diff --git a/maps/agent-access-map/projects.md b/maps/agent-access-map/projects.md
index 28884fc62d6..32bd0a3b74b 100644
--- a/maps/agent-access-map/projects.md
+++ b/maps/agent-access-map/projects.md
@@ -148,3 +148,9 @@ Evidence: `source-only` — reviewed at `9ef434fe79c57d976b8b03b14c5242db270b832
 Verification: `not-run` — Verify allowed creation and reads as the actual operator/agent, then compare project and task access after adding/removing a person. Reject ordinary members’ audience changes, agent member/visibility mutations, foreign-company targets, and owner removal. After opening the project, inspect protected tasks and independent direct grants rather than inferring task publication from project discovery.
 
 Gaps: The dedicated create_project tool does not advertise a visibility field; explicit private selection uses REST or admitted call_api. Private-project creation through each client, inherited task audiences, and responsible-user combinations need separate live evidence. The map does not infer filesystem isolation from these app-record permissions.
+
+Project configuration responses also expose effective workspace storage through
+`workspaceProvider`, separate from the stored execution policy. Existing project
+read/update permissions apply. Omitted provider IDs inherit; null explicitly selects
+Core/local. [Offline API coverage](../../server/src/__tests__/project-workspace-provider.integration.test.ts)
+checks overrides and cross-company denial; live agent credential verification remains unqualified.
diff --git a/maps/feature-map/projects.md b/maps/feature-map/projects.md
index 86676190a17..b793d57d678 100644
--- a/maps/feature-map/projects.md
+++ b/maps/feature-map/projects.md
@@ -29,6 +29,8 @@ Open `/projects`, create a project, and enter its overview or Issues view.
 ### `repository-settings`
 
 Open `/projects/:projectId/configuration` and its repository/workspace settings.
+Workspace storage shows the inherited installed default and allows an explicit
+provider or Core/local choice. Conflicting defaults remain visible for repair.
 
 ### `project-access`
 
@@ -46,6 +48,8 @@ Manual: Create a project, add a task from its view, and reload. Verify the task
 
 ### `repository-settings`
 
+Automated: [provider defaults and API overrides](../../server/src/__tests__/project-workspace-provider.integration.test.ts) and [storage selection UI](../../ui/src/components/ProjectProperties.concurrency.test.tsx) cover inherited choices, explicit overrides, and configuration errors. These offline checks do not qualify live provider storage.
+
 Automated: [repository persistence](../../server/src/__tests__/project-repositories-persistence.test.ts) and [repository browser suite](../../tests/e2e/project-repositories.spec.ts) cover configured repository workflows.
 
 Manual: Attach a small repository, save, and create a project task. Inspect the actual checkout/revision used by its run. Test an invalid repository and missing credentials without treating a saved URL as a working workspace.
diff --git a/packages/plugins/sdk/README.md b/packages/plugins/sdk/README.md
index 03907ed52f5..5db1363d7d7 100644
--- a/packages/plugins/sdk/README.md
+++ b/packages/plugins/sdk/README.md
@@ -1315,10 +1315,43 @@ implement `onResourceLifecycle` and `onWorkspaceOperation`. Project lifecycle
 creates and retains the storage; workspace operations manage task checkouts in
 that storage. Execution remains a separate environment driver contract.
 
-Set `project.executionWorkspacePolicy.storageProviderPluginId` to the installed
-plugin's UUID. Core then reserves an execution-workspace row and binds the task
-before it calls `onWorkspaceOperation`. Projects without this setting keep their
-current local behavior. Existing managed workspaces retain their original owner.
+Set `project.executionWorkspacePolicy.storageProviderPluginId` to an installed
+plugin's UUID for an explicit selection, or `null` for explicit Core/local storage.
+Omit the field to inherit the installed company-enabled default. A provider claims
+that default by declaring, for example:
+
+```ts
+workspaceProvider: {
+  modes: ["isolated_workspace", "operator_branch"],
+  strategies: ["git_worktree"],
+  defaultForProjects: { mode: "isolated_workspace", strategy: "git_worktree" },
+}
+```
+
+The declared defaults must be supported by the provider. Core applies missing mode
+and strategy settings to Git projects, including existing unconfigured projects,
+without writing their policy. Explicit settings remain intact; incompatible
+settings fail with a configuration error. Multiple enabled default claims require
+an explicit project choice or disabling a conflicting provider. Worker health does
+not change the selected default: unavailable providers fail without local fallback.
+No company settings row means enabled, matching the normal plugin contract.
+
+New and imported tasks leave an unspecified project mode inherited. Provider-owned
+workspaces retain explicit project and task strategies in shared and operator-branch
+modes. If neither supplies a strategy, those modes use `project_primary`; an agent's
+Git strategy remains a fallback only for isolated mode.
+
+Project responses keep the stored `executionWorkspacePolicy` and expose the
+separate `workspaceProvider` configuration, including its source, effective policy,
+provider choices and configuration error. The project configuration UI supports
+inheritance, explicit plugins and Core/local storage. Conflicts remain readable so
+operators can resolve them through this flow.
+
+Core reserves an execution-workspace row and binds the task before calling
+`onWorkspaceOperation`. Source-free task directories do not prepare project storage. The resolved provider
+choice, including Core/local, stays fixed through source resolution and preparation.
+Existing workspaces, including local workspaces, retain their original owner. Changing defaults never migrates, resets or recreates them;
+normal retirement and cleanup gates still apply on disable/uninstall.
 
 The hook receives a company, project, source revision, execution-workspace ID,
 lifecycle generation, deadline, and stable operation ID. Run and agent IDs are
diff --git a/packages/plugins/sdk/tests/workspace-provider.test.ts b/packages/plugins/sdk/tests/workspace-provider.test.ts
index 14b9f6af83e..f64aa7ece68 100644
--- a/packages/plugins/sdk/tests/workspace-provider.test.ts
+++ b/packages/plugins/sdk/tests/workspace-provider.test.ts
@@ -103,6 +103,13 @@ describe("workspace provider SDK", () => {
       resourceLifecycle: ["project"],
     };
     expect(pluginManifestV1Schema.safeParse(manifest).success).toBe(true);
+    const withDefault = { ...manifest, workspaceProvider: { ...manifest.workspaceProvider,
+      defaultForProjects: { mode: "isolated_workspace", strategy: "git_worktree" } } };
+    expect(pluginManifestV1Schema.parse(withDefault).workspaceProvider?.defaultForProjects).toEqual({
+      mode: "isolated_workspace", strategy: "git_worktree",
+    });
+    expect(pluginManifestV1Schema.safeParse({ ...withDefault, workspaceProvider: { ...withDefault.workspaceProvider,
+      defaultForProjects: { mode: "shared_workspace", strategy: "git_worktree" } } }).success).toBe(false);
     expect(
       pluginManifestV1Schema.safeParse({
         ...manifest,
diff --git a/packages/shared/src/index.ts b/packages/shared/src/index.ts
index 2b204b3cb88..f9f6db272b6 100644
--- a/packages/shared/src/index.ts
+++ b/packages/shared/src/index.ts
@@ -933,6 +933,7 @@ export type {
   ProjectManagedByPlugin,
   ProjectVisibility,
   ProjectWorkspace,
+  ProjectWorkspaceProviderConfiguration,
   CompanySearchCountType,
   CompanySearchExtractIssueResult,
   CompanySearchExtractKind,
diff --git a/packages/shared/src/types/index.ts b/packages/shared/src/types/index.ts
index d654b94f5df..c89aa62b1e3 100644
--- a/packages/shared/src/types/index.ts
+++ b/packages/shared/src/types/index.ts
@@ -367,6 +367,7 @@ export type {
   ProjectManagedByPlugin,
   ProjectVisibility,
   ProjectWorkspace,
+  ProjectWorkspaceProviderConfiguration,
 } from "./project.js";
 export type {
   CompanySearchCountType,
diff --git a/packages/shared/src/types/plugin.ts b/packages/shared/src/types/plugin.ts
index ef4d7be5550..3f121a74f45 100644
--- a/packages/shared/src/types/plugin.ts
+++ b/packages/shared/src/types/plugin.ts
@@ -698,6 +698,10 @@ export interface PaperclipPluginManifestV1 {
   workspaceProvider?: {
     modes: Array<"shared_workspace" | "isolated_workspace" | "operator_branch">;
     strategies: Array<"project_primary" | "git_worktree">;
+    defaultForProjects?: {
+      mode: "shared_workspace" | "isolated_workspace" | "operator_branch";
+      strategy: "project_primary" | "git_worktree";
+    };
   };
   /** Durable, acknowledged resource events delivered to onResourceLifecycle. Requires events.subscribe. */
   resourceLifecycle?: Array<"agent" | "project" | "agent_runtime">;
diff --git a/packages/shared/src/types/project.ts b/packages/shared/src/types/project.ts
index 17e3d8ef1bc..7cc1fb202d1 100644
--- a/packages/shared/src/types/project.ts
+++ b/packages/shared/src/types/project.ts
@@ -101,6 +101,15 @@ export interface ProjectDiscoveryPage {
   nextCursor: string | null;
 }
 
