: 2,
+        parentId: 1,
+        peakPopulation: 20,
+        extinctTick: undefined,
+        population: 12,
+      }),
+    };
+
+    const result = computePhylogeny(speciesById, 50);
+    const extinct = result.nodes.find((n) => n.id === 1);
+    const alive = result.nodes.find((n) => n.id === 2);
+
+    expect(extinct?.alive).toBe(false);
+    expect(extinct?.endTick).toBe(3);
+    expect(alive?.alive).toBe(true);
+    expect(alive?.endTick).toBe(50);
+  });
+
+  it("keeps the most significant lineages when maxNodes is hit", () => {
+    const speciesById: Record<number, Species> = {
+      1: species({ id: 1, peakPopulation: 5 }),
+      2: species({ id: 2, peakPopulation: 50 }),
+      3: species({ id: 3, peakPopulation: 30 }),
+      4: species({ id: 4, peakPopulation: 20 }),
+      5: species({ id: 5, peakPopulation: 15 }),
+      6: species({ id: 6, peakPopulation: 10 }),
+    };
+
+    const result = computePhylogeny(speciesById, 20, {
+      minPeak: 0,
+      maxNodes: 3,
+    });
+
+    const ids = new Set(result.nodes.map((n) => n.id));
+    expect(result.nodes).toHaveLength(3);
+    expect(ids.has(2)).toBe(true);
+    expect(ids.has(3)).toBe(true);
+    expect(ids.has(4)).toBe(true);
+  });
+
+  it("assigns unique rows and computes t0 with bornTick bounds", () => {
+    const speciesById: Record<number, Species> = {
+      1: species({ id: 1, parentId: null, bornTick: 10, peakPopulation: 100 }),
+      2: species({ id: 2, parentId: 1, bornTick: 0, peakPopulation: 90 }),
+      3: species({ id: 3, parentId: 1, bornTick: 5, peakPopulation: 80 }),
+      4: species({ id: 4, parentId: 2, bornTick: -5, peakPopulation: 70 }),
+    };
+
+    const result = computePhylogeny(speciesById, 20, { minPeak: 0 });
+
+    const rows = result.nodes.map((n) => n.row);
+    const uniqueRows = new Set(rows);
+    expect(uniqueRows.size).toBe(result.nodes.length);
+    expect(result.rows).toBe(result.nodes.length);
+    expect(result.t0).toBeLessThanOrEqual(-5);
+  });
+});
diff --git a/tsconfig.tsbuildinfo b/tsconfig.tsbuildinfo
deleted file mode 100644
index 1353151..0000000
--- a/tsconfig.tsbuildinfo
+++ /dev/null
@@ -1 +0,0 @@
-{"root":["./src/app.tsx","./src/main.tsx","./src/store.ts","./src/narrator/heuristic.ts","./src/narrator/llm.ts","./src/render/worldcanvas.tsx","./src/render/palette.ts","./src/sim/config.ts","./src/sim/events.ts","./src/sim/genome.ts","./src/sim/history.ts","./src/sim/phylogeny.ts","./src/sim/protocol.ts","./src/sim/rng.ts","./src/sim/sim.test.ts","./src/sim/simulation.ts","./src/sim/spatial.ts","./src/sim/speciation.ts","./src/sim/stats.ts","./src/sim/types.ts","./src/sim/worker.ts","./src/sim/world.ts","./src/ui/controls.tsx","./src/ui/creatureinspector.tsx","./src/ui/eventslog.tsx","./src/ui/narratorpanel.tsx","./src/ui/phylogeny.tsx","./src/ui/shockpanel.tsx","./src/ui/statspanel.tsx","./src/ui/timeline.tsx","./scripts/headless.ts","./scripts/inspect.ts","./scripts/narrator-server.ts","./scripts/lib/dashboard.ts","./scripts/lib/font.ts","./scripts/lib/phylo.ts","./scripts/lib/png.ts","./scripts/lib/render.ts","./vite.config.ts"],"version":"5.9.3"}
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