fix(agents): exclude subagents from UI model selection override

Subagents (explore, librarian, oracle, etc.) now use their own fallback
chain instead of inheriting the UI-selected model. This fixes the issue
where explore agent was incorrectly using Opus instead of Haiku.

- Add AgentMode type and static mode property to AgentFactory
- Each agent declares its own mode via factory.mode = MODE pattern
- createBuiltinAgents() checks source.mode before passing uiSelectedModel

src/agents/atlas.ts

@@ -1,5 +1,7 @@
 import type { AgentConfig } from "@opencode-ai/sdk"
-import type { AgentPromptMetadata } from "./types"
+import type { AgentMode, AgentPromptMetadata } from "./types"
+
+const MODE: AgentMode = "primary"
 import type { AvailableAgent, AvailableSkill, AvailableCategory } from "./dynamic-agent-prompt-builder"
 import { buildCategorySkillsDelegationGuide } from "./dynamic-agent-prompt-builder"
 import type { CategoryConfig } from "../config/schema"
@@ -530,7 +532,7 @@ export function createAtlasAgent(ctx: OrchestratorContext): AgentConfig {
   return {
     description:
       "Orchestrates work via delegate_task() to complete ALL tasks in a todo list until fully done. (Atlas - OhMyOpenCode)",
-    mode: "primary" as const,
+    mode: MODE,
     ...(ctx.model ? { model: ctx.model } : {}),
     temperature: 0.1,
     prompt: buildDynamicOrchestratorPrompt(ctx),
@@ -539,6 +541,7 @@ export function createAtlasAgent(ctx: OrchestratorContext): AgentConfig {
     ...restrictions,
   } as AgentConfig
 }
+createAtlasAgent.mode = MODE
 
 export const atlasPromptMetadata: AgentPromptMetadata = {
   category: "advisor",

src/agents/explore.ts

@@ -1,7 +1,9 @@
 import type { AgentConfig } from "@opencode-ai/sdk"
-import type { AgentPromptMetadata } from "./types"
+import type { AgentMode, AgentPromptMetadata } from "./types"
 import { createAgentToolRestrictions } from "../shared/permission-compat"
 
+const MODE: AgentMode = "subagent"
+
 export const EXPLORE_PROMPT_METADATA: AgentPromptMetadata = {
   category: "exploration",
   cost: "FREE",
@@ -34,7 +36,7 @@ export function createExploreAgent(model: string): AgentConfig {
   return {
     description:
       'Contextual grep for codebases. Answers "Where is X?", "Which file has Y?", "Find the code that does Z". Fire multiple in parallel for broad searches. Specify thoroughness: "quick" for basic, "medium" for moderate, "very thorough" for comprehensive analysis. (Explore - OhMyOpenCode)',
-    mode: "subagent" as const,
+    mode: MODE,
     model,
     temperature: 0.1,
     ...restrictions,
@@ -119,4 +121,4 @@ Use the right tool for the job:
 Flood with parallel calls. Cross-validate findings across multiple tools.`,
   }
 }
-
+createExploreAgent.mode = MODE

src/agents/librarian.ts

@@ -325,4 +325,4 @@ grep_app_searchGitHub(query: "useQuery")
 `,
   }
 }
-
+createLibrarianAgent.mode = MODE

src/agents/metis.ts

@@ -1,7 +1,9 @@
 import type { AgentConfig } from "@opencode-ai/sdk"
-import type { AgentPromptMetadata } from "./types"
+import type { AgentMode, AgentPromptMetadata } from "./types"
 import { createAgentToolRestrictions } from "../shared/permission-compat"
 
+const MODE: AgentMode = "subagent"
+
 /**
  * Metis - Plan Consultant Agent
  *
@@ -311,7 +313,7 @@ export function createMetisAgent(model: string): AgentConfig {
   return {
     description:
       "Pre-planning consultant that analyzes requests to identify hidden intentions, ambiguities, and AI failure points. (Metis - OhMyOpenCode)",
-    mode: "subagent" as const,
+    mode: MODE,
     model,
     temperature: 0.3,
     ...metisRestrictions,
@@ -319,7 +321,7 @@ export function createMetisAgent(model: string): AgentConfig {
     thinking: { type: "enabled", budgetTokens: 32000 },
   } as AgentConfig
 }
-
+createMetisAgent.mode = MODE
 
 export const metisPromptