fix(guardrails): route PII validation through app runtime (#7227)

* fix(guardrails): route PII validation through app runtime * fix(guardrails): bound PII validation results
TheodoreSpeaks · Aug 29, 2026 · Aug 28, 2026 · Aug 28, 2026 · Aug 28, 2026 · Aug 28, 2026
commit 1ade0f4b96162a355b9269cdead66c7897ec9bd8
diff --git a/apps/sim/app/api/guardrails/pii/validate/route.test.ts b/apps/sim/app/api/guardrails/pii/validate/route.test.ts
@@ -0,0 +1,67 @@
+/**
+ * @vitest-environment node
+ */
+import { createMockRequest, hybridAuthMockFns } from '@sim/testing'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+const { mockValidatePII } = vi.hoisted(() => ({
+  mockValidatePII: vi.fn(),
+}))
+
+vi.mock('@/lib/guardrails/validate_pii', () => ({
+  validatePII: mockValidatePII,
+}))
+
+import { POST } from '@/app/api/guardrails/pii/validate/route'
+
+describe('POST /api/guardrails/pii/validate', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    hybridAuthMockFns.mockCheckInternalAuth.mockResolvedValue({ success: true })
+    mockValidatePII.mockResolvedValue({ passed: true, detectedEntities: [] })
+  })
+
+  it('authenticates before validating the request body', async () => {
+    hybridAuthMockFns.mockCheckInternalAuth.mockResolvedValue({
+      success: false,
+      error: 'Internal authentication required',
+    })
+
+    const response = await POST(createMockRequest('POST', { text: 42 }))
+
+    expect(response.status).toBe(401)
+    expect(mockValidatePII).not.toHaveBeenCalled()
+  })
+
+  it('runs Presidio validation inside the app boundary', async () => {
+    const request = createMockRequest('POST', {
+      text: 'email a@b.com',
+      entityTypes: ['EMAIL_ADDRESS'],
+      mode: 'mask',
+      language: 'en',
+    })
+
+    const response = await POST(request)
+
+    expect(response.status).toBe(200)
+    await expect(response.json()).resolves.toEqual({ passed: true, detectedEntities: [] })
+    expect(mockValidatePII).toHaveBeenCalledWith({
+      text: 'email a@b.com',
+      entityTypes: ['EMAIL_ADDRESS'],
+      mode: 'mask',
+      language: 'en',
+      customPatterns: undefined,
+      requestId: 'mock-request-id',
+      abortSignal: request.signal,
+    })
+  })
+
+  it('rejects malformed input before calling Presidio', async () => {
+    const response = await POST(
+      createMockRequest('POST', { text: 'claim', entityTypes: [], mode: 'invalid' })
+    )
+
+    expect(response.status).toBe(400)
+    expect(mockValidatePII).not.toHaveBeenCalled()
+  })
+})
diff --git a/apps/sim/app/api/guardrails/pii/validate/route.ts b/apps/sim/app/api/guardrails/pii/validate/route.ts
@@ -0,0 +1,35 @@
+import { type NextRequest, NextResponse } from 'next/server'
+import { guardrailsPiiValidateContract } from '@/lib/api/contracts'
+import { parseRequest } from '@/lib/api/server'
+import { checkInternalAuth } from '@/lib/auth/hybrid'
+import { generateRequestId } from '@/lib/core/utils/request'
+import { withRouteHandler } from '@/lib/core/utils/with-route-handler'
+import { validatePII } from '@/lib/guardrails/validate_pii'
+
+/**
+ * App-container capability boundary for single-text PII validation. Presidio is
+ * intentionally ECS-internal, so remote workflow runtimes authenticate here
+ * instead of importing its client and attempting to reach `PII_URL` directly.
+ */
+export const POST = withRouteHandler(async (request: NextRequest) => {
+  const auth = await checkInternalAuth(request, { requireWorkflowId: false })
+  if (!auth.success) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+  }
+
+  const parsed = await parseRequest(guardrailsPiiValidateContract, request, {})
+  if (!parsed.success) return parsed.response
+
+  const { text, entityTypes, mode, language, customPatterns } = parsed.data.body
+  const result = await validatePII({
+    text,
+    entityTypes,
+    mode,
+    language,
+    customPatterns,
+    requestId: generateRequestId(),
+    abortSignal: request.signal,
+  })
+
+  return NextResponse.json(guardrailsPiiValidateContract.response.schema.parse(result))
+})
diff --git a/apps/sim/lib/api/contracts/hotspots.ts b/apps/sim/lib/api/contracts/hotspots.ts
@@ -8,6 +8,10 @@ import {
 import { defineRouteContract } from '@/lib/api/contracts/types'
 import { DEFAULT_CODE_LANGUAGE } from '@/lib/execution/languages'
 import { PRIVATE_SECRET_PROVENANCE_FIELD } from '@/lib/execution/private-tool-metadata'
+import {
+  MAX_PII_VALIDATION_DETECTED_ENTITIES,
+  MAX_PII_VALIDATION_TEXT_CHARACTERS,
+} from '@/lib/guardrails/pii-limits'
 