+export interface ProjectWorkspaceProviderConfiguration {
+  source: "project" | "default" | "core";
+  pluginId: string | null;
+  displayName: string;
+  providers: Array<{ id: string; displayName: string; isDefault: boolean }>;
+  effectivePolicy: ProjectExecutionWorkspacePolicy | null;
+  error: string | null;
+}
+
 export interface Project {
   id: string;
   companyId: string;
@@ -126,6 +135,7 @@ export interface Project {
   pauseReason: PauseReason | null;
   pausedAt: Date | null;
   executionWorkspacePolicy: ProjectExecutionWorkspacePolicy | null;
+  workspaceProvider?: ProjectWorkspaceProviderConfiguration;
   codebase: ProjectCodebase;
   workspaces: ProjectWorkspace[];
   primaryWorkspace: ProjectWorkspace | null;
diff --git a/packages/shared/src/types/workspace-runtime.ts b/packages/shared/src/types/workspace-runtime.ts
index 88d81fec115..00ab237577d 100644
--- a/packages/shared/src/types/workspace-runtime.ts
+++ b/packages/shared/src/types/workspace-runtime.ts
@@ -171,6 +171,7 @@ export interface ExecutionWorkspaceCloseReadiness {
 
 export interface ProjectExecutionWorkspacePolicy {
   enabled: boolean;
+  storageProviderPluginId?: string | null;
   sharedWorkspaceConcurrency?: SharedWorkspaceConcurrency;
   defaultMode?: ProjectExecutionWorkspaceDefaultMode;
   allowIssueOverride?: boolean;
diff --git a/packages/shared/src/validators/plugin.ts b/packages/shared/src/validators/plugin.ts
index 6f011359783..7e333572d83 100644
--- a/packages/shared/src/validators/plugin.ts
+++ b/packages/shared/src/validators/plugin.ts
@@ -793,6 +793,10 @@ export const pluginManifestV1Schema = z.object({
   workspaceProvider: z.object({
     modes: z.array(z.enum(["shared_workspace", "isolated_workspace", "operator_branch"])).min(1).max(3),
     strategies: z.array(z.enum(["project_primary", "git_worktree"])).min(1).max(2),
+    defaultForProjects: z.object({
+      mode: z.enum(["shared_workspace", "isolated_workspace", "operator_branch"]),
+      strategy: z.enum(["project_primary", "git_worktree"]),
+    }).strict().optional(),
   }).strict().optional(),
   resourceLifecycle: z.array(z.enum(["agent", "project", "agent_runtime"])).min(1).max(3).optional(),
   aiConnectionRouter: z.object({ name: z.string().trim().min(1).max(100), description: z.string().trim().min(1).max(500) }).strict().optional(),
@@ -826,6 +830,10 @@ export const pluginManifestV1Schema = z.object({
   if (manifest.workspaceProvider && (!manifest.capabilities.includes("workspaces.manage") || !manifest.resourceLifecycle?.includes("project"))) {
     ctx.addIssue({ code: z.ZodIssueCode.custom, path: ["workspaceProvider"], message: "Workspace providers require workspaces.manage and project resource lifecycle" });
   }
+  const defaults = manifest.workspaceProvider?.defaultForProjects;
+  if (defaults && (!manifest.workspaceProvider!.modes.includes(defaults.mode) || !manifest.workspaceProvider!.strategies.includes(defaults.strategy))) {
+    ctx.addIssue({ code: z.ZodIssueCode.custom, path: ["workspaceProvider", "defaultForProjects"], message: "Project defaults must use a declared workspace mode and strategy" });
+  }
   if (manifest.resourceLifecycle && !manifest.capabilities.includes("events.subscribe")) {
     ctx.addIssue({ code: z.ZodIssueCode.custom, message: "Resource lifecycle delivery requires events.subscribe", path: ["capabilities"] });
   }
diff --git a/server/src/__tests__/execution-workspace-policy.test.ts b/server/src/__tests__/execution-workspace-policy.test.ts
index 77da199bc44..e44ea327f3a 100644
--- a/server/src/__tests__/execution-workspace-policy.test.ts
+++ b/server/src/__tests__/execution-workspace-policy.test.ts
@@ -41,6 +41,23 @@ describe("execution workspace policy helpers", () => {
       }),
     ).toEqual({ mode: "shared_workspace" });
     expect(defaultIssueExecutionWorkspaceSettingsForProject(null)).toBeNull();
+    expect(defaultIssueExecutionWorkspaceSettingsForProject({ enabled: true })).toBeNull();
+  });
+
+  it.each(["shared_workspace", "operator_branch"] as const)("keeps declared provider strategy for %s", mode => {
+    const config = buildExecutionWorkspaceAdapterConfig({ agentConfig: {}, issueSettings: null, mode, legacyUseProjectWorkspace: null,
+      projectPolicy: { enabled: true, storageProviderPluginId: "10000000-0000-4000-8000-000000000001", defaultMode: mode,
+        workspaceStrategy: { type: "git_worktree", baseRef: "release" } } });
+    expect(config.workspaceStrategy).toEqual({ type: "git_worktree", baseRef: "release" });
+    expect(resolveEffectiveWorkspaceStrategyType(mode, config)).toBe("git_worktree");
+  });
+
+  it.each(["shared_workspace", "operator_branch"] as const)("keeps the primary-source fallback for %s providers without a project strategy", mode => {
+    const config = buildExecutionWorkspaceAdapterConfig({ agentConfig: { workspaceStrategy: { type: "git_worktree", baseRef: "agent-branch" } },
+      issueSettings: null, mode, legacyUseProjectWorkspace: null,
+      projectPolicy: { enabled: true, storageProviderPluginId: "10000000-0000-4000-8000-000000000001" } });
+    expect(config.workspaceStrategy).toEqual({ type: "project_primary" });
+    expect(resolveEffectiveWorkspaceStrategyType(mode, config)).toBe("project_primary");
   });
 
