diff --git a/backend/src/app.ts b/backend/src/app.ts
index f948453b..d8b8905b 100644
--- a/backend/src/app.ts
+++ b/backend/src/app.ts
@@ -21,6 +21,7 @@ import { ReadinessManager } from "./runtime/readiness-manager.js";
 import { MaintenanceBarrier } from "./runtime/maintenance-gate.js";
 import { WorkspaceRegistry } from "./workspaces/registry.js";
 import { GitWorkspaceRepository } from "./workspaces/git-repository.js";
+import { WorkspaceAuthorGitService } from "./workspaces/author-git-service.js";
 import { WorkspaceFsAtV1 } from "./workspaces/workspace-fs-at.js";
 import { VerifiedWorkspaceLockRootLeaseFactory } from "./workspaces/workspace-lock-root-lease.js";
 import { CapabilityAwareRegistryPublicationLifecycleOwner, canonicalBootstrapRequestDigest } from "./workspaces/registry-publication.js";
@@ -39,6 +40,7 @@ export interface BuildAppDeps {
   readiness?: ReadinessManager;
   hub?: SseHub;
   workspaceRegistry?: WorkspaceRegistry;
+  workspaceAuthorService?: WorkspaceAuthorGitService;
   workspaceDiagnoser?: WorkspaceDiagnoser;
   workspaceRuntimeSupport?: (workspace: WorkspaceDescriptor) => boolean;
   maintenanceBarrier?: MaintenanceBarrier;
@@ -94,6 +96,7 @@ export function buildApp(config: AppConfig, deps?: BuildAppDeps): FastifyInstanc
   const mgr = deps?.mgr ?? new PiProcessManager(config, deps?.spawnFn ? { spawnFn: deps.spawnFn } : undefined);
   const hub = deps?.hub ?? new SseHub();
   const workspaceRegistry = deps?.workspaceRegistry ?? createWorkspaceRegistry(config);
+  const workspaceAuthorService = deps?.workspaceAuthorService ?? new WorkspaceAuthorGitService(new GitWorkspaceRepository(config.workspaceRegistry));
   const workspaceDiagnoser = deps?.workspaceDiagnoser
     ?? createProductionWorkspaceDiagnoser(config.workspaceDiagnosticTimeoutMs, undefined, {
       internalQdrantUrl: config.internalQdrantUrl,
@@ -181,7 +184,7 @@ export function buildApp(config: AppConfig, deps?: BuildAppDeps): FastifyInstanc
   });
   sqlRoutes(app, { tht: tht as ThtRunner, getSettings, workspaceRegistry });
   metaRoutes(app, { harnessDir: config.harnessDir, listModels });
-  workspaceRoutes(app, { registry: workspaceRegistry, config: config.workspaceRegistry, diagnose: workspaceDiagnoser });
+  workspaceRoutes(app, { registry: workspaceRegistry, config: config.workspaceRegistry, diagnose: workspaceDiagnoser, authorService: workspaceAuthorService });
   settingsRoutes(app, { cfg: config, listModels, getSettings });
   piManagementRoutes(app, { config, service: piManagement });
 
diff --git a/backend/src/routes/workspaces.ts b/backend/src/routes/workspaces.ts
index 104591f8..3aa71746 100644
--- a/backend/src/routes/workspaces.ts
+++ b/backend/src/routes/workspaces.ts
@@ -6,6 +6,7 @@ import yauzl from "yauzl";
 import yazl from "yazl";
 import { z } from "zod";
 import type { WorkspaceRegistryConfig } from "../workspaces/types.js";
+import type { WorkspaceAuthorGitService } from "../workspaces/author-git-service.js";
 import { WorkspaceRegistryError } from "../workspaces/git-repository.js";
 import { addressedRunId } from "../workspaces/registry-publication.js";
 import {
@@ -38,6 +39,7 @@ interface WorkspaceRoutesDeps {
   registry: WorkspaceRegistry;
   config: WorkspaceRegistryConfig;
   diagnose: WorkspaceDiagnoser;
+  authorService: WorkspaceAuthorGitService;
 }
 