 const guardrailsMaskBatchBodySchema = z.object({
   texts: z.array(z.string()).max(100_000),
@@ -20,6 +24,38 @@ const guardrailsMaskBatchResponseSchema = z.object({
   masked: z.array(z.string()),
 })
 
+export const guardrailsPiiValidateBodySchema = z
+  .object({
+    text: z.string().max(MAX_PII_VALIDATION_TEXT_CHARACTERS, 'Text is too long'),
+    entityTypes: z.array(z.string().min(1, 'Entity type cannot be empty')).max(200),
+    mode: z.enum(['block', 'mask']),
+    language: z.string().min(1, 'Language cannot be empty').max(20).optional(),
+    customPatterns: z.array(customPatternSchema).max(20).optional(),
+  })
+  .strict()
+
+export const detectedPiiEntitySchema = z
+  .object({
+    type: z.string().min(1, 'Entity type cannot be empty').max(100),
+    start: z.number().int().nonnegative(),
+    end: z.number().int().nonnegative(),
+    score: z.number().min(0).max(1),
+    text: z.string().max(MAX_PII_VALIDATION_TEXT_CHARACTERS, 'Detected text is too long'),
+  })
+  .strict()
+
+export const guardrailsPiiValidateResponseSchema = z
+  .object({
+    passed: z.boolean(),
+    error: z.string().max(1_000).optional(),
+    detectedEntities: z.array(detectedPiiEntitySchema).max(MAX_PII_VALIDATION_DETECTED_ENTITIES),
+    maskedText: z
+      .string()
+      .max(MAX_PII_VALIDATION_TEXT_CHARACTERS, 'Masked text is too long')
+      .optional(),
+  })
+  .strict()
+
 /**
  * Internal batch PII masking. Called server-to-server (internal JWT) from the
  * log-redaction persist path so Presidio always runs in the app container,
@@ -38,6 +74,23 @@ export const guardrailsMaskBatchContract = defineRouteContract({
 export type GuardrailsMaskBatchBody = z.input<typeof guardrailsMaskBatchBodySchema>
 export type GuardrailsMaskBatchResult = z.output<typeof guardrailsMaskBatchResponseSchema>
 
+/**
+ * Internal single-text PII validation. The workflow executor can run outside
+ * the app network, while only the app task can reach the Presidio service.
+ */
+export const guardrailsPiiValidateContract = defineRouteContract({
+  method: 'POST',
+  path: '/api/guardrails/pii/validate',
+  body: guardrailsPiiValidateBodySchema,
+  response: {
+    mode: 'json',
+    schema: guardrailsPiiValidateResponseSchema,
+  },
+})
+
+export type GuardrailsPiiValidateBody = z.input<typeof guardrailsPiiValidateBodySchema>
+export type GuardrailsPiiValidateResult = z.output<typeof guardrailsPiiValidateResponseSchema>
+
 const chatMessageSchema = z.object({
   role: z.enum(['user', 'assistant', 'system']),
   content: z.string(),

