diff --git a/plugins/voyage/lib/validators/profile-validator.mjs b/plugins/voyage/lib/validators/profile-validator.mjs
new file mode 100644
index 0000000..48e84d6
--- /dev/null
+++ b/plugins/voyage/lib/validators/profile-validator.mjs
@@ -0,0 +1,184 @@
+// lib/validators/profile-validator.mjs
+// Validate model-profile YAML files (lib/profiles/*.yaml + custom voyage-profiles/*.yaml).
+//
+// Profile schema (v4.1, profile_version 1.0):
+//   name                       : string
+//   phase_models               : list-of-dicts [{phase: string, model: string}, ...]
+//                                  6 entries required (brief, research, plan, execute, review, continue)
+//   parallel_agents_min        : number (≥ 1)
+//   parallel_agents_max        : number (≥ parallel_agents_min)
+//   external_research_enabled  : boolean
+//   brief_reviewer_iter_cap    : number (≥ 1)
+//
+// Issue codes:
+//   PROFILE_MISSING_FIELD  — required top-level frontmatter field absent
+//   PROFILE_INVALID_MODEL  — phase_models[N].model not in allowlist
+//   PROFILE_INVALID_ENUM   — wrong-type value (e.g. external_research_enabled is string)
+//   PROFILE_READ_ERROR     — file unreadable or parse-error
+//   PROFILE_NOT_FOUND      — file does not exist
+//
+// Allowed model values: ['sonnet', 'opus']. Haiku is allowed only when
+// VOYAGE_ALLOW_HAIKU=1 (per global CLAUDE.md modellvalg-prinsipp: Haiku skal
+// ikke brukes som default; eksplisitt opt-in for spesielle bruksmønstre).
+
+import { readFileSync, existsSync } from 'node:fs';
+import { parseDocument } from '../util/frontmatter.mjs';
+import { issue, ok, fail } from '../util/result.mjs';
+
+export const PROFILE_REQUIRED_FIELDS = Object.freeze([
+  'name',
+  'phase_models',
+  'parallel_agents_min',
+  'parallel_agents_max',
+  'external_research_enabled',
+  'brief_reviewer_iter_cap',
+]);
+
+export const PROFILE_REQUIRED_PHASES = Object.freeze([
+  'brief', 'research', 'plan', 'execute', 'review', 'continue',
+]);
+
+const BASE_ALLOWED_MODELS = Object.freeze(['sonnet', 'opus']);
+
+function getAllowedModels(env = process.env) {
+  if (env.VOYAGE_ALLOW_HAIKU === '1') {
+    return [...BASE_ALLOWED_MODELS, 'haiku'];
+  }
+  return BASE_ALLOWED_MODELS;
+}
+
+export function validateProfileContent(text, opts = {}) {
+  const env = opts.env || process.env;
+  const allowedModels = getAllowedModels(env);
+
+  const doc = parseDocument(text);
+  if (!doc.valid) {
+    return fail(issue('PROFILE_READ_ERROR', `Frontmatter parse error: ${doc.errors[0]?.message || 'unknown'}`));
+  }
+
+  const fm = doc.parsed.frontmatter || {};
+  const errors = [];
+  const warnings = [];
+
+  // Required field presence
+  for (const k of PROFILE_REQUIRED_FIELDS) {
+    if (!(k in fm)) {
+      errors.push(issue('PROFILE_MISSING_FIELD', `Required profile field missing: ${k}`));
+    }
+  }
+
+  // Type checks for scalar fields
+  if ('name' in fm && typeof fm.name !== 'string') {
+    errors.push(issue('PROFILE_INVALID_ENUM', `name must be string (got ${typeof fm.name})`));
+  }
+
+  if ('parallel_agents_min' in fm && typeof fm.parallel_agents_min !== 'number') {
+    errors.push(issue('PROFILE_INVALID_ENUM',
+      `parallel_agents_min must be number (got ${typeof fm.parallel_agents_min})`));
+  }
+
+  if ('parallel_agents_max' in fm && typeof fm.parallel_agents_max !== 'number') {
+    errors.push(issue('PROFILE_INVALID_ENUM',
+      `parallel_agents_max must be number (got ${typeof fm.parallel_agents_max})`));
+  }
+
+  if (typeof fm.parallel_agents_min === 'number' && typeof fm.parallel_agents_max === 'number') {
+    if (fm.parallel_agents_max < fm.parallel_agents_min) {
+      errors.push(issue('PROFILE_INVALID_ENUM',
+        `parallel_agents_max (${fm.parallel_agents_max}) < parallel_agents_min (${fm.parallel_agents_min})`));
