refactor(hooks): remove beast-mode system integration

Remove the beast-mode-system hook and all transform wiring so Copilot-specific prompt injection is fully eliminated from the runtime pipeline.

src/config/schema.test.ts

@@ -7,6 +7,7 @@ import {
   CategoryConfigSchema,
   ExperimentalConfigSchema,
   GitMasterConfigSchema,
+  HookNameSchema,
   OhMyOpenCodeConfigSchema,
 } from "./schema"
 
@@ -393,6 +394,19 @@ describe("BuiltinCategoryNameSchema", () => {
   })
 })
 
+describe("HookNameSchema", () => {
+  test("rejects removed beast-mode-system hook name", () => {
+    //#given
+    const input = "beast-mode-system"
+
+    //#when
+    const result = HookNameSchema.safeParse(input)
+
+    //#then
+    expect(result.success).toBe(false)
+  })
+})
+
 describe("Sisyphus-Junior agent override", () => {
   test("schema accepts agents['Sisyphus-Junior'] and retains the key after parsing", () => {
     // given

src/config/schema/hooks.ts

@@ -25,7 +25,6 @@ export const HookNameSchema = z.enum([
   "interactive-bash-session",
 
   "thinking-block-validator",
-  "beast-mode-system",
   "ralph-loop",
   "category-skill-reminder",
 

src/hooks/beast-mode-system/hook.test.ts

@@ -1,54 +0,0 @@
-import { describe, expect, test } from "bun:test"
-import { clearSessionModel, setSessionModel } from "../../shared/session-model-state"
-import { createBeastModeSystemHook, BEAST_MODE_SYSTEM_PROMPT } from "./hook"
-
-describe("beast-mode-system hook", () => {
-  test("injects beast mode prompt for copilot gpt-4.1", async () => {
-    //#given
-    const sessionID = "ses_beast"
-    setSessionModel(sessionID, { providerID: "github-copilot", modelID: "gpt-4.1" })
-    const hook = createBeastModeSystemHook()
-    const output = { system: [] as string[] }
-
-    //#when
-    await hook["experimental.chat.system.transform"]?.({ sessionID }, output)
-
-    //#then
-    expect(output.system[0]).toContain("Beast Mode")
-    expect(output.system[0]).toContain(BEAST_MODE_SYSTEM_PROMPT.trim().slice(0, 20))
-
-    clearSessionModel(sessionID)
-  })
-
-  test("does not inject for other models", async () => {
-    //#given
-    const sessionID = "ses_no_beast"
-    setSessionModel(sessionID, { providerID: "anthropic", modelID: "gpt-5.3-codex" })
-    const hook = createBeastModeSystemHook()
-    const output = { system: [] as string[] }
-
-    //#when
-    await hook["experimental.chat.system.transform"]?.({ sessionID }, output)
-
-    //#then
-    expect(output.system.length).toBe(0)
-
-    clearSessionModel(sessionID)
-  })
-
-  test("avoids duplicate insertion", async () => {
-    //#given
-    const sessionID = "ses_dupe"
-    setSessionModel(sessionID, { providerID: "github-copilot", modelID: "gpt-4.1" })
-    const hook = createBeastModeSystemHook()
-    const output = { system: [BEAST_MODE_SYSTEM_PROMPT] }
-
-    //#when
-    await hook["experimental.chat.system.transform"]?.({ sessionID }, output)
-
-    //#then
-    expect(output.system.length).toBe(1)
-
-    clearSessionModel(sessionID)
-  })
-})