diff --git a/apps/sim/lib/guardrails/pii-limits.ts b/apps/sim/lib/guardrails/pii-limits.ts
@@ -0,0 +1,8 @@
+/** Maximum characters accepted or returned by single-text PII validation. */
+export const MAX_PII_VALIDATION_TEXT_CHARACTERS = 10_000_000
+
+/** Maximum detected spans materialized into one guardrail verdict. */
+export const MAX_PII_VALIDATION_DETECTED_ENTITIES = 10_000
+
+/** Maximum bytes read or serialized for one PII validation result. */
+export const MAX_PII_VALIDATION_RESPONSE_BYTES = 10 * 1024 * 1024
diff --git a/apps/sim/lib/guardrails/validate_pii.test.ts b/apps/sim/lib/guardrails/validate_pii.test.ts
@@ -2,6 +2,10 @@
  * @vitest-environment node
  */
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import {
+  MAX_PII_VALIDATION_DETECTED_ENTITIES,
+  MAX_PII_VALIDATION_RESPONSE_BYTES,
+} from '@/lib/guardrails/pii-limits'
 import { maskPIIBatch, validatePII } from '@/lib/guardrails/validate_pii'
 
 interface Span {
@@ -177,5 +181,73 @@ describe('validate_pii (Presidio service)', () => {
       expect(res.passed).toBe(true)
       expect(res.detectedEntities).toHaveLength(0)
     })
+
+    it('fails closed before materializing too many detected entities', async () => {
+      const spans = Array.from({ length: MAX_PII_VALIDATION_DETECTED_ENTITIES + 1 }, () => ({
+        entity_type: 'CUSTOM_0',
+        start: 0,
+        end: 1,
+        score: 0.8,
+      }))
+      fetchMock.mockResolvedValueOnce(Response.json(spans))
+
+      const res = await validatePII({
+        text: 'claim',
+        entityTypes: [],
+        mode: 'block',
+        requestId: 'entity-limit',
+      })
+
+      expect(res).toMatchObject({ passed: false, detectedEntities: [] })
+      expect(res.error).toContain(
+        `more than ${MAX_PII_VALIDATION_DETECTED_ENTITIES} detected entities`
+      )
+      expect(fetchMock).toHaveBeenCalledOnce()
+    })
+
+    it('fails closed before parsing an oversized anonymizer response', async () => {
+      fetchMock
+        .mockResolvedValueOnce(
+          Response.json([{ entity_type: 'EMAIL_ADDRESS', start: 0, end: 1, score: 0.9 }])
+        )
+        .mockResolvedValueOnce(
+          new Response('{"text":"masked"}', {
+            headers: { 'content-length': String(MAX_PII_VALIDATION_RESPONSE_BYTES + 1) },
+          })
+        )
+
+      const res = await validatePII({
+        text: 'a',
+        entityTypes: [],
+        mode: 'mask',
+        requestId: 'output-limit',
+      })
+
+      expect(res).toMatchObject({ passed: false, detectedEntities: [] })
+      expect(res.error).toContain('PII anonymizer response exceeds maximum size')
+      expect(fetchMock).toHaveBeenCalledTimes(2)
+    })
+
+    it('fails closed before materializing oversized detected-entity text', async () => {
+      const text = 'x'.repeat(6_000)
+      const spans = Array.from({ length: 2_000 }, () => ({
+        entity_type: 'CUSTOM_0',
+        start: 0,
+        end: text.length,
+        score: 0.8,
+      }))
+      fetchMock.mockResolvedValueOnce(Response.json(spans))
+
+      const res = await validatePII({
+        text,
+        entityTypes: [],
+        mode: 'block',
+        requestId: 'entity-byte-limit',
+      })
+
+      expect(res).toMatchObject({ passed: false, detectedEntities: [] })
+      expect(res.error).toContain('detected entities exceed the validation response size limit')
+      expect(fetchMock).toHaveBeenCalledOnce()
+    })
   })
 })