diff --git a/apps/sim/app/api/guardrails/mask-batch/route.test.ts b/apps/sim/app/api/guardrails/mask-batch/route.test.ts
new file mode 100644
index 00000000000..cbb5b12265f
--- /dev/null
+++ b/apps/sim/app/api/guardrails/mask-batch/route.test.ts
@@ -0,0 +1,64 @@
+/**
+ * @vitest-environment node
+ */
+import { createMockRequest } from '@sim/testing'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+const { mockCheckInternalAuth, mockMaskPIIBatch } = vi.hoisted(() => ({
+  mockCheckInternalAuth: vi.fn(),
+  mockMaskPIIBatch: vi.fn(),
+}))
+
+vi.mock('@/lib/auth/hybrid', () => ({
+  checkInternalAuth: mockCheckInternalAuth,
+}))
+
+vi.mock('@/lib/guardrails/validate_pii', () => ({
+  maskPIIBatch: mockMaskPIIBatch,
+}))
+
+import { POST } from '@/app/api/guardrails/mask-batch/route'
+
+describe('POST /api/guardrails/mask-batch', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    mockCheckInternalAuth.mockResolvedValue({ success: true })
+    mockMaskPIIBatch.mockImplementation(async (texts: string[]) => texts.map((t) => `M(${t})`))
+  })
+
+  it('returns 401 without internal auth', async () => {
+    mockCheckInternalAuth.mockResolvedValue({
+      success: false,
+      error: 'Internal authentication required',
+    })
+
+    const res = await POST(
+      createMockRequest('POST', { texts: ['a@b.com'], entityTypes: ['EMAIL_ADDRESS'] })
+    )
+
+    expect(res.status).toBe(401)
+    expect(mockMaskPIIBatch).not.toHaveBeenCalled()
+  })
+
+  it('masks the batch in-process and preserves order', async () => {
+    const res = await POST(
+      createMockRequest('POST', {
+        texts: ['a@b.com', 'hello'],
+        entityTypes: ['EMAIL_ADDRESS'],
+        language: 'en',
+      })
+    )
+
+    expect(res.status).toBe(200)
+    const json = await res.json()
+    expect(json.masked).toEqual(['M(a@b.com)', 'M(hello)'])
+    expect(mockMaskPIIBatch).toHaveBeenCalledWith(['a@b.com', 'hello'], ['EMAIL_ADDRESS'], 'en')
+  })
+
+  it('rejects an invalid body with 400', async () => {
+    const res = await POST(createMockRequest('POST', { texts: 'not-an-array', entityTypes: [] }))
+
+    expect(res.status).toBe(400)
+    expect(mockMaskPIIBatch).not.toHaveBeenCalled()
+  })
+})
diff --git a/apps/sim/app/api/guardrails/mask-batch/route.ts b/apps/sim/app/api/guardrails/mask-batch/route.ts
new file mode 100644
index 00000000000..43979c611c9
--- /dev/null
+++ b/apps/sim/app/api/guardrails/mask-batch/route.ts
@@ -0,0 +1,45 @@
+import { createLogger } from '@sim/logger'
+import { getErrorMessage } from '@sim/utils/errors'
+import { type NextRequest, NextResponse } from 'next/server'
+import { guardrailsMaskBatchContract } from '@/lib/api/contracts'
+import { parseRequest } from '@/lib/api/server'
+import { checkInternalAuth } from '@/lib/auth/hybrid'
+import { withRouteHandler } from '@/lib/core/utils/with-route-handler'
+import { maskPIIBatch } from '@/lib/guardrails/validate_pii'
+
+const logger = createLogger('GuardrailsMaskBatchAPI')
+
+/**
+ * Internal batch PII masking. The log-redaction persist path runs in both the
+ * Next.js server and the trigger.dev runtime, but Presidio (Python venv) lives
+ * only in the app container — so redaction calls this endpoint server-to-server
+ * (internal JWT) to keep Presidio centralized here.
+ */
+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(guardrailsMaskBatchContract, request, {})
+  if (!parsed.success) return parsed.response
+
+  const { texts, entityTypes, language } = parsed.data.body
+
+  try {
+    const masked = await maskPIIBatch(texts, entityTypes, language)
+    logger.info('Masked PII batch', { count: texts.length })
+    return NextResponse.json({ masked })
+  } catch (error) {
+    // A broken/absent venv makes maskPIIBatch throw; fail loudly here (the
+    // caller scrubs to REDACTION_FAILED, so PII is never leaked).
+    logger.error('PII batch masking failed', {
+      error: getErrorMessage(error),
+      count: texts.length,
+    })
+    return NextResponse.json(
+      { error: getErrorMessage(error, 'PII masking failed') },
+      { status: 500 }
+    )
+  }
+})
diff --git a/apps/sim/lib/api/contracts/hotspots.ts b/apps/sim/lib/api/contracts/hotspots.ts
index 6c280898c39..897c99fad56 100644
--- a/apps/sim/lib/api/contracts/hotspots.ts
+++ b/apps/sim/lib/api/contracts/hotspots.ts
@@ -45,6 +45,34 @@ export const guardrailsValidateContract = defineRouteContract({
   },
 })
 
