diff --git a/app/api/__tests__/safety.spec.ts b/app/api/__tests__/safety.spec.ts
index 35575bfc3..46a484d7c 100644
--- a/app/api/__tests__/safety.spec.ts
+++ b/app/api/__tests__/safety.spec.ts
@@ -81,3 +81,23 @@ it('e2e tests are only in test/e2e or test/visual', () => {
     expect(file).toMatch(/^test\/(e2e|visual)/)
   }
 })
+
+// 8-4-4-4-12 hex digits
+const UUID_RE = '[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}'
+
+// RFC 4122: version nibble (3rd group, 1st char) is 1-5,
+// variant nibble (4th group, 1st char) is 8, 9, a, or b
+const VALID_UUID_RE =
+  /^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i
+
+it('all UUIDs in mock-api files are valid RFC 4122', () => {
+  const output = execSync(`git grep -n -oP '${UUID_RE}' -- 'mock-api/'`).toString().trim()
+  const invalid = output.split('\n').filter((line) => {
+    const uuid = line.split(':').slice(2).join(':')
+    return !VALID_UUID_RE.test(uuid)
+  })
+  expect(
+    invalid,
+    `Invalid UUIDs found:\n${invalid.join('\n')}\n\nUse a reliable generator (e.g., uuidgen) to create valid v4 UUIDs.`
+  ).toEqual([])
+})
diff --git a/mock-api/disk.ts b/mock-api/disk.ts
index 3d403e238..cee030157 100644
--- a/mock-api/disk.ts
+++ b/mock-api/disk.ts
@@ -229,7 +229,7 @@ export const disks: Json<Disk>[] = [
     read_only: false,
   },
   {
-    id: 'a1b2c3d4-e5f6-7890-abcd-ef1234567890',
+    id: 'a1b2c3d4-e5f6-4890-abcd-ef1234567890',
     name: 'read-only-disk',
     description: 'A read-only disk created from a snapshot',
     project_id: project.id,
diff --git a/mock-api/floating-ip.ts b/mock-api/floating-ip.ts
index 986f51b2f..fb6e32e61 100644
--- a/mock-api/floating-ip.ts
+++ b/mock-api/floating-ip.ts
@@ -44,7 +44,7 @@ export const floatingIp2: Json<FloatingIp> = {
 
 // An IPv6 floating IP for testing IP version filtering (from ip-pool-2)
 export const floatingIp3: Json<FloatingIp> = {
-  id: 'b1c2d3e4-5f6a-7b8c-9d0e-1f2a3b4c5d6e',
+  id: 'b1c2d3e4-5f6a-4b8c-9d0e-1f2a3b4c5d6e',
   name: 'ipv6-float',
   description: 'An IPv6 address.',
   instance_id: undefined,
diff --git a/mock-api/project.ts b/mock-api/project.ts
index 53220f020..42d60fbfc 100644
--- a/mock-api/project.ts
+++ b/mock-api/project.ts
@@ -56,7 +56,7 @@ export const projectNoVpcs: DbProject = {
 
 // Projects for test silos (different IP pool configurations)
 export const projectKosman: DbProject = {
-  id: 'a1b2c3d4-e5f6-7890-abcd-ef1234567890',
+  id: 'a1b2c3d4-e5f6-4890-abcd-ef1234567890',
   name: 'kosman-project',
   description: 'project in myriad silo (v4-only default pool)',
   time_created: new Date(2024, 0, 5).toISOString(),
@@ -65,7 +65,7 @@ export const projectKosman: DbProject = {
 }
 
 export const projectAnscombe: DbProject = {
-  id: 'b2c3d4e5-f6a7-8901-bcde-f12345678901',
+  id: 'b2c3d4e5-f6a7-4901-bcde-f12345678901',
   name: 'anscombe-project',
   description: 'project in thrax silo (v6-only default pool)',
   time_created: new Date(2024, 0, 7).toISOString(),
@@ -74,7 +74,7 @@ export const projectAnscombe: DbProject = {
 }
 
 export const projectAdorno: DbProject = {
-  id: 'c3d4e5f6-a7b8-9012-cdef-123456789012',
+  id: '738c46df-35b1-44a2-ae1f-31005a0cbfee',
   name: 'adorno-project',
   description: 'project in pelerines silo (no default pools)',
   time_created: new Date(2024, 0, 9).toISOString(),
diff --git a/mock-api/silo.ts b/mock-api/silo.ts
index 69870aa61..35b65a27c 100644
--- a/mock-api/silo.ts
+++ b/mock-api/silo.ts
@@ -45,7 +45,7 @@ export const silos: Json<Silo[]> = [
   },
   // Test silos for IP pool configuration scenarios
   {
-    id: '7a1b2c3d-4e5f-6a7b-8c9d-0e1f2a3b4c5d',
+    id: '7a1b2c3d-4e5f-4a7b-8c9d-0e1f2a3b4c5d',
     name: 'thrax',
     description: 'silo with v6-only default pool',
     time_created: new Date(2024, 0, 1).toISOString(),
@@ -55,7 +55,7 @@ export const silos: Json<Silo[]> = [
     mapped_fleet_roles: {},
   },
   {
-    id: '8b2c3d4e-5f6a-7b8c-9d0e-1f2a3b4c5d6e',
+    id: '8b2c3d4e-5f6a-4b8c-9d0e-1f2a3b4c5d6e',
     name: 'pelerines',
     description: 'silo with no default pools',
     time_created: new Date(2024, 0, 3).toISOString(),
@@ -65,7 +65,7 @@ export const silos: Json<Silo[]> = [
     mapped_fleet_roles: {},
   },
   {
-    id: '9c3d4e5f-6a7b-7c9d-8e1f-2a3b4c5d6e7f',
+    id: '9c3d4e5f-6a7b-4c9d-8e1f-2a3b4c5d6e7f',
     name: 'no-pools',
     description: 'silo with no IP pools',
     time_created: new Date(2024, 0, 11).toISOString(),
@@ -218,13 +218,13 @@ type DbScimToken = Json<ScimClientBearerToken> & { siloId: string }
 