 const workspaceId = z.string().regex(/^[a-z][a-z0-9-]{2,62}$/);
@@ -372,6 +374,9 @@ export function workspaceRoutes(app: FastifyInstance, deps: WorkspaceRoutesDeps)
     try {
       const requestValue = publishRequest(request.body);
       const identity = recoveryIdentity();
+      // Revalidate the active addressed snapshot before authoring. This pins the
+      // accepted base while the author service stages and pushes its commit.
+      await deps.registry.ensureBootstrapAddressed(identity);
       const id = requestValue.action === "delete" ? requestValue.id : requestValue.workspace.workspace.id;
       const addressed = {
         mode: "create" as const, operation: "registry_pull" as const, runId: addressedRunId(),
@@ -381,7 +386,10 @@ export function workspaceRoutes(app: FastifyInstance, deps: WorkspaceRoutesDeps)
         remoteRefIdentitySha256: identity.remoteRefIdentitySha256,
         expectedBaseCommit: requestValue.baseCommit as Revision40,
       };
-      const result = await deps.registry.publishAddressed(addressed, { authoring: requestValue });
+      // Authoring is intentionally split from activation: this service creates and pushes
+      // the remote commit only. The addressed registry is the sole pointer owner.
+      await deps.authorService.publish(requestValue);
+      const result = await deps.registry.publishAddressed(addressed);
       return { revision: revisionFromPublication(result, id) };
     } catch (error) {
       return errorReply(reply, error);
diff --git a/backend/src/workspaces/author-git-service.ts b/backend/src/workspaces/author-git-service.ts
new file mode 100644
index 00000000..9f97050f
--- /dev/null
+++ b/backend/src/workspaces/author-git-service.ts
@@ -0,0 +1,106 @@
+import { WorkspaceConflictError, type PublishWorkspaceRequest } from "./registry.js";
+import { GitWorkspaceRepository, WorkspaceRegistryError, WorkspaceRepositoryLock } from "./git-repository.js";
+import { parseWorkspaceYaml, renderWorkspaceDocs, serializeWorkspaceYaml, validateOperationalWorkspace, type CanonicalWorkspace, type WorkspaceDescriptor } from "./schema.js";
+
+
+function changedFields(left: unknown, right: unknown, path = ""): string[] {
+  if (JSON.stringify(left) === JSON.stringify(right)) return [];
+  if (!left || !right || typeof left !== "object" || typeof right !== "object" || Array.isArray(left) || Array.isArray(right)) return [path || "workspace"];
+  const keys = new Set([...Object.keys(left as object), ...Object.keys(right as object)]);
+  return [...keys].sort().flatMap(key => changedFields((left as Record<string, unknown>)[key], (right as Record<string, unknown>)[key], path ? `${path}.${key}` : key));
+}
+
+export interface WorkspaceAuthorGitResult {
+  readonly id: string;
+  readonly commit: string;
+  readonly blob: string;
+}
+
+/**
+ * The authoring side of workspace publication.  This service owns only the author
+ * checkout and the remote commit; activation is deliberately left to the addressed
+ * registry owner.  In particular, this class never writes state/active.json or a
+ * snapshot pointer.
+ */
+export class WorkspaceAuthorGitService {
+  private readonly lock: WorkspaceRepositoryLock;
+
+  constructor(private readonly repository: GitWorkspaceRepository) {
+    this.lock = new WorkspaceRepositoryLock(repository.locksPath);
+  }
+
+  async publish(request: PublishWorkspaceRequest): Promise<WorkspaceAuthorGitResult> {
+    await this.repository.ensureLayout();
+    return this.lock.run(async () => {
+      const status = await this.repository.pull();
+      const id = request.action === "delete" ? request.id : request.workspace.workspace.id;
+      const path = `workspaces/${id}.yaml`;
+      const current = await this.currentDescriptor(status.head!, path);
+      const currentBlob = current ? await this.repository.blob(path) : undefined;
+
+      if (request.baseCommit !== status.head) {
+        if (request.action !== "create" && currentBlob === request.baseBlob) {
+          throw new WorkspaceRegistryError("workspace_stale", "Workspace revision is stale");
+        }
+        const base = await this.currentDescriptor(request.baseCommit, path);
+        throw this.conflict(request, status.head!, current, currentBlob, base);
+      }
+      if (request.action === "create" && current) throw this.conflict(request, status.head!, current, currentBlob, current);
+      if (request.action !== "create" && !current) throw this.conflict(request, status.head!, current, currentBlob, current);
+      if (request.action !== "create") {
+        if (currentBlob !== request.baseBlob) throw this.conflict(request, status.head!, current, currentBlob, current);
+      }
+      if (request.action !== "delete") await this.assertEvidence(request.workspace, status.head!);
+
+      const docs = {
+        contract: `workspace-docs/${id}/contract.env.example`,
+        readme: `workspace-docs/${id}/README.md`,
+      };
+      if (request.action === "delete") {
+        await this.repository.removeRegistryFile(path);
+        await this.repository.removeRegistryFile(docs.contract);
+        await this.repository.removeRegistryFile(docs.readme);
+      } else {
+        await this.repository.writeRegistryFile(path, serializeWorkspaceYaml(request.workspace));
+        const rendered = renderWorkspaceDocs(request.workspace);
+        await this.repository.writeRegistryFile(docs.contract, rendered.envExample);
+        await this.repository.writeRegistryFile(docs.readme, rendered.markdown);
+      }
+      const published = await this.repository.commitAndPush(
+        [path, docs.contract, docs.readme],
+        request.action === "delete" ? `Delete workspace ${id}` : `Publish workspace ${id}`,
+      );
+      const commit = published.head;
+      if (!commit) throw new WorkspaceRegistryError("git_unavailable", "Workspace Git service is unavailable");
+      if (request.action === "delete") return { id, commit, blob: request.baseBlob };
+      return { id, commit, blob: await this.repository.blob(path) };
+    });
+  }
+
+  private async currentDescriptor(commit: string, path: string): Promise<WorkspaceDescriptor | undefined> {
+    try {
+      return parseWorkspaceYaml(await this.repository.readWorkspaceAt(commit, path));
+    } catch (error) {
+      if (error instanceof WorkspaceRegistryError && error.code === "git_unavailable") return undefined;
+      throw error;
+    }
+  }
+
+  private async assertEvidence(workspace: CanonicalWorkspace, commit: string): Promise<void> {
+    if (workspace.evidence?.source.type !== "filesystem") return;
+    const uri = workspace.evidence.source.uri;
+    if (!/^workspace-content\/[a-z][a-z0-9-]{2,62}\/evidence$/.test(uri)) {
+      throw new WorkspaceRegistryError("workspace_invalid", "Workspace Evidence root is invalid");
+    }
+    await this.repository.assertTreeAtRevision(commit, uri);
+  }
+
+  private conflict(request: PublishWorkspaceRequest, commit: string, remote: WorkspaceDescriptor | undefined, blob: string | undefined, base: WorkspaceDescriptor | undefined): WorkspaceConflictError {
+    const local = request.action === "delete" ? undefined : request.workspace;
+    const expected = { commit: request.baseCommit, ...(request.action === "create" ? {} : { blob: request.baseBlob }) };
+    const actual = { commit, ...(blob ? { blob } : {}) };
+    const remoteChanges = changedFields(base, remote);
+    const fields = remoteChanges;
+    return new WorkspaceConflictError(fields, expected, actual, base, local, remote);
+  }
+}
diff --git a/backend/test/routes-workspaces.test.ts b/backend/test/routes-workspaces.test.ts
index b21af38d..c5feff26 100644
--- a/backend/test/routes-workspaces.test.ts
+++ b/backend/test/routes-workspaces.test.ts
@@ -143,6 +143,7 @@ function appFor(registry: RegistryFake, diagnose = vi.fn(async () => ({ activata
   }), {
     thtRunner: {} as any,
     workspaceRegistry: registry as WorkspaceRegistry,
+    workspaceAuthorService: { publish: vi.fn(async () => ({ id: workspace.workspace.id, commit: revision.commit, blob: revision.blob })) } as any,
     workspaceDiagnoser: diagnose,
   } as any);
 }
@@ -397,15 +398,15 @@ test("maps a stale registry commit to HTTP 409 without conflict payloads", async
 });
 