+const guardrailsMaskBatchBodySchema = z.object({
+  texts: z.array(z.string()).max(100_000),
+  entityTypes: z.array(z.string().min(1, 'Entity type cannot be empty')).max(200),
+  language: z.string().min(1).max(20).optional(),
+})
+
+const guardrailsMaskBatchResponseSchema = z.object({
+  masked: z.array(z.string()),
+})
+
+/**
+ * Internal batch PII masking. Called server-to-server (internal JWT) from the
+ * log-redaction persist path so Presidio always runs in the app container,
+ * including for async executions that persist inside the trigger.dev runtime.
+ */
+export const guardrailsMaskBatchContract = defineRouteContract({
+  method: 'POST',
+  path: '/api/guardrails/mask-batch',
+  body: guardrailsMaskBatchBodySchema,
+  response: {
+    mode: 'json',
+    schema: guardrailsMaskBatchResponseSchema,
+  },
+})
+
+export type GuardrailsMaskBatchBody = z.input<typeof guardrailsMaskBatchBodySchema>
+export type GuardrailsMaskBatchResult = z.output<typeof guardrailsMaskBatchResponseSchema>
+
 const chatMessageSchema = z.object({
   role: z.enum(['user', 'assistant', 'system']),
   content: z.string(),
diff --git a/apps/sim/lib/guardrails/mask-client.test.ts b/apps/sim/lib/guardrails/mask-client.test.ts
new file mode 100644
index 00000000000..d1c4ad5b843
--- /dev/null
+++ b/apps/sim/lib/guardrails/mask-client.test.ts
@@ -0,0 +1,68 @@
+/**
+ * @vitest-environment node
+ */
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+
+const { mockToken, mockBaseUrl } = vi.hoisted(() => ({
+  mockToken: vi.fn(),
+  mockBaseUrl: vi.fn(),
+}))
+
+vi.mock('@/lib/auth/internal', () => ({ generateInternalToken: mockToken }))
+vi.mock('@/lib/core/utils/urls', () => ({ getInternalApiBaseUrl: mockBaseUrl }))
+
+import { maskPIIBatchViaHttp } from '@/lib/guardrails/mask-client'
+
+describe('maskPIIBatchViaHttp', () => {
+  let fetchMock: ReturnType<typeof vi.fn>
+
+  beforeEach(() => {
+    vi.clearAllMocks()
+    mockToken.mockResolvedValue('tok')
+    mockBaseUrl.mockReturnValue('http://app.internal:3000')
+    fetchMock = vi.fn(async (_url: string, init: { body: string }) => {
+      const { texts } = JSON.parse(init.body) as { texts: string[] }
+      return new Response(JSON.stringify({ masked: texts.map((t) => `M(${t})`) }), {
+        status: 200,
+        headers: { 'content-type': 'application/json' },
+      })
+    })
+    vi.stubGlobal('fetch', fetchMock)
+  })
+
+  afterEach(() => {
+    vi.unstubAllGlobals()
+  })
+
+  it('masks a small batch in a single request, with an abort timeout', async () => {
+    const out = await maskPIIBatchViaHttp(['a', 'b', 'c'], ['EMAIL_ADDRESS'])
+
+    expect(out).toEqual(['M(a)', 'M(b)', 'M(c)'])
+    expect(fetchMock).toHaveBeenCalledTimes(1)
+    expect(fetchMock.mock.calls[0][1].signal).toBeInstanceOf(AbortSignal)
+  })
+
+  it('splits by count into multiple requests, preserving global order', async () => {
+    const texts = Array.from({ length: 5000 }, (_, i) => `t${i}`)
+
+    const out = await maskPIIBatchViaHttp(texts, [])
+
+    expect(out).toHaveLength(5000)
+    expect(out[0]).toBe('M(t0)')
+    expect(out[4999]).toBe('M(t4999)')
+    expect(fetchMock).toHaveBeenCalledTimes(3) // 2000-per-request cap
+  })
+
+  it('throws on a non-2xx response so the caller can scrub', async () => {
+    fetchMock.mockResolvedValueOnce(new Response('boom', { status: 500 }))
+
+    await expect(maskPIIBatchViaHttp(['a'], [])).rejects.toThrow(/mask-batch request failed/)
+  })
+
+  it('returns [] without any request for empty input', async () => {
+    const out = await maskPIIBatchViaHttp([], [])
+
+    expect(out).toEqual([])
+    expect(fetchMock).not.toHaveBeenCalled()
+  })
+})
diff --git a/apps/sim/lib/guardrails/mask-client.ts b/apps/sim/lib/guardrails/mask-client.ts
new file mode 100644
index 00000000000..8e94495334b
