diff --git a/apps/cloud/src/mcp-session.e2e.node.test.ts b/apps/cloud/src/mcp-session.e2e.node.test.ts
index b0fb06992..d90d89ba3 100644
--- a/apps/cloud/src/mcp-session.e2e.node.test.ts
+++ b/apps/cloud/src/mcp-session.e2e.node.test.ts
@@ -146,10 +146,19 @@ const openSession = (
       return { client, clientTransport, serverTransport };
     }),
     ({ clientTransport, serverTransport }) =>
-      Effect.promise(async () => {
-        await clientTransport.close().catch(() => undefined);
-        await serverTransport.close().catch(() => undefined);
-      }),
+      Effect.all(
+        [
+          Effect.tryPromise({
+            try: () => clientTransport.close(),
+            catch: (cause) => cause,
+          }).pipe(Effect.ignore),
+          Effect.tryPromise({
+            try: () => serverTransport.close(),
+            catch: (cause) => cause,
+          }).pipe(Effect.ignore),
+        ],
+        { discard: true },
+      ),
   ).pipe(Effect.map(({ client }) => ({ client })));
 
 const nextOrgId = (() => {
diff --git a/apps/cloud/src/observability.ts b/apps/cloud/src/observability.ts
index ae9f624ae..6a3bde420 100644
--- a/apps/cloud/src/observability.ts
+++ b/apps/cloud/src/observability.ts
@@ -42,6 +42,7 @@ export const sentryPayloadForCause = (
   if (Cause.isCause(input)) {
     const pretty = Cause.pretty(input);
     const errors = Cause.prettyErrors(input);
+    // oxlint-disable-next-line executor/no-error-constructor -- boundary: Sentry captureException needs an Error-like primary payload for pretty Effect causes
     return { primary: errors[0] ?? new Error(pretty), pretty };
   }
   return { primary: input, pretty: null };
diff --git a/apps/cloud/src/org/handlers.ts b/apps/cloud/src/org/handlers.ts
index 6093fec02..8ec4d6014 100644
--- a/apps/cloud/src/org/handlers.ts
+++ b/apps/cloud/src/org/handlers.ts
@@ -1,5 +1,5 @@
 import { HttpApiBuilder } from "effect/unstable/httpapi";
-import { Effect } from "effect";
+import { Cause, Effect } from "effect";
 
 import { UserStoreService } from "../auth/context";
 import { AuthContext } from "../auth/middleware";
@@ -103,7 +103,7 @@ const reserveMemberSlot = Effect.gen(function* () {
     Effect.catchCause((cause) =>
       Effect.gen(function* () {
         yield* Effect.logError("members.seats lookup failed; failing closed").pipe(
-          Effect.annotateLogs({ "org.id": auth.organizationId, cause: String(cause) }),
+          Effect.annotateLogs({ "org.id": auth.organizationId, cause: Cause.pretty(cause) }),
         );
         return yield* new Forbidden();
       }),
diff --git a/apps/cloud/src/routes/billing_.plans.tsx b/apps/cloud/src/routes/billing_.plans.tsx
index ae95a4674..95e719786 100644
--- a/apps/cloud/src/routes/billing_.plans.tsx
+++ b/apps/cloud/src/routes/billing_.plans.tsx
@@ -346,6 +346,7 @@ function SlackContactCta() {
     }
     setSubmitting(true);
     setError(null);
+    // oxlint-disable-next-line executor/no-try-catch-or-throw -- boundary: browser fetch submit path maps network failures to public UI copy
     try {
       const res = await fetch("/api/contact/slack", {
         method: "POST",
@@ -358,7 +359,10 @@ function SlackContactCta() {
           turnstileToken,
         }),
       });
-      const data = (await res.json().catch(() => ({}))) as { url?: string; error?: string };
+      const data = (await res.json().then(
+        (value) => value,
+        () => ({}),
+      )) as { url?: string; error?: string };
       if (!res.ok) {
         setError(data.error ?? "Something went wrong. Please try again.");
         return;
diff --git a/apps/cloud/src/secrets-isolation.e2e.node.test.ts b/apps/cloud/src/secrets-isolation.e2e.node.test.ts
index 64773bf66..5973b522a 100644
--- a/apps/cloud/src/secrets-isolation.e2e.node.test.ts
+++ b/apps/cloud/src/secrets-isolation.e2e.node.test.ts
@@ -27,7 +27,7 @@
 // SDK-level change — coverage for it belongs after the fix.
 
 import { describe, expect, it } from "@effect/vitest";
-import { Effect } from "effect";
+import { Effect, Result } from "effect";
 
 import { ScopeId, SecretId } from "@executor-js/sdk";
 