   it("prefers explicit issue mode over project policy and legacy overrides", () => {
diff --git a/server/src/__tests__/project-workspace-provider.integration.test.ts b/server/src/__tests__/project-workspace-provider.integration.test.ts
new file mode 100644
index 00000000000..0d7cc1ad8f8
--- /dev/null
+++ b/server/src/__tests__/project-workspace-provider.integration.test.ts
@@ -0,0 +1,207 @@
+import { randomUUID } from "node:crypto";
+import express from "express";
+import request from "supertest";
+import { afterAll, beforeAll, beforeEach, describe, expect, it } from "vitest";
+import { eq, sql } from "drizzle-orm";
+import { companies, createDb, executionWorkspaces, heartbeatRuns, issues, pluginCompanySettings, plugins, projects } from "@paperclipai/db";
+import { createPluginWorkspaceFixture } from "./helpers/plugin-workspaces.js";
+import { getEmbeddedPostgresTestSupport, startEmbeddedPostgresTestDatabase } from "./helpers/embedded-postgres.js";
+import { effectiveProjectWorkspacePolicy, listProjectWorkspaceProviders, resolveProjectWorkspaceProvider } from "../services/project-workspace-provider.js";
+import { preparePluginWorkspace } from "../services/plugin-workspaces.js";
+import { executionWorkspaceService } from "../services/execution-workspaces.js";
+import { issueService } from "../services/issues.js";
+import { instanceSettingsService } from "../services/instance-settings.js";
+import { buildExecutionWorkspaceAdapterConfig, parseIssueExecutionWorkspaceSettings, resolveEffectiveWorkspaceStrategyType, resolveExecutionWorkspaceMode } from "../services/execution-workspace-policy.js";
+import { projectService } from "../services/projects.js";
+import { projectRoutes } from "../routes/projects.js";
+import { errorHandler } from "../middleware/index.js";
+
+const support = await getEmbeddedPostgresTestSupport();
+describe.skipIf(!support.supported)("installed project workspace defaults", () => {
+  let database: Awaited<ReturnType<typeof startEmbeddedPostgresTestDatabase>>;
+  let db: ReturnType<typeof createDb>;
+  beforeAll(async () => {
+    database = await startEmbeddedPostgresTestDatabase("project-provider-defaults");
+    db = createDb(database.connectionString);
+  }, 120_000);
+  afterAll(async () => { await db?.$client.end(); await database?.cleanup(); });
+  beforeEach(async () => { await db.execute(sql`truncate companies, plugins cascade`); });
+
+  async function fixture() {
+    const f = await createPluginWorkspaceFixture(db);
+    const [plugin] = await db.select().from(plugins).where(eq(plugins.id, f.pluginId));
+    await db.update(plugins).set({ manifestJson: { ...plugin.manifestJson, workspaceProvider: {
+      ...plugin.manifestJson.workspaceProvider!, defaultForProjects: { mode: "isolated_workspace", strategy: "git_worktree" },
+    } } }).where(eq(plugins.id, f.pluginId));
+    await db.update(projects).set({ executionWorkspacePolicy: null }).where(eq(projects.id, f.input.projectId));
+    return f;
+  }
+
+  it("resolves new and existing unconfigured projects without persisting the inherited choice", async () => {
+    const f = await fixture();
+    const svc = projectService(db);
+    const created = await svc.create(f.companyId, { name: "New project" });
+    for (const projectId of [created!.id, f.input.projectId]) {
+      const project = await svc.getById(projectId);
+      expect(project!.workspaceProvider).toMatchObject({ source: "default", pluginId: f.pluginId });
+      expect(project!.executionWorkspacePolicy).toBeNull();
+    }
+    expect((await svc.getById(f.input.projectId))!.workspaceProvider!.effectivePolicy).toMatchObject({
+      enabled: true, defaultMode: "isolated_workspace", workspaceStrategy: { type: "git_worktree" }, storageProviderPluginId: f.pluginId,
+    });
+    expect(await executionWorkspaceService(db).resolveSourceWorkspaceStrategy({ companyId: f.companyId,
+      projectId: f.input.projectId, sourceWorkspaceId: f.input.projectWorkspaceId, executionWorkspacePolicy: null })).toBe("git_worktree");
+    const prepared = await preparePluginWorkspace(db, f.workers, f.input);
+    expect(prepared).toMatchObject({ providerType: "plugin" });
+    expect(f.calls[0].operation).toMatchObject({ mode: "isolated_workspace", strategy: "git_worktree" });
+  });
+
+  it.each(["create", "import"] as const)("%s leaves an unspecified task mode inherited from the effective provider", async method => {
+    const f = await fixture();
+    await instanceSettingsService(db).updateExperimental({ enableIsolatedWorkspaces: true });
+    await db.update(projects).set({ executionWorkspacePolicy: { enabled: true } }).where(eq(projects.id, f.input.projectId));
+    let issueId: string;
+    if (method === "create") {
+      const created = await issueService(db).create(f.companyId, { title: "Use inherited storage", projectId: f.input.projectId, assigneeAgentId: f.input.agentId });
+      issueId = created.id;
+    } else {
+      issueId = randomUUID();
+      await issueService(db).importIssues(f.companyId, [{ id: issueId, ref: "inherited", title: "Import inherited storage", projectId: f.input.projectId,
+        projectWorkspaceId: null, description: null, assigneeAgentId: f.input.agentId, status: "todo", priority: "medium", billingCode: null,
+        assigneeAdapterOverrides: null, executionWorkspaceSettings: null, labelIds: [], monitorNotes: null, monitorScheduledBy: null }]);
+    }
+    const [task] = await db.select().from(issues).where(eq(issues.id, issueId));
+    expect(task.executionWorkspaceSettings?.mode).toBeUndefined();
+    const policy = await effectiveProjectWorkspacePolicy(db, f.companyId, { enabled: true }, true);
+    const settings = parseIssueExecutionWorkspaceSettings(task.executionWorkspaceSettings);
+    const mode = resolveExecutionWorkspaceMode({ projectPolicy: policy, issueSettings: settings, legacyUseProjectWorkspace: null });
+    const config = buildExecutionWorkspaceAdapterConfig({ agentConfig: {}, projectPolicy: policy, issueSettings: settings, mode, legacyUseProjectWorkspace: null });
+    const [run] = await db.insert(heartbeatRuns).values({ companyId: f.companyId, agentId: f.input.agentId,
+      issueId, scopeKind: "issue", status: "running", runtimeMode: "legacy" }).returning();
+    await preparePluginWorkspace(db, f.workers, { ...f.input, runId: run.id, issueId, mode, strategy: resolveEffectiveWorkspaceStrategyType(mode, config) });
+    expect(f.calls[0].operation).toMatchObject({ mode: "isolated_workspace", strategy: "git_worktree" });
+  });
+
+  it("pins and unpins the same effective owner without retiring its active workspace", async () => {
+    const f = await fixture();
+    const workspace = await preparePluginWorkspace(db, f.workers, f.input);
+    const svc = projectService(db);
+    expect((await svc.update(f.input.projectId, { executionWorkspacePolicy: { enabled: true, storageProviderPluginId: f.pluginId } }))!.workspaceProvider)
+      .toMatchObject({ source: "project", pluginId: f.pluginId });
+    expect((await svc.update(f.input.projectId, { executionWorkspacePolicy: { enabled: true } }))!.workspaceProvider)
+      .toMatchObject({ source: "default", pluginId: f.pluginId });
+    expect((await db.select().from(executionWorkspaces).where(eq(executionWorkspaces.id, workspace!.id)))[0]).toEqual(workspace);
+    await expect(svc.update(f.input.projectId, { executionWorkspacePolicy: { enabled: true, storageProviderPluginId: null } }))
+      .rejects.toThrow("Retire managed execution workspaces");
+  });
+
+  it("preserves explicit alternatives and the explicit Core/local choice", async () => {
+    const f = await fixture(), other = await createPluginWorkspaceFixture(db, f.companyId);
+    const providers = await listProjectWorkspaceProviders(db, f.companyId);
+    expect(resolveProjectWorkspaceProvider({ enabled: true, storageProviderPluginId: other.pluginId }, providers, true))
+      .toMatchObject({ source: "project", pluginId: other.pluginId });
+    const local = { enabled: true, storageProviderPluginId: null };
+    await projectService(db).update(f.input.projectId, { executionWorkspacePolicy: local });
+    expect((await projectService(db).getById(f.input.projectId))!.executionWorkspacePolicy).toEqual(local);
+    expect(await preparePluginWorkspace(db, f.workers, f.input)).toBeNull();
+    expect(f.calls).toHaveLength(0);
+  });
+
+  it.each(["disabled", "uninstalled"] as const)("does not inherit an instance %s provider", async status => {
+    const f = await fixture();
+    await db.update(plugins).set({ status }).where(eq(plugins.id, f.pluginId));
+    expect(await effectiveProjectWorkspacePolicy(db, f.companyId, null, true)).toBeNull();
+  });
+
+  it("scopes company enablement and does not borrow another company's override", async () => {
+    const f = await fixture();
+    const [other] = await db.insert(companies).values({ name: "Other", issuePrefix: "OTH" }).returning();
+    await db.insert(pluginCompanySettings).values({ companyId: f.companyId, pluginId: f.pluginId, enabled: false });
+    await db.insert(pluginCompanySettings).values({ companyId: other.id, pluginId: f.pluginId, enabled: true });
+    expect(await effectiveProjectWorkspacePolicy(db, f.companyId, null, true)).toBeNull();
+    expect(await effectiveProjectWorkspacePolicy(db, other.id, null, true)).toMatchObject({ storageProviderPluginId: f.pluginId });
+    await expect(effectiveProjectWorkspacePolicy(db, f.companyId, { enabled: true, storageProviderPluginId: f.pluginId }, true))
+      .rejects.toThrow("unavailable");
+  });
+
+  it.each(["error", "installed", "upgrade_pending", "ready"] as const)("retains the selected %s provider when its worker is unavailable", async status => {
+    const f = await fixture();
+    await db.update(plugins).set({ status }).where(eq(plugins.id, f.pluginId));
+    expect(await effectiveProjectWorkspacePolicy(db, f.companyId, null, true)).toMatchObject({ storageProviderPluginId: f.pluginId });
+    await expect(preparePluginWorkspace(db, undefined, f.input)).rejects.toThrow("unavailable");
+    expect(await db.select().from(executionWorkspaces)).toHaveLength(0);
+  });
+
+  it("never falls back when a selected default is disabled during preparation", async () => {
+    const f = await fixture();
+    const policy = await effectiveProjectWorkspacePolicy(db, f.companyId, null, true);
+    await db.insert(pluginCompanySettings).values({ companyId: f.companyId, pluginId: f.pluginId, enabled: false });
+    await expect(preparePluginWorkspace(db, f.workers, { ...f.input, selectedProviderPluginId: policy!.storageProviderPluginId }))
+      .rejects.toThrow("unavailable");
+    expect(await db.select().from(executionWorkspaces)).toHaveLength(0);
+  });
+
+  it("reports conflicting declarations and still lets configuration select an alternative", async () => {
+    const f = await fixture();
+    const other = await createPluginWorkspaceFixture(db, f.companyId);
+    const [plugin] = await db.select().from(plugins).where(eq(plugins.id, f.pluginId));
+    await db.update(plugins).set({ manifestJson: { ...plugin.manifestJson, id: `test.${other.pluginId}` } }).where(eq(plugins.id, other.pluginId));
+    await expect(preparePluginWorkspace(db, f.workers, f.input)).rejects.toThrow("Multiple workspace storage plugins");
+    const project = await projectService(db).getById(f.input.projectId);
+    expect(project!.workspaceProvider!.error).toContain("Select a storage provider in project configuration");
+    expect(await effectiveProjectWorkspacePolicy(db, f.companyId, { enabled: true, storageProviderPluginId: f.pluginId }, true))
+      .toMatchObject({ storageProviderPluginId: f.pluginId });
+  });
+
+  it.each([
+    { enabled: false },
+    { enabled: true, defaultMode: "shared_workspace" },
+    { enabled: true, workspaceStrategy: { type: "project_primary" } },
+  ])("rejects incompatible explicit settings: %j", async policy => {
+    const f = await fixture();
+    await expect(effectiveProjectWorkspacePolicy(db, f.companyId, policy, true)).rejects.toThrow("explicit project workspace settings");
+  });
+
+  it("preserves compatible explicit fields while supplying only missing defaults", async () => {
+    const f = await fixture();
+    const policy = { enabled: true, defaultMode: "operator_branch", workspaceStrategy: { type: "git_worktree", baseRef: "release", branchTemplate: "kept" } };
+    expect(await effectiveProjectWorkspacePolicy(db, f.companyId, policy, true)).toEqual({ ...policy, storageProviderPluginId: f.pluginId });
+    expect(await effectiveProjectWorkspacePolicy(db, f.companyId, null, false)).toEqual({ enabled: true, storageProviderPluginId: f.pluginId });
+  });
+
+  it("retains both plugin and local workspace ownership when defaults change", async () => {
+    const f = await fixture();
+    const workspace = await preparePluginWorkspace(db, f.workers, f.input);
+    await db.update(projects).set({ executionWorkspacePolicy: { enabled: true, storageProviderPluginId: null } }).where(eq(projects.id, f.input.projectId));
+    expect(await preparePluginWorkspace(db, f.workers, { ...f.input, existingWorkspaceId: workspace!.id })).toMatchObject({ id: workspace!.id });
+    await db.update(plugins).set({ status: "error" }).where(eq(plugins.id, f.pluginId));
+    await expect(preparePluginWorkspace(db, f.workers, { ...f.input, existingWorkspaceId: workspace!.id })).rejects.toThrow("unavailable");
+    const [local] = await db.insert(executionWorkspaces).values({ companyId: f.companyId, projectId: f.input.projectId,
+      projectWorkspaceId: f.input.projectWorkspaceId, mode: "shared_workspace", strategyType: "project_primary", name: "Retained local", providerType: "local_fs", cwd: "/fixture/kept" }).returning();
+    await db.update(projects).set({ executionWorkspacePolicy: null }).where(eq(projects.id, f.input.projectId));
+    expect(await preparePluginWorkspace(db, f.workers, { ...f.input, existingWorkspaceId: local.id })).toBeNull();
+    expect((await db.select().from(executionWorkspaces).where(eq(executionWorkspaces.id, local.id)))[0]).toEqual(local);
+  });
+
+  it("exposes inherited selection through the normal API and round-trips overrides with company access checks", async () => {
+    const f = await fixture();
+    const app = express();
+    app.use(express.json());
+    app.use((req, _res, next) => { req.actor = { type: "board", source: "local_implicit", isInstanceAdmin: true }; next(); });
+    app.use("/api", projectRoutes(db));
+    app.use(errorHandler);
+    const url = `/api/projects/${f.input.projectId}`;
+    expect((await request(app).get(url)).body.workspaceProvider).toMatchObject({ source: "default", pluginId: f.pluginId });
+    const patch = await request(app).patch(url).send({ executionWorkspacePolicy: { enabled: true, storageProviderPluginId: null } });
+    expect(patch.status).toBe(200);
+    expect(patch.body.workspaceProvider).toMatchObject({ source: "project", pluginId: null });
+    const inherit = await request(app).patch(url).send({ executionWorkspacePolicy: { enabled: true } });
+    expect(inherit.status).toBe(200);
+    expect(inherit.body.executionWorkspacePolicy).not.toHaveProperty("storageProviderPluginId");
+    expect(inherit.body.workspaceProvider).toMatchObject({ source: "default", pluginId: f.pluginId });
+    const denied = express();
+    denied.use((req, _res, next) => { req.actor = { type: "agent", agentId: f.input.agentId, companyId: "00000000-0000-4000-8000-000000000099" }; next(); });
+    denied.use("/api", projectRoutes(db)); denied.use(errorHandler);
+    expect((await request(denied).get(url)).status).toBe(404);
+  });
+});
diff --git a/server/src/services/execution-workspace-policy.ts b/server/src/services/execution-workspace-policy.ts
index 37fc7a7ff88..f25ee1451f0 100644
--- a/server/src/services/execution-workspace-policy.ts
+++ b/server/src/services/execution-workspace-policy.ts
@@ -130,7 +130,7 @@ export function parseProjectExecutionWorkspacePolicy(raw: unknown): ProjectExecu
   })();
   return {
     enabled,
-    ...(typeof parsed.storageProviderPluginId === "string" ? { storageProviderPluginId: parsed.storageProviderPluginId } : {}),
+    ...(typeof parsed.storageProviderPluginId === "string" || parsed.storageProviderPluginId === null ? { storageProviderPluginId: parsed.storageProviderPluginId } : {}),
     ...(sharedWorkspaceConcurrency ? { sharedWorkspaceConcurrency } : {}),
     ...(normalizedDefaultMode ? { defaultMode: normalizedDefaultMode } : {}),
     ...(allowIssueOverride !== undefined ? { allowIssueOverride } : {}),
@@ -345,7 +345,7 @@ export function resolveExecutionWorkspaceEnvironmentId(input: {
 export function defaultIssueExecutionWorkspaceSettingsForProject(
   projectPolicy: ProjectExecutionWorkspacePolicy | null,
 ): IssueExecutionWorkspaceSettings | null {
-  if (!projectPolicy?.enabled) return null;
+  if (!projectPolicy?.enabled || projectPolicy.defaultMode === undefined) return null;
   return {
     mode:
       projectPolicy.defaultMode === "isolated_workspace"
@@ -450,7 +450,8 @@ export function buildExecutionWorkspaceAdapterConfig(input: {
   const hasWorkspaceControl = projectHasPolicy || issueHasWorkspaceOverrides || input.legacyUseProjectWorkspace === false;
 
