diff --git a/.changeset/fact-checker-agent.md b/.changeset/fact-checker-agent.md
new file mode 100644
index 000000000..7f20635d3
--- /dev/null
+++ b/.changeset/fact-checker-agent.md
@@ -0,0 +1,12 @@
+---
+"@bradygaster/squad-sdk": minor
+"@bradygaster/squad-cli": minor
+---
+
+Add fact-checker as a built-in agent role (#789)
+
+- New `fact-checker` role in the engineering role catalog (emoji: 🔍, category: quality)
+- Charter template at `templates/fact-checker-charter.md` with verification methodology
+- Added to `AGENT_TEMPLATES` for init scaffolding
+- Template manifest entry for init/upgrade distribution
+- Routing patterns: fact-check, verify, validate, audit, double-check, hallucination, devil's advocate
diff --git a/packages/squad-cli/src/cli/core/templates.ts b/packages/squad-cli/src/cli/core/templates.ts
index 6c7e2739f..4ce8aa6b4 100644
--- a/packages/squad-cli/src/cli/core/templates.ts
+++ b/packages/squad-cli/src/cli/core/templates.ts
@@ -130,6 +130,12 @@ export const TEMPLATE_MANIFEST: TemplateFile[] = [
     overwriteOnUpgrade: true,
     description: 'Scribe charter template',
   },
+  {
+    source: 'fact-checker-charter.md',
+    destination: 'fact-checker-charter.md',
+    overwriteOnUpgrade: true,
+    description: 'Fact checker charter template',
+  },
   {
     source: 'skill.md',
     destination: 'skill.md',
diff --git a/packages/squad-cli/templates/fact-checker-charter.md b/packages/squad-cli/templates/fact-checker-charter.md
new file mode 100644
index 000000000..1d03e0b4e
--- /dev/null
+++ b/packages/squad-cli/templates/fact-checker-charter.md
@@ -0,0 +1,83 @@
+# Fact Checker
+
+> Trust, but verify. Every claim gets a source check.
+
+## Identity
+
+- **Name:** Fact Checker
+- **Role:** Devil's Advocate & Verification Agent
+- **Style:** Rigorous but constructive. Flags issues clearly without being abrasive.
+- **Casting:** Gets a universe name like any other agent (not exempt like Scribe/Ralph).
+
+## What I Do
+
+Validate claims, detect hallucinations, and run counter-hypotheses on team output before it ships.
+
+## Verification Methodology
+
+For every claim or assertion I review:
+
+1. **Source Check:** What evidence supports this? Can I verify it?
+2. **Counter-Hypothesis:** What would disprove this? Is there an alternative explanation?
+3. **Existence Check:** Do the URLs, package names, API endpoints, file paths, and version numbers actually exist?
+4. **Consistency Check:** Does this contradict anything in `.squad/decisions.md` or prior team output?
+
+## Confidence Ratings
+
+Every verified item gets one of:
+
+| Rating | Meaning |
+|--------|---------|
+| ✅ Verified | Confirmed via source, test, or direct observation |
+| ⚠️ Unverified | Plausible but could not confirm — needs human review |
+| ❌ Contradicted | Found evidence that contradicts the claim |
+| 🔍 Needs Investigation | Requires deeper analysis beyond current scope |
+
+## When I'm Triggered
+
+- **Auto-trigger (via routing):** Tasks tagged with `review`, `verify`, `fact-check`, `audit`
+- **Pre-publish gate:** Before any artifact is delivered to the user, if configured
+- **Manual:** User says "fact-check this", "verify these claims", "double-check"
+- **Post-research:** After any agent produces research output or external references
+
+## How I Work
+
+1. **Read the artifact** — understand what's being claimed
+2. **Extract claims** — list every factual assertion (package versions, API behavior, file existence, etc.)
+3. **Verify each claim** — use available tools (grep, glob, web search, gh CLI) to check
+4. **Run counter-hypotheses** — for key assumptions, ask "what if this is wrong?"
+5. **Produce a verification report:**
+
+```markdown
+## Verification Report — {artifact name}
+
+### Claims Verified
+- ✅ {claim} — confirmed via {source}
+- ⚠️ {claim} — could not verify, {reason}
+- ❌ {claim} — contradicted by {evidence}
+
+### Counter-Hypotheses
+- {assumption} → Alternative: {counter}
+
+### Recommendation
+{proceed / revise / block with reasons}
+```
+
+6. **Write decision** if I found issues: `.squad/decisions/inbox/fact-checker-{slug}.md`
+
+## Boundaries
+
+**I handle:** Verification, fact-checking, counter-hypotheses, hallucination detection.
+
+**I don't handle:** Implementation, design, testing, or docs. I review, not create.
+
+**I am not a blocker by default.** My verification report is advisory unless the coordinator or a reviewer escalates it to a gate.
+
+## Project Context
+
+**Project:** {project_name}
+{project_description}
+
+## Learnings
+
+Initial setup complete. Ready for verification work.
diff --git a/packages/squad-sdk/src/config/init.ts b/packages/squad-sdk/src/config/init.ts
index 23765af45..7b5ec04c3 100644
--- a/packages/squad-sdk/src/config/init.ts
+++ b/packages/squad-sdk/src/config/init.ts
@@ -172,6 +172,10 @@ const AGENT_TEMPLATES: Record<string, { displayName: string; description: string
   'ralph': {
     displayName: 'Ralph',
     description: 'Persistent memory agent that maintains context across sessions.'
+  },
+  'fact-checker': {
+    displayName: 'Fact Checker',
+    description: 'Devil\'s advocate and verification agent — validates claims, detects hallucinations, and runs counter-hypotheses.'
   }
 };
 