 test("publishes accepted CRUD through the addressed request and returns its terminal revision", async () => {
-  const publishAddressed = vi.fn(async (request: any) => ({
-    plan: { targetCommit: revision.commit, targetManifestSha256: "a".repeat(64), targetWorkspaces: [{ workspaceId: request.mutation.workspace.workspace.id, revision: revision.commit, descriptorBlob: revision.blob, manifestSha256: "b".repeat(64) }] },
+  const publishAddressed = vi.fn(async (_request: any) => ({
+    plan: { targetCommit: revision.commit, targetManifestSha256: "a".repeat(64), targetWorkspaces: [{ workspaceId: workspace.workspace.id, revision: revision.commit, descriptorBlob: revision.blob, manifestSha256: "b".repeat(64) }] },
   }));
   const registry = registryFake({ publishAddressed });
   const app = appFor(registry);
   const response = await app.inject({ method: "POST", url: "/workspaces/publish", payload: { action: "create", workspace, baseCommit: revision.commit } });
   expect(response.statusCode).toBe(200);
   expect(response.json()).toEqual({ revision: { id: workspace.workspace.id, commit: revision.commit, blob: revision.blob, snapshotPath: revision.snapshotPath } });
-  expect(publishAddressed).toHaveBeenCalledWith(expect.objectContaining({ mode: "create", operation: "registry_pull", mutation: expect.objectContaining({ action: "create", baseCommit: revision.commit }) }));
+  expect(publishAddressed).toHaveBeenCalledWith(expect.objectContaining({ mode: "create", operation: "registry_pull", expectedBaseCommit: revision.commit }));
 });
 
