diff --git a/.github/scripts/run-agent-task/execute-native-agent-task.mjs b/.github/scripts/run-agent-task/execute-native-agent-task.mjs
index 41023496..162f7748 100644
--- a/.github/scripts/run-agent-task/execute-native-agent-task.mjs
+++ b/.github/scripts/run-agent-task/execute-native-agent-task.mjs
@@ -10,7 +10,7 @@ import { readNativeResult } from "./native-result-file.mjs"
 import { assertNoRuntimeSourcePaths, sanitizeRuntimeSourceJson, sanitizeRuntimeSourceText, sanitizeRuntimeSourceValue } from "./runtime-source-sanitizer.mjs"
 import { publishRunnerWorkspace } from "./runner-workspace-publisher.mjs"
 import { createRunnerWorkspaceSeedSnapshot, RUNNER_WORKSPACE_SEED_EXCLUDES } from "./runner-workspace-seed-snapshot.mjs"
-import { createTrustedArtifactSnapshot } from "./trusted-artifact-snapshot.mjs"
+import { createTrustedArtifactApplyChannel, trustedArtifactApplyRefs } from "./trusted-artifact-snapshot.mjs"
 
 const requestPath = process.env.AGENT_TASK_REQUEST_PATH || ".codebox/agent-task-request.json"
 const workspace = resolve(process.env.AGENT_TASK_WORKSPACE || process.cwd())
@@ -24,6 +24,7 @@ let privateRuntimeSourceRoot = ""
 let privateRuntimeSourceRootForSanitization = ""
 let runnerWorkspaceSeedSnapshot
 let reviewerEvidence
+let trustedApplyArtifactRoot
 
 const SIGNAL_EXIT_CODES = { SIGINT: 130, SIGTERM: 143, SIGHUP: 129 }
 let materializedSourceCleanup
@@ -37,6 +38,10 @@ function claimMaterializedSourcePaths() {
     paths.push(privateRuntimeSourceRoot)
     privateRuntimeSourceRoot = ""
   }
+  if (trustedApplyArtifactRoot) {
+    paths.push(trustedApplyArtifactRoot)
+    trustedApplyArtifactRoot = ""
+  }
   return paths
 }
 // Single idempotent cleanup coordinator for the private runtime source
@@ -152,8 +157,8 @@ function safeEnvironment(extra = {}) {
   return { PATH: process.env.PATH || "", HOME: process.env.HOME || "", CI: process.env.CI || "true", ...extra }
 }
 
-function agentEnvironment() {
-  return safeEnvironment(Object.fromEntries(["OPENAI_API_KEY", "MODEL_PROVIDER_SECRET_1", "MODEL_PROVIDER_SECRET_2", "MODEL_PROVIDER_SECRET_3", "MODEL_PROVIDER_SECRET_4", "MODEL_PROVIDER_SECRET_5", "GITHUB_TOKEN"].map((name) => [name, process.env[name]]).filter(([, value]) => value)))
+function agentEnvironment(extra = {}) {
+  return safeEnvironment({ ...Object.fromEntries(["OPENAI_API_KEY", "MODEL_PROVIDER_SECRET_1", "MODEL_PROVIDER_SECRET_2", "MODEL_PROVIDER_SECRET_3", "MODEL_PROVIDER_SECRET_4", "MODEL_PROVIDER_SECRET_5", "GITHUB_TOKEN"].map((name) => [name, process.env[name]]).filter(([, value]) => value)), ...extra })
 }
 
 function command(command, args, cwd, env = safeEnvironment()) {
@@ -605,8 +610,9 @@ const taskInput = {
 await writeFile(executionInputPath, `${JSON.stringify(taskInput, null, 2)}\n`)
 
 let execution = { code: 0, stdout: "", stderr: "", stdout_truncated: false, stderr_truncated: false }
- if (request.run_agent && !request.dry_run) {
-   execution = await command("node", [codeboxCliPath, "agent-task-run", "--input-file", executionInputPath, "--result-file", nativeResultPath], workspace, agentEnvironment())
+if (request.run_agent && !request.dry_run) {
+   if (request.runner_workspace?.enabled) trustedApplyArtifactRoot = await createTrustedArtifactApplyChannel()