--- /dev/null
+++ b/apps/sim/lib/guardrails/mask-client.ts
@@ -0,0 +1,99 @@
+import type { GuardrailsMaskBatchResult } from '@/lib/api/contracts'
+import { generateInternalToken } from '@/lib/auth/internal'
+import { getInternalApiBaseUrl } from '@/lib/core/utils/urls'
+
+/**
+ * Per-request limits. A chunk is flushed when it hits either bound, keeping each
+ * request small enough for one short Presidio pass under a tight timeout and far
+ * below the contract's 100k-entry cap — so large executions split across
+ * requests instead of failing validation.
+ */
+const REQUEST_MAX_BYTES = 256 * 1024
+const REQUEST_MAX_COUNT = 2_000
+/** Slightly above the 30s Python subprocess timeout so a hung app container aborts gracefully. */
+const REQUEST_TIMEOUT_MS = 45_000
+
+/**
+ * Mask PII across many strings via the internal app-container endpoint.
+ *
+ * Presidio (a Python venv) only exists in the app container, but the
+ * log-redaction persist path also runs inside the trigger.dev runtime — so
+ * redaction always routes through HTTP, the same way the guardrails tool does.
+ * Strings are grouped into byte/count-budgeted chunks; order is preserved, so
+ * the returned array matches `texts` length.
+ *
+ * Rejects on any non-2xx, timeout, or shape mismatch so the caller can apply
+ * its own fail-safe (scrubbing rather than leaking).
+ */
+export async function maskPIIBatchViaHttp(
+  texts: string[],
+  entityTypes: string[],
+  language?: string
+): Promise<string[]> {
+  if (texts.length === 0) return []
+
+  const url = `${getInternalApiBaseUrl()}/api/guardrails/mask-batch`
+
+  const masked: string[] = []
+  let batch: string[] = []
+  let batchBytes = 0
+
+  const flush = async () => {
+    if (batch.length === 0) return
+    const out = await postChunk(url, batch, entityTypes, language)
+    if (out.length !== batch.length) {
+      throw new Error('PII mask-batch returned an unexpected result')
+    }
+    for (const item of out) masked.push(item)
+    batch = []
+    batchBytes = 0
+  }
+
+  for (const text of texts) {
+    const bytes = Buffer.byteLength(text, 'utf8')
+    if (
+      batch.length > 0 &&
+      (batch.length >= REQUEST_MAX_COUNT || batchBytes + bytes > REQUEST_MAX_BYTES)
+    ) {
+      await flush()
+    }
+    batch.push(text)
+    batchBytes += bytes
+  }
+  await flush()
+
+  return masked
+}
+
+async function postChunk(
+  url: string,
+  texts: string[],
+  entityTypes: string[],
+  language: string | undefined
+): Promise<string[]> {
+  // Mint per request: a single token (5min TTL) can expire mid-batch when a
+  // large execution fans out into many sequential chunk requests.
+  const token = await generateInternalToken()
+
+  // boundary-raw-fetch: internal server-to-server call to the app container (internal JWT auth, configurable base URL)
+  const response = await fetch(url, {
+    method: 'POST',
+    headers: {
+      'content-type': 'application/json',
+      authorization: `Bearer ${token}`,
+    },
+    body: JSON.stringify({ texts, entityTypes, language }),
+    signal: AbortSignal.timeout(REQUEST_TIMEOUT_MS),
+  })
+
+  if (!response.ok) {
+    const detail = await response.text().catch(() => '')
+    throw new Error(`PII mask-batch request failed (${response.status}): ${detail.slice(0, 200)}`)
+  }
+
+  const data = (await response.json()) as GuardrailsMaskBatchResult
+  if (!Array.isArray(data.masked)) {
+    throw new Error('PII mask-batch returned an unexpected result')
+  }
+  return data.masked
+}
diff --git a/apps/sim/lib/guardrails/setup.sh b/apps/sim/lib/guardrails/setup.sh
index 233e9a51a27..20eba4247ee 100755
--- a/apps/sim/lib/guardrails/setup.sh
+++ b/apps/sim/lib/guardrails/setup.sh
@@ -30,6 +30,11 @@ source "$VENV_DIR/bin/activate"
 pip install --upgrade pip
 pip install -r "$SCRIPT_DIR/requirements.txt"
 