+    }
+  }
+
+  if ('external_research_enabled' in fm && typeof fm.external_research_enabled !== 'boolean') {
+    errors.push(issue('PROFILE_INVALID_ENUM',
+      `external_research_enabled must be boolean (got ${typeof fm.external_research_enabled})`));
+  }
+
+  if ('brief_reviewer_iter_cap' in fm && typeof fm.brief_reviewer_iter_cap !== 'number') {
+    errors.push(issue('PROFILE_INVALID_ENUM',
+      `brief_reviewer_iter_cap must be number (got ${typeof fm.brief_reviewer_iter_cap})`));
+  }
+
+  // phase_models validation
+  if ('phase_models' in fm) {
+    if (!Array.isArray(fm.phase_models)) {
+      errors.push(issue('PROFILE_INVALID_ENUM', `phase_models must be a list-of-dicts (got ${typeof fm.phase_models})`));
+    } else {
+      const seenPhases = new Set();
+      for (let i = 0; i < fm.phase_models.length; i++) {
+        const entry = fm.phase_models[i];
+        if (!entry || typeof entry !== 'object') {
+          errors.push(issue('PROFILE_INVALID_ENUM',
+            `phase_models[${i}] must be a dict {phase, model} (got ${typeof entry})`,
+            undefined,
+            `phase_models[${i}]`));
+          continue;
+        }
+        if (typeof entry.phase !== 'string') {
+          errors.push(issue('PROFILE_INVALID_ENUM',
+            `phase_models[${i}].phase must be string`,
+            undefined,
+            `phase_models[${i}].phase`));
+        } else {
+          seenPhases.add(entry.phase);
+          if (!PROFILE_REQUIRED_PHASES.includes(entry.phase)) {
+            errors.push(issue('PROFILE_INVALID_ENUM',
+              `phase_models[${i}].phase "${entry.phase}" not in [${PROFILE_REQUIRED_PHASES.join(', ')}]`,
+              undefined,
+              `phase_models[${i}].phase`));
+          }
+        }
+        if (typeof entry.model !== 'string') {
+          errors.push(issue('PROFILE_INVALID_MODEL',
+            `phase_models[${i}].model must be string`,
+            undefined,
+            `phase_models[${i}].model`));
+        } else if (!allowedModels.includes(entry.model)) {
+          errors.push(issue('PROFILE_INVALID_MODEL',
+            `phase_models[${i}].model "${entry.model}" not in [${allowedModels.join(', ')}]` +
+              (entry.model === 'haiku' ? ' (set VOYAGE_ALLOW_HAIKU=1 to allow)' : ''),
+            undefined,
+            `phase_models[${i}].model`));
+        }
+      }
+      // All 6 required phases must be present
+      for (const required of PROFILE_REQUIRED_PHASES) {
+        if (!seenPhases.has(required)) {
+          errors.push(issue('PROFILE_MISSING_FIELD',
+            `phase_models missing required phase entry: ${required}`));
+        }
+      }
+    }
+  }
+
+  return { valid: errors.length === 0, errors, warnings, parsed: { frontmatter: fm } };
+}
+
+export function validateProfile(filePath, opts = {}) {
+  if (!existsSync(filePath)) {
+    return fail(issue('PROFILE_NOT_FOUND', `Profile file not found: ${filePath}`));
+  }
+  let text;
+  try { text = readFileSync(filePath, 'utf-8'); }
+  catch (e) { return fail(issue('PROFILE_READ_ERROR', `Cannot read ${filePath}: ${e.message}`)); }
+  const r = validateProfileContent(text, opts);
+  return { ...r, parsed: { ...(r.parsed || {}), filePath } };
+}
+
+if (import.meta.url === `file://${process.argv[1]}`) {
+  const args = process.argv.slice(2);
+  const filePath = args.find(a => !a.startsWith('--'));
+  if (!filePath) {
+    process.stderr.write('Usage: profile-validator.mjs [--json] <profile.yaml>\n');
+    process.exit(2);
+  }
+  const r = validateProfile(filePath);
+  if (args.includes('--json')) {
+    process.stdout.write(JSON.stringify({ valid: r.valid, errors: r.errors, warnings: r.warnings }, null, 2) + '\n');
+  } else {