+   execution = await command("node", [codeboxCliPath, "agent-task-run", "--input-file", executionInputPath, "--result-file", nativeResultPath], workspace, agentEnvironment(trustedApplyArtifactRoot ? { WP_CODEBOX_TRUSTED_APPLY_ARTIFACT_ROOT: trustedApplyArtifactRoot } : {}))
  }
 
 // Public package bytes are embedded in the runtime recipe and consumed only by
@@ -638,16 +644,16 @@ if (execution.code === 0 && runtimeResult.success === true && request.runner_wor
     const publicCore = await import(pathToFileURL(join(codeboxRoot, "packages/runtime-core/dist/public.js")).href)
     const refs = publicCore.normalizePublicArtifactRefDTOs(runtimeResult)
       .filter((ref) => ref.kind === "codebox-patch" || ref.kind === "codebox-changed-files")
-    const trustedArtifacts = await createTrustedArtifactSnapshot(artifactsPath, refs)
-    try {
-      workspaceApply = await runnerWorkspaceCore.applyRunnerWorkspacePatch({ artifactRoot: trustedArtifacts.root, artifactRefs: trustedArtifacts.refs, workspaceRoot: workspace, writablePaths, seedIdentity: runnerWorkspaceSeedSnapshot?.provenance.identity })
-    } finally {
-      await rm(trustedArtifacts.root, { recursive: true, force: true })
-    }
+    const trustedArtifacts = await trustedArtifactApplyRefs(trustedApplyArtifactRoot, refs)
+    workspaceApply = await runnerWorkspaceCore.applyRunnerWorkspacePatch({ artifactRoot: trustedArtifacts.root, artifactRefs: trustedArtifacts.refs, workspaceRoot: workspace, writablePaths, seedIdentity: runnerWorkspaceSeedSnapshot?.provenance.identity })
   } catch (error) {
     downstreamFailure = { stage: "apply", message: bounded(error instanceof Error ? error.message : String(error), MAX_WORKFLOW_OUTPUT_BYTES), ...(error?.evidence ? { evidence: error.evidence } : {}) }
   }
 }
+if (trustedApplyArtifactRoot) {
+  await rm(trustedApplyArtifactRoot, { recursive: true, force: true })
+  trustedApplyArtifactRoot = ""
+}
 runtimeResult = sanitizeRuntimeSourceValue(runtimeResult, runtimeSourceOutputRoots)
 privateRuntimeSourceRootForSanitization = runtimeSourceOutputRoots
 assertNoRuntimeSourcePaths(runtimeResult, privateRuntimeSourceRootForSanitization)
diff --git a/.github/scripts/run-agent-task/trusted-artifact-snapshot.mjs b/.github/scripts/run-agent-task/trusted-artifact-snapshot.mjs
index 0df2700c..57bdd8a2 100644
--- a/.github/scripts/run-agent-task/trusted-artifact-snapshot.mjs
+++ b/.github/scripts/run-agent-task/trusted-artifact-snapshot.mjs
@@ -1,4 +1,5 @@
-import { lstat, mkdir, mkdtemp, readFile, realpath, rm, writeFile } from "node:fs/promises"
+import { createHash } from "node:crypto"
+import { lstat, mkdtemp, readFile, realpath } from "node:fs/promises"
 import { tmpdir } from "node:os"
 import { isAbsolute, join, relative, resolve } from "node:path"
 
@@ -10,29 +11,30 @@ function underRoot(root, candidate) {
 }
 
 /**
- * Copies selected regular artifacts to a private temporary root before a later
- * durable-artifact transformation. Callers retain their artifact references,
- * with paths rewritten relative to the trusted copy.
+ * Opens a workflow-owned private root that the runtime may use before durable
+ * artifact redaction. This root is never part of the artifact bundle.
