diff --git a/src/assets/__tests__/cdk-synth-validation.test.ts b/src/assets/__tests__/cdk-synth-validation.test.ts
new file mode 100644
index 00000000..090fae93
--- /dev/null
+++ b/src/assets/__tests__/cdk-synth-validation.test.ts
@@ -0,0 +1,501 @@
+/**
+ * CDK Synthesis Validation Tests
+ *
+ * Validates that realistic agentcore.json configurations can be synthesized
+ * into valid CloudFormation templates by the vended CDK stack.
+ *
+ * These tests catch schema mismatches and construct bugs before deploy time.
+ */
+import { AgentCoreStack } from '../cdk/lib/cdk-stack';
+import { setSessionProjectRoot } from '@aws/agentcore-cdk';
+import type { AgentCoreProjectSpec } from '@aws/agentcore-cdk';
+import * as cdk from 'aws-cdk-lib';
+import { Match, Template } from 'aws-cdk-lib/assertions';
+import { mkdirSync, mkdtempSync, rmSync, writeFileSync } from 'fs';
+import { tmpdir } from 'os';
+import { join } from 'path';
+import { afterAll, beforeAll, describe, it } from 'vitest';
+
+// ─── CFN Resource Types ──────────────────────────────────────────────────────
+
+const CFN_RUNTIME = 'AWS::BedrockAgentCore::Runtime';
+const CFN_MEMORY = 'AWS::BedrockAgentCore::Memory';
+const CFN_EVALUATOR = 'AWS::BedrockAgentCore::Evaluator';
+const CFN_POLICY_ENGINE = 'AWS::BedrockAgentCore::PolicyEngine';
+const CFN_POLICY = 'AWS::BedrockAgentCore::Policy';
+const CFN_ECR_REPO = 'AWS::ECR::Repository';
+const CFN_CODEBUILD = 'AWS::CodeBuild::Project';
+const CFN_IAM_ROLE = 'AWS::IAM::Role';
+
+// ─── Test project directory ──────────────────────────────────────────────────
+// AgentCoreApplication calls findConfigRoot() which walks up from cwd looking
+// for agentcore/agentcore.json. We use setSessionProjectRoot() to point it at
+// our temp directory instead of mutating process.cwd().
+
+let tmpDir: string;
+
+beforeAll(() => {
+  tmpDir = mkdtempSync(join(tmpdir(), 'agentcore-cdk-synth-test-'));
+  const agentcoreDir = join(tmpDir, 'agentcore');
+  mkdirSync(agentcoreDir, { recursive: true });
+  // Create minimal agentcore.json so findConfigRoot() succeeds
+  writeFileSync(join(agentcoreDir, 'agentcore.json'), '{}');
+  // Create agent code directories that constructs may reference
+  const agentNames = [
+    'myagent',
+    'agent1',
+    'agent2',
+    'primaryagent',
+    'secondaryagent',
+    'containeragent',
+    'mcpagent',
+    'a2aagent',
+    'a'.repeat(48),
+  ];
+  const minimalPyproject = '[project]\nname = "agent"\nversion = "0.1.0"\n';
+  for (const dir of agentNames) {
+    mkdirSync(join(tmpDir, 'agents', dir), { recursive: true });
+    writeFileSync(join(tmpDir, 'agents', dir, 'main.py'), '# placeholder');
+    writeFileSync(join(tmpDir, 'agents', dir, 'pyproject.toml'), minimalPyproject);
+    writeFileSync(join(tmpDir, 'agents', dir, 'Dockerfile'), 'FROM python:3.12-slim\n');
+  }
+  // Tell the CDK L3 construct where the project root is
+  setSessionProjectRoot(tmpDir);
+});
+
+afterAll(() => {
+  rmSync(tmpDir, { recursive: true, force: true });
+});
+
+// ─── Helpers ──────────────────────────────────────────────────────────────────
+
+function synthStack(
+  spec: AgentCoreProjectSpec,
+  mcpSpec?: AgentCoreProjectSpec['agentCoreGateways'],
+  credentials?: Record<string, { credentialProviderArn: string; clientSecretArn?: string }>
+): Template {
+  const app = new cdk.App();
+  const stack = new AgentCoreStack(app, `TestStack${Date.now()}`, {
+    spec,
+    mcpSpec: mcpSpec ? { agentCoreGateways: mcpSpec } : undefined,
+    credentials,
+    env: { account: '123456789012', region: 'us-east-1' },
+  });
+  return Template.fromStack(stack);
+}
+
+function baseSpec(overrides: Partial<AgentCoreProjectSpec> = {}): AgentCoreProjectSpec {
+  return {
+    name: 'testproject',
+    version: 1,
+    managedBy: 'CDK',
+    runtimes: [],
+    memories: [],
+    credentials: [],
+    evaluators: [],
+    onlineEvalConfigs: [],
+    policyEngines: [],
+    agentCoreGateways: [],
+    ...overrides,
+  };
+}
+
+function makeRuntime(
+  name: string,