+    process.stdout.write(`profile-validator: ${r.valid ? 'PASS' : 'FAIL'} ${filePath}\n`);
+    for (const e of r.errors) process.stderr.write(`  ERROR  [${e.code}] ${e.message}${e.location ? ' at ' + e.location : ''}\n`);
+    for (const w of r.warnings) process.stderr.write(`  WARN   [${w.code}] ${w.message}\n`);
+  }
+  process.exit(r.valid ? 0 : 1);
+}
diff --git a/plugins/voyage/tests/fixtures/profile-invalid-enum.yaml b/plugins/voyage/tests/fixtures/profile-invalid-enum.yaml
new file mode 100644
index 0000000..34ea789
--- /dev/null
+++ b/plugins/voyage/tests/fixtures/profile-invalid-enum.yaml
@@ -0,0 +1,21 @@
+---
+profile_version: "1.0"
+name: invalid-enum
+phase_models:
+  - phase: brief
+    model: sonnet
+  - phase: research
+    model: sonnet
+  - phase: plan
+    model: opus
+  - phase: execute
+    model: sonnet
+  - phase: review
+    model: opus
+  - phase: continue
+    model: sonnet
+parallel_agents_min: 4
+parallel_agents_max: 6
+external_research_enabled: "yes"
+brief_reviewer_iter_cap: 2
+---
diff --git a/plugins/voyage/tests/fixtures/profile-invalid-model.yaml b/plugins/voyage/tests/fixtures/profile-invalid-model.yaml
new file mode 100644
index 0000000..7dfb028
--- /dev/null
+++ b/plugins/voyage/tests/fixtures/profile-invalid-model.yaml
@@ -0,0 +1,21 @@
+---
+profile_version: "1.0"
+name: invalid-model
+phase_models:
+  - phase: brief
+    model: sonnet
+  - phase: research
+    model: sonnet
+  - phase: plan
+    model: gpt-4
+  - phase: execute
+    model: sonnet
+  - phase: review
+    model: opus
+  - phase: continue
+    model: sonnet
+parallel_agents_min: 2
+parallel_agents_max: 4
+external_research_enabled: false
+brief_reviewer_iter_cap: 2
+---
diff --git a/plugins/voyage/tests/validators/profile-validator.test.mjs b/plugins/voyage/tests/validators/profile-validator.test.mjs
new file mode 100644
index 0000000..c0e5792
--- /dev/null
+++ b/plugins/voyage/tests/validators/profile-validator.test.mjs
@@ -0,0 +1,150 @@
+// tests/validators/profile-validator.test.mjs
+// SC #1, #2, #3: profile-validator validates lib/profiles/{economy,balanced,premium}.yaml
+// (innebygde profiler) plus rejects invalid models and invalid enum types.
+
+import { test } from 'node:test';
+import { strict as assert } from 'node:assert';
+import { join } from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { dirname } from 'node:path';
+import {
+  validateProfile,
+  validateProfileContent,
+  PROFILE_REQUIRED_FIELDS,
+  PROFILE_REQUIRED_PHASES,
+} from '../../lib/validators/profile-validator.mjs';
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const REPO_ROOT = join(__dirname, '..', '..');
+
+// SC #1: alle 3 innebygde profiler grønne
+
+for (const profileName of ['economy', 'balanced', 'premium']) {
+  test(`SC #1: lib/profiles/${profileName}.yaml validates clean`, () => {
+    const r = validateProfile(join(REPO_ROOT, 'lib', 'profiles', `${profileName}.yaml`));
+    assert.equal(r.valid, true,
+      `expected valid, got errors: ${JSON.stringify(r.errors, null, 2)}`);
+    assert.equal(r.errors.length, 0);
+    // Spot-check: all 6 phases present
+    const phases = r.parsed.frontmatter.phase_models.map(p => p.phase);
+    for (const required of PROFILE_REQUIRED_PHASES) {
+      assert.ok(phases.includes(required), `${profileName} missing phase: ${required}`);
+    }
+  });
+}
+
+// SC #2: PROFILE_INVALID_MODEL fired when phase_models[N].model not in allowlist
+
+test('SC #2: profile-invalid-model.yaml rejected with PROFILE_INVALID_MODEL at phase_models[2].model', () => {
+  const r = validateProfile(join(REPO_ROOT, 'tests', 'fixtures', 'profile-invalid-model.yaml'));
+  assert.equal(r.valid, false);
+  const found = r.errors.find(e => e.code === 'PROFILE_INVALID_MODEL');