+# Presidio's default AnalyzerEngine loads the en_core_web_lg spaCy model; it is
+# not a pip dependency, so download the version compatible with the installed spaCy.
+echo "Downloading spaCy model (en_core_web_lg)..."
+python -m spacy download en_core_web_lg
+
 echo ""
 echo "✅ Setup complete! Guardrails validators are ready to use."
 echo ""
diff --git a/apps/sim/lib/guardrails/validate_pii.ts b/apps/sim/lib/guardrails/validate_pii.ts
index ba6886bb92d..3e1ec90edb3 100644
--- a/apps/sim/lib/guardrails/validate_pii.ts
+++ b/apps/sim/lib/guardrails/validate_pii.ts
@@ -13,6 +13,33 @@ const DEFAULT_TIMEOUT = 30000 // 30 seconds
  */
 const PII_CHUNK_MAX_BYTES = 256 * 1024
 
+/**
+ * Resolve the guardrails Presidio interpreter + script path.
+ *
+ * `process.cwd()` is not stable across runtimes — the Next standalone container
+ * launches from the monorepo root while local dev and some paths run from
+ * `apps/sim` — so probe both layouts (mirrors the candidate-path resolution in
+ * `lib/execution/isolated-vm.ts`). Requires the bundled venv: throws if it is
+ * absent rather than silently falling back to the system `python3`, which has no
+ * Presidio and reports a misleading "not installed".
+ */
+function resolveGuardrailsPython(): { pythonCmd: string; scriptPath: string } {
+  const candidateDirs = [
+    path.join(process.cwd(), 'apps', 'sim', 'lib', 'guardrails'),
+    path.join(process.cwd(), 'lib', 'guardrails'),
+  ]
+  for (const dir of candidateDirs) {
+    const venvPython = path.join(dir, 'venv', 'bin', 'python3')
+    if (fs.existsSync(venvPython)) {
+      return { pythonCmd: venvPython, scriptPath: path.join(dir, 'validate_pii.py') }
+    }
+  }
+  const probed = candidateDirs.map((d) => path.join(d, 'venv', 'bin', 'python3')).join(', ')
+  throw new Error(
+    `Guardrails Presidio venv not found (looked in ${probed}). Provision it with apps/sim/lib/guardrails/setup.sh locally, or verify the image build installs it.`
+  )
+}
+
 export interface PIIValidationInput {
   text: string
   entityTypes: string[] // e.g., ["PERSON", "EMAIL_ADDRESS", "CREDIT_CARD"]
@@ -136,10 +163,7 @@ export async function maskPIIBatch(
  */
 function runPythonScript<T>(payload: Record<string, unknown>): Promise<T> {
   return new Promise((resolve, reject) => {
-    const guardrailsDir = path.join(process.cwd(), 'lib/guardrails')
-    const scriptPath = path.join(guardrailsDir, 'validate_pii.py')
-    const venvPython = path.join(guardrailsDir, 'venv/bin/python3')
-    const pythonCmd = fs.existsSync(venvPython) ? venvPython : 'python3'
+    const { pythonCmd, scriptPath } = resolveGuardrailsPython()
 
     const python = spawn(pythonCmd, [scriptPath])
     let stdout = ''
@@ -208,14 +232,7 @@ async function executePythonPIIDetection(
   requestId: string
 ): Promise<PIIValidationResult> {
   return new Promise((resolve, reject) => {
-    // Use path relative to project root
-    // In Next.js, process.cwd() returns the project root
-    const guardrailsDir = path.join(process.cwd(), 'lib/guardrails')
-    const scriptPath = path.join(guardrailsDir, 'validate_pii.py')
-    const venvPython = path.join(guardrailsDir, 'venv/bin/python3')
-
-    // Use venv Python if it exists, otherwise fall back to system python3
-    const pythonCmd = fs.existsSync(venvPython) ? venvPython : 'python3'
+    const { pythonCmd, scriptPath } = resolveGuardrailsPython()
 
     const python = spawn(pythonCmd, [scriptPath])
 
diff --git a/apps/sim/lib/logs/execution/pii-redaction.test.ts b/apps/sim/lib/logs/execution/pii-redaction.test.ts
index dccbc59cc38..5a2da7a5996 100644
--- a/apps/sim/lib/logs/execution/pii-redaction.test.ts
+++ b/apps/sim/lib/logs/execution/pii-redaction.test.ts
@@ -7,8 +7,8 @@ const { mockMaskPIIBatch } = vi.hoisted(() => ({
   mockMaskPIIBatch: vi.fn(),
 }))
 
