diff --git a/apps/server/src/patches/patch-service.test.ts b/apps/server/src/patches/patch-service.test.ts
index e0559d3..a2273d5 100644
--- a/apps/server/src/patches/patch-service.test.ts
+++ b/apps/server/src/patches/patch-service.test.ts
@@ -1,9 +1,23 @@
-import { describe, expect, it } from "vitest";
+import { mkdtemp, rm } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+
+import { afterEach, describe, expect, it } from "vitest";
 
 import { createPatchProposalService } from "./patch-service.js";
 import type { JsonPatchOperation } from "./patch-schema.js";
+import { createAuditLogService } from "../audit/audit-service.js";
+import { createWorkflowRegistryService } from "../workflows/workflow-service.js";
 import type { WorkflowDefinition } from "@agentdeck/workflow-core";
 
+const tempDirs: string[] = [];
+
+async function createTempStorePath(): Promise<string> {
+  const tempDir = await mkdtemp(join(tmpdir(), "agentdeck-patch-service-"));
+  tempDirs.push(tempDir);
+  return join(tempDir, "workflows.json");
+}
+
 const baseWorkflow: WorkflowDefinition = {
   id: "code-review",
   name: "Code Review",
@@ -32,6 +46,10 @@ const baseWorkflow: WorkflowDefinition = {
 };
 
 describe("createPatchProposalService", () => {
+  afterEach(async () => {
+    await Promise.all(tempDirs.splice(0).map((dir) => rm(dir, { recursive: true, force: true })));
+  });
+
   it("proposes and previews a valid workflow patch without mutating the target", async () => {
     const service = createPatchProposalService({
       now: () => "2026-05-29T01:00:00.000Z",
@@ -97,4 +115,77 @@ describe("createPatchProposalService", () => {
     expect(applied.proposal.approvalState).toBe("applied");
     expect(baseWorkflow.status).toBe("draft");
   });
+
+  it("applies approved workflow patches through the workflow registry and audits success", async () => {
+    const workflowRegistry = createWorkflowRegistryService({
+      storePath: await createTempStorePath(),
+      now: () => "2026-05-29T01:00:00.000Z",
+    });
+    const auditLog = createAuditLogService({
+      now: () => "2026-05-29T02:00:00.000Z",
+      nextId: () => "audit-apply",
+    });
+    const service = createPatchProposalService({
+      nextId: () => "patch-persist",
+      workflowRegistry,
+      auditLog,
+    });
+    await workflowRegistry.create(baseWorkflow);
+    const proposal = await service.proposeWorkflowPatch({
+      targetWorkflow: baseWorkflow,
+      baseVersion: 2,
+      patch: [
+        { op: "replace", path: "/name", value: "Code Review v3" },
+        { op: "replace", path: "/version", value: 3 },
+      ],
+    });
+    await service.setApprovalState(proposal.id, "approved");
+
+    const applied = await service.apply(proposal.id);
+    const persisted = await workflowRegistry.get("code-review");
+
+    expect(applied.workflow.name).toBe("Code Review v3");
+    expect(applied.workflow.version).toBe(3);
+    expect(persisted?.name).toBe("Code Review v3");
+    expect(persisted?.version).toBe(3);
+    expect(await auditLog.list()).toEqual([
+      expect.objectContaining({
+        action: "patch.proposal",
+        patchProposalId: "patch-persist",
+        diffSummary: "replace /name; replace /version",
+        approvalDecision: "approved",
+      }),
+    ]);
+  });
+
+  it("rejects stale patch base versions and audits rejected apply attempts", async () => {
+    const workflowRegistry = createWorkflowRegistryService({
+      storePath: await createTempStorePath(),
+    });
+    const auditLog = createAuditLogService({ nextId: () => "audit-stale" });
+    const service = createPatchProposalService({
+      nextId: () => "patch-stale",
+      workflowRegistry,
+      auditLog,
+    });
+    await workflowRegistry.create({ ...baseWorkflow, version: 3 });
+    const proposal = await service.proposeWorkflowPatch({
+      targetWorkflow: baseWorkflow,
+      baseVersion: 2,
+      patch: [{ op: "replace", path: "/name", value: "Stale update" }],
+    });
+    await service.setApprovalState(proposal.id, "approved");
+
+    await expect(service.apply(proposal.id)).rejects.toThrow(
+      'Patch proposal "patch-stale" targets workflow version 2, but current version is 3.',
+    );
+    expect((await workflowRegistry.get("code-review"))?.name).toBe("Code Review");
+    expect(await auditLog.list()).toEqual([
+      expect.objectContaining({
+        action: "approval.decision",
+        patchProposalId: "patch-stale",
+        approvalDecision: "rejected",
+      }),
+    ]);
+  });
 });
diff --git a/apps/server/src/patches/patch-service.ts b/apps/server/src/patches/patch-service.ts
index d94c702..63fe655 100644
--- a/apps/server/src/patches/patch-service.ts
+++ b/apps/server/src/patches/patch-service.ts
@@ -10,6 +10,8 @@ import type {
   ProposeWorkflowPatchInput,
   WorkflowPatchProposal,
 } from "./patch-schema.js";
+import type { AuditLogService } from "../audit/audit-service.js";
+import type { WorkflowRegistryService } from "../workflows/workflow-service.js";
 