+  assert.ok(found, `expected PROFILE_INVALID_MODEL, got: ${JSON.stringify(r.errors)}`);
+  assert.equal(found.location, 'phase_models[2].model',
+    `expected location phase_models[2].model, got ${found.location}`);
+  assert.match(found.message, /gpt-4/);
+});
+
+// SC #3: PROFILE_INVALID_ENUM for wrong-type values
+
+test('SC #3: profile-invalid-enum.yaml rejected with PROFILE_INVALID_ENUM (external_research_enabled is string)', () => {
+  const r = validateProfile(join(REPO_ROOT, 'tests', 'fixtures', 'profile-invalid-enum.yaml'));
+  assert.equal(r.valid, false);
+  const found = r.errors.find(e => e.code === 'PROFILE_INVALID_ENUM' && /external_research_enabled/.test(e.message));
+  assert.ok(found, `expected PROFILE_INVALID_ENUM for external_research_enabled, got: ${JSON.stringify(r.errors)}`);
+  assert.match(found.message, /boolean/);
+});
+
+// VOYAGE_ALLOW_HAIKU env-var allows haiku model
+
+test('VOYAGE_ALLOW_HAIKU=1 allows haiku in phase_models', () => {
+  const haikuProfile = `---
+profile_version: "1.0"
+name: haiku-allowed
+phase_models:
+  - phase: brief
+    model: haiku
+  - phase: research
+    model: sonnet
+  - phase: plan
+    model: opus
+  - phase: execute
+    model: sonnet
+  - phase: review
+    model: opus
+  - phase: continue
+    model: sonnet
+parallel_agents_min: 2
+parallel_agents_max: 4
+external_research_enabled: false
+brief_reviewer_iter_cap: 1
+---
+`;
+  // Default env: haiku rejected
+  const denied = validateProfileContent(haikuProfile, { env: { /* no VOYAGE_ALLOW_HAIKU */ } });
+  assert.equal(denied.valid, false);
+  const haikuErr = denied.errors.find(e => e.code === 'PROFILE_INVALID_MODEL' && /haiku/.test(e.message));
+  assert.ok(haikuErr, `expected haiku rejection: ${JSON.stringify(denied.errors)}`);
+  assert.match(haikuErr.message, /VOYAGE_ALLOW_HAIKU/);
+
+  // With opt-in: haiku accepted
+  const allowed = validateProfileContent(haikuProfile, { env: { VOYAGE_ALLOW_HAIKU: '1' } });
+  assert.equal(allowed.valid, true,
+    `expected valid with VOYAGE_ALLOW_HAIKU=1, got: ${JSON.stringify(allowed.errors)}`);
+});
+
+// Required fields presence
+
+test('PROFILE_MISSING_FIELD when name absent', () => {
+  const r = validateProfileContent(`---
+profile_version: "1.0"
+phase_models:
+  - phase: brief
+    model: sonnet
+  - phase: research
+    model: sonnet
+  - phase: plan
+    model: opus
+  - phase: execute
+    model: sonnet
+  - phase: review
+    model: opus
+  - phase: continue
+    model: sonnet
+parallel_agents_min: 2
+parallel_agents_max: 4
+external_research_enabled: false
+brief_reviewer_iter_cap: 1
+---
+`);
+  assert.equal(r.valid, false);
+  const found = r.errors.find(e => e.code === 'PROFILE_MISSING_FIELD' && /name/.test(e.message));
+  assert.ok(found, `expected PROFILE_MISSING_FIELD for name, got: ${JSON.stringify(r.errors)}`);
+});
+
+// PROFILE_NOT_FOUND for missing file
+
+test('PROFILE_NOT_FOUND for non-existent file', () => {
+  const r = validateProfile('/tmp/does-not-exist-profile-xyz.yaml');
+  assert.equal(r.valid, false);
+  assert.ok(r.errors.find(e => e.code === 'PROFILE_NOT_FOUND'));
+});
+
+// REQUIRED_FIELDS frontmatter contract drift-pin
+
+test('PROFILE_REQUIRED_FIELDS export drift-pin', () => {
+  assert.deepEqual(
+    [...PROFILE_REQUIRED_FIELDS].sort(),
+    ['brief_reviewer_iter_cap', 'external_research_enabled', 'name',
+     'parallel_agents_max', 'parallel_agents_min', 'phase_models'].sort(),
+    'PROFILE_REQUIRED_FIELDS contract drift — pin contract',
+  );
+});
+
+test('PROFILE_REQUIRED_PHASES export drift-pin', () => {
+  assert.deepEqual(
+    [...PROFILE_REQUIRED_PHASES].sort(),
+    ['brief', 'research', 'plan', 'execute', 'review', 'continue'].sort(),
+    'PROFILE_REQUIRED_PHASES contract drift — pin contract',
+  );
+});