diff --git a/apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.test.ts b/apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.test.ts
index 5f2caa3f3e26a..0c61165924917 100644
--- a/apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.test.ts
+++ b/apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.test.ts
@@ -1008,12 +1008,9 @@ describe("ClaudeAdapterV2 approval cancellation", () => {
         decision: ProviderApprovalDecision;
         feedback?: string;
       }>();
-      const controller = new AbortController();
-      controller.abort();
-
       const result = yield* ClaudeAdapterV2.awaitClaudeApprovalDecision(
         decision,
-        controller.signal,
+        AbortSignal.abort(),
       );
 
       assert.deepEqual(result, { decision: "cancel" });
@@ -1364,14 +1361,14 @@ describe("ClaudeAdapterV2 resume compaction", () => {
           Stream.runHead,
           Effect.forkScoped,
         );
-        const controller = new AbortController();
+        const signal = yield* Effect.abortSignal;
         const dialog = yield* Effect.promise(() =>
           callback!(
             {
               dialogKind: "resume_return",
               payload: { sessionAgeMinutes: 90, estimatedTokens: 120000 },
             },
-            { signal: controller.signal, requestId: "dialog-resume-1" },
+            { signal, requestId: "dialog-resume-1" },
           ),
         ).pipe(Effect.forkScoped);
         const event = yield* Fiber.join(requestEvent);
@@ -1387,8 +1384,6 @@ describe("ClaudeAdapterV2 resume compaction", () => {
         });
         assert.deepEqual(yield* Fiber.join(dialog), { behavior: "completed", result: "compact" });
 
-        const cancelledController = new AbortController();
-        cancelledController.abort();
         assert.deepEqual(
           yield* Effect.promise(() =>
             callback!(
@@ -1396,7 +1391,7 @@ describe("ClaudeAdapterV2 resume compaction", () => {
                 dialogKind: "resume_return",
                 payload: { sessionAgeMinutes: 90, estimatedTokens: 120000 },
               },
-              { signal: cancelledController.signal, requestId: "dialog-resume-2" },
+              { signal: AbortSignal.abort(), requestId: "dialog-resume-2" },
             ),
           ),
           { behavior: "cancelled" },
diff --git a/apps/server/src/orchestration-v2/Adapters/ClaudeAgentSdkQueryRunner.test.ts b/apps/server/src/orchestration-v2/Adapters/ClaudeAgentSdkQueryRunner.test.ts
index 2ba8f78c451b5..5723c488d8889 100644
--- a/apps/server/src/orchestration-v2/Adapters/ClaudeAgentSdkQueryRunner.test.ts
+++ b/apps/server/src/orchestration-v2/Adapters/ClaudeAgentSdkQueryRunner.test.ts
@@ -196,6 +196,7 @@ describe.skipIf(HostProcess.Platform.defaultValue() === "win32")("Claude CLI pro
         args: [],
         cwd: dir,
         env: process.env,
+        // @effect-diagnostics-next-line abortControllerInEffect:off - This crash fixture closes pipes itself; aborting on test teardown raises an unrelated process error.
         signal: new AbortController().signal,
       }) as NodeChildProcess.ChildProcess;
       yield* Effect.addFinalizer(() =>
diff --git a/apps/server/src/orchestration-v2/ClaudeAutomaticDelivery.integration.test.ts b/apps/server/src/orchestration-v2/ClaudeAutomaticDelivery.integration.test.ts
index 934805ac30fea..bde3af2c2aea9 100644
--- a/apps/server/src/orchestration-v2/ClaudeAutomaticDelivery.integration.test.ts
+++ b/apps/server/src/orchestration-v2/ClaudeAutomaticDelivery.integration.test.ts
@@ -139,6 +139,7 @@ it.effect.each(deliveries)(
         const sdkMessages = yield* Queue.unbounded<SDKMessage>();
         const offers: SDKUserMessage[] = [];
         const nativeQueue: SDKUserMessage[] = [];
+        // @effect-diagnostics-next-line abortControllerInEffect:off - The fake SDK interrupts its batch independently of the test fiber.
         const batchAbort = new AbortController();
         const adapter = yield* ClaudeAdapterV2.makeClaudeAdapterV2({
           instanceId: modelSelection.instanceId,
diff --git a/packages/provider-opencode/src/server/adapter.ts b/packages/provider-opencode/src/server/adapter.ts
index a81a1e65d8a91..c9f95ba6298ed 100644
--- a/packages/provider-opencode/src/server/adapter.ts
+++ b/packages/provider-opencode/src/server/adapter.ts
@@ -983,6 +983,7 @@ export const makeOpenCodeAdapterV2 = Effect.fn("makeOpenCodeAdapterV2")(function
           if (settledNativeRequestIds.size >= 2_048) settledNativeRequestIds.clear();
           settledNativeRequestIds.add(nativeRequestId);
         };
+        // @effect-diagnostics-next-line abortControllerInEffect:off - Session closure aborts this stream independently of the creation fiber.
         const abortController = new AbortController();
         let closing = false;
         let hasConnected = false;
@@ -3159,6 +3160,7 @@ export const makeOpenCodeAdapterV2 = Effect.fn("makeOpenCodeAdapterV2")(function
                 admissionMessageObserved: false,
                 idleDuringAdmission: false,
                 admissionSettled: Deferred.makeUnsafe<void>(),
+                // @effect-diagnostics-next-line abortControllerInEffect:off - Turn interruption owns prompt admission cancellation.
                 admissionAbortController: new AbortController(),
               };
               if (turn.admissionMessageId !== null)
@@ -3325,6 +3327,7 @@ export const makeOpenCodeAdapterV2 = Effect.fn("makeOpenCodeAdapterV2")(function
               turn.admissionMessageObserved = false;
               turn.idleDuringAdmission = false;
               turn.admissionSettled = Deferred.makeUnsafe<void>();
+              // @effect-diagnostics-next-line abortControllerInEffect:off - Steering replaces the admission request independently of this command fiber.
               turn.admissionAbortController = new AbortController();
               if (turn.admissionMessageId !== null)
                 turn.usage.promptMessageIds.add(turn.admissionMessageId);
diff --git a/tsconfig.base.json b/tsconfig.base.json
index d1e755d99c6be..b69040ba5c673 100644
--- a/tsconfig.base.json
+++ b/tsconfig.base.json
@@ -24,6 +24,7 @@
         "namespaceImportPackages": ["@effect/platform-node", "effect"],
         "effectFn": ["span", "inferred-span", "suggested-span"],
         "diagnosticSeverity": {
+          "abortControllerInEffect": "error",
           "runEffectInsideEffect": "error",
           "flatMapConditionalToFilterOrFail": "error",
           "catchConditionalRefailToCatchIf": "error",