diff --git a/decnet_web/src/components/PersonaGeneration/helpers.test.ts b/decnet_web/src/components/PersonaGeneration/helpers.test.ts
new file mode 100644
index 00000000..29db6c7a
--- /dev/null
+++ b/decnet_web/src/components/PersonaGeneration/helpers.test.ts
@@ -0,0 +1,89 @@
+import { describe, it, expect } from 'vitest';
+import { coercePersona, mergePersonas, validate, BLANK } from './helpers';
+import type { EmailPersona } from './types';
+
+const persona = (over: Partial<EmailPersona> = {}): EmailPersona => ({
+  ...BLANK, name: 'Jane', email: 'jane@example.com', role: 'admin', ...over,
+});
+
+describe('validate', () => {
+  it('rejects missing required fields', () => {
+    expect(validate({ ...BLANK })).toBe('name is required');
+    expect(validate(persona({ email: '' }))).toBe('email is required');
+    expect(validate(persona({ email: 'bad' }))).toMatch(/user@domain/);
+    expect(validate(persona({ role: '' }))).toBe('role is required');
+  });
+
+  it('requires tone_custom when tone=custom', () => {
+    expect(validate(persona({ tone: 'custom' }))).toMatch(/custom tone/);
+    expect(validate(persona({ tone: 'custom', tone_custom: 'wry' }))).toBeNull();
+  });
+
+  it('caps mannerisms at 12', () => {
+    const many = Array.from({ length: 13 }, (_, i) => `m${i}`);
+    expect(validate(persona({ mannerisms: many }))).toMatch(/at most 12/);
+  });
+
+  it('returns null for a valid persona', () => {
+    expect(validate(persona())).toBeNull();
+  });
+});
+
+describe('coercePersona', () => {
+  it('rejects non-objects and missing fields', () => {
+    expect(coercePersona(null)).toEqual({ error: 'entry is not an object' });
+    expect(coercePersona({})).toEqual({ error: 'missing name' });
+    expect(coercePersona({ name: 'a' })).toEqual({ error: 'missing email' });
+    expect(coercePersona({ name: 'a', email: 'a@b.c' })).toEqual({ error: 'missing role' });
+  });
+
+  it('rejects invalid emails', () => {
+    const r = coercePersona({ name: 'a', email: 'noat', role: 'r' });
+    expect('error' in r && r.error).toMatch(/invalid email/);
+  });
+
+  it('clamps mannerisms and slices long tone_custom', () => {
+    const long = 'x'.repeat(200);
+    const r = coercePersona({
+      name: 'a', email: 'a@b.c', role: 'r',
+      tone: 'custom', tone_custom: long,
+      mannerisms: Array.from({ length: 20 }, (_, i) => `m${i}`).concat([42, null]),
+    });
+    expect('ok' in r).toBe(true);
+    if ('ok' in r) {
+      expect(r.ok.tone_custom?.length).toBe(128);
+      expect(r.ok.mannerisms.length).toBe(12);
+      expect(r.ok.mannerisms.every((m) => typeof m === 'string')).toBe(true);
+    }
+  });
+
+  it('falls back tone/reply_latency to defaults on bad input', () => {
+    const r = coercePersona({
+      name: 'a', email: 'a@b.c', role: 'r',
+      tone: 'bogus', reply_latency: 'wat',
+    });
+    expect('ok' in r).toBe(true);
+    if ('ok' in r) {
+      expect(r.ok.tone).toBe('formal');
+      expect(r.ok.reply_latency).toBe('normal');
+    }
+  });
+
+  it('rejects tone=custom without tone_custom', () => {
+    const r = coercePersona({
+      name: 'a', email: 'a@b.c', role: 'r', tone: 'custom',
+    });
+    expect('error' in r && r.error).toMatch(/tone="custom"/);
+  });
+});
+
+describe('mergePersonas', () => {
+  it('adds new and replaces by lowercased email', () => {
+    const current = [persona({ email: 'A@x.com', name: 'old' })];
+    const incoming = [persona({ email: 'a@x.com', name: 'new' }), persona({ email: 'b@x.com' })];
+    const r = mergePersonas(current, incoming);
+    expect(r.added).toBe(1);
+    expect(r.replaced).toBe(1);
+    expect(r.merged.find((p) => p.email.toLowerCase() === 'a@x.com')?.name).toBe('new');
+  });
+});
diff --git a/decnet_web/src/components/PersonaGeneration/helpers.ts b/decnet_web/src/components/PersonaGeneration/helpers.ts
new file mode 100644
index 00000000..e4be38c8
--- /dev/null
+++ b/decnet_web/src/components/PersonaGeneration/helpers.ts
@@ -0,0 +1,124 @@
+import type { ApiError } from '../../utils/api';
+import type { EmailPersona, ReplyLatency, Tone } from './types';
+
+export const TONES: Tone[] = ['formal', 'direct', 'casual', 'technical', 'custom'];
+export const LATENCIES: ReplyLatency[] = ['fast', 'normal', 'slow'];
+
+export const BLANK: EmailPersona = {
+  name: '',
+  email: '',
+  role: '',
+  tone: 'formal',
+  tone_custom: null,
+  mannerisms: [],
+  language: 'en',
+  signature: null,
+  active_hours: '09:00-18:00',
+  reply_latency: 'normal',
+  uses_llms_heavily: false,
+};
+
+export const TEMPLATE: { personas: EmailPersona[] } = {
+  personas: [
+    {
+      name: 'Jane Operator',
+      email: 'jane@example.com',
+      role: 'Network Admin',
+      tone: 'formal',
+      tone_custom: null,
+      mannerisms: ["uses bullet points", "signs off with 'Best regards'"],
+      language: 'en',
+      signature: 'Jane Operator\nNetwork Admin',
+      active_hours: '09:00-18:00',
+      reply_latency: 'normal',
+      uses_llms_heavily: false,
+    },
+  ],
+};
+
+export function extractErrorDetail(err: unknown, fallback: string): string {
+  const e = err as ApiError;
+  if (e?.response?.data?.detail) return e.response.data.detail;
+  if (e?.response?.status === 403) return 'Insufficient permissions (admin only)';
+  if (e?.response?.status === 401) return 'Session expired — please log in again';
+  if (e?.message) return e.message;
+  return fallback;
+}
+
+/** Light client-side validation — server re-validates with the same
+ *  Pydantic schema the worker uses, this is just the early-warn UX. */
+export function validate(p: EmailPersona): string | null {
+  if (!p.name.trim()) return 'name is required';
+  if (!p.email.trim()) return 'email is required';
+  if (!p.email.includes('@') || !p.email.split('@')[1]?.includes('.')) {
+    return 'email must look like user@domain.tld';
+  }
+  if (!p.role.trim()) return 'role is required';
+  if (p.tone === 'custom' && !(p.tone_custom ?? '').trim()) {
+    return 'custom tone requires a description';
+  }
+  if (p.mannerisms.length > 12) return 'at most 12 mannerisms per persona';
+  return null;
+}
+
+/** Soft client-side normalizer for an uploaded persona entry.