+  overrides: Partial<AgentCoreProjectSpec['runtimes'][number]> = {}
+): AgentCoreProjectSpec['runtimes'][number] {
+  return {
+    name,
+    build: 'CodeZip',
+    entrypoint: 'main.py',
+    codeLocation: `agents/${name}`,
+    runtimeVersion: 'PYTHON_3_12',
+    ...overrides,
+  };
+}
+
+function makeMemory(
+  name: string,
+  strategies: AgentCoreProjectSpec['memories'][number]['strategies'] = []
+): AgentCoreProjectSpec['memories'][number] {
+  return {
+    name,
+    eventExpiryDuration: 30,
+    strategies,
+  };
+}
+
+function makeEvaluator(name: string): AgentCoreProjectSpec['evaluators'][number] {
+  return {
+    name,
+    level: 'SESSION',
+    config: {
+      llmAsAJudge: {
+        model: 'anthropic.claude-3-haiku-20240307-v1:0',
+        instructions: 'Rate the response quality based on helpfulness and accuracy.',
+        ratingScale: {
+          numerical: [
+            { value: 1, label: 'Poor', definition: 'Unhelpful or incorrect' },
+            { value: 3, label: 'Good', definition: 'Mostly helpful and accurate' },
+            { value: 5, label: 'Excellent', definition: 'Very helpful and fully accurate' },
+          ],
+        },
+      },
+    },
+  };
+}
+
+function makeOnlineEvalConfig(
+  name: string,
+  agent: string,
+  evaluators: string[]
+): AgentCoreProjectSpec['onlineEvalConfigs'][number] {
+  return {
+    name,
+    agent,
+    evaluators,
+    samplingRate: 50,
+  };
+}
+
+function makeCredential(
+  name: string,
+  authorizerType: 'ApiKeyCredentialProvider' | 'OAuthCredentialProvider' = 'ApiKeyCredentialProvider'
+): AgentCoreProjectSpec['credentials'][number] {
+  if (authorizerType === 'OAuthCredentialProvider') {
+    return {
+      authorizerType,
+      name,
+      discoveryUrl: 'https://example.com/.well-known/openid-configuration',
+      scopes: ['openid'],
+    };
+  }
+  return { authorizerType, name };
+}
+
+function makePolicyEngine(name: string): AgentCoreProjectSpec['policyEngines'][number] {
+  return {
+    name,
+    policies: [
+      {
+        name: `${name}Policy`,
+        statement: 'permit(principal, action, resource);',
+      },
+    ],
+  };
+}
+
+// ─── Tests ────────────────────────────────────────────────────────────────────
+
+describe('CDK Synthesis Validation', () => {
+  // ─── Empty and minimal specs ──────────────────────────────────────────────
+
+  it('synthesizes empty spec with only StackNameOutput', () => {
+    const template = synthStack(baseSpec());
+    template.hasOutput('StackNameOutput', {
+      Description: 'Name of the CloudFormation Stack',
+    });
+  });
+
+  // ─── Agent specs ──────────────────────────────────────────────────────────
+
+  it('synthesizes a single CodeZip agent', () => {
+    const template = synthStack(
+      baseSpec({
+        runtimes: [makeRuntime('myagent')],
+      })
+    );
+
+    template.hasResourceProperties(CFN_RUNTIME, {
+      AgentRuntimeName: Match.stringLikeRegexp('myagent'),
+    });
+
+    template.hasResourceProperties(CFN_IAM_ROLE, {
+      AssumeRolePolicyDocument: Match.objectLike({
+        Statement: Match.arrayWith([
+          Match.objectLike({
+            Effect: 'Allow',
+            Principal: Match.objectLike({
+              Service: Match.anyValue(),
+            }),
+          }),
+        ]),
+      }),
+    });
+  });
+
+  it('synthesizes a Container agent with ECR and CodeBuild', () => {
+    const template = synthStack(
+      baseSpec({
+        runtimes: [makeRuntime('containeragent', { build: 'Container' })],
+      })
+    );
+
+    template.hasResourceProperties(CFN_ECR_REPO, {
+      RepositoryName: Match.stringLikeRegexp('containeragent'),
+    });
+
+    template.hasResourceProperties(CFN_CODEBUILD, {
+      Source: Match.objectLike({
+        Type: Match.anyValue(),
+      }),
+    });
+  });
+
+  it('synthesizes multiple agents', () => {
+    const template = synthStack(
+      baseSpec({
+        runtimes: [makeRuntime('agent1'), makeRuntime('agent2')],
+      })
+    );
+
+    template.resourceCountIs(CFN_RUNTIME, 2);
+  });
+
+  // ─── Memory specs ─────────────────────────────────────────────────────────
+
+  it('synthesizes agent with short-term memory (no strategies)', () => {
+    const template = synthStack(
+      baseSpec({
+        runtimes: [makeRuntime('myagent')],
+        memories: [makeMemory('ShortTermMem')],
+      })
+    );
+
+    template.hasResourceProperties(CFN_RUNTIME, {
+      AgentRuntimeName: Match.stringLikeRegexp('myagent'),
+    });
+    template.hasResourceProperties(CFN_MEMORY, {
+      Name: Match.stringLikeRegexp('ShortTermMem'),
+    });
+  });
+
+  it('synthesizes agent with long-term memory strategies', () => {
+    const template = synthStack(
+      baseSpec({
+        runtimes: [makeRuntime('myagent')],
+        memories: [
+          makeMemory('LongTermMem', [{ type: 'SEMANTIC' }, { type: 'SUMMARIZATION' }, { type: 'USER_PREFERENCE' }]),
+        ],
+      })
+    );
+
+    template.hasResourceProperties(CFN_MEMORY, {
+      Name: Match.stringLikeRegexp('LongTermMem'),
+    });
+  });
+
+  // ─── Credential specs ─────────────────────────────────────────────────────
+
+  it('synthesizes agent with API key credential', () => {
+    const template = synthStack(
+      baseSpec({
+        runtimes: [makeRuntime('myagent')],
+        credentials: [makeCredential('MyApiKey')],
+      })
+    );
+
+    template.hasResourceProperties(CFN_RUNTIME, {
+      AgentRuntimeName: Match.stringLikeRegexp('myagent'),
+    });
+  });
+
+  it('synthesizes agent with OAuth credential', () => {
+    const template = synthStack(
+      baseSpec({
+        runtimes: [makeRuntime('myagent')],
+        credentials: [makeCredential('MyOAuth', 'OAuthCredentialProvider')],
+      })
+    );
+
+    template.hasResourceProperties(CFN_RUNTIME, {
+      AgentRuntimeName: Match.stringLikeRegexp('myagent'),
+    });
+  });
+
+  // ─── Evaluator specs ──────────────────────────────────────────────────────
+
+  it('synthesizes custom evaluator', () => {
+    const template = synthStack(
+      baseSpec({
+        runtimes: [makeRuntime('myagent')],
+        evaluators: [makeEvaluator('QualityCheck')],
+      })
+    );
+
+    template.hasResourceProperties(CFN_EVALUATOR, {
+      EvaluatorName: Match.stringLikeRegexp('QualityCheck'),
+    });
+  });
+
+  // ─── Online eval config specs ─────────────────────────────────────────────
+
+  it('synthesizes online eval config referencing project agent', () => {
+    const template = synthStack(
+      baseSpec({
+        runtimes: [makeRuntime('myagent')],
+        evaluators: [makeEvaluator('QualityCheck')],
+        onlineEvalConfigs: [makeOnlineEvalConfig('MonitorQuality', 'myagent', ['QualityCheck'])],
+      })
+    );
+
+    template.hasResourceProperties(CFN_EVALUATOR, {
+      EvaluatorName: Match.stringLikeRegexp('QualityCheck'),
+    });
+  });
+
+  it('synthesizes online eval config with builtin evaluator', () => {
+    const template = synthStack(
+      baseSpec({
+        runtimes: [makeRuntime('myagent')],
+        onlineEvalConfigs: [makeOnlineEvalConfig('BuiltinMonitor', 'myagent', ['Builtin.GoalSuccessRate'])],
+      })
+    );
+
+    template.hasResourceProperties(CFN_RUNTIME, {
+      AgentRuntimeName: Match.stringLikeRegexp('myagent'),
+    });
+  });
+
+  // ─── Policy engine specs ──────────────────────────────────────────────────
+
+  it('synthesizes policy engine', () => {
+    const template = synthStack(
+      baseSpec({
+        runtimes: [makeRuntime('myagent')],
+        policyEngines: [makePolicyEngine('SafetyGuard')],
+      })
+    );
+
+    template.hasResourceProperties(CFN_POLICY_ENGINE, {
+      Name: Match.stringLikeRegexp('SafetyGuard'),
+    });
+    template.hasResourceProperties(CFN_POLICY, {
+      Definition: Match.objectLike({
+        Cedar: Match.objectLike({
+          Statement: Match.stringLikeRegexp('permit'),
+        }),
+      }),
+    });
+  });
+
+  // ─── Full project specs ───────────────────────────────────────────────────
+
+  it('synthesizes a complete project with all resource types', () => {
