diff --git a/client/src/components/lanes/__tests__/AddLaneModal.test.tsx b/client/src/components/lanes/__tests__/AddLaneModal.test.tsx
index 453be98..1ffb1fe 100644
--- a/client/src/components/lanes/__tests__/AddLaneModal.test.tsx
+++ b/client/src/components/lanes/__tests__/AddLaneModal.test.tsx
@@ -34,6 +34,10 @@ vi.mock("../../../lib/api", () => ({
 }));
 
 function laneFixture(over: Partial<Lane> = {}): Lane {
+  // `as Lane`: spreading a Partial<Lane> widens every field it may carry to
+  // `T | undefined`, which no longer satisfies Lane's required fields. The
+  // base object below still lists all of them, so the cast asserts what the
+  // literal already proves.
   return {
     id: 9,
     title: "",
@@ -64,7 +68,7 @@ function laneFixture(over: Partial<Lane> = {}): Lane {
     slot: null,
     ports: {},
     ...over,
-  };
+  } as Lane;
 }
 
 const SUGGESTIONS: CwdSuggestion[] = [
diff --git a/client/src/components/lanes/__tests__/DestructiveLaneModal.test.tsx b/client/src/components/lanes/__tests__/DestructiveLaneModal.test.tsx
index 2cdd703..c546e38 100644
--- a/client/src/components/lanes/__tests__/DestructiveLaneModal.test.tsx
+++ b/client/src/components/lanes/__tests__/DestructiveLaneModal.test.tsx
@@ -21,6 +21,10 @@ import { DestructiveLaneModal } from "../DestructiveLaneModal";
 import type { Lane, LanePurgePreflight, LaneWorktreePreflight } from "../../../lib/types";
 
 function makeLane(overrides: Partial<Lane> = {}): Lane {
+  // `as Lane`: spreading a Partial<Lane> widens every field it may carry to
+  // `T | undefined`, which no longer satisfies Lane's required fields. The
+  // base object below still lists all of them, so the cast asserts what the
+  // literal already proves.
   return {
     id: 1,
     title: "demo",
@@ -50,7 +54,7 @@ function makeLane(overrides: Partial<Lane> = {}): Lane {
     slot: null,
     ports: {},
     ...overrides,
-  };
+  } as Lane;
 }
 
 function worktreePreflight(overrides: Partial<LaneWorktreePreflight> = {}): LaneWorktreePreflight {
diff --git a/client/src/components/lanes/__tests__/LaneCard.test.tsx b/client/src/components/lanes/__tests__/LaneCard.test.tsx
index ec25250..6320d15 100644
--- a/client/src/components/lanes/__tests__/LaneCard.test.tsx
+++ b/client/src/components/lanes/__tests__/LaneCard.test.tsx
@@ -12,7 +12,7 @@ import { describe, it, expect, vi, beforeEach } from "vitest";
 import { render, screen, waitFor } from "@testing-library/react";
 import userEvent from "@testing-library/user-event";
 import LaneCard from "../LaneCard";
-import type { Lane } from "../../../lib/types";
+import type { Lane, LaneRuntime } from "../../../lib/types";
 import { api } from "../../../lib/api";
 
 vi.mock("../../../lib/api", () => ({
@@ -48,6 +48,10 @@ vi.mocked(api.locks.list).mockReset();
 vi.mocked(api.locks.list).mockResolvedValue({ locks: [] });
 
 function makeLane(overrides: Partial<Lane> = {}): Lane {
+  // `as Lane`: spreading a Partial<Lane> widens every field it may carry to
+  // `T | undefined`, which no longer satisfies Lane's required fields. The
+  // base object below still lists all of them, so the cast asserts what the
+  // literal already proves.
   return {
     id: 1,
     title: "demo",
@@ -78,7 +82,7 @@ function makeLane(overrides: Partial<Lane> = {}): Lane {
     slot: null,
     ports: {},
     ...overrides,
-  };
+  } as Lane;
 }
 
 describe("LaneCard status badge", () => {
@@ -396,6 +400,9 @@ describe("LaneCard — named locks", () => {
 
 describe("agents install / mcp sync / integration badges / sync check", () => {
   beforeEach(() => {
+    // Only the fields this describe block's assertions read; `as LaneRuntime`
+    // keeps the double from having to restate a shape the component never
+    // touches here.
     vi.mocked(api.lanes.runtime).mockResolvedValue({
       available: true as const,
       provisioned: true as const,
@@ -403,7 +410,7 @@ describe("agents install / mcp sync / integration badges / sync check", () => {
       slot: 1,
       profileDir: "/work/demo/.ccam/profile",
       ports: {},
-    });
+    } as unknown as LaneRuntime);
     vi.mocked(api.lanes.integration).mockImplementation((_id, name) =>
       Promise.resolve({ enabled: name === "tracker" })
     );
diff --git a/client/src/lib/api.ts b/client/src/lib/api.ts
index d136408..9204a12 100644
--- a/client/src/lib/api.ts
+++ b/client/src/lib/api.ts
@@ -394,6 +394,7 @@ import type {
   LaneGitFacts,
   LaneRuntime,
   ModelPricing,
+  NamedLock,
   Session,
   SessionDrillIn,
   SessionStats,
diff --git a/client/src/pages/__tests__/Workspace.test.tsx b/client/src/pages/__tests__/Workspace.test.tsx
index 1605db0..fbf6b0c 100644
--- a/client/src/pages/__tests__/Workspace.test.tsx
+++ b/client/src/pages/__tests__/Workspace.test.tsx
@@ -24,6 +24,7 @@ type LaneFixture = {
   pipeline_nodes: never[];
   detected_signal: string | null;
   run_id: string | null;
+  active_feature_id?: number | null;
 };
 
 let lanesToReturn: LaneFixture[] = [
@@ -583,7 +584,8 @@ describe("Workspace — proof gallery", () => {
       ],
     });
     // Set active_feature_id and ensure features list is populated
-    lanesToReturn[0].active_feature_id = 1;
+    // (indexed access is `| undefined` under noUncheckedIndexedAccess)
+    lanesToReturn[0]!.active_feature_id = 1;
     vi.mocked(api.lanes.features.list).mockResolvedValue({
       features: [
         {