+ *  Mirrors the Pydantic rules in decnet/realism/personas.py.
+ *  Server re-validates on save, so this is just early-warn UX. */
+export function coercePersona(raw: unknown): { ok: EmailPersona } | { error: string } {
+  if (!raw || typeof raw !== 'object') return { error: 'entry is not an object' };
+  const r = raw as Record<string, unknown>;
+  const name = typeof r.name === 'string' ? r.name.trim() : '';
+  const email = typeof r.email === 'string' ? r.email.trim() : '';
+  const role = typeof r.role === 'string' ? r.role.trim() : '';
+  if (!name) return { error: 'missing name' };
+  if (!email) return { error: 'missing email' };
+  if (!email.includes('@') || !email.split('@')[1]?.includes('.')) {
+    return { error: `invalid email "${email}"` };
+  }
+  if (!role) return { error: 'missing role' };
+  const tone = TONES.includes(r.tone as Tone) ? (r.tone as Tone) : 'formal';
+  const tone_custom = typeof r.tone_custom === 'string' && r.tone_custom.trim()
+    ? r.tone_custom.slice(0, 128) : null;
+  if (tone === 'custom' && !tone_custom) {
+    return { error: 'tone="custom" requires a non-empty tone_custom' };
+  }
+  const reply_latency = LATENCIES.includes(r.reply_latency as ReplyLatency)
+    ? (r.reply_latency as ReplyLatency) : 'normal';
+  const mannerisms = Array.isArray(r.mannerisms)
+    ? r.mannerisms.filter((m): m is string => typeof m === 'string').slice(0, 12)
+    : [];
+  const language = typeof r.language === 'string' && r.language
+    ? r.language.slice(0, 8) : null;
+  const signature = typeof r.signature === 'string' && r.signature
+    ? r.signature : null;
+  const active_hours = typeof r.active_hours === 'string' && r.active_hours
+    ? r.active_hours : '09:00-18:00';
+  return {
+    ok: {
+      name, email, role, tone, tone_custom, mannerisms, language, signature,
+      active_hours, reply_latency,
+      uses_llms_heavily: r.uses_llms_heavily === true,
+    },
+  };
+}
+
+export interface MergeResult {
+  merged: EmailPersona[];
+  added: number;
+  replaced: number;
+}
+
+/** Dedupe by lowercased email; uploaded entries replace existing matches. */
+export function mergePersonas(current: EmailPersona[], incoming: EmailPersona[]): MergeResult {
+  const byEmail = new Map<string, EmailPersona>();
+  for (const p of current) byEmail.set(p.email.toLowerCase(), p);
+  let added = 0;
+  let replaced = 0;
+  for (const p of incoming) {
+    const key = p.email.toLowerCase();
+    if (byEmail.has(key)) replaced += 1;
+    else added += 1;
+    byEmail.set(key, p);
+  }
+  return { merged: Array.from(byEmail.values()), added, replaced };
+}
diff --git a/decnet_web/src/components/PersonaGeneration/types.ts b/decnet_web/src/components/PersonaGeneration/types.ts
new file mode 100644
index 00000000..5f3691e8
--- /dev/null
+++ b/decnet_web/src/components/PersonaGeneration/types.ts
@@ -0,0 +1,25 @@
+export type Tone = 'formal' | 'direct' | 'casual' | 'technical' | 'custom';
+export type ReplyLatency = 'fast' | 'normal' | 'slow';
+
+export interface EmailPersona {
+  name: string;
+  email: string;
+  role: string;
+  tone: Tone;
+  tone_custom: string | null;
+  mannerisms: string[];
+  language: string | null;
+  signature: string | null;
+  active_hours: string;
+  reply_latency: ReplyLatency;
+  uses_llms_heavily: boolean;
+}
+
+export interface PersonasResponse {
+  path?: string;
+  topology_name?: string;
+  language_default?: string;
+  personas: EmailPersona[];
+}
+
+export type FilterKey = 'all' | Tone;