refactor(agents): unify Metis/Momus to use factory pattern

Convert static agent exports to factory functions for consistency:
- Metis: add createMetisAgent(model) factory function
- Update agentSources to use createMetisAgent, createMomusAgent

This ensures model overrides work consistently across all agents.

src/agents/metis.ts

@@ -278,16 +278,22 @@ const metisRestrictions = createAgentToolRestrictions([
   "sisyphus_task",
 ])
 
-export const metisAgent: AgentConfig = {
-  description:
-    "Pre-planning consultant that analyzes requests to identify hidden intentions, ambiguities, and AI failure points.",
-  mode: "subagent" as const,
-  model: "anthropic/claude-opus-4-5",
-  temperature: 0.3,
-  ...metisRestrictions,
-  prompt: METIS_SYSTEM_PROMPT,
-  thinking: { type: "enabled", budgetTokens: 32000 },
-} as AgentConfig
+const DEFAULT_MODEL = "anthropic/claude-opus-4-5"
+
+export function createMetisAgent(model: string = DEFAULT_MODEL): AgentConfig {
+  return {
+    description:
+      "Pre-planning consultant that analyzes requests to identify hidden intentions, ambiguities, and AI failure points.",
+    mode: "subagent" as const,
+    model,
+    temperature: 0.3,
+    ...metisRestrictions,
+    prompt: METIS_SYSTEM_PROMPT,
+    thinking: { type: "enabled", budgetTokens: 32000 },
+  } as AgentConfig
+}
+
+export const metisAgent: AgentConfig = createMetisAgent()
 
 export const metisPromptMetadata: AgentPromptMetadata = {
   category: "advisor",

src/agents/utils.ts

@@ -7,9 +7,9 @@ import { createExploreAgent, EXPLORE_PROMPT_METADATA } from "./explore"
 import { createFrontendUiUxEngineerAgent, FRONTEND_PROMPT_METADATA } from "./frontend-ui-ux-engineer"
 import { createDocumentWriterAgent, DOCUMENT_WRITER_PROMPT_METADATA } from "./document-writer"
 import { createMultimodalLookerAgent, MULTIMODAL_LOOKER_PROMPT_METADATA } from "./multimodal-looker"
-import { metisAgent } from "./metis"
+import { createMetisAgent } from "./metis"
 import { createOrchestratorSisyphusAgent, orchestratorSisyphusAgent } from "./orchestrator-sisyphus"
-import { momusAgent } from "./momus"
+import { createMomusAgent } from "./momus"
 import type { AvailableAgent } from "./sisyphus-prompt-builder"
 import { deepMerge } from "../shared"
 import { DEFAULT_CATEGORIES } from "../tools/sisyphus-task/constants"
@@ -25,8 +25,8 @@ const agentSources: Record<BuiltinAgentName, AgentSource> = {
   "frontend-ui-ux-engineer": createFrontendUiUxEngineerAgent,
   "document-writer": createDocumentWriterAgent,
   "multimodal-looker": createMultimodalLookerAgent,
-  "Metis (Plan Consultant)": metisAgent,
-  "Momus (Plan Reviewer)": momusAgent,
+  "Metis (Plan Consultant)": createMetisAgent,
+  "Momus (Plan Reviewer)": createMomusAgent,
   "orchestrator-sisyphus": orchestratorSisyphusAgent,
 }