diff --git a/biome.jsonc b/biome.jsonc
index 53431934..b4a8d25d 100644
--- a/biome.jsonc
+++ b/biome.jsonc
@@ -72,6 +72,7 @@
         "**/src/**/*.{ts,tsx}",
         "!**/src/app-server/connection/**",
         "!**/src/app-server/protocol/server-requests.ts",
+        "!**/src/app-server/protocol/thread.ts",
         "!**/src/app-server/protocol/turn.ts"
       ]
     },
diff --git a/src/app-server/protocol/thread.ts b/src/app-server/protocol/thread.ts
index c991930c..aa491b5a 100644
--- a/src/app-server/protocol/thread.ts
+++ b/src/app-server/protocol/thread.ts
@@ -1,14 +1,15 @@
 import type { Thread, ThreadProvenance } from "../../domain/threads/model";
+import type { Thread as GeneratedThread } from "../../generated/app-server/v2/Thread";
 
-export interface ThreadRecord {
-  id: string;
-  preview: string;
-  name: string | null;
-  createdAt: number;
-  updatedAt: number;
-  recencyAt?: number | null;
-  [key: string]: unknown;
-}
+type RequiredThreadRecordFields = "id" | "preview" | "name" | "createdAt" | "updatedAt";
+
+export type ThreadRecord = Pick<GeneratedThread, RequiredThreadRecordFields> &
+  Partial<Omit<GeneratedThread, RequiredThreadRecordFields | "source" | "status" | "turns">> & {
+    /** Kept unknown at the protocol edge so a newer SessionSource variant degrades to `other` instead of breaking thread lists. */
+    source?: unknown;
+    status?: unknown;
+    turns?: readonly GeneratedThread["turns"][number][];
+  };
 
 export function threadFromThreadRecord(thread: ThreadRecord, options: { archived?: boolean } = {}): Thread {
   const hasRecencyAt = Object.hasOwn(thread, "recencyAt");
diff --git a/src/app-server/services/rollout-token-usage.ts b/src/app-server/services/rollout-token-usage.ts
index 9733caf1..410fa443 100644
--- a/src/app-server/services/rollout-token-usage.ts
+++ b/src/app-server/services/rollout-token-usage.ts
@@ -3,7 +3,7 @@ import type { ThreadTokenUsage, TokenUsageBreakdown } from "../../domain/runtime
 const ROLLOUT_TOKEN_USAGE_READ_TIMEOUT_MS = 2_000;
 const ROLLOUT_TOKEN_USAGE_MAX_BASE64_BYTES = 12 * 1024 * 1024;
 
-export type RolloutReadFileBase64 = (path: string, options: { timeoutMs: number }) => Promise<string>;
+export type RolloutReadFileBase64 = (path: string, options: { timeoutMs: number }) => Promise<string | null>;
 
 export async function recoverRolloutTokenUsage(
   path: string | null,
@@ -11,12 +11,13 @@ export async function recoverRolloutTokenUsage(
 ): Promise<ThreadTokenUsage | null> {
   if (!path || !isAbsolutePath(path)) return null;
 
-  let dataBase64: string;
+  let dataBase64: string | null;
   try {
     dataBase64 = await readFileBase64(path, { timeoutMs: ROLLOUT_TOKEN_USAGE_READ_TIMEOUT_MS });
   } catch {
     return null;
   }
+  if (dataBase64 === null) return null;
   if (dataBase64.length > ROLLOUT_TOKEN_USAGE_MAX_BASE64_BYTES) return null;
 
   const text = decodeBase64Text(dataBase64);
diff --git a/src/app-server/services/threads.ts b/src/app-server/services/threads.ts
index c4434a8e..6cd8a359 100644
--- a/src/app-server/services/threads.ts
+++ b/src/app-server/services/threads.ts
@@ -25,10 +25,6 @@ import type { AppServerRequestClient } from "./request-client";
 const THREAD_LIST_PAGE_LIMIT = 100;
 
 export type ThreadTurnSortDirection = "asc" | "desc";
-export type TurnTranscriptSummaryClient = AppServerRequestClient;
-export type ThreadForkClient = AppServerRequestClient;
-export type ThreadRollbackClient = AppServerRequestClient;
-export type ThreadCompactionClient = AppServerRequestClient;
 