   if (hasWorkspaceControl) {
-    if (input.mode === "isolated_workspace") {
+    if (input.mode === "isolated_workspace" ||
+        (projectHasPolicy && input.projectPolicy?.storageProviderPluginId && input.mode !== "agent_default")) {
       const projectStrategy = projectHasPolicy ? input.projectPolicy?.workspaceStrategy : undefined;
       const issueStrategy = input.issueSettings?.workspaceStrategy;
       // An issue that changes its branch still needs the project's setup hooks.
@@ -458,8 +459,8 @@ export function buildExecutionWorkspaceAdapterConfig(input: {
       const strategy = issueStrategy && projectStrategy?.type === issueStrategy.type
         ? { ...projectStrategy, ...issueStrategy }
         : issueStrategy ?? projectStrategy ??
-        parseExecutionWorkspaceStrategy(nextConfig.workspaceStrategy) ??
-        ({ type: "git_worktree" } satisfies ExecutionWorkspaceStrategy);
+        (input.mode === "isolated_workspace" ? parseExecutionWorkspaceStrategy(nextConfig.workspaceStrategy) : undefined) ??
+        ({ type: input.mode === "isolated_workspace" ? "git_worktree" : "project_primary" } satisfies ExecutionWorkspaceStrategy);
       if (issueStrategy?.existingBranch && issueStrategy.branchTemplate === undefined && strategy !== issueStrategy) {
         delete strategy.branchTemplate;
       }
diff --git a/server/src/services/execution-workspaces.ts b/server/src/services/execution-workspaces.ts
index 13830397cee..1065fcc1362 100644
--- a/server/src/services/execution-workspaces.ts
+++ b/server/src/services/execution-workspaces.ts
@@ -1,3 +1,4 @@
+import { effectiveProjectWorkspacePolicy } from "./project-workspace-provider.js";
 import { inspectPluginWorkspace, removePluginWorkspace, restorePluginWorkspace, type WorkspaceWorkers } from "./plugin-workspaces.js";
 import { acquireExecutionWorkspaceLifecycleLock, withExecutionWorkspaceLifecycleLock } from "./execution-workspace-lifecycle-lock.js";
 import { measureRunTransaction } from "./execution-transaction-timing.js";
@@ -1406,6 +1407,7 @@ export function executionWorkspaceService(db: Db, opts: ExecutionWorkspaceServic
     companyId: string; issueId?: string | null; assigneeAgentId?: string | null;
     assigneeAdapterOverrides?: unknown; executionWorkspaceSettings?: unknown;
     executionWorkspacePolicy: unknown; typedSelection?: boolean; projectId?: string | null; executionPolicy?: unknown;
+    sourceWorkspaceId?: string | null; inheritProviderDefaults?: boolean;
   }, reader: Db | DbTransaction = db) {
     const [task] = input.issueId ? await reader.select().from(issues).where(and(
       eq(issues.id, input.issueId), eq(issues.companyId, input.companyId),
@@ -1415,12 +1417,21 @@ export function executionWorkspaceService(db: Db, opts: ExecutionWorkspaceServic
       .where(and(eq(agents.id, assigneeAgentId), eq(agents.companyId, input.companyId))) : [];
     const overrides = assigneeAgentId ? parseIssueAssigneeAdapterOverrides(task ? task.assigneeAdapterOverrides : input.assigneeAdapterOverrides) : null;
     const experimental = await instanceSettingsService(db).getExperimental();
+    const sourceId = input.sourceWorkspaceId ?? task?.projectWorkspaceId;
+    const sourceProjectId = input.projectId ?? task?.projectId;
+    const [source] = sourceId || sourceProjectId ? await reader.select({ repoUrl: projectWorkspaces.repoUrl }).from(projectWorkspaces).where(and(
+      eq(projectWorkspaces.companyId, input.companyId),
+      sourceId ? eq(projectWorkspaces.id, sourceId) : eq(projectWorkspaces.projectId, sourceProjectId!),
+    )).orderBy(desc(projectWorkspaces.isPrimary), asc(projectWorkspaces.createdAt), asc(projectWorkspaces.id)).limit(1) : [];
+    const effectivePolicy = input.inheritProviderDefaults === false
+      ? parseProjectExecutionWorkspacePolicy(input.executionWorkspacePolicy)
+      : await effectiveProjectWorkspacePolicy(reader, input.companyId, input.executionWorkspacePolicy, Boolean(source?.repoUrl));
     const projectPolicy = applyDefaultIsolatedExecutionWorkspacePolicy({
-      projectPolicy: gateProjectExecutionWorkspacePolicy(parseProjectExecutionWorkspacePolicy(input.executionWorkspacePolicy), experimental.enableIsolatedWorkspaces),
+      projectPolicy: gateProjectExecutionWorkspacePolicy(effectivePolicy, experimental.enableIsolatedWorkspaces || Boolean(effectivePolicy?.storageProviderPluginId)),
       defaultIsolatedWorkspacesEnabled: experimental.enableIsolatedWorkspaces && experimental.enableIsolatedWorkspacesByDefault,
       hasProjectWorkspace: true,
     });
-    const settingsEnabled = experimental.enableIsolatedWorkspaces || input.typedSelection || task?.workspaceSelection || task?.executionWorkspaceId;
+    const settingsEnabled = experimental.enableIsolatedWorkspaces || Boolean(effectivePolicy?.storageProviderPluginId) || input.typedSelection || task?.workspaceSelection || task?.executionWorkspaceId;
     const issueSettings = settingsEnabled ? parseIssueExecutionWorkspaceSettings(input.executionWorkspaceSettings) : null;
     const projectId = task ? task.projectId : input.projectId;
     const [organization] = projectId ? await reader.select({ companyId: projects.companyId, executionWorkspacePolicy: projects.executionWorkspacePolicy })
@@ -1477,7 +1488,7 @@ export function executionWorkspaceService(db: Db, opts: ExecutionWorkspaceServic
         executionWorkspaceSettings = { ...parseObject(task.settings), mode };
       }
       await resolveSourceWorkspaceStrategy({ ...input, typedSelection: true,
-        executionWorkspaceSettings, executionWorkspacePolicy: source.executionWorkspacePolicy }, reader);
+        executionWorkspaceSettings, executionWorkspacePolicy: source.executionWorkspacePolicy, sourceWorkspaceId: source.id }, reader);
       await assertTaskWorkspaceSourceProjectAccess(reader, input.actor, input.companyId, source.projectId);
       return { executionWorkspaceId: null, projectWorkspaceId: source.id, executionWorkspacePreference: null,
         executionWorkspaceSettings };
@@ -1567,7 +1578,7 @@ export function executionWorkspaceService(db: Db, opts: ExecutionWorkspaceServic
             eq(projectWorkspaces.companyId, input.companyId), eq(projectWorkspaces.id, patch.projectWorkspaceId!),
           ));
         const { strategy, config } = await resolveSourceWorkspaceConfiguration({ ...input, typedSelection: true,
-          executionWorkspacePolicy: source?.policy, executionWorkspaceSettings: patch.executionWorkspaceSettings }, tx);
+          executionWorkspacePolicy: source?.policy, executionWorkspaceSettings: patch.executionWorkspaceSettings, sourceWorkspaceId: patch.projectWorkspaceId }, tx);
         if (strategy === "git_worktree") {
           const workspaceStrategy = { ...parseObject(config.workspaceStrategy), type: "git_worktree",
             existingBranch: null, branchTemplate: "retry-{{issue.id}}" };
@@ -1636,7 +1647,7 @@ export function executionWorkspaceService(db: Db, opts: ExecutionWorkspaceServic
     if (!sourceProject) throw notFound("Workspace source is unavailable or inaccessible");
     await resolveSourceWorkspaceStrategy({ companyId: task.companyId, issueId: task.id,
       executionWorkspaceSettings: task.executionWorkspaceSettings,
-      executionWorkspacePolicy: sourceProject.executionWorkspacePolicy }, tx);
+      executionWorkspacePolicy: sourceProject.executionWorkspacePolicy, sourceWorkspaceId: sourceId, inheritProviderDefaults: !workspace }, tx);
   }
 
   async function prepareTaskWorkspaceUpdate(input: {
diff --git a/server/src/services/heartbeat.ts b/server/src/services/heartbeat.ts
index 0d2d33e61d8..81672288f4e 100644
--- a/server/src/services/heartbeat.ts
+++ b/server/src/services/heartbeat.ts
@@ -508,6 +508,7 @@ import {
 
 import { resolveAndRetainRunTrustPreset } from "./run-trust-preset.js";
 