 export const scimTokens: DbScimToken[] = [
   {
-    id: 'a1b2c3d4-e5f6-7890-abcd-ef1234567890',
+    id: 'a1b2c3d4-e5f6-4890-abcd-ef1234567890',
     time_created: new Date(2025, 8, 15).toISOString(),
     time_expires: null,
     siloId: defaultSilo.id,
   },
   {
-    id: 'b2c3d4e5-f6a7-8901-bcde-f12345678901',
+    id: 'b2c3d4e5-f6a7-4901-bcde-f12345678901',
     time_created: new Date(2025, 8, 20).toISOString(),
     time_expires: null,
     siloId: defaultSilo.id,
diff --git a/mock-api/user.ts b/mock-api/user.ts
index a87ffa943..af8dbd1fe 100644
--- a/mock-api/user.ts
+++ b/mock-api/user.ts
@@ -48,25 +48,25 @@ export const user6: Json<User> = {
 
 // Users for test silos (different IP pool configurations)
 export const userKosman: Json<User> = {
-  id: '9a8b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d',
+  id: '9a8b7c6d-5e4f-4a2b-9c0d-9e8f7a6b5c4d',
   display_name: 'Aryeh Kosman',
   silo_id: myriadSilo.id,
 }
 
 export const userAnscombe: Json<User> = {
-  id: 'a9b8c7d6-e5f4-a3b2-c1d0-e9f8a7b6c5d4',
+  id: 'a9b8c7d6-e5f4-43b2-81d0-e9f8a7b6c5d4',
   display_name: 'Elizabeth Anscombe',
   silo_id: thraxSilo.id,
 }
 
 export const userAdorno: Json<User> = {
-  id: 'b0c9d8e7-f6a5-b4c3-d2e1-f0a9b8c7d6e5',
+  id: 'b0c9d8e7-f6a5-44c3-92e1-f0a9b8c7d6e5',
   display_name: 'Theodor Adorno',
   silo_id: pelerinesSilo.id,
 }
 
 export const userNoPools: Json<User> = {
-  id: 'c1d0e9f8-a7b6-c5d4-e3f2-a1b0c9d8e7f6',
+  id: 'c1d0e9f8-a7b6-45d4-a3f2-a1b0c9d8e7f6',
   display_name: 'Antonio Gramsci',
   silo_id: noPoolsSilo.id,
 }
diff --git a/mock-api/vpc.ts b/mock-api/vpc.ts
index ae97ffa5a..80861df50 100644
--- a/mock-api/vpc.ts
+++ b/mock-api/vpc.ts
@@ -45,7 +45,7 @@ export const vpc2: Json<Vpc> = {
 
 // VPCs for test silos (IP pool configuration testing)
 export const vpcKosman: Json<Vpc> = {
-  id: 'd1e2f3a4-b5c6-7890-abcd-ef1234567890',
+  id: 'd1e2f3a4-b5c6-4890-abcd-ef1234567890',
   name: 'kosman-vpc',
   description: 'VPC in myriad silo',
   dns_name: 'kosman-vpc',
@@ -57,7 +57,7 @@ export const vpcKosman: Json<Vpc> = {
 }
 
 export const vpcAnscombe: Json<Vpc> = {
-  id: 'e2f3a4b5-c6d7-8901-bcde-f12345678901',
+  id: 'e2f3a4b5-c6d7-4901-bcde-f12345678901',
   name: 'anscombe-vpc',
   description: 'VPC in thrax silo',
   dns_name: 'anscombe-vpc',
@@ -69,7 +69,7 @@ export const vpcAnscombe: Json<Vpc> = {
 }
 
 export const vpcAdorno: Json<Vpc> = {
-  id: 'f3a4b5c6-d7e8-9012-cdef-123456789012',
+  id: 'f3a4b5c6-d7e8-4012-8def-123456789012',
   name: 'adorno-vpc',
   description: 'VPC in pelerines silo',
   dns_name: 'adorno-vpc',
@@ -213,7 +213,7 @@ export const vpcSubnet2: Json<VpcSubnet> = {
 
 // Subnets for test silos
 export const subnetKosman: Json<VpcSubnet> = {
-  id: 'a1b2c3d4-e5f6-7890-1234-567890abcdef',
+  id: 'a1b2c3d4-e5f6-4890-9234-567890abcdef',
   name: 'kosman-subnet',
   description: 'subnet in myriad silo',
   time_created,
@@ -224,7 +224,7 @@ export const subnetKosman: Json<VpcSubnet> = {
 }
 
 export const subnetAnscombe: Json<VpcSubnet> = {
-  id: 'b2c3d4e5-f6a7-8901-2345-67890abcdef1',
+  id: 'b2c3d4e5-f6a7-4901-a345-67890abcdef1',
   name: 'anscombe-subnet',
   description: 'subnet in thrax silo',
   time_created,
@@ -235,7 +235,7 @@ export const subnetAnscombe: Json<VpcSubnet> = {
 }
 
 export const subnetAdorno: Json<VpcSubnet> = {
-  id: 'c3d4e5f6-a7b8-9012-3456-7890abcdef12',
+  id: 'c3d4e5f6-a7b8-4012-b456-7890abcdef12',
   name: 'adorno-subnet',
   description: 'subnet in pelerines silo',
   time_created,