 interface TurnTranscriptSummaryPage {
   summaries: TurnTranscriptSummary[];
@@ -165,7 +161,7 @@ export async function readThreadForArchiveExport(client: AppServerRequestClient,
 }
 
 export async function readCompletedTurnTranscriptSummariesPage(
-  client: TurnTranscriptSummaryClient,
+  client: AppServerRequestClient,
   threadId: string,
   cursor: string | null,
   limit: number,
@@ -179,7 +175,7 @@ export async function readCompletedTurnTranscriptSummariesPage(
 }
 
 export async function readReferencedThreadTurnTranscriptSummaries(
-  client: TurnTranscriptSummaryClient,
+  client: AppServerRequestClient,
   threadId: string,
   limit = REFERENCED_THREAD_TURN_LIMIT,
 ): Promise<TurnTranscriptSummary[]> {
@@ -208,13 +204,13 @@ function threadRollbackSnapshotFromAppServerResponse(response: ThreadRollbackRes
   };
 }
 
-export async function rollbackThread(client: ThreadRollbackClient, threadId: string, numTurns?: number): Promise<ThreadRollbackSnapshot> {
+export async function rollbackThread(client: AppServerRequestClient, threadId: string, numTurns?: number): Promise<ThreadRollbackSnapshot> {
   const response = await client.request("thread/rollback", { threadId, numTurns: numTurns ?? 1 });
   return threadRollbackSnapshotFromAppServerResponse(response);
 }
 
 export async function forkThread(
-  client: ThreadForkClient,
+  client: AppServerRequestClient,
   threadId: string,
   cwd: string,
   lastTurnId: string | null = null,
@@ -234,7 +230,7 @@ export interface EphemeralThreadForkSnapshot {
 }
 
 export async function forkEphemeralThread(
-  client: ThreadForkClient,
+  client: AppServerRequestClient,
   sourceThreadId: string,
   cwd: string,
 ): Promise<EphemeralThreadForkSnapshot> {
@@ -252,7 +248,7 @@ export async function forkEphemeralThread(
   };
 }
 
-export async function compactThread(client: ThreadCompactionClient, threadId: string): Promise<void> {
+export async function compactThread(client: AppServerRequestClient, threadId: string): Promise<void> {
   await client.request("thread/compact/start", { threadId });
 }
 
diff --git a/src/domain/runtime/permissions.ts b/src/domain/runtime/permissions.ts
index 00c7982f..804ac187 100644
--- a/src/domain/runtime/permissions.ts
+++ b/src/domain/runtime/permissions.ts
@@ -38,8 +38,11 @@ export interface RuntimePermissionState {
 }
 
 export interface RuntimePermissionKnownState {
+  /** True when the active-thread layer is authoritative, including an authoritative null meaning the detail was not reported. */
   readonly approvalPolicyKnown: boolean;
+  /** True prevents fallback to a different config profile's sandbox; null still displays as not reported. */
   readonly sandboxPolicyKnown: boolean;
+  /** True when the active profile identity, including an authoritative null, supersedes config fallback. */
   readonly permissionProfileKnown: boolean;
 }
 
diff --git a/src/features/chat/app-server/session-gateway.ts b/src/features/chat/app-server/session-gateway.ts
index 75b09920..dce46157 100644
--- a/src/features/chat/app-server/session-gateway.ts
+++ b/src/features/chat/app-server/session-gateway.ts
@@ -23,7 +23,7 @@ interface ChatThreadReferenceResolverOptions {
 export interface ChatAppServerGateway extends ChatSessionTransports, ChatMetadataTransports {
   clientAccess: AppServerClientAccess;
   connectionAvailable(): boolean;
-  readFileBase64(path: string, options?: { timeoutMs?: number }): Promise<string>;
+  readFileBase64(path: string, options?: { timeoutMs?: number }): Promise<string | null>;
   threadReferences(options: ChatThreadReferenceResolverOptions): ThreadReferenceResolver;
 }
 