+import { effectiveProjectWorkspacePolicy } from "./project-workspace-provider.js";
 import type { PluginWorkerManager } from "./plugin-worker-manager.js";
 
 import { computeTaskDrain, applyTaskDrain, startTaskDrain, stopTaskDrain, readTaskDrain } from "./task-admission.js";
@@ -2208,19 +2209,6 @@ export function heartbeatService(
       const [taskWorkspaceIntentRow] = issueId && !externalProvider ? await db.select({ intent: issues.workspaceSelection }).from(issues)
         .where(and(eq(issues.id, issueId), eq(issues.companyId, agent.companyId))) : [];
       const freshWorkspace = await readFreshWorkspaceReadiness(db, run);
-      const runtimeWorkspaceSelectionEnabled = !externalProvider && (freshWorkspace?.mode === "fresh_isolated_workspace" || taskWorkspaceRuntimeSelectionEnabled({ legacyUiEnabled: isolatedWorkspacesEnabled, hasTypedSelection: Boolean(taskWorkspaceIntentRow?.intent), hasBinding: Boolean(issueContext?.executionWorkspaceId) }));
-      const parsedIssueExecutionWorkspaceSettings =
-        parseIssueExecutionWorkspaceSettings(
-          issueContext?.executionWorkspaceSettings,
-        );
-      const issueExecutionWorkspaceSettings = runtimeWorkspaceSelectionEnabled
-        ? parsedIssueExecutionWorkspaceSettings
-        : null;
-      const environmentExecutionWorkspaceSettings =
-        selectEnvironmentExecutionWorkspaceSettings(
-          parsedIssueExecutionWorkspaceSettings,
-          runtimeWorkspaceSelectionEnabled,
-        );
       const contextProjectId = readNonEmptyString(context.projectId);
       const boundSourceWorkspace = !externalProvider && issueContext?.executionWorkspaceId
         ? await executionWorkspacesSvc.getStoredById(agent.companyId, issueContext.executionWorkspaceId) : null;
@@ -2242,6 +2230,9 @@ export function heartbeatService(
                       or nullif(btrim(${projectWorkspaces.repoUrl}), '') is not null)`,
                   )),
               ).mapWith(Boolean),
+              hasGitSource: exists(db.select({ id: projectWorkspaces.id }).from(projectWorkspaces)
+                .where(and(eq(projectWorkspaces.projectId, projects.id), eq(projectWorkspaces.companyId, agent.companyId),
+                  sql`nullif(btrim(${projectWorkspaces.repoUrl}), '') is not null`))).mapWith(Boolean),
               env: projects.env,
               updatedAt: projects.updatedAt,
             })
@@ -2377,21 +2368,33 @@ export function heartbeatService(
         !boundSourceWorkspace && !taskWorkspaceIntentRow?.intent && !issueContext?.projectWorkspaceId
           ? taskProjectContext : null
       );
-      const parsedProjectExecutionWorkspacePolicy =
-        parseProjectExecutionWorkspacePolicy(
-          workspacePolicyContext?.executionWorkspacePolicy,
-        );
+      const parsedProjectExecutionWorkspacePolicy = workspacePolicyContext && !boundSourceWorkspace
+        ? await effectiveProjectWorkspacePolicy(db, agent.companyId, workspacePolicyContext.executionWorkspacePolicy, workspacePolicyContext.hasGitSource)
+        : parseProjectExecutionWorkspacePolicy(workspacePolicyContext?.executionWorkspacePolicy);
       const projectExecutionWorkspacePolicy =
         applyDefaultIsolatedExecutionWorkspacePolicy({
           projectPolicy: gateProjectExecutionWorkspacePolicy(
             parsedProjectExecutionWorkspacePolicy,
-            isolatedWorkspacesEnabled,
+            isolatedWorkspacesEnabled || Boolean(parsedProjectExecutionWorkspacePolicy?.storageProviderPluginId),
           ),
           defaultIsolatedWorkspacesEnabled,
           // Projects without workspace configuration get a plain managed
           // directory. The operator default cannot turn it into a worktree.
           hasProjectWorkspace: workspaceProjectContext?.hasWorkspace ?? false,
         });
+      const runtimeWorkspaceSelectionEnabled = !externalProvider && (freshWorkspace?.mode === "fresh_isolated_workspace" || taskWorkspaceRuntimeSelectionEnabled({ legacyUiEnabled: isolatedWorkspacesEnabled || Boolean(projectExecutionWorkspacePolicy?.storageProviderPluginId), hasTypedSelection: Boolean(taskWorkspaceIntentRow?.intent), hasBinding: Boolean(issueContext?.executionWorkspaceId) }));
+      const parsedIssueExecutionWorkspaceSettings =
+        parseIssueExecutionWorkspaceSettings(
+          issueContext?.executionWorkspaceSettings,
+        );
+      const issueExecutionWorkspaceSettings = runtimeWorkspaceSelectionEnabled
+        ? parsedIssueExecutionWorkspaceSettings
+        : null;
+      const environmentExecutionWorkspaceSettings =
+        selectEnvironmentExecutionWorkspaceSettings(
+          parsedIssueExecutionWorkspaceSettings,
+          runtimeWorkspaceSelectionEnabled,
+        );
       const retainedTrust = await resolveAndRetainRunTrustPreset(db, {
         companyId: agent.companyId,
         agentId: agent.id,
diff --git a/server/src/services/heartbeat/workspace-preparation.test.ts b/server/src/services/heartbeat/workspace-preparation.test.ts
index b6fcedaab42..cc4d2e16dc7 100644
--- a/server/src/services/heartbeat/workspace-preparation.test.ts
+++ b/server/src/services/heartbeat/workspace-preparation.test.ts
@@ -25,7 +25,8 @@ import { isolatedRemoteSourcePath } from "../isolated-remote-workspace-source.js
 import { cleanupExecutionWorkspaceArtifacts } from "../workspace-runtime.js";
 import { buildProjectMentionHref } from "@paperclipai/shared";
 import { trace } from "@opentelemetry/api";
-import { buildExecutionWorkspaceAdapterConfig } from "../execution-workspace-policy.js";
+import { effectiveProjectWorkspacePolicy } from "../project-workspace-provider.js";
+import { resolveExecutionWorkspaceMode, buildExecutionWorkspaceAdapterConfig } from "../execution-workspace-policy.js";
 import { createLocalDiskStorageProvider } from "../../storage/local-disk-provider.js";
 import { createStorageService } from "../../storage/service.js";
 import { InMemorySpanExporter, SimpleSpanProcessor, TracerProvider } from "@opentelemetry/sdk-trace";
@@ -53,7 +54,7 @@ describe.skipIf(!support.supported)("heartbeat workspace preparation boundary",
   });
   beforeEach(async () => {
     vi.restoreAllMocks();
-    await db.execute(sql`truncate table companies restart identity cascade`);
+    await db.execute(sql`truncate table companies, plugins restart identity cascade`);
     await instanceSettingsService(db).updateExperimental({ enableIsolatedWorkspaces: true });
   });
 