 export interface PatchProposalService {
   readonly proposeWorkflowPatch: (
@@ -30,6 +32,8 @@ export interface CreatePatchProposalServiceOptions {
   readonly now?: () => string;
   readonly nextId?: () => string;
   readonly workflowValidation?: WorkflowSafetyValidatorOptions;
+  readonly workflowRegistry?: WorkflowRegistryService;
+  readonly auditLog?: AuditLogService;
 }
 
 export function createPatchProposalService(
@@ -90,21 +94,82 @@ export function createPatchProposalService(
         throw new Error(`Patch proposal "${id}" has validation errors.`);
       }
 
+      const workflow = await applyWorkflowPatch(proposal, options);
       const applied = {
         ...proposal,
         approvalState: "applied" as const,
+        diffPreview: {
+          ...proposal.diffPreview,
+          after: workflow,
+        },
         updatedAt: now(),
       };
       proposals.set(id, applied);
+      await options.auditLog?.record({
+        action: "patch.proposal",
+        actor: { type: "system", id: "patch-service" },
+        patchProposalId: proposal.id,
+        diffSummary: proposal.diffPreview.summary.join("; "),
+        approvalDecision: "approved",
+        metadata: {
+          targetType: proposal.targetType,
+          targetId: proposal.targetId,
+          baseVersion: proposal.baseVersion,
+        },
+      });
 
       return {
         proposal: applied,
-        workflow: cloneJson(applied.diffPreview.after),
+        workflow: cloneJson(workflow),
       };
     },
   };
 }
 
+async function applyWorkflowPatch(
+  proposal: WorkflowPatchProposal,
+  options: CreatePatchProposalServiceOptions,
+): Promise<WorkflowDefinition> {
+  const workflowRegistry = options.workflowRegistry;
+  if (!workflowRegistry) {
+    return cloneJson(proposal.diffPreview.after);
+  }
+
+  const currentWorkflow = await workflowRegistry.get(proposal.targetId);
+  if (!currentWorkflow) {
+    throw new Error(`Workflow "${proposal.targetId}" was not found.`);
+  }
+
+  if (currentWorkflow.version !== proposal.baseVersion) {
+    await options.auditLog?.record({
+      action: "approval.decision",
+      actor: { type: "system", id: "patch-service" },
+      patchProposalId: proposal.id,
+      diffSummary: proposal.diffPreview.summary.join("; "),
+      approvalDecision: "rejected",
+      metadata: {
+        targetType: proposal.targetType,
+        targetId: proposal.targetId,
+        baseVersion: proposal.baseVersion,
+        currentVersion: currentWorkflow.version,
+      },
+    });
+    throw new Error(
+      `Patch proposal "${proposal.id}" targets workflow version ${proposal.baseVersion}, but current version is ${currentWorkflow.version}.`,
+    );
+  }
+
+  return await workflowRegistry.update(proposal.targetId, {
+    name: proposal.diffPreview.after.name,
+    version: proposal.diffPreview.after.version,
+    status: proposal.diffPreview.after.status,
+    variables: proposal.diffPreview.after.variables,
+    permissions: proposal.diffPreview.after.permissions,
+    nodes: proposal.diffPreview.after.nodes,
+    edges: proposal.diffPreview.after.edges,
+  });
+}
+
 function assertBaseVersion(workflow: WorkflowDefinition, baseVersion: number): void {
   if (workflow.version !== baseVersion) {
     throw new Error(
diff --git a/docs/development/task-backlog.md b/docs/development/task-backlog.md
index 1d7aa26..820d6ab 100644
--- a/docs/development/task-backlog.md
+++ b/docs/development/task-backlog.md
@@ -641,10 +641,10 @@ Status markers:
 
 **Tasks:**
 
-- [ ] Apply approved workflow patch proposals through the workflow registry.
-- [ ] Reject stale base versions before apply.
-- [ ] Audit approved and rejected apply attempts.
-- [ ] Commit with message `feat: integrate patch apply workflow persistence`.
+- [x] Apply approved workflow patch proposals through the workflow registry.
+- [x] Reject stale base versions before apply.
+- [x] Audit approved and rejected apply attempts.
+- [x] Commit with message `feat: integrate patch apply workflow persistence`.
 
 **Acceptance Criteria:**