@@ -237,7 +237,7 @@ describe("cloud secret isolation (HTTP, user-org scope stack)", () => {
           })
           .pipe(Effect.result),
       );
-      expect(result._tag).toBe("Failure");
+      expect(Result.isFailure(result)).toBe(true);
 
       // And nothing landed in the foreign org — a fresh session pointed
       // at that org must not see `wrong-scope`.
diff --git a/apps/cloud/src/services/__test-harness__/api-harness.ts b/apps/cloud/src/services/__test-harness__/api-harness.ts
index 4ae4d5ff5..6fc3587cc 100644
--- a/apps/cloud/src/services/__test-harness__/api-harness.ts
+++ b/apps/cloud/src/services/__test-harness__/api-harness.ts
@@ -135,6 +135,7 @@ const TestExecutionStackMiddleware = HttpRouter.middleware<{
         const request = yield* HttpServerRequest.HttpServerRequest;
         const orgId = request.headers[TEST_ORG_HEADER];
         if (!orgId || typeof orgId !== "string") {
+          // oxlint-disable-next-line executor/no-effect-escape-hatch, executor/no-error-constructor -- boundary: test HTTP harness has no request context without x-test-org-id
           return yield* Effect.die(new Error("missing x-test-org-id"));
         }
         const userHeader = request.headers[TEST_USER_HEADER];
diff --git a/apps/cloud/src/services/secrets-api.node.test.ts b/apps/cloud/src/services/secrets-api.node.test.ts
index 97214f41b..c07150e75 100644
--- a/apps/cloud/src/services/secrets-api.node.test.ts
+++ b/apps/cloud/src/services/secrets-api.node.test.ts
@@ -2,7 +2,7 @@
 // and error fidelity within a single org.
 
 import { describe, expect, it } from "@effect/vitest";
-import { Effect } from "effect";
+import { Effect, Result } from "effect";
 
 import { ScopeId, SecretId } from "@executor-js/sdk";
 
@@ -128,7 +128,7 @@ describe("secrets api (HTTP)", () => {
           .remove({ params: { scopeId: ScopeId.make(org), secretId: SecretId.make(missing) } })
           .pipe(Effect.result),
       );
-      expect(result._tag).toBe("Success");
+      expect(Result.isSuccess(result)).toBe(true);
     }),
   );
 
diff --git a/apps/cloud/src/services/sources-refresh.node.test.ts b/apps/cloud/src/services/sources-refresh.node.test.ts
index c6ee73334..fd0a6cfd7 100644
--- a/apps/cloud/src/services/sources-refresh.node.test.ts
+++ b/apps/cloud/src/services/sources-refresh.node.test.ts
@@ -84,9 +84,12 @@ const serveMutableSpec = () => {
 
 describe("sources.refresh (HTTP)", () => {
   it.effect("addSpec from URL → canRefresh:true; refresh re-fetches and updates tools", () =>
-    Effect.gen(function* () {
-      const server = yield* Effect.promise(() => serveMutableSpec());
-      try {
+    Effect.scoped(
+      Effect.gen(function* () {
+        const server = yield* Effect.acquireRelease(
+          Effect.promise(() => serveMutableSpec()),
+          (server) => Effect.promise(() => server.close()),
+        );
         const org = `org_${crypto.randomUUID()}`;
         const namespace = `ns_${crypto.randomUUID().replace(/-/g, "_")}`;
 
@@ -139,10 +142,8 @@ describe("sources.refresh (HTTP)", () => {
         expect(afterTools.length).toBe(2);
         expect(afterTools.some((t) => t.name.startsWith("ping"))).toBe(true);
         expect(afterTools.some((t) => t.name.startsWith("pong"))).toBe(true);
-      } finally {
-        yield* Effect.promise(() => server.close());
-      }
-    }),
+      }),
+    ),
   );
 
   it.effect("addSpec from raw text → canRefresh:false; refresh is a no-op", () =>
diff --git a/apps/cloud/vitest.config.ts b/apps/cloud/vitest.config.ts
index 460cd46b8..68be4ca21 100644
--- a/apps/cloud/vitest.config.ts
+++ b/apps/cloud/vitest.config.ts
@@ -17,6 +17,7 @@ export default defineConfig({
     // the socket is closing anyway — so filter it out rather than fail
     // the run with noise.
     onUnhandledError(error) {
+      // oxlint-disable-next-line executor/no-unknown-error-message -- boundary: Vitest unhandled-error hook receives unknown host errors
       if (error && (error as Error).message === "Stream was cancelled.") {
         return false;
       }