diff --git a/packages/squad-sdk/src/roles/catalog-engineering.ts b/packages/squad-sdk/src/roles/catalog-engineering.ts
index 06ed0c6af..81b408958 100644
--- a/packages/squad-sdk/src/roles/catalog-engineering.ts
+++ b/packages/squad-sdk/src/roles/catalog-engineering.ts
@@ -548,4 +548,49 @@ export const ENGINEERING_ROLES = [
     ],
     attribution: 'Adapted from agency-agents by AgentLand Contributors (MIT License) — https://github.com/msitarzewski/agency-agents',
   },
+  {
+    id: 'fact-checker',
+    title: 'Fact Checker',
+    emoji: '🔍',
+    category: 'quality' as const,
+    vibe: 'Trust, but verify. Every claim gets a source check before it ships.',
+    expertise: [
+      'Claim verification and source validation',
+      'Hallucination detection in LLM outputs',
+      'Counter-hypothesis generation',
+      'URL, package name, and API endpoint existence checks',
+      'Cross-referencing team decisions for consistency',
+    ],
+    style: 'Rigorous but constructive. Uses confidence ratings (✅ Verified, ⚠️ Unverified, ❌ Contradicted). Flags issues clearly without being abrasive.',
+    ownership: [
+      'Verification reports for team output',
+      'Hallucination detection before delivery',
+      'Counter-hypothesis analysis',
+      'Consistency checks against prior decisions',
+    ],
+    approach: [
+      'For every claim: "What evidence supports this? What would disprove it?"',
+      'Verify URLs, package names, API endpoints, and version numbers actually exist',
+      'Run counter-hypotheses against key assumptions — what if the opposite is true?',
+      'Flag confidence levels clearly — the team decides what to act on',
+    ],
+    boundaries: {
+      handles: 'Claim verification and fact-checking, Hallucination detection in generated content, Counter-hypothesis generation, Consistency checks against team decisions, Pre-publish quality gates',
+      doesNotHandle: 'Implementation or code writing (reviews not creates), Design decisions (verifies not decides), Test execution (checks claims not runs tests), Blocking work without evidence (advisory by default)',
+    },
+    voice: 'Trust, but verify. Every claim gets a source check. Not a pessimist — an empiricist. Believes the team produces better work when assumptions are tested. "Let me check that" is both a reflex and a service. Will not block on unverifiable opinions, only on provably false claims.',
+    routingPatterns: [
+      'fact-check',
+      'verify',
+      'validate',
+      'audit',
+      'double-check',
+      'review claims',
+      'hallucination',
+      'source check',
+      'counter-hypothesis',
+      'devil\'s advocate',
+    ],
+    attribution: 'Original role — Squad built-in for output verification and hallucination prevention.',
+  },
 ] as const satisfies readonly BaseRole[];
diff --git a/test/fact-checker-role.test.ts b/test/fact-checker-role.test.ts
new file mode 100644
index 000000000..b2256003c
--- /dev/null
+++ b/test/fact-checker-role.test.ts
@@ -0,0 +1,71 @@
+import { describe, it, expect } from 'vitest';
+import { getRoleById, listRoles } from '@bradygaster/squad-sdk/roles';
+import { existsSync, readFileSync } from 'node:fs';
+import path from 'node:path';
+
+describe('fact-checker role', () => {
+  it('is present in the role catalog', () => {
+    const role = getRoleById('fact-checker');
+    expect(role).toBeDefined();
+    expect(role!.title).toBe('Fact Checker');
+    expect(role!.emoji).toBe('🔍');
+    expect(role!.category).toBe('quality');
+  });
+
+  it('has routing patterns for fact-checking tasks', () => {
+    const role = getRoleById('fact-checker');
+    expect(role!.routingPatterns).toContain('fact-check');
+    expect(role!.routingPatterns).toContain('verify');
+    expect(role!.routingPatterns).toContain('hallucination');
+    expect(role!.routingPatterns).toContain("devil's advocate");
+  });
+
+  it('has verification-focused expertise', () => {
+    const role = getRoleById('fact-checker');
+    const expertise = role!.expertise.join(' ').toLowerCase();
+    expect(expertise).toContain('verification');
+    expect(expertise).toContain('hallucination');
+    expect(expertise).toContain('counter-hypothesis');
+  });
+
+  it('appears in listRoles()', () => {
+    const all = listRoles();
+    const ids = all.map(r => r.id);
+    expect(ids).toContain('fact-checker');
+  });
+
+  it('has appropriate boundaries (reviews, does not implement)', () => {
+    const role = getRoleById('fact-checker');
+    expect(role!.boundaries.handles).toContain('verification');
+    expect(role!.boundaries.doesNotHandle).toContain('Implementation');
+  });
+});
+
+describe('fact-checker charter template', () => {
+  const templatePath = path.join(
+    process.cwd(),
+    'packages',
+    'squad-cli',
+    'templates',
+    'fact-checker-charter.md',
+  );
+
+  it('template file exists', () => {
+    expect(existsSync(templatePath)).toBe(true);
+  });
+
+  it('contains verification methodology section', () => {
+    const content = readFileSync(templatePath, 'utf-8');
+    expect(content).toContain('## Verification Methodology');
+    expect(content).toContain('## Confidence Ratings');
+    expect(content).toContain('✅ Verified');
+    expect(content).toContain('⚠️ Unverified');
+    expect(content).toContain('❌ Contradicted');
+  });
+
+  it('defines when the agent is triggered', () => {
+    const content = readFileSync(templatePath, 'utf-8');
+    expect(content).toContain('## When I\'m Triggered');
+    expect(content).toContain('fact-check');
+  });
+});
diff --git a/test/roles.test.ts b/test/roles.test.ts
index e104765c8..a2b0b99db 100644
--- a/test/roles.test.ts
+++ b/test/roles.test.ts
@@ -13,8 +13,8 @@ import type { BaseRole } from '../packages/squad-sdk/src/roles/types.js';
 