  */
-export async function createTrustedArtifactSnapshot(artifactRoot, refs, maxFileBytes = MAX_SNAPSHOT_FILE_BYTES) {
-  const root = await realpath(resolve(artifactRoot))
-  const snapshotRoot = await mkdtemp(join(tmpdir(), "wp-codebox-trusted-artifacts-"))
-  try {
-    const copiedRefs = await Promise.all(refs.map(async (ref) => {
-      const requested = isAbsolute(ref.path) ? resolve(ref.path) : resolve(root, ref.path)
-      const stat = await lstat(requested)
-      if (!stat.isFile() || stat.isSymbolicLink() || stat.size > maxFileBytes) throw new Error("Trusted artifact snapshot requires a bounded regular file.")
-      const source = await realpath(requested)
-      if (!underRoot(root, source)) throw new Error("Trusted artifact snapshot escapes the artifact root.")
-      const path = relative(root, source).replaceAll("\\", "/")
-      const destination = join(snapshotRoot, path)
-      await mkdir(resolve(destination, ".."), { recursive: true })
-      await writeFile(destination, await readFile(source))
-      return { ...ref, path }
-    }))
-    return { root: snapshotRoot, refs: copiedRefs }
-  } catch (error) {
-    await rm(snapshotRoot, { recursive: true, force: true })
-    throw error
+export async function createTrustedArtifactApplyChannel() {
+  return mkdtemp(join(tmpdir(), "wp-codebox-trusted-apply-"))
+}
+
+/** Validates and projects only the two canonical private apply artifacts. */
+export async function trustedArtifactApplyRefs(root, refs, maxFileBytes = MAX_SNAPSHOT_FILE_BYTES) {
+  const channelRoot = await realpath(resolve(root))
+  const expectedPaths = {
+    "codebox-patch": "files/patch.diff",
+    "codebox-changed-files": "files/changed-files.json",
   }
+  const copiedRefs = await Promise.all(refs.map(async (ref) => {
+    const path = expectedPaths[ref.kind]
+    if (!path) throw new Error("Trusted apply artifacts must use canonical artifact kinds.")
+    const requested = join(channelRoot, path)
+    const stat = await lstat(requested)
+    if (!stat.isFile() || stat.isSymbolicLink() || stat.size > maxFileBytes) throw new Error("Trusted artifact snapshot requires a bounded regular file.")
+    const source = await realpath(requested)
+    if (!underRoot(channelRoot, source)) throw new Error("Trusted artifact snapshot escapes the artifact root.")
+    const bytes = await readFile(source)
+    return { ...ref, path, ...(ref.kind === "codebox-patch" ? { sha256: createHash("sha256").update(bytes).digest("hex") } : {}) }
+  }))
+  return { root: channelRoot, refs: copiedRefs }
 }
diff --git a/package.json b/package.json
index 1e931b09..fdb00c73 100644
--- a/package.json
+++ b/package.json
@@ -132,6 +132,7 @@
     "test:source-root-preparation": "tsx tests/source-root-preparation.test.ts",
     "test:workspace-preload-artifacts": "tsx tests/workspace-preload-artifacts.test.ts",
     "test:runner-workspace-apply": "tsx tests/runner-workspace-apply.test.ts",
+    "test:trusted-apply-artifact-channel": "tsx tests/trusted-apply-artifact-channel.integration.test.ts",
     "test:runner-workspace-publisher": "node tests/runner-workspace-publisher.test.mjs",
     "test:native-agent-task-lifecycle": "node tests/execute-native-agent-task-lifecycle.test.mjs",
