feat(hooks): add ultrawork-model-override hook for per-agent model swap

src/config/schema/agent-overrides.ts

@@ -32,6 +32,11 @@ export const AgentOverrideConfigSchema = z.object({
       budgetTokens: z.number().optional(),
     })
     .optional(),
+  /** Ultrawork model override configuration. */
+  ultrawork: z.object({
+    model: z.string(),
+    variant: z.string().optional(),
+  }).optional(),
   /** Reasoning effort level (OpenAI). Overrides category and default settings. */
   reasoningEffort: z.enum(["low", "medium", "high", "xhigh"]).optional(),
   /** Text verbosity level. */

src/config/schema/hooks.ts

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

src/hooks/index.ts

@@ -46,3 +46,5 @@ export { createPreemptiveCompactionHook } from "./preemptive-compaction";
 export { createTasksTodowriteDisablerHook } from "./tasks-todowrite-disabler";
 export { createWriteExistingFileGuardHook } from "./write-existing-file-guard";
 export { createHashlineReadEnhancerHook } from "./hashline-read-enhancer";
+
+export { createUltraworkModelOverrideHook } from "./ultrawork-model-override";

src/hooks/ultrawork-model-override/hook.ts

@@ -0,0 +1,83 @@
+import type { AgentOverrides } from "../../config"
+import { log } from "../../shared"
+import { getAgentConfigKey } from "../../shared/agent-display-names"
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === "object" && value !== null
+}
+
+function getUltraworkConfig(agents: AgentOverrides | undefined, configKey: string) {
+  if (!agents) return undefined
+
+  for (const [agentKey, override] of Object.entries(agents)) {
+    if (getAgentConfigKey(agentKey) === configKey) {
+      return override?.ultrawork
+    }
+  }
+
+  return undefined
+}
+
+export function createUltraworkModelOverrideHook(args: { agents?: AgentOverrides }) {
+  let didLogSpikeInput = false
+
+  return {
+    "chat.params": async (input: unknown, output: unknown): Promise<void> => {
+      if (!didLogSpikeInput) {
+        didLogSpikeInput = true
+
+        const inputRecord = isRecord(input) ? input : null
+        const messageRecord = isRecord(inputRecord?.message) ? inputRecord.message : null
+
+        log("ultrawork-model-override spike: raw chat.params input", {
+          inputType: typeof input,
+          outputType: typeof output,
+          hasMessage: messageRecord !== null,
+          messageKeys: messageRecord ? Object.keys(messageRecord) : [],
+          hasMessageModel: messageRecord ? "model" in messageRecord : false,
+          messageModelType: messageRecord ? typeof messageRecord.model : "undefined",
+        })
+      }
+
+      if (!isRecord(input)) return
+
+      const message = input.message
+      if (!isRecord(message)) return
+      if (message.variant !== "max") return
+
+      const agentName = input.agent
+      if (typeof agentName !== "string") return
+
+      const configKey = getAgentConfigKey(agentName)
+      const ultrawork = getUltraworkConfig(args.agents, configKey)
+      if (!ultrawork?.model) return
+
+      const separatorIndex = ultrawork.model.indexOf("/")
+      const providerID = separatorIndex === -1 ? ultrawork.model : ultrawork.model.slice(0, separatorIndex)
+      const modelID = separatorIndex === -1 ? "" : ultrawork.model.slice(separatorIndex + 1)
+
+      const previousModel = isRecord(message.model)
+        ? {
+            providerID:
+              typeof message.model.providerID === "string" ? message.model.providerID : undefined,
+            modelID: typeof message.model.modelID === "string" ? message.model.modelID : undefined,
+          }
+        : undefined
+
+      message.model = { providerID, modelID }
+
+      if (ultrawork.variant !== undefined) {
+        message.variant = ultrawork.variant
+      }
+
+      log("ultrawork-model-override: swapped model", {
+        sessionID: typeof input.sessionID === "string" ? input.sessionID : undefined,
+        agent: agentName,
+        configKey,
+        from: previousModel,
+        to: message.model,
+        variant: message.variant,
+      })
+    },
+  }
+}

src/hooks/ultrawork-model-override/index.ts

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

src/plugin-interface.ts

@@ -30,7 +30,11 @@ export function createPluginInterface(args: {
   return {
     tool: tools,
 
-    "chat.params": createChatParamsHandler({ anthropicEffort: hooks.anthropicEffort }),
+    "chat.params": async (input, output) => {
+      await hooks.ultraworkModelOverride?.["chat.params"]?.(input, output)
+      const handler = createChatParamsHandler({ anthropicEffort: hooks.anthropicEffort })
+      await handler(input, output)
+    },
 
     "chat.message": createChatMessageHandler({
       ctx,

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

@@ -25,6 +25,7 @@ import {
   createPreemptiveCompactionHook,
 } from "../../hooks"
 import { createAnthropicEffortHook } from "../../hooks/anthropic-effort"
+import { createUltraworkModelOverrideHook } from "../../hooks/ultrawork-model-override"
 import {
   detectExternalNotificationPlugin,
   getNotificationConflictWarning,
@@ -55,6 +56,7 @@ export type SessionHooks = {
   questionLabelTruncator: ReturnType<typeof createQuestionLabelTruncatorHook>
   taskResumeInfo: ReturnType<typeof createTaskResumeInfoHook>
   anthropicEffort: ReturnType<typeof createAnthropicEffortHook> | null
+  ultraworkModelOverride: ReturnType<typeof createUltraworkModelOverrideHook> | null
 }
 
 export function createSessionHooks(args: {
@@ -169,6 +171,10 @@ export function createSessionHooks(args: {
     ? safeHook("anthropic-effort", () => createAnthropicEffortHook())
     : null
 
+  const ultraworkModelOverride = isHookEnabled("ultrawork-model-override")
+    ? safeHook("ultrawork-model-override", () => createUltraworkModelOverrideHook({ agents: pluginConfig.agents }))
+    : null
+
   return {
     contextWindowMonitor,
     preemptiveCompaction,
@@ -191,5 +197,6 @@ export function createSessionHooks(args: {
     questionLabelTruncator,
     taskResumeInfo,
     anthropicEffort,
+    ultraworkModelOverride,
   }
 }