 test("exports generated public artifacts without secret values", async () => {
@@ -664,7 +665,7 @@ test("real publish create/update, pull, list, and read preserve a complete Evide
 
 test("real route reports a safe field for an Evidence-only concurrent edit", async () => {
   const fixture = await createRealRouteFixture(httpEvidenceWorkspace);
-  await fixture.registry.bootstrap();
+  await fixture.registry.ensureBootstrapAddressed(fixture.registry.recoveryIdentity());
   const base = await fixture.registry.read("psd-clinical");
   const remote = withEvidence(
     { ...httpEvidenceWorkspace.evidence!.source },
@@ -700,7 +701,7 @@ test.each([
   ["cross-workspace", "workspace-content/research/evidence"],
 ])("real publish rejects %s filesystem Evidence paths without changing HEAD", async (_label, uri) => {
   const fixture = await createRealRouteFixture();
-  await fixture.registry.bootstrap();
+  await fixture.registry.ensureBootstrapAddressed(fixture.registry.recoveryIdentity());
   const base = await fixture.registry.read("psd-clinical");
   const invalid = structuredClone(filesystemEvidenceWorkspace) as any;
   invalid.evidence.source.uri = uri;
@@ -732,7 +733,7 @@ test.each([
   },
 ])("real publish rejects $label without echoing it or changing HEAD", async ({ source }) => {
   const fixture = await createRealRouteFixture();
-  await fixture.registry.bootstrap();
+  await fixture.registry.ensureBootstrapAddressed(fixture.registry.recoveryIdentity());
   const base = await fixture.registry.read("psd-clinical");
   const invalid = structuredClone(base.workspace) as any;
   invalid.evidence = { source };
@@ -753,7 +754,7 @@ test.each([
 
 test("real publish and pull fail safely when the contextual Evidence Git tree is missing", async () => {
   const fixture = await createRealRouteFixture();
-  await fixture.registry.bootstrap();
+  await fixture.registry.ensureBootstrapAddressed(fixture.registry.recoveryIdentity());
   const current = await fixture.registry.read("psd-clinical");
   const missing = validateWorkspaceDescriptor({
     ...workspace,
@@ -791,7 +792,7 @@ test("real export and import preserve stable public Evidence artifacts without E
   const secretDirectory = join(fixture.root, "fixture-secrets");
   mkdirSync(secretDirectory);
   writeFileSync(join(secretDirectory, "credential"), SECRET_CANARY);
-  await fixture.registry.bootstrap();
+  await fixture.registry.ensureBootstrapAddressed(fixture.registry.recoveryIdentity());
 
   const firstResponse = await fixture.app.inject({ method: "GET", url: "/workspaces/psd-clinical/export" });
   const secondResponse = await fixture.app.inject({ method: "GET", url: "/workspaces/psd-clinical/export" });