     "test:native-agent-task-interruption": "node tests/execute-native-agent-task-interruption.test.mjs",
diff --git a/packages/runtime-playground/src/artifact-bundle-builder.ts b/packages/runtime-playground/src/artifact-bundle-builder.ts
index 5afbb872..bb3bcd7d 100644
--- a/packages/runtime-playground/src/artifact-bundle-builder.ts
+++ b/packages/runtime-playground/src/artifact-bundle-builder.ts
@@ -45,6 +45,7 @@ import {
 import { normalizeJsonValue, stripUndefined } from "@automattic/wp-codebox-core/internals"
 import type { BrowserArtifact } from "./browser-artifacts.js"
 import { firstCommandWordPressAdminAuthRequirement } from "./command-auth-requirements.js"
+import { writeTrustedApplyArtifacts } from "./trusted-apply-artifact-channel.js"
 import {
   ArtifactRedactor,
   artifactContentDigest,
@@ -160,6 +161,7 @@ export class ArtifactBundleBuilder {
     const replayExportPackageFiles = replayExportPackageManifestFiles(source.artifactRoot, source.commands)
     const capturedMounts = await source.captureMountedFiles(filesDirectory, redactor)
     const { mountDiffs, changedFiles, patch, diagnostics: mountDiffDiagnostics } = await source.captureMountDiffs(filesDirectory, redactor)
+    await writeTrustedApplyArtifacts(changedFiles, patch)
     const changedFilesJson = redactor.redact(CHANGED_FILES_ARTIFACT_PATH, `${JSON.stringify(changedFiles, null, 2)}\n`)
     const redactedPatch = redactor.redact("files/patch.diff", patch)
     const patchContentDigest = artifactContentDigest(changedFilesJson, redactedPatch)
diff --git a/packages/runtime-playground/src/trusted-apply-artifact-channel.ts b/packages/runtime-playground/src/trusted-apply-artifact-channel.ts
new file mode 100644
index 00000000..695e2414
--- /dev/null
+++ b/packages/runtime-playground/src/trusted-apply-artifact-channel.ts
@@ -0,0 +1,30 @@
+import { lstat, mkdir, writeFile } from "node:fs/promises"
+import { join, resolve } from "node:path"
+
+const CHANNEL_ROOT_ENV = "WP_CODEBOX_TRUSTED_APPLY_ARTIFACT_ROOT"
+const MAX_APPLY_ARTIFACT_BYTES = 5 * 1024 * 1024
+
+/**
+ * The workflow creates this private temporary root. It is deliberately outside
+ * the durable bundle so canonical apply bytes never enter manifests or uploads.
+ */
+export async function writeTrustedApplyArtifacts(changedFiles: unknown, patch: string): Promise<void> {
+  const root = process.env[CHANNEL_ROOT_ENV]
+  if (!root) return
+
+  const changedFilesContents = `${JSON.stringify(changedFiles, null, 2)}\n`
+  if (Buffer.byteLength(changedFilesContents) > MAX_APPLY_ARTIFACT_BYTES || Buffer.byteLength(patch) > MAX_APPLY_ARTIFACT_BYTES) {
+    throw new Error("Trusted apply artifacts must be bounded.")
+  }
+
+  const rootStat = await lstat(resolve(root))
+  if (!rootStat.isDirectory() || rootStat.isSymbolicLink()) throw new Error("Trusted apply artifact root must be a directory.")
+  const files = join(root, "files")
+  await mkdir(files, { recursive: true, mode: 0o700 })
+  const filesStat = await lstat(files)
+  if (!filesStat.isDirectory() || filesStat.isSymbolicLink()) throw new Error("Trusted apply artifact files directory must be a directory.")