+    const template = synthStack(
+      baseSpec({
+        runtimes: [makeRuntime('primaryagent'), makeRuntime('secondaryagent')],
+        memories: [makeMemory('ProjectMemory', [{ type: 'SEMANTIC' }])],
+        credentials: [makeCredential('ProdApiKey'), makeCredential('OAuthProvider', 'OAuthCredentialProvider')],
+        evaluators: [makeEvaluator('ResponseQuality')],
+        onlineEvalConfigs: [
+          makeOnlineEvalConfig('LiveMonitor', 'primaryagent', ['Builtin.GoalSuccessRate', 'ResponseQuality']),
+        ],
+        policyEngines: [makePolicyEngine('ContentFilter')],
+      })
+    );
+
+    template.resourceCountIs(CFN_RUNTIME, 2);
+    template.hasResourceProperties(CFN_MEMORY, {
+      Name: Match.stringLikeRegexp('ProjectMemory'),
+    });
+    template.hasResourceProperties(CFN_EVALUATOR, {
+      EvaluatorName: Match.stringLikeRegexp('ResponseQuality'),
+    });
+    template.hasResourceProperties(CFN_POLICY_ENGINE, {
+      Name: Match.stringLikeRegexp('ContentFilter'),
+    });
+  });
+
+  // ─── Agent configuration variants ─────────────────────────────────────────
+
+  it('synthesizes agent with custom environment variables', () => {
+    const template = synthStack(
+      baseSpec({
+        runtimes: [
+          makeRuntime('myagent', {
+            envVars: [
+              { name: 'MODEL_ID', value: 'anthropic.claude-3-haiku-20240307-v1:0' },
+              { name: 'TEMPERATURE', value: '0.7' },
+            ],
+          }),
+        ],
+      })
+    );
+
+    template.hasResourceProperties(CFN_RUNTIME, {
+      AgentRuntimeName: Match.stringLikeRegexp('myagent'),
+    });
+  });
+
+  it('synthesizes agent with MCP protocol', () => {
+    const template = synthStack(
+      baseSpec({
+        runtimes: [makeRuntime('mcpagent', { protocol: 'MCP' })],
+      })
+    );
+
+    template.hasResourceProperties(CFN_RUNTIME, {
+      AgentRuntimeName: Match.stringLikeRegexp('mcpagent'),
+    });
+  });
+
+  it('synthesizes agent with A2A protocol', () => {
+    const template = synthStack(
+      baseSpec({
+        runtimes: [makeRuntime('a2aagent', { protocol: 'A2A' })],
+      })
+    );
+
+    template.hasResourceProperties(CFN_RUNTIME, {
+      AgentRuntimeName: Match.stringLikeRegexp('a2aagent'),
+    });
+  });
+
+  // ─── Edge cases ───────────────────────────────────────────────────────────
+
+  it('synthesizes with memories but no agents', () => {
+    const template = synthStack(
+      baseSpec({
+        memories: [makeMemory('StandaloneMemory')],
+      })
+    );
+
+    template.hasResourceProperties(CFN_MEMORY, {
+      Name: Match.stringLikeRegexp('StandaloneMemory'),
+    });
+    template.resourceCountIs(CFN_RUNTIME, 0);
+  });
+
+  it('synthesizes with evaluators but no online eval configs', () => {
+    const template = synthStack(
+      baseSpec({
+        runtimes: [makeRuntime('myagent')],
+        evaluators: [makeEvaluator('UnusedEval')],
+      })
+    );
+
+    template.hasResourceProperties(CFN_EVALUATOR, {
+      EvaluatorName: Match.stringLikeRegexp('UnusedEval'),
+    });
+  });
+
+  it('synthesizes spec with maximum name lengths', () => {
+    const longAgentName = 'a'.repeat(48);
+    const longMemoryName = 'M'.repeat(48);
+
+    const template = synthStack(
+      baseSpec({
+        runtimes: [makeRuntime(longAgentName)],
+        memories: [makeMemory(longMemoryName)],
+      })
+    );
+
+    template.hasResourceProperties(CFN_RUNTIME, {
+      AgentRuntimeName: Match.stringLikeRegexp(longAgentName),
+    });
+    template.hasResourceProperties(CFN_MEMORY, {
+      Name: Match.stringLikeRegexp(longMemoryName),
+    });
+  });
+});
diff --git a/vitest.config.ts b/vitest.config.ts
index fec90f1c..7cbf21e3 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -29,6 +29,7 @@ export default defineConfig({
   resolve: {
     alias: {
       '@': path.resolve(__dirname, './src'),
+      '@aws/agentcore-cdk': path.resolve(__dirname, './node_modules/@aws/agentcore-cdk/dist/index.js'),
     },
   },
   plugins: [textLoaderPlugin],