@@ -95,12 +96,26 @@ describe.skipIf(!support.supported)("heartbeat workspace preparation boundary",
     };
     return { input, source, issue, run, envOrchestrator };
   }
-  it("prepares managed storage before acquisition without touching a Core checkout", async () => {
+  it.each([
+    { inherited: false, mode: "isolated_workspace" as const },
+    { inherited: true, mode: "isolated_workspace" as const },
+    { inherited: true, mode: "operator_branch" as const },
+  ])("prepares managed storage before acquisition (inherited: $inherited, mode: $mode) without touching a Core checkout", async ({ inherited, mode: defaultMode }) => {
     const { input, source, issue } = await fixture(true);
     const [plugin] = await db.insert(plugins).values({ pluginKey: "test.managed-storage", packageName: "test-storage", version: "1.0.0", apiVersion: 1, status: "ready", categories: ["workspace"],
       manifestJson: { id: "test.managed-storage", apiVersion: 1, version: "1.0.0", displayName: "Storage", description: "Storage", author: "Test", categories: ["workspace"],
-        workspaceProvider: { modes: ["isolated_workspace", "operator_branch"], strategies: ["git_worktree"] }, capabilities: ["workspaces.manage", "events.subscribe"], resourceLifecycle: ["project"], entrypoints: { worker: "./worker.js" } } }).returning();
-    await db.update(projects).set({ executionWorkspacePolicy: { enabled: true, storageProviderPluginId: plugin.id } }).where(eq(projects.id, issue.projectId!));
+        workspaceProvider: { modes: ["isolated_workspace", "operator_branch"], strategies: ["git_worktree"], ...(inherited ? { defaultForProjects: { mode: defaultMode, strategy: "git_worktree" as const } } : {}) }, capabilities: ["workspaces.manage", "events.subscribe"], resourceLifecycle: ["project"], entrypoints: { worker: "./worker.js" } } }).returning();
+    const explicitPolicy = { enabled: true, storageProviderPluginId: plugin.id, defaultMode: "isolated_workspace" as const,
+      workspaceStrategy: { type: "git_worktree" as const, baseRef: "main", branchTemplate: "test-{{issue.identifier}}" } };
+    if (!inherited) await db.update(projects).set({ executionWorkspacePolicy: explicitPolicy }).where(eq(projects.id, issue.projectId!));
+    {
+      const policy = await effectiveProjectWorkspacePolicy(db, input.agent.companyId, inherited ? null : explicitPolicy, true);
+      const mode = resolveExecutionWorkspaceMode({ projectPolicy: policy, issueSettings: null, legacyUseProjectWorkspace: null });
+      input.policy.projectExecutionWorkspacePolicy = policy;
+      input.policy.requestedExecutionWorkspaceMode = mode;
+      input.policy.effectiveExecutionWorkspaceMode = mode;
+      input.config.mergedConfig = buildExecutionWorkspaceAdapterConfig({ agentConfig: input.config.mergedConfig, projectPolicy: policy, issueSettings: null, mode, legacyUseProjectWorkspace: null });
+    }
     await db.update(projectWorkspaces).set({ cwd: null, sourceType: "remote_managed", repoUrl: "https://github.com/example/repo.git" }).where(eq(projectWorkspaces.id, issue.projectWorkspaceId!));
     await rm(source, { recursive: true });
     const sequence: string[] = [];
@@ -124,8 +139,41 @@ describe.skipIf(!support.supported)("heartbeat workspace preparation boundary",
     await expect(access(source)).rejects.toThrow();
     const [task] = await db.select().from(issues).where(eq(issues.id, issue.id));
     const [workspace] = await db.select().from(executionWorkspaces).where(eq(executionWorkspaces.id, task.executionWorkspaceId!));
-    expect(workspace).toMatchObject({ providerType: "plugin", cwd: null, branchName: "test-WSP-1" });
+    expect(workspace).toMatchObject({ providerType: "plugin", cwd: null, mode: defaultMode, strategyType: "git_worktree", branchName: inherited ? "WSP-1-prepare-this-workspace" : "test-WSP-1" });
   });
+  async function installDefault() {
+    const [plugin] = await db.insert(plugins).values({ pluginKey: "test.default-storage", packageName: "test-storage", version: "1.0.0", status: "ready",
+      manifestJson: { id: "test.default-storage", apiVersion: 1, version: "1.0.0", displayName: "Default storage", description: "Storage", author: "Test", categories: ["workspace"],
+        workspaceProvider: { modes: ["isolated_workspace"], strategies: ["git_worktree"], defaultForProjects: { mode: "isolated_workspace", strategy: "git_worktree" } },
+        capabilities: ["workspaces.manage", "events.subscribe"], resourceLifecycle: ["project"], entrypoints: { worker: "./worker.js" } } }).returning();
+    return plugin;
+  }
+  it("keeps source-free project tasks outside installed provider preparation", async () => {
+    const { input, issue } = await fixture();
+    await installDefault();
+    await db.update(issues).set({ projectWorkspaceId: null }).where(eq(issues.id, issue.id));
+    await db.delete(projectWorkspaces).where(eq(projectWorkspaces.id, issue.projectWorkspaceId!));
+    input.task.issueRef = { ...issue, projectWorkspaceId: null };
+    input.policy.projectExecutionWorkspacePolicy = await effectiveProjectWorkspacePolicy(db, input.agent.companyId, null, false);
+    const call = vi.fn();
+    input.services.workspaceWorkers = { getWorker: () => ({ supportedMethods: ["workspaceOperation"] }), call } as any;
+    const prepared = await prepareHeartbeatWorkspace(db, input);
+    expect(prepared.executionWorkspace.cwd).toBeTruthy();
+    expect(prepared.persistedExecutionWorkspace?.providerType).not.toBe("plugin");
+    expect(call).not.toHaveBeenCalled();
+  });
+  it("pins a resolved Core choice through source selection when a default appears during setup", async () => {
+    const { input, source } = await fixture();
+    expect(input.policy.projectExecutionWorkspacePolicy).toBeNull();
+    await installDefault();
+    const call = vi.fn();
+    input.services.workspaceWorkers = { getWorker: () => ({ supportedMethods: ["workspaceOperation"] }), call } as any;
+    const prepared = await prepareHeartbeatWorkspace(db, input);
+    expect(prepared.executionWorkspace.cwd).toBe(source);
+    expect(prepared.persistedExecutionWorkspace?.providerType).not.toBe("plugin");
+    expect(call).not.toHaveBeenCalled();
+  });
+
   const readIssue = (id: string) => db.select().from(issues).where(eq(issues.id, id)).then(rows => rows[0]!);
   const readRun = (id: string) => db.select().from(heartbeatRuns).where(eq(heartbeatRuns.id, id)).then(rows => rows[0]!);
   const leases = (id: string) => db.select().from(environmentLeases).where(eq(environmentLeases.heartbeatRunId, id));
@@ -135,6 +183,7 @@ describe.skipIf(!support.supported)("heartbeat workspace preparation boundary",
     await db.update(projects).set({ executionWorkspacePolicy: {
       enabled: true, storageProviderPluginId: "bbbbbbbb-bbbb-4bbb-8bbb-bbbbbbbbbbbb",
     } }).where(eq(projects.id, issue.projectId!));
+    input.policy.projectExecutionWorkspacePolicy = { enabled: true, storageProviderPluginId: "bbbbbbbb-bbbb-4bbb-8bbb-bbbbbbbbbbbb" };
     input.task.freshWorkspace = { mode: "fresh_isolated_workspace", retryIntentId: input.run.id,
       sourceRunId: input.run.id, retainedSourceIds: [] };
     const call = vi.fn();
diff --git a/server/src/services/heartbeat/workspace-preparation.ts b/server/src/services/heartbeat/workspace-preparation.ts
index 21e0d0c44da..8b1cca96500 100644
--- a/server/src/services/heartbeat/workspace-preparation.ts
+++ b/server/src/services/heartbeat/workspace-preparation.ts
@@ -27,7 +27,7 @@ import path from "node:path";
 import { CONTROLLER_PROVISION_COPY_ONLY, workspaceRequiresCopyOnlyProvisioning } from "../workspace-host-provision.js";
 import { and, asc, eq } from "drizzle-orm";
 import { type ExecutionWorkspace } from "@paperclipai/shared";
-import { heartbeatRuns, issues, projects, projectWorkspaces } from "@paperclipai/db";
+import { heartbeatRuns, issues, projectWorkspaces } from "@paperclipai/db";
 import { getStartupTracer } from "../../instrumentation.js";
 import { createHostDuplexObservabilityRecorder } from "../duplex-observability-recorder.js";
 import { incrementToolRuntimeMetricCounter } from "../tool-runtime-metrics.js";
@@ -330,6 +330,7 @@ async function prepareHeartbeatWorkspaceLocked(db: Db, input: HeartbeatWorkspace
           useProjectWorkspace:
             requestedExecutionWorkspaceMode !== "agent_default",
           configuredCwd: readNonEmptyString(mergedConfig.cwd),
+          storageProviderPluginId: projectExecutionWorkspacePolicy?.storageProviderPluginId ?? null,
           anchorWorkspace: !pluginTaskWorkspace && requestedShouldReuseExisting && reusableExistingExecutionWorkspace?.strategyType === "git_worktree"
             ? await resolveReusedGitWorkspaceAnchor({
                 agent,
@@ -375,14 +376,10 @@ async function prepareHeartbeatWorkspaceLocked(db: Db, input: HeartbeatWorkspace
   }));
   const hostProvisionDriver = selectedEnvironmentForConfig?.driver ?? lowTrustPreflightEnvironmentDriver;
   if (fresh && !isDotRun) {
-    const [project] = resolvedWorkspace.projectId ? await db.select({
-      policy: projects.executionWorkspacePolicy,
-    }).from(projects).where(and(eq(projects.id, resolvedWorkspace.projectId),
-      eq(projects.companyId, agent.companyId))) : [];
     const sourceWorkspace = reusableExistingExecutionWorkspace ?? existingExecutionWorkspace;
     if (sourceWorkspace?.providerType === "plugin" ||
         readWorkspaceProviderBinding(sourceWorkspace?.metadata) ||
-        project?.policy?.storageProviderPluginId) {
+        (resolvedWorkspace.workspaceId && projectExecutionWorkspacePolicy?.storageProviderPluginId)) {
       throw new WorkspaceValidationFailure("A fresh attempt is unavailable for this workspace storage provider. The existing workspace is retained.", {
         reason: "fresh_workspace_storage_unsupported",
       });
@@ -392,6 +389,7 @@ async function prepareHeartbeatWorkspaceLocked(db: Db, input: HeartbeatWorkspace
     companyId: agent.companyId, projectId: resolvedWorkspace.projectId, projectWorkspaceId: resolvedWorkspace.workspaceId,
     issueId, runId: run.id, agentId: agent.id, responsibleUserId,
     existingWorkspaceId: reusableExistingExecutionWorkspace?.id ?? issueRef?.executionWorkspaceId ?? null,
+    selectedProviderPluginId: projectExecutionWorkspacePolicy?.storageProviderPluginId ?? null,
     mode: requestedExecutionWorkspaceMode,
     strategy: resolveEffectiveWorkspaceStrategyType(requestedExecutionWorkspaceMode, mergedConfig),
     branchMode: typeof parseObject(mergedConfig.workspaceStrategy).existingBranch === "string" ? "existing" : "create",
diff --git a/server/src/services/heartbeat/workspaces.ts b/server/src/services/heartbeat/workspaces.ts
index fa12c39490a..5e4ef54f870 100644
--- a/server/src/services/heartbeat/workspaces.ts
+++ b/server/src/services/heartbeat/workspaces.ts
@@ -1,3 +1,4 @@
+import { effectiveProjectWorkspacePolicy } from "../project-workspace-provider.js";
 import { canonicalRepositoryRoot } from "../execution-workspace-source-roots.js";
 import { assertTaskWorkspaceExecutionAccess } from "../task-workspace-access.js";
 import { selectRestoredProjectRepositories, type GitWorkspaceContents } from "../git-workspace-contents.js";
@@ -3406,7 +3407,7 @@ export function createHeartbeatWorkspaceResolver(db: Db) {
     agent: typeof agents.$inferSelect,
     context: Record<string, unknown>,
     previousSessionParams: Record<string, unknown> | null,
-    opts?: { useProjectWorkspace?: boolean | null; configuredCwd?: string | null; executionEnvironmentDriver?: string | null },
+    opts?: { useProjectWorkspace?: boolean | null; configuredCwd?: string | null; executionEnvironmentDriver?: string | null; storageProviderPluginId?: string | null },
   ): Promise<ResolvedAnchorWorkspaceForRun> {
     const issueId =
       readNonEmptyString(context.issueId) ?? readNonEmptyString(context.taskId);
@@ -3508,8 +3509,11 @@ export function createHeartbeatWorkspaceResolver(db: Db) {
       }
       const [sourceProject] = projectWorkspaceRows.length ? await db.select({ policy: projects.executionWorkspacePolicy }).from(projects)
         .where(and(eq(projects.id, workspaceProjectId!), eq(projects.companyId, agent.companyId))) : [];
+      const storageProviderPluginId = opts?.storageProviderPluginId !== undefined ? opts.storageProviderPluginId : sourceProject?.policy?.storageProviderPluginId ??
+        (sourceProject ? (await effectiveProjectWorkspacePolicy(db, agent.companyId, sourceProject.policy,
+          projectWorkspaceRows.some(workspace => Boolean(workspace.repoUrl))))?.storageProviderPluginId : null);
       for (const workspace of projectWorkspaceRows) {
-        if (sourceProject?.policy?.storageProviderPluginId) {
+        if (storageProviderPluginId) {
           return { cwd: `/workspaces/${workspace.id}`, source: "project_primary" as const,
             projectId: workspace.projectId, workspaceId: workspace.id, repoUrl: workspace.repoUrl,
             repoRef: workspace.repoRef, workspaceHints, warnings: [], baseCwdFallback: false, materializationFailures: [] };
@@ -3676,6 +3680,7 @@ export function createHeartbeatWorkspaceResolver(db: Db) {
       useProjectWorkspace?: boolean | null;
       configuredCwd?: string | null;
       executionEnvironmentDriver?: string | null;
+      storageProviderPluginId?: string | null;
       anchorWorkspace?: ResolvedAnchorWorkspaceForRun;
     },
   ): Promise<ResolvedWorkspaceForRun> {
diff --git a/server/src/services/issues.ts b/server/src/services/issues.ts
index b95d7058b04..ff1aac804be 100644
--- a/server/src/services/issues.ts
+++ b/server/src/services/issues.ts
@@ -10235,7 +10235,7 @@ export function issueService(db: Db) {
           if (projectWorkspaceId && isolatedWorkspacesEnabled) {
             const sourceStrategy = await executionWorkspaceService(db).resolveSourceWorkspaceStrategy({ companyId,
               assigneeAgentId: issueData.assigneeAgentId, assigneeAdapterOverrides: issueData.assigneeAdapterOverrides,
-              executionWorkspaceSettings, executionWorkspacePolicy: projectPolicy,
+              executionWorkspaceSettings, executionWorkspacePolicy: projectPolicy, sourceWorkspaceId: projectWorkspaceId,
               typedSelection: false, projectId: issueData.projectId, executionPolicy: issueData.executionPolicy }, tx);
             if (sourceStrategy === "git_worktree") workspaceIntent = { version: 1, source: "project",
               selection: { kind: "configured_source", projectWorkspaceId, mode: "managed_isolated" } };
@@ -10248,7 +10248,7 @@ export function issueService(db: Db) {
           if (!readableSource) throw notFound("Workspace source is unavailable or inaccessible");
           await executionWorkspaceService(db).resolveSourceWorkspaceStrategy({ companyId,
             assigneeAgentId: issueData.assigneeAgentId, assigneeAdapterOverrides: issueData.assigneeAdapterOverrides,
-            executionWorkspaceSettings, executionWorkspacePolicy: readableSource.executionWorkspacePolicy,
+            executionWorkspaceSettings, executionWorkspacePolicy: readableSource.executionWorkspacePolicy, sourceWorkspaceId: projectWorkspaceId,
             typedSelection: Boolean(workspaceIntent), projectId: issueData.projectId, executionPolicy: issueData.executionPolicy }, tx);
           await assertTaskWorkspaceSourceProjectAccess(tx, workspaceActor, companyId, readableSource.projectId);
         }
diff --git a/server/src/services/plugin-workspaces.ts b/server/src/services/plugin-workspaces.ts
index 70715598d93..e519bd7123a 100644
--- a/server/src/services/plugin-workspaces.ts
+++ b/server/src/services/plugin-workspaces.ts
@@ -1,3 +1,4 @@
+import { effectiveProjectWorkspacePolicy, isWorkspaceProvider } from "./project-workspace-provider.js";
 import { randomUUID, createHash } from "node:crypto";
 import { and, eq, sql } from "drizzle-orm";
 import {
@@ -56,9 +57,7 @@ async function provider(
     !plugin ||
     plugin.status !== "ready" ||
     settings?.enabled === false ||
-    !plugin.manifestJson.workspaceProvider ||
-    !plugin.manifestJson.capabilities.includes("workspaces.manage") ||
-    !plugin.manifestJson.resourceLifecycle?.includes("project") ||
+    !isWorkspaceProvider(plugin.manifestJson) ||
     !workers
       .getWorker(pluginId)
       ?.supportedMethods?.includes("workspaceOperation")
@@ -164,6 +163,7 @@ export async function preparePluginWorkspace(
     existingWorkspaceId: string | null;
     mode: string;
     strategy: string;
+    selectedProviderPluginId?: string | null;
     branchMode?: "create" | "existing";
     branchName?: string | null;
     baseRef?: string | null;
@@ -185,6 +185,7 @@ export async function preparePluginWorkspace(
     existing?.metadata?.workspaceProviderRemoval
   )
     throw conflict("Workspace storage is retired or awaiting cleanup");
+  if (!existing && (!input.projectId || !input.projectWorkspaceId)) return null;
   const saved = readWorkspaceProviderBinding(existing?.metadata);
   const mode = existing?.mode ?? input.mode,
     strategy = existing?.strategyType ?? input.strategy;
@@ -200,10 +201,10 @@ export async function preparePluginWorkspace(
           ),
         )
     : [];
-  const owner =
-    saved?.pluginId ??
-    existing?.metadata?.workspaceProviderOwner ??
-    project?.executionWorkspacePolicy?.storageProviderPluginId;
+  if (existing && existing.providerType !== "plugin" && !saved && !existing.metadata?.workspaceProviderOwner) return null;
+  const owner = saved?.pluginId ?? existing?.metadata?.workspaceProviderOwner ??
+    (!existing && input.selectedProviderPluginId !== undefined ? input.selectedProviderPluginId :
+      !existing && project ? (await effectiveProjectWorkspacePolicy(db, input.companyId, project.executionWorkspacePolicy, false))?.storageProviderPluginId : null);
   const pluginId = typeof owner === "string" ? owner : null;
   if (!pluginId) {
     if (existing?.providerType === "plugin")
@@ -341,7 +342,7 @@ export async function preparePluginWorkspace(
       if (
         !currentProject ||
         currentProject.archivedAt ||
-        currentProject.executionWorkspacePolicy?.storageProviderPluginId !==
+        (await effectiveProjectWorkspacePolicy(tx, input.companyId, currentProject.executionWorkspacePolicy, false))?.storageProviderPluginId !==
           pluginId ||
         !currentSource ||
         currentSource.repoUrl !== source.repoUrl ||
diff --git a/server/src/services/project-workspace-provider.ts b/server/src/services/project-workspace-provider.ts
new file mode 100644
index 00000000000..cc8e8272b2c
--- /dev/null
+++ b/server/src/services/project-workspace-provider.ts
@@ -0,0 +1,72 @@
+import { and, eq, notInArray } from "drizzle-orm";
+import { pluginCompanySettings, plugins, type Db } from "@paperclipai/db";
+import type { PaperclipPluginManifestV1, ProjectWorkspaceProviderConfiguration } from "@paperclipai/shared";
+import { parseProjectExecutionWorkspacePolicy } from "./execution-workspace-policy.js";
+import { conflict } from "../errors.js";
+
+export function isWorkspaceProvider(manifest: PaperclipPluginManifestV1) {
+  return Boolean(manifest.workspaceProvider && manifest.capabilities.includes("workspaces.manage") &&
+    manifest.resourceLifecycle?.includes("project"));
+}
+
+type ProviderDb = Pick<Db, "select">;
+
+export async function listProjectWorkspaceProviders(db: ProviderDb, companyId: string) {
+  const rows = await db.select({ plugin: plugins, enabled: pluginCompanySettings.enabled })
+    .from(plugins)
+    .leftJoin(pluginCompanySettings, and(eq(pluginCompanySettings.pluginId, plugins.id),
+      eq(pluginCompanySettings.companyId, companyId)))
+    .where(notInArray(plugins.status, ["disabled", "uninstalled"]));
+  return rows.filter(row => row.enabled !== false && isWorkspaceProvider(row.plugin.manifestJson))
+    .map(row => row.plugin);
+}
+
+type Provider = Awaited<ReturnType<typeof listProjectWorkspaceProviders>>[number];
+
+export function resolveProjectWorkspaceProvider(
+  rawPolicy: unknown,
+  providers: Provider[],
+  hasGitSource: boolean,
+): ProjectWorkspaceProviderConfiguration {
+  const policy = parseProjectExecutionWorkspacePolicy(rawPolicy);
+  const explicit = policy?.storageProviderPluginId !== undefined;
+  const defaults = providers.filter(plugin => plugin.manifestJson.workspaceProvider?.defaultForProjects);
+  const selected = explicit ? providers.find(plugin => plugin.id === policy?.storageProviderPluginId)
+    : defaults.length === 1 ? defaults[0] : undefined;
+  const pluginId = explicit ? policy?.storageProviderPluginId ?? null : selected?.id ?? null;
+  let error = !explicit && defaults.length > 1
+    ? `Multiple workspace storage plugins claim the project default: ${defaults.map(plugin => plugin.manifestJson.displayName).sort().join(", ")}. Select a storage provider in project configuration or disable a conflicting default.`
+    : null;
+  const declaration = selected?.manifestJson.workspaceProvider;
+  const supplied = hasGitSource ? declaration?.defaultForProjects : undefined;
+  const effectivePolicy = pluginId ? parseProjectExecutionWorkspacePolicy({
+    enabled: true,
+    ...(supplied ? { defaultMode: supplied.mode } : {}),
+    ...policy,
+    storageProviderPluginId: pluginId,
+    ...(supplied ? { workspaceStrategy: { type: supplied.strategy, ...policy?.workspaceStrategy } } : {}),
+  }) : policy;
+  if (pluginId && !selected) error = "The workspace storage plugin is unavailable";
+  if (declaration && effectivePolicy && hasGitSource && (
+    effectivePolicy.enabled === false ||
+    (effectivePolicy.defaultMode && !declaration.modes.includes(effectivePolicy.defaultMode as "isolated_workspace")) ||
+    (effectivePolicy.workspaceStrategy?.type && !declaration.strategies.includes(effectivePolicy.workspaceStrategy.type as "git_worktree"))
+  )) {
+    error = "The storage plugin does not support the explicit project workspace settings. Change the workspace mode or strategy, or select another storage provider in project configuration.";
+  }
+  return {
+    source: explicit ? "project" : selected || error ? "default" : "core",
+    pluginId,
+    displayName: selected?.manifestJson.displayName ?? (pluginId ? "Unavailable provider" : "Core / local"),
+    providers: providers.map(plugin => ({ id: plugin.id, displayName: plugin.manifestJson.displayName,
+      isDefault: Boolean(plugin.manifestJson.workspaceProvider?.defaultForProjects) })),
+    effectivePolicy,
+    error,
+  };
+}
+
+export async function effectiveProjectWorkspacePolicy(db: ProviderDb, companyId: string, rawPolicy: unknown, hasGitSource: boolean) {
+  const configuration = resolveProjectWorkspaceProvider(rawPolicy, await listProjectWorkspaceProviders(db, companyId), hasGitSource);
+  if (configuration.error) throw conflict(configuration.error);
+  return configuration.effectivePolicy;
+}
diff --git a/server/src/services/projects.ts b/server/src/services/projects.ts
index acb4121a6dc..7f6795d2132 100644
--- a/server/src/services/projects.ts
+++ b/server/src/services/projects.ts
@@ -1,3 +1,4 @@
+import { listProjectWorkspaceProviders, resolveProjectWorkspaceProvider } from "./project-workspace-provider.js";
 import { retireRemovedPluginWorkspaceDependents } from "./plugin-workspaces.js";
 import { DELIVERY_QUEUES, notifyDeliveryWork } from "./delivery-work-notifications.js";
 import { enqueueProjectSkillSource, detachProjectSkillSource } from "./project-skill-source-bindings.js";
@@ -138,6 +139,7 @@ interface ProjectWithGoals extends Omit<ProjectRow, "executionWorkspacePolicy">
   goalIds: string[];
   goals: ProjectGoalRef[];
   executionWorkspacePolicy: ProjectExecutionWorkspacePolicy | null;
+  workspaceProvider?: import("@paperclipai/shared").ProjectWorkspaceProviderConfiguration;
   codebase: ProjectCodebase;
   workspaces: ProjectWorkspace[];
   primaryWorkspace: ProjectWorkspace | null;
@@ -311,6 +313,7 @@ function pickPrimaryWorkspace(
 async function attachWorkspaces(db: Db, rows: ProjectWithGoals[]): Promise<ProjectWithGoals[]> {
   if (rows.length === 0) return [];
 