+  await Promise.all([
+    writeFile(join(files, "changed-files.json"), changedFilesContents, { mode: 0o600 }),
+    writeFile(join(files, "patch.diff"), patch, { mode: 0o600 }),
+  ])
+}
diff --git a/tests/execute-native-agent-task-lifecycle.test.mjs b/tests/execute-native-agent-task-lifecycle.test.mjs
index a9857a19..9588e4ba 100644
--- a/tests/execute-native-agent-task-lifecycle.test.mjs
+++ b/tests/execute-native-agent-task-lifecycle.test.mjs
@@ -74,12 +74,21 @@ const output = process.argv[process.argv.indexOf("--result-file") + 1]
 const input = JSON.parse(await readFile(process.argv[process.argv.indexOf("--input-file") + 1], "utf8"))
 const root = join(process.cwd(), ".codebox", "agent-task-artifacts", "files")
 await mkdir(root, { recursive: true })
+const trustedRoot = process.env.WP_CODEBOX_TRUSTED_APPLY_ARTIFACT_ROOT
+if (trustedRoot) await mkdir(join(trustedRoot, "files"), { recursive: true })
 const patch = ${JSON.stringify(noOp ? "" : applyReject ? "--- a/README.md\n+++ b/README.md\n@@ -1,2 +1,2 @@\n OPENAI_API_KEY\n-not-before\n+after\n" : "--- a/README.md\n+++ b/README.md\n@@ -1,2 +1,2 @@\n OPENAI_API_KEY\n-before\n+after\n")}
 await writeFile(join(root, "patch.diff"), patch)
 await writeFile(join(root, "changed-files.json"), JSON.stringify({
   schema: "wp-codebox/changed-files/v1",
   files: ${noOp} ? [] : [{ path: "/workspace/README.md", relativePath: "README.md", status: "modified", beforeMode: "100644", afterMode: "100644" }],
 }))
+if (trustedRoot) {
+   await writeFile(join(trustedRoot, "files", "patch.diff"), patch)
+   await writeFile(join(trustedRoot, "files", "changed-files.json"), JSON.stringify({
+     schema: "wp-codebox/changed-files/v1",
+     files: ${noOp} ? [] : [{ path: "/workspace/README.md", relativePath: "README.md", status: "modified", beforeMode: "100644", afterMode: "100644" }],
+   }))
+ }
 ${mismatch ? "await writeFile(join(process.cwd(), \"README.md\"), \"diverged\\n\")" : ""}
 await writeFile(join(process.cwd(), ".codebox", "order"), "runtime\\n")
 const summary = {
@@ -169,7 +178,7 @@ process.stdout.write(JSON.stringify({
 }
 
 const success = await run()
-assert.equal(success.code, 0, success.stderr)
+assert.equal(success.code, 0, `${success.stderr}\n${JSON.stringify(success.result)}`)
 assert.equal(await readFile(join(success.workspace, "README.md"), "utf8"), "OPENAI_API_KEY\nafter\n")
 const durablePatch = await readFile(join(success.workspace, ".codebox", "agent-task-artifacts", "files", "patch.diff"), "utf8")
 assert(!durablePatch.includes("OPENAI_API_KEY"), "durable patch artifacts redact configured secret values")
diff --git a/tests/trusted-apply-artifact-channel.integration.test.ts b/tests/trusted-apply-artifact-channel.integration.test.ts
new file mode 100644
index 00000000..bc29468f
--- /dev/null
+++ b/tests/trusted-apply-artifact-channel.integration.test.ts
@@ -0,0 +1,85 @@
+import assert from "node:assert/strict"
+import { execFile } from "node:child_process"
+import { mkdir, mkdtemp, readFile, rm, writeFile } from "node:fs/promises"
+import { tmpdir } from "node:os"
+import { join } from "node:path"
+import { promisify } from "node:util"
+import { ArtifactBundleBuilder } from "../packages/runtime-playground/src/artifact-bundle-builder.js"
+import { captureMountedFiles, captureMountDiffs } from "../packages/runtime-playground/src/mounted-artifact-capture.js"
+import { applyRunnerWorkspacePatch } from "../packages/runtime-core/src/runner-workspace-apply.js"
+
+const execFileAsync = promisify(execFile)
+const root = await mkdtemp(join(tmpdir(), "wp-codebox-trusted-apply-integration-"))
+const artifactRoot = join(root, "artifacts")
+const trustedRoot = join(root, "trusted")
