From 5984a0ad0448cd34f4512995bf0c4cef2605f4a9 Mon Sep 17 00:00:00 2001
From: Ophir Lojkine <contact@ophir.dev>
Date: Thu, 8 Oct 2026 21:47:34 +0000
Subject: [PATCH] Enable Biome checks for async mistakes and import cycles

---
 CONTRIBUTING.md | 7 +++++++
 biome.json      | 8 +++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 252c86e9d..0d46ee99b 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -73,6 +73,13 @@ npm test # the check CI runs: biome, typecheck, and the frontend unit tests
 ```
 
 `npm test` checks the entire frontend codebase (html, css, js, ts).
+Biome also rejects promise-valued conditions and synchronous callbacks that discard
+promises (`noMisusedPromises`), awaiting synchronous values (`useAwaitThenable`),
+and runtime import cycles (`noImportCycles`). Type-only imports may form cycles.
+Keep async Playwright assertions and actions awaited or returned;
+`noPlaywrightMissingAwait` checks these even when TypeScript inference cannot
+follow the shared fixture's types. The promise and Playwright rules are in
+Biome's nursery group, so review their diagnostics when upgrading Biome.
 
 ## Testing
 
diff --git a/biome.json b/biome.json
index 5d53a9f58..0e5c22347 100644
--- a/biome.json
+++ b/biome.json
@@ -24,7 +24,13 @@
   "linter": {
     "rules": {
       "nursery": {
-        "noFloatingPromises": "error"
+        "noFloatingPromises": "error",
+        "noMisusedPromises": "error",
+        "useAwaitThenable": "error",
+        "noPlaywrightMissingAwait": "error"
+      },
+      "suspicious": {
+        "noImportCycles": "error"
       }
     }
   }