diff --git a/src/hooks/ralph-loop/completion-promise-detector-test-input.ts b/src/hooks/ralph-loop/completion-promise-detector-test-input.test.ts
similarity index 75%
rename from src/hooks/ralph-loop/completion-promise-detector-test-input.ts
rename to src/hooks/ralph-loop/completion-promise-detector-test-input.test.ts
index 4a1e6c259..07b517667 100644
--- a/src/hooks/ralph-loop/completion-promise-detector-test-input.ts
+++ b/src/hooks/ralph-loop/completion-promise-detector-test-input.test.ts
@@ -16,8 +16,8 @@ export function createPluginInput(messages: SessionMessage[]): PluginInput {
 		$: {} as PluginInput["$"],
 	} as PluginInput
 
-	pluginInput.client.session.messages =
-		(async () => ({ data: messages })) as unknown as PluginInput["client"]["session"]["messages"]
+	const messagesFunction = testCoerce<PluginInput["client"]["session"]["messages"]>(async () => ({ data: messages }))
+	pluginInput.client.session.messages = messagesFunction
 
 	return pluginInput
 }
diff --git a/src/hooks/ralph-loop/completion-promise-detector.test.ts b/src/hooks/ralph-loop/completion-promise-detector.test.ts
index d59151a7b..2241ddcd0 100644
--- a/src/hooks/ralph-loop/completion-promise-detector.test.ts
+++ b/src/hooks/ralph-loop/completion-promise-detector.test.ts
@@ -1,7 +1,7 @@
 /// <reference types="bun-types" />
 import { describe, expect, test } from "bun:test"
 import { detectCompletionInSessionMessages } from "./completion-promise-detector"
-import { createPluginInput } from "./completion-promise-detector-test-input"
+import { createPluginInput } from "./completion-promise-detector-test-input.test"
 
 describe("detectCompletionInSessionMessages", () => {
   describe("#given session with prior DONE and new messages", () => {
diff --git a/src/hooks/ralph-loop/completion-promise-session-negative.test.ts b/src/hooks/ralph-loop/completion-promise-session-negative.test.ts
index 7acd7f879..d33059e05 100644
--- a/src/hooks/ralph-loop/completion-promise-session-negative.test.ts
+++ b/src/hooks/ralph-loop/completion-promise-session-negative.test.ts
@@ -1,7 +1,7 @@
 /// <reference types="bun-types" />
 import { describe, expect, test } from "bun:test"
 import { detectCompletionInSessionMessages } from "./completion-promise-detector"
-import { createPluginInput } from "./completion-promise-detector-test-input"
+import { createPluginInput } from "./completion-promise-detector-test-input.test"
 
 describe("detectCompletionInSessionMessages negative cases", () => {
 	describe("#given natural language completion text without explicit promise", () => {
diff --git a/src/hooks/ralph-loop/reset-strategy-race-condition.test.ts b/src/hooks/ralph-loop/reset-strategy-race-condition.test.ts
index 15de66084..9713d45fd 100644
--- a/src/hooks/ralph-loop/reset-strategy-race-condition.test.ts
+++ b/src/hooks/ralph-loop/reset-strategy-race-condition.test.ts
@@ -44,7 +44,7 @@ describe("ralph-loop reset strategy race condition", () => {
     const selectSessionDeferred = createDeferred()
 
     const hook = createRalphLoopHook(
-      {
+      testCoerce<Parameters<typeof createRalphLoopHook>[0]>({
         directory: process.cwd(),
         client: {
           session: {
@@ -86,7 +86,7 @@ describe("ralph-loop reset strategy race condition", () => {
             },
           },
         },
-      } as unknown as Parameters<typeof createRalphLoopHook>[0],
+      }),
       { idleSettleMs: 0 },
     )
 
diff --git a/src/hooks/ralph-loop/ulw-loop-verification.test.ts b/src/hooks/ralph-loop/ulw-loop-verification.test.ts
index 54041f452..d0bc564c8 100644
--- a/src/hooks/ralph-loop/ulw-loop-verification.test.ts
+++ b/src/hooks/ralph-loop/ulw-loop-verification.test.ts
@@ -15,7 +15,7 @@ describe("ulw-loop verification", () => {
 	let oracleTranscriptPath: string
 
 	function createMockPluginInput() {
-		return {
+		return testCoerce<Parameters<typeof createRalphLoopHook>[0]>({
 			client: {
 				session: {
 					promptAsync: async (opts: { path: { id: string }; body: { parts: Array<{ type: string; text: string }> } }) => {
@@ -39,7 +39,7 @@ describe("ulw-loop verification", () => {
 				},
 			},
 			directory: testDir,
-		} as unknown as Parameters<typeof createRalphLoopHook>[0]
+		})
 	}
 
 	beforeEach(() => {