+const baseline = join(root, "baseline")
+const mounted = join(root, "mounted")
+const host = join(root, "host")
+const secretName = "CONFIGURED_SECRET"
+const previousChannel = process.env.WP_CODEBOX_TRUSTED_APPLY_ARTIFACT_ROOT
+
+try {
+  for (const directory of [baseline, mounted, host, trustedRoot]) {
+    await mkdir(directory, { recursive: true })
+    await writeFile(join(directory, "README.md"), `${secretName}\nbefore\n`)
+  }
+  await writeFile(join(mounted, "README.md"), `${secretName}\nafter\n`)
+  await execFileAsync("git", ["init"], { cwd: host })
+  process.env.WP_CODEBOX_TRUSTED_APPLY_ARTIFACT_ROOT = trustedRoot
+
+  const mounts = [{ source: mounted, target: "/workspace", mode: "readwrite", metadata: { baselineSource: baseline } }]
+  await new ArtifactBundleBuilder({
+    artifactRoot,
+    runtimeId: "trusted-apply-test",
+    runtimeCreatedAt: new Date().toISOString(),
+    spec: { environment: { blueprint: {} }, secretEnv: { [secretName]: "secret-value" } },
+    mounts,
+    commands: [], observations: [], snapshots: [], events: [],
+    info: async () => ({ id: "trusted-apply-test", backend: "playground", status: "ready", environment: { version: "latest" } }),
+    previewInfo: async () => undefined,
+    browserReviewSummary: () => undefined,
+    browserArtifacts: () => [],
+    captureMountedFiles: (filesDirectory, redactor) => captureMountedFiles(filesDirectory, mounts, redactor),
+    captureMountDiffs: (filesDirectory, redactor) => captureMountDiffs(artifactRoot, filesDirectory, mounts, redactor),
+    redactBrowserArtifacts: async () => {}, redactPluginCheckArtifacts: async () => {}, redactThemeCheckArtifacts: async () => {},
+    browserManifestFiles: () => [], pluginCheckArtifactPaths: () => [], themeCheckArtifactPaths: () => [], observationManifestFiles: () => [], pluginCheckManifestFiles: () => [], themeCheckManifestFiles: () => [],
+    formatRuntimeLog: () => "", formatCommandsLog: () => "", recordArtifactsCollected: () => {},
+  } as any).build()
+
+  const durablePatch = await readFile(join(artifactRoot, "files", "patch.diff"), "utf8")
+  assert(!durablePatch.includes(secretName), "durable artifact redacts configured secret names")
+  assert.match(durablePatch, /\[REDACTED:configured-secret-name\]/)
+  await assert.rejects(
+    applyRunnerWorkspacePatch({
+      artifactRoot,
+      artifactRefs: [
+        { kind: "codebox-patch", path: "files/patch.diff" },
+        { kind: "codebox-changed-files", path: "files/changed-files.json" },
+      ],
+      workspaceRoot: host,
+      writablePaths: ["README.md"],
+    }),
+    /Host git apply failed/,
+    "the durable redacted patch cannot apply where configured secret context is unchanged",
+  )
+  const trustedPatch = await readFile(join(trustedRoot, "files", "patch.diff"), "utf8")
+  assert.match(trustedPatch, new RegExp(secretName), "private apply bytes retain unchanged diff context")
+
+  const applied = await applyRunnerWorkspacePatch({
+    artifactRoot: trustedRoot,
+    artifactRefs: [
+      { kind: "codebox-patch", path: "files/patch.diff" },
+      { kind: "codebox-changed-files", path: "files/changed-files.json" },
+    ],
+    workspaceRoot: host,
+    writablePaths: ["README.md"],
+  })
+  assert.equal(applied.status, "applied", "the host applies pre-redaction bytes")
+  assert.equal(await readFile(join(host, "README.md"), "utf8"), `${secretName}\nafter\n`)
+} finally {
+  if (previousChannel === undefined) delete process.env.WP_CODEBOX_TRUSTED_APPLY_ARTIFACT_ROOT
+  else process.env.WP_CODEBOX_TRUSTED_APPLY_ARTIFACT_ROOT = previousChannel
+  await rm(root, { recursive: true, force: true })
+}
+
+console.log("trusted apply artifact channel integration ok")