src/hooks/beast-mode-system/hook.ts

@@ -1,31 +0,0 @@
-import { getSessionModel } from "../../shared/session-model-state"
-
-export const BEAST_MODE_SYSTEM_PROMPT = `Beast Mode (Copilot GPT-4.1)
-
-You are an autonomous coding agent. Execute the task end-to-end.
-- Make a brief plan, then act.
-- Prefer concrete edits and verification over speculation.
-- Run relevant tests when feasible.
-- Do not ask the user to perform actions you can do yourself.
-- If blocked, state exactly what is needed to proceed.
-- Keep responses concise and actionable.`
-
-function isBeastModeModel(model: { providerID: string; modelID: string } | undefined): boolean {
-  return model?.providerID === "github-copilot" && model.modelID === "gpt-4.1"
-}
-
-export function createBeastModeSystemHook() {
-  return {
-    "experimental.chat.system.transform": async (
-      input: { sessionID: string },
-      output: { system: string[] },
-    ): Promise<void> => {
-      const model = getSessionModel(input.sessionID)
-      if (!isBeastModeModel(model)) return
-
-      if (output.system.some((entry) => entry.includes("Beast Mode"))) return
-
-      output.system.unshift(BEAST_MODE_SYSTEM_PROMPT)
-    },
-  }
-}

src/hooks/beast-mode-system/index.ts

@@ -1 +0,0 @@
-export { createBeastModeSystemHook, BEAST_MODE_SYSTEM_PROMPT } from "./hook"

src/hooks/index.ts

@@ -49,5 +49,4 @@ export { createTasksTodowriteDisablerHook } from "./tasks-todowrite-disabler";
 export { createRuntimeFallbackHook, type RuntimeFallbackHook, type RuntimeFallbackOptions } from "./runtime-fallback";
 export { createWriteExistingFileGuardHook } from "./write-existing-file-guard";
 export { createHashlineReadEnhancerHook } from "./hashline-read-enhancer";
-export { createBeastModeSystemHook, BEAST_MODE_SYSTEM_PROMPT } from "./beast-mode-system";
 export { createJsonErrorRecoveryHook, JSON_ERROR_TOOL_EXCLUDE_LIST, JSON_ERROR_PATTERNS, JSON_ERROR_REMINDER } from "./json-error-recovery";

src/plugin-interface.ts

@@ -50,9 +50,7 @@ export function createPluginInterface(args: {
       hooks,
     }),
 
-    "experimental.chat.system.transform": createSystemTransformHandler({
+    "experimental.chat.system.transform": createSystemTransformHandler(),
-      hooks,
-    }),
 
     config: managers.configHandler,
 

src/plugin/hooks/create-transform-hooks.ts

@@ -5,7 +5,6 @@ import {
   createClaudeCodeHooksHook,
   createKeywordDetectorHook,
   createThinkingBlockValidatorHook,
-  createBeastModeSystemHook,
 } from "../../hooks"
 import {
   contextCollector,
@@ -18,7 +17,6 @@ export type TransformHooks = {
   keywordDetector: ReturnType<typeof createKeywordDetectorHook> | null
   contextInjectorMessagesTransform: ReturnType<typeof createContextInjectorMessagesTransformHook>
   thinkingBlockValidator: ReturnType<typeof createThinkingBlockValidatorHook> | null
-  beastModeSystem: ReturnType<typeof createBeastModeSystemHook> | null
 }
 
 export function createTransformHooks(args: {
@@ -65,19 +63,10 @@ export function createTransformHooks(args: {
       )
     : null
 
-  const beastModeSystem = isHookEnabled("beast-mode-system")
-    ? safeCreateHook(
-        "beast-mode-system",
-        () => createBeastModeSystemHook(),
-        { enabled: safeHookEnabled },
-      )
-    : null
-
   return {
     claudeCodeHooks,
     keywordDetector,
     contextInjectorMessagesTransform,
     thinkingBlockValidator,
-    beastModeSystem,
   }
 }

src/plugin/system-transform.ts

@@ -1,12 +1,6 @@
-import type { CreatedHooks } from "../create-hooks"
+export function createSystemTransformHandler(): (
-
+  input: { sessionID: string },
-export function createSystemTransformHandler(args: {
+  output: { system: string[] },
-  hooks: CreatedHooks
+) => Promise<void> {
-}): (input: { sessionID: string }, output: { system: string[] }) => Promise<void> {
+  return async (): Promise<void> => {}
-  return async (input, output): Promise<void> => {
-    await args.hooks.beastModeSystem?.["experimental.chat.system.transform"]?.(
-      input,
-      output,
-    )
-  }
 }