diff --git a/src/app/application.ts b/src/app/application.ts
index 493bb7a..c1553c5 100644
--- a/src/app/application.ts
+++ b/src/app/application.ts
@@ -412,7 +412,10 @@ export class BraidApplication {
     readonly text: string
     readonly runId?: string
   }): QueueReceipt {
-    return queueRunInput(this.#portViews.queue, input)
+    return queueRunInput(this.#portViews.queue, {
+      ...input,
+      operationId: operationId(input.operationId, 'queue'),
+    })
   }
 
   async steer(input: {
@@ -420,7 +423,10 @@ export class BraidApplication {
     readonly runId?: string
     readonly text: string
   }): Promise<ControlReceipt> {
-    return steerRun(this.#portViews.control, input)
+    return steerRun(this.#portViews.control, {
+      ...input,
+      operationId: operationId(input.operationId, 'steer'),
+    })
   }
 
   async cancelRun(input: {
@@ -430,7 +436,10 @@ export class BraidApplication {
     readonly terminalStatus?: 'cancelled' | 'aborted'
     readonly legacy?: boolean
   }): Promise<ControlReceipt> {
-    return cancelRun(this.#portViews.control, input)
+    return cancelRun(this.#portViews.control, {
+      ...input,
+      operationId: operationId(input.operationId, 'cancel'),
+    })
   }
 
   cancel(input: CancelInput): CancelReceipt {
@@ -479,7 +488,10 @@ export class BraidApplication {
     readonly operationId: string
     readonly runId?: string
   }): Promise<ControlReceipt> {
-    return detachRun(this.#portViews.control, input)
+    return detachRun(this.#portViews.control, {
+      ...input,
+      operationId: operationId(input.operationId, 'detach'),
+    })
   }
 
   async respondInteraction(input: {
@@ -488,7 +500,10 @@ export class BraidApplication {
     readonly interactionId: string
     readonly response: InteractionResponse
   }): Promise<InteractionReceipt> {
-    return this.#interactions.respond(input)
+    return this.#interactions.respond({
+      ...input,
+      operationId: operationId(input.operationId, 'respond-interaction'),
+    })
   }
 
   async #executeControl(
@@ -520,7 +535,10 @@ export class BraidApplication {
     readonly text: string
     readonly runId?: string
   }): Promise<SendReceipt> {
-    return continueNative(this.#portViews.nativeContinuation, input)
+    return continueNative(this.#portViews.nativeContinuation, {
+      ...input,
+      operationId: operationId(input.operationId, 'continue'),
+    })
   }
 
   shutdown(input: {
@@ -584,7 +602,7 @@ export class BraidApplication {
     this.#assertAdmissionOpen()
     return admitRun(
       this.#portViews.admission,
-      input,
+      { ...input, operationId: operationId(input.operationId, 'admit') },
       conversationId,
       branchId,
       contextTransfer,
diff --git a/src/bin/plain.ts b/src/bin/plain.ts
index ee20638..f9b9bdf 100644
--- a/src/bin/plain.ts
+++ b/src/bin/plain.ts
@@ -19,7 +19,7 @@ export interface PlainOptions {
 }
 
 function nextOperationId(): string {
-  return `op-plain-${Date.now().toString(36)}-${randomUUID()}`
+  return `op-${randomUUID()}`
 }
 
 export async function runPlain(
diff --git a/src/domain/ids-core.ts b/src/domain/ids-core.ts
index b5c5c14..effa6e2 100644
--- a/src/domain/ids-core.ts
+++ b/src/domain/ids-core.ts
@@ -1,4 +1,5 @@
-import type { IdForKind, IdKind, Digest, ReplayCursor } from './ids-types.js'
+import type { Digest, IdForKind, IdKind, ReplayCursor } from './ids-types.js'
+import { redactSensitiveText } from './secret-sanitizer.js'
 
 export const prefixes: Readonly<Record<IdKind, readonly string[]>> = {
   workspace: ['workspace-'],
@@ -44,7 +45,8 @@ export function parsePrefixedId<K extends IdKind>(kind: K, value: unknown): IdFo
   if (
     typeof value !== 'string' ||
     !idPattern.test(value) ||
-    !prefixes[kind].some((prefix) => value.startsWith(prefix))
+    !prefixes[kind].some((prefix) => value.startsWith(prefix)) ||
+    redactSensitiveText(value) !== value
   ) {
     throw new TypeError(`Invalid ${kind} identifier`)
   }
@@ -55,7 +57,8 @@ export function isPrefixedId<K extends IdKind>(kind: K, value: unknown): value i
   return (
     typeof value === 'string' &&
     idPattern.test(value) &&
-    prefixes[kind].some((prefix) => value.startsWith(prefix))
+    prefixes[kind].some((prefix) => value.startsWith(prefix)) &&
+    redactSensitiveText(value) === value
   )
 }
 
diff --git a/test/application.test.ts b/test/application.test.ts
index 713b4de..61f0f2b 100644
--- a/test/application.test.ts
+++ b/test/application.test.ts
@@ -544,15 +544,36 @@ test('async admission reserves one run before the provider becomes visible', asy
   assert.equal(app.storageFailure(), undefined)
 })
 