+  const providerCatalog = await listProjectWorkspaceProviders(db, rows[0]!.companyId);
   const projectIds = rows.map((r) => r.id);
   const workspaceRows = await db
     .select()
@@ -393,6 +396,8 @@ async function attachWorkspaces(db: Db, rows: ProjectWithGoals[]): Promise<Proje
       workspaces,
       primaryWorkspace,
       managedByPlugin: managedByProjectId.get(row.id) ?? null,
+      workspaceProvider: resolveProjectWorkspaceProvider(row.executionWorkspacePolicy, providerCatalog,
+        workspaces.some(workspace => Boolean(workspace.repoUrl))),
     };
   });
 }
@@ -974,7 +979,10 @@ export function projectService(db: Db, options: { captureWorkspaceUpdates?: bool
       if (!existingProject) return null;
       if (projectData.executionWorkspacePolicy !== undefined &&
           projectData.executionWorkspacePolicy?.storageProviderPluginId !== existingProject.executionWorkspacePolicy?.storageProviderPluginId) {
-        await retireRemovedPluginWorkspaceDependents(db, id);
+        const providers = await listProjectWorkspaceProviders(db, existingProject.companyId);
+        const previousOwner = resolveProjectWorkspaceProvider(existingProject.executionWorkspacePolicy, providers, false).pluginId;
+        const nextOwner = resolveProjectWorkspaceProvider(projectData.executionWorkspacePolicy, providers, false).pluginId;
+        if (previousOwner !== nextOwner) await retireRemovedPluginWorkspaceDependents(db, id);
       }
       if (ids && ids.length > 0) {
         await assertGoalsBelongToCompany(db, existingProject.companyId, ids);
diff --git a/ui/src/components/ProjectProperties.concurrency.test.tsx b/ui/src/components/ProjectProperties.concurrency.test.tsx
index a59924c2e90..ec8c14cac2e 100644
--- a/ui/src/components/ProjectProperties.concurrency.test.tsx
+++ b/ui/src/components/ProjectProperties.concurrency.test.tsx
@@ -138,3 +138,36 @@ it("hides project isolation controls without rewriting its policy", () => {
   expect(container.querySelector('select[aria-label="Shared workspace concurrency"]')).toBeNull();
   expect(onFieldUpdate).not.toHaveBeenCalled();
 });
+
+
+describe("ProjectProperties — workspace storage selection", () => {
+  const inherited = {
+    source: "default" as const, pluginId: "provider-one", displayName: "Managed storage", error: null,
+    effectivePolicy: { enabled: true, defaultMode: "isolated_workspace" as const, storageProviderPluginId: "provider-one", workspaceStrategy: { type: "git_worktree" as const } },
+    providers: [{ id: "provider-one", displayName: "Managed storage", isDefault: true }, { id: "provider-two", displayName: "Alternative", isDefault: false }],
+  };
+  function storageSelect() { return container.querySelector<HTMLSelectElement>('select[aria-label="Workspace storage provider"]')!; }
+  it("displays the inherited default without saving it as an override", () => {
+    render(makeProject({ executionWorkspacePolicy: null, workspaceProvider: inherited }), vi.fn());
+    expect(storageSelect().value).toBe("inherit");
+    expect(container.textContent).toContain("Inherited default: Managed storage");
+  });
+  it.each(["core", "provider-two", "inherit"])("saves the deliberate %s choice while preserving explicit settings", value => {
+    const onFieldUpdate = vi.fn();
+    render(makeProject({ executionWorkspacePolicy: { enabled: true, storageProviderPluginId: "provider-one", sharedWorkspaceConcurrency: "serialize" }, workspaceProvider: inherited }), onFieldUpdate);
+    act(() => { storageSelect().value = value; storageSelect().dispatchEvent(new Event("change", { bubbles: true })); });
+    const policy = { enabled: true, sharedWorkspaceConcurrency: "serialize", ...(value === "inherit" ? {} : { storageProviderPluginId: value === "core" ? null : value }) };
+    expect(onFieldUpdate).toHaveBeenCalledWith("workspace_storage_provider", { executionWorkspacePolicy: policy });
+  });
+  it("does not copy inherited mode, strategy, or provider when another setting changes", () => {
+    const onFieldUpdate = vi.fn();
+    render(makeProject({ executionWorkspacePolicy: null, workspaceProvider: inherited }), onFieldUpdate);
+    act(() => { concurrencySelect().value = "allow"; concurrencySelect().dispatchEvent(new Event("change", { bubbles: true })); });
+    expect(onFieldUpdate).toHaveBeenCalledWith("execution_workspace_shared_concurrency", { executionWorkspacePolicy: { enabled: true, sharedWorkspaceConcurrency: "allow" } });
+  });
+  it("shows default conflicts and keeps the provider control usable", () => {
+    render(makeProject({ workspaceProvider: { ...inherited, error: "Select a storage provider in project configuration" } }), vi.fn());
+    expect(container.querySelector('[role="alert"]')?.textContent).toContain("Select a storage provider");
+    expect(storageSelect().disabled).toBe(false);
+  });
+});
diff --git a/ui/src/components/ProjectProperties.tsx b/ui/src/components/ProjectProperties.tsx
index aa65c10ee50..a1c631c1546 100644
--- a/ui/src/components/ProjectProperties.tsx
+++ b/ui/src/components/ProjectProperties.tsx
@@ -47,6 +47,7 @@ export type ProjectConfigFieldKey =
   | "visibility"
   | "goals"
   | "env"
+  | "workspace_storage_provider"
   | "execution_workspace_enabled"
   | "execution_workspace_default_mode"
   | "execution_workspace_shared_concurrency"
@@ -273,7 +274,9 @@ export function ProjectProperties({ project, repositories, onUpdate, onFieldUpda
   const codebase = project.codebase;
   const primaryCodebaseWorkspace = project.primaryWorkspace ?? null;
   const hasAdditionalLegacyWorkspaces = workspaces.some((workspace) => workspace.id !== primaryCodebaseWorkspace?.id && !workspace.metadata?.githubRepositoryId);
-  const executionWorkspacePolicy = project.executionWorkspacePolicy ?? null;
+  const storedExecutionWorkspacePolicy = project.executionWorkspacePolicy ?? null;
+  const providerConfiguration = project.workspaceProvider;
+  const executionWorkspacePolicy = providerConfiguration?.effectivePolicy ?? storedExecutionWorkspacePolicy;
   const executionWorkspacesEnabled = executionWorkspacePolicy?.enabled === true;
   const isolatedWorkspacesEnabled = experimentalSettings?.enableIsolatedWorkspaces === true;
   const executionWorkspaceDefaultMode =
@@ -352,9 +355,7 @@ export function ProjectProperties({ project, repositories, onUpdate, onFieldUpda
     return {
       executionWorkspacePolicy: {
         enabled: executionWorkspacesEnabled,
-        defaultMode: executionWorkspaceDefaultMode,
-        allowIssueOverride: executionWorkspacePolicy?.allowIssueOverride ?? true,
-        ...executionWorkspacePolicy,
+        ...storedExecutionWorkspacePolicy,
         ...patch,
       },
     };
@@ -729,6 +730,41 @@ export function ProjectProperties({ project, repositories, onUpdate, onFieldUpda
           )}
         </div>}
 