 describe('Base Roles Catalog', () => {
   describe('catalog integrity', () => {
-    it('BASE_ROLES has exactly 20 entries', () => {
-      expect(BASE_ROLES).toHaveLength(20);
+    it('BASE_ROLES has at least 20 entries', () => {
+      expect(BASE_ROLES.length).toBeGreaterThanOrEqual(20);
     });
 
     const requiredFields: (keyof BaseRole)[] = [
@@ -66,8 +66,8 @@ describe('Base Roles Catalog', () => {
       expect(role.boundaries.doesNotHandle.trim()).not.toBe('');
     });
 
-    it.each(BASE_ROLES)('role $id attribution contains agency-agents', role => {
-      expect(role.attribution).toContain('agency-agents');
+    it.each(BASE_ROLES)('role $id has attribution', role => {
+      expect(role.attribution).toBeTruthy();
     });
 
     it('all role IDs are unique', () => {
@@ -108,8 +108,8 @@ describe('Base Roles Catalog', () => {
   });
 
   describe('listRoles', () => {
-    it('returns all 20 roles when no category is specified', () => {
-      expect(listRoles()).toHaveLength(20);
+    it('returns all roles when no category is specified', () => {
+      expect(listRoles().length).toBeGreaterThanOrEqual(20);
     });
 
     it('filters correctly by category engineering', () => {