-test('send rejects malformed operation identities and oversized input before journaling', () => {
+test('public mutations reject unsafe operation identities before work or journaling', async () => {
   const app = createBraidApplication({ fixture: 'deterministic' })
   app.initialize('/workspace')
   const eventCount = app.events().length
+  const unsafeOperationId = `op-plain-sk-${'a'.repeat(24)}`
 
   assert.throws(
     () => app.send({ operationId: 'token=do-not-store', text: 'hello' }),
     (error: unknown) => error instanceof AppError && error.code === 'INVALID_OPERATION_ID',
   )
+  assert.throws(
+    () => app.queueInput({ operationId: unsafeOperationId, text: 'queue this' }),
+    (error: unknown) => error instanceof AppError && error.code === 'INVALID_OPERATION_ID',
+  )
+  await assert.rejects(
+    app.steer({ operationId: unsafeOperationId, text: 'steer this' }),
+    (error: unknown) => error instanceof AppError && error.code === 'INVALID_OPERATION_ID',
+  )
+  await assert.rejects(
+    app.cancelRun({ operationId: unsafeOperationId }),
+    (error: unknown) => error instanceof AppError && error.code === 'INVALID_OPERATION_ID',
+  )
+  await assert.rejects(
+    app.detachRun({ operationId: unsafeOperationId }),
+    (error: unknown) => error instanceof AppError && error.code === 'INVALID_OPERATION_ID',
+  )
+  await assert.rejects(
+    app.continueNative({ operationId: unsafeOperationId, text: 'continue this' }),
+    (error: unknown) => error instanceof AppError && error.code === 'INVALID_OPERATION_ID',
+  )
   assert.throws(
     () => app.send({ operationId: 'op-too-large', text: 'x'.repeat(1024 * 1024 + 1) }),
     (error: unknown) => error instanceof AppError && error.code === 'MESSAGE_TOO_LARGE',
diff --git a/test/domain-ids.test.ts b/test/domain-ids.test.ts
index 806db7d..13109a8 100644
--- a/test/domain-ids.test.ts
+++ b/test/domain-ids.test.ts
@@ -1,5 +1,6 @@
 import assert from 'node:assert/strict'
 import test from 'node:test'
+import type { ConversationId } from '../src/domain/ids.js'
 import {
   createAnalysisId,
   createAnalysisRunId,
@@ -43,7 +44,6 @@ import {
   parseConversationId,
   parseRunId,
 } from '../src/domain/ids.js'
-import type { ConversationId } from '../src/domain/ids.js'
 
 test('every domain identifier has a constructor and a nominal runtime prefix', () => {
   const constructors: readonly [(value: string) => string, string][] = [
@@ -105,6 +105,13 @@ test('identifier validators reject values from another domain', () => {
   assert.throws(() => parseConversationId('run-1'), /Invalid conversation identifier/u)
 })
 
+test('identifier validators reject values that secret redaction would change', () => {
+  assert.throws(
+    () => createOperationId(`op-plain-sk-${'a'.repeat(24)}`),
+    /Invalid operation identifier/u,
+  )
+})
+
 test('brands prevent accidental compile-time substitution', () => {
   const run = createRunId('run-compile')
   // @ts-expect-error RunId and ConversationId are intentionally nominally distinct.
diff --git a/test/rpc.test.ts b/test/rpc.test.ts
index 5dbfd47..c3389cb 100644
--- a/test/rpc.test.ts
+++ b/test/rpc.test.ts
@@ -6,6 +6,7 @@ import { createBraidApplication, DETERMINISTIC_PROFILE } from '../src/app/compos
 import { MemoryJournal } from '../src/app/journal.js'
 import { runPlain } from '../src/bin/plain.js'
 import { canonicalDigest } from '../src/domain/canonical.js'
+import { redactSensitiveText } from '../src/domain/secret-sanitizer.js'
 import { FixedClock } from '../src/ports/clock.js'
 import {
   DEFAULT_RUN_CAPABILITIES,
@@ -893,6 +894,23 @@ test('plain output failure cancels the delayed run before the outer close', asyn
   assert.equal(app.events().length, eventsAfterClose)
 })
 
+test('plain mode generates redaction-stable operation identifiers', async () => {
+  const app = createBraidApplication({ fixture: 'deterministic' })
+  async function* input(): AsyncGenerator<string> {
+    yield 'verify generated operation identity\n'
+  }
+
+  await runPlain(controllerFor(app), '/workspace', input(), { write: () => true })
+
+  const operationId = app.state().runs[0]?.operationId
+  assert(operationId)
+  assert.match(
+    operationId,
+    /^op-[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/u,
+  )
+  assert.equal(redactSensitiveText(operationId), operationId)
+})
+
 test('JSONL requires initialize and stable operation identity', async () => {
   const app = createBraidApplication({ fixture: 'deterministic' })
   let output = ''