fix: tighten lowercase helper typing

src/agents/pi-bundle-mcp-names.ts

@@ -33,7 +33,9 @@ export function sanitizeToolName(raw: string): string {
 
 export function normalizeReservedToolNames(names?: Iterable<string>): Set<string> {
   return new Set(
-    Array.from(names ?? [], (name) => normalizeOptionalLowercaseString(name)).filter(Boolean),
+    Array.from(names ?? [], (name) => normalizeOptionalLowercaseString(name)).filter(
+      (name): name is string => Boolean(name),
+    ),
   );
 }
 

src/agents/pi-embedded-runner/model.inline-provider.ts

@@ -75,7 +75,7 @@ function isLegacyFoundryVisionModelCandidate(params: {
   const normalizedCandidates = [params.modelId, params.modelName]
     .filter((value): value is string => typeof value === "string")
     .map((value) => normalizeOptionalLowercaseString(value))
-    .filter(Boolean);
+    .filter((value): value is string => Boolean(value));
   return normalizedCandidates.some(
     (candidate) =>
       candidate.startsWith("gpt-") ||

src/agents/tools/sessions-list-tool.ts

@@ -77,7 +77,7 @@ export function createSessionsListTool(opts?: {
 
       const kindsRaw = readStringArrayParam(params, "kinds")
         ?.map((value) => normalizeOptionalLowercaseString(value))
-        .filter(Boolean);
+        .filter((value): value is string => Boolean(value));
       const allowedKindsList = (kindsRaw ?? []).filter((value) =>
         ["main", "group", "cron", "hook", "node", "other"].includes(value),
       );