-vi.mock('@/lib/guardrails/validate_pii', () => ({
-  maskPIIBatch: mockMaskPIIBatch,
+vi.mock('@/lib/guardrails/mask-client', () => ({
+  maskPIIBatchViaHttp: mockMaskPIIBatch,
 }))
 
 import { REDACTION_FAILED_MARKER, redactPIIFromExecution } from '@/lib/logs/execution/pii-redaction'
diff --git a/apps/sim/lib/logs/execution/pii-redaction.ts b/apps/sim/lib/logs/execution/pii-redaction.ts
index 7b4794fd483..8cd0fac5326 100644
--- a/apps/sim/lib/logs/execution/pii-redaction.ts
+++ b/apps/sim/lib/logs/execution/pii-redaction.ts
@@ -1,5 +1,6 @@
 import { createLogger } from '@sim/logger'
 import { getErrorMessage } from '@sim/utils/errors'
+import { maskPIIBatchViaHttp } from '@/lib/guardrails/mask-client'
 
 const logger = createLogger('PiiRedaction')
 
@@ -158,11 +159,9 @@ export async function redactPIIFromExecution(
     masked = collected.map(() => REDACTION_FAILED_MARKER)
   } else {
     try {
-      // Lazy import keeps the Python-spawning guardrails module (child_process +
-      // a `lib/guardrails` dir reference) out of the static middleware/RSC graph;
-      // it's only loaded at runtime on the Node log-persist path.
-      const { maskPIIBatch } = await import('@/lib/guardrails/validate_pii')
-      masked = await maskPIIBatch(collected, entityTypes, language)
+      // Presidio runs only in the app container; the persist path also runs in
+      // the trigger.dev runtime, so masking always goes over HTTP to the app.
+      masked = await maskPIIBatchViaHttp(collected, entityTypes, language)
     } catch (error) {
       logger.error('PII masking failed; scrubbing text to avoid leaking PII', {
         error: getErrorMessage(error),
diff --git a/docker/app.Dockerfile b/docker/app.Dockerfile
index 67eb5f02c77..2323ebb1df4 100644
--- a/docker/app.Dockerfile
+++ b/docker/app.Dockerfile
@@ -118,11 +118,14 @@ COPY --from=builder --chown=nextjs:nodejs /app/apps/sim/lib/execution/sandbox/bu
 COPY --from=builder --chown=nextjs:nodejs /app/apps/sim/lib/guardrails/requirements.txt ./apps/sim/lib/guardrails/requirements.txt
 COPY --from=builder --chown=nextjs:nodejs /app/apps/sim/lib/guardrails/validate_pii.py ./apps/sim/lib/guardrails/validate_pii.py
 
-# Install Python dependencies with pip cache mount for faster rebuilds
+# Install Python dependencies with pip cache mount for faster rebuilds.
+# Presidio's default AnalyzerEngine loads en_core_web_lg, which is not a pip
+# dependency — download the spaCy model into the venv after installing Presidio.
 RUN --mount=type=cache,target=/root/.cache/pip \
     python3 -m venv ./apps/sim/lib/guardrails/venv && \
     ./apps/sim/lib/guardrails/venv/bin/pip install --upgrade pip && \
     ./apps/sim/lib/guardrails/venv/bin/pip install -r ./apps/sim/lib/guardrails/requirements.txt && \
+    ./apps/sim/lib/guardrails/venv/bin/python -m spacy download en_core_web_lg && \
     chown -R nextjs:nodejs /app/apps/sim/lib/guardrails
 
 # Create .next/cache directory with correct ownership
diff --git a/scripts/check-api-validation-contracts.ts b/scripts/check-api-validation-contracts.ts
index 09744c629ba..17f0a25fa29 100644
--- a/scripts/check-api-validation-contracts.ts
+++ b/scripts/check-api-validation-contracts.ts
@@ -9,8 +9,8 @@ const QUERY_HOOKS_DIR = path.join(ROOT, 'apps/sim/hooks/queries')
 const SELECTOR_HOOKS_DIR = path.join(ROOT, 'apps/sim/hooks/selectors')
 
 const BASELINE = {
-  totalRoutes: 859,
-  zodRoutes: 859,
+  totalRoutes: 860,
+  zodRoutes: 860,
   nonZodRoutes: 0,
 } as const