diff --git a/lib/game/skills.test.ts b/lib/game/skills.test.ts
new file mode 100644
index 0000000..4c11604
--- /dev/null
+++ b/lib/game/skills.test.ts
@@ -0,0 +1,50 @@
+import { describe, expect, it } from 'vitest'
+import type { SkillName } from './crew-costs'
+import { grantXp, levelFromXp, powerForLevel, titleFor, type SkillRow } from './skills'
+const pilot = { name: 'BEN OKONKWO', role: 'PILOT' }
+const row = (crewId: string, skill: SkillName, level: number, xp: number): SkillRow =>
+  ({ saveId: 's1', crewId, skill, level, xp })
+const XP: [number, number][] = [[4, 0], [5, 1], [10, 2], [15, 3], [25, 5], [100, 5]]
+describe('levelFromXp (thresholds [5,10,15,20,25], cap 5)', () => {
+  it('maps cumulative xp → highest level reached', () => {
+    for (const [xp, lvl] of XP) expect(levelFromXp(xp), `xp ${xp}`).toBe(lvl)
+  })
+})
+const POWER: [number, number][] = [[0, 1], [2, 1], [3, 2], [4, 2], [5, 3]]
+describe('powerForLevel (bands [1,1,1,2,2,3])', () => {
+  it('L0–2 → 1 · L3–4 → 2 · L5 → 3', () => {
+    for (const [lvl, p] of POWER) expect(powerForLevel(lvl), `L${lvl}`).toBe(p)
+  })
+})
+describe('grantXp — +1 XP to every listed member; event only on a titled-band crossing', () => {
+  const pilotRows = (): SkillRow[] => [
+    row('c1', 'NAVIGATION', 2, 14), row('c1', 'SCANNING', 0, 0),
+    row('c1', 'ENGINEERING', 0, 0), row('c1', 'RESEARCH', 0, 0),
+  ]
+  it('L0 → L1: xp 4 +1 → 5 (L1), no event (no event for plain L1/L2)', () => {
+    const { rows, events } = grantXp([row('c1', 'NAVIGATION', 0, 4)], ['c1'], 'NAVIGATION', { c1: pilot })
+    expect(rows[0]).toEqual({ saveId: 's1', crewId: 'c1', skill: 'NAVIGATION', level: 1, xp: 5 })
+    expect(events).toEqual([])
+  })
+  it('L2 → L3: xp 14 +1 → 15, SENIOR event in the exact spec §6 text', () => {
+    const { rows, events } = grantXp(pilotRows(), ['c1'], 'NAVIGATION', { c1: pilot })
+    expect(rows.find((r) => r.skill === 'NAVIGATION')!.level).toBe(3)
+    expect(events).toEqual(['BEN OKONKWO is now a SENIOR PILOT — NAVIGATION L3'])
+  })
+  it('L4 → L5: xp 24 +1 → 25, MASTER event', () => {
+    const { events } = grantXp([row('c1', 'NAVIGATION', 4, 24), row('c1', 'SCANNING', 0, 0)], ['c1'], 'NAVIGATION', { c1: pilot })
+    expect(events).toEqual(['BEN OKONKWO is now a MASTER PILOT — NAVIGATION L5'])
+  })
+})
+describe('titleFor — from the member\'s HIGHEST skill level', () => {
+  it('SCIENTIST with SCANNING L3 + RESEARCH L5 → MASTER SCIENTIST (highest wins)', () => {
+    const scientist = { name: 'AVA VANCE', role: 'SCIENTIST' }
+    const rows = [row('c2', 'SCANNING', 3, 15), row('c2', 'RESEARCH', 5, 25), row('c2', 'NAVIGATION', 0, 0), row('c2', 'ENGINEERING', 0, 0)]
+    expect(titleFor(scientist, rows)).toBe('MASTER SCIENTIST')
+  })
+  it('GUNNER with all L0 → null', () => {
+    const gunner = { name: 'RIG HOLLOWAY', role: 'GUNNER' }
+    const rows = [row('c3', 'NAVIGATION', 0, 0), row('c3', 'SCANNING', 0, 0), row('c3', 'ENGINEERING', 0, 0), row('c3', 'RESEARCH', 0, 0)]
+    expect(titleFor(gunner, rows)).toBe(null)
+  })
+})
diff --git a/lib/game/skills.ts b/lib/game/skills.ts
new file mode 100644
index 0000000..cdbb334
--- /dev/null
+++ b/lib/game/skills.ts
@@ -0,0 +1,53 @@
+// Pure skill-progression module (spec §6): XP accrual, level→power, titles. No lib/db imports — operates on plain SkillRow data (Task 12's crew_skills table); the frontend imports it for the CREW-tab display.
+import type { SkillName } from './crew-costs'
+import { POWER_BANDS, XP_THRESHOLDS } from './crew-costs'
+export interface SkillRow {
+  saveId: string
+  crewId: string
+  skill: SkillName
+  level: number
+  xp: number
+}
+export type CrewIdentity = { name: string; role: string }
+// Highest level 0–5 with xp ≥ XP_THRESHOLDS[level−1]; thresholds [5,10,15,20,25], cap 5.
+export function levelFromXp(xp: number): number {
+  let level = 0
+  for (let l = 1; l <= XP_THRESHOLDS.length; l++) if (xp >= XP_THRESHOLDS[l - 1]) level = l
+  return level
+}
+// L0–2 → 1 · L3–4 → 2 · L5 → 3 (direct lookup into crew-costs POWER_BANDS).
+export function powerForLevel(level: number): number {
+  return POWER_BANDS[level]
+}
+// From the member's HIGHEST skill level: ≥5 → "MASTER <ROLE>", ≥3 → "SENIOR <ROLE>", below → null.
+export function titleFor(member: CrewIdentity, skillRows: SkillRow[]): string | null {
+  const highest = skillRows.reduce((max, r) => Math.max(max, r.level), 0)
+  if (highest >= 5) return `MASTER ${member.role}`
+  if (highest >= 3) return `SENIOR ${member.role}`
+  return null
+}
+// +1 XP to every listed member's row for `skill`; returns updated rows + any level-up events. An event
+// fires when the gained skill steps into a titled band (3 → SENIOR, 5 → MASTER), e.g. "BEN OKONKWO is now a SENIOR PILOT — NAVIGATION L3" (title from the member's HIGHEST skill).
+export function grantXp(
+  skillRows: SkillRow[],
+  crewIds: string[],
+  skill: SkillName,
+  members: Record<string, CrewIdentity>,
+): { rows: SkillRow[]; events: string[] } {
+  const rows = skillRows.map((r) =>
+    r.skill === skill && crewIds.includes(r.crewId)
+      ? { ...r, xp: r.xp + 1, level: levelFromXp(r.xp + 1) }
+      : r,
+  )
+  const events: string[] = []
+  for (const crewId of crewIds) {
+    const member = members[crewId]
+    if (!member) continue
+    const newLevel = rows.find((r) => r.crewId === crewId && r.skill === skill)?.level ?? 0
+    if (newLevel === 3 || newLevel === 5) {
+      const title = titleFor(member, rows.filter((r) => r.crewId === crewId))
+      if (title) events.push(`${member.name} is now a ${title} — ${skill} L${newLevel}`)
+    }
+  }
+  return { rows, events }
+}