@@ -70,9 +70,9 @@ async function readCurrentClientFileBase64(
   host: ChatAppServerGatewayHost,
   path: string,
   options: { timeoutMs?: number } = {},
-): Promise<string> {
+): Promise<string | null> {
   const client = host.currentClient();
-  if (!client) return "";
+  if (!client) return null;
   const response = await client.request("fs/readFile", { path }, options);
-  return host.currentClient() === client ? response.dataBase64 : "";
+  return host.currentClient() === client ? response.dataBase64 : null;
 }
diff --git a/src/features/chat/app-server/thread-reference-resolver.ts b/src/features/chat/app-server/thread-reference-resolver.ts
index 96ecb9c1..7f58ebd4 100644
--- a/src/features/chat/app-server/thread-reference-resolver.ts
+++ b/src/features/chat/app-server/thread-reference-resolver.ts
@@ -1,4 +1,5 @@
-import { readReferencedThreadTurnTranscriptSummaries, type TurnTranscriptSummaryClient } from "../../../app-server/services/threads";
+import type { AppServerRequestClient } from "../../../app-server/services/request-client";
+import { readReferencedThreadTurnTranscriptSummaries } from "../../../app-server/services/threads";
 import { type CodexInput, codexTextInputWithAttachments } from "../../../domain/chat/input";
 import { shortThreadId } from "../../../domain/threads/id";
 import type { Thread } from "../../../domain/threads/model";
@@ -7,7 +8,7 @@ import type { ComposerInputSnapshot } from "../application/composer/input-snapsh
 import type { ThreadReferenceInput } from "../application/turns/slash-command-execution";
 
 interface ThreadReferenceResolverHost {
-  currentClient(): TurnTranscriptSummaryClient | null;
+  currentClient(): AppServerRequestClient | null;
   prepareInput(text: string, snapshot: ComposerInputSnapshot): { text: string; input: CodexInput };
   addSystemMessage(text: string): void;
   setStatus(status: string): void;
diff --git a/src/features/chat/app-server/transports/session-transports.ts b/src/features/chat/app-server/transports/session-transports.ts
index 50ffdcbb..d2a6b5e6 100644
--- a/src/features/chat/app-server/transports/session-transports.ts
+++ b/src/features/chat/app-server/transports/session-transports.ts
@@ -45,9 +45,6 @@ interface ChatAppServerTransportHost extends ConnectedChatAppServerClientHost {
   vaultPath: string;
 }
 
-type ChatThreadHistoryClient = AppServerRequestClient;
-type ChatThreadResumeClient = AppServerRequestClient;
-
 interface AppServerThreadTurnsPage {
   readonly data: ThreadTurnsPage["turns"];
   readonly nextCursor: string | null;
@@ -244,7 +241,7 @@ async function withCurrentChatAppServerClient<T>(
 }
 
 async function readChatThreadHistoryPage(
-  client: ChatThreadHistoryClient,
+  client: AppServerRequestClient,
   threadId: string,
   cursor: string | null,
   limit = 20,
@@ -260,7 +257,7 @@ function chatThreadHistoryPageFromTurnsPage(page: ThreadTurnsPage): ThreadHistor
   };
 }
 
-async function resumeChatThread(client: ChatThreadResumeClient, threadId: string, cwd: string): Promise<ThreadResumeSnapshot> {
+async function resumeChatThread(client: AppServerRequestClient, threadId: string, cwd: string): Promise<ThreadResumeSnapshot> {
   const response = await resumeThread(client, threadId, cwd);
   return {
     activation: threadActivationSnapshotFromAppServerResponse(response),
diff --git a/tests/scripts/grit-policy.test.mjs b/tests/scripts/grit-policy.test.mjs
index 9121caf4..376c4579 100644
--- a/tests/scripts/grit-policy.test.mjs
+++ b/tests/scripts/grit-policy.test.mjs
@@ -96,6 +96,7 @@ describe("Biome Grit plugin wiring", () => {
       "**/src/**/*.{ts,tsx}",
       "!**/src/app-server/connection/**",
       "!**/src/app-server/protocol/server-requests.ts",
+      "!**/src/app-server/protocol/thread.ts",
       "!**/src/app-server/protocol/turn.ts",
     ]);
     expect(projectPluginIncludes("no-restricted-css-policy.grit")).toEqual(["**/src/styles/**/*.css"]);