+        {providerConfiguration ? (
+          <div className="py-1.5 space-y-2">
+            <label className="flex items-center gap-2 text-sm font-medium" htmlFor="workspace-storage-provider">
+              Workspace storage
+              <SaveIndicator state={fieldState("workspace_storage_provider")} />
+            </label>
+            <select
+              id="workspace-storage-provider"
+              aria-label="Workspace storage provider"
+              className="w-full rounded-md border border-border bg-background px-3 py-2 text-sm"
+              disabled={!onUpdate && !onFieldUpdate}
+              value={storedExecutionWorkspacePolicy?.storageProviderPluginId === null ? "core" : storedExecutionWorkspacePolicy?.storageProviderPluginId ?? "inherit"}
+              onChange={(event) => {
+                const policy = { enabled: true, ...storedExecutionWorkspacePolicy };
+                if (event.target.value === "inherit") delete policy.storageProviderPluginId;
+                else policy.storageProviderPluginId = event.target.value === "core" ? null : event.target.value;
+                commitField("workspace_storage_provider", { executionWorkspacePolicy: policy });
+              }}
+            >
+              <option value="inherit">Inherit installed default</option>
+              <option value="core">Core / local</option>
+              {providerConfiguration.providers.map(provider => (
+                <option key={provider.id} value={provider.id}>{provider.displayName}{provider.isDefault ? " (default)" : ""}</option>
+              ))}
+              {storedExecutionWorkspacePolicy?.storageProviderPluginId && !providerConfiguration.providers.some(provider => provider.id === storedExecutionWorkspacePolicy.storageProviderPluginId) ? (
+                <option value={storedExecutionWorkspacePolicy.storageProviderPluginId}>Unavailable provider</option>
+              ) : null}
+            </select>
+            <p className="text-xs text-muted-foreground">
+              {providerConfiguration.source === "default" ? `Inherited default: ${providerConfiguration.displayName}` : `Selected: ${providerConfiguration.displayName}`}
+            </p>
+            {providerConfiguration.error ? <p role="alert" className="text-xs text-destructive">{providerConfiguration.error}</p> : null}
+          </div>
+        ) : null}
+
         {isolatedWorkspacesEnabled && workspaceIsolationControlsVisible ? (
           <>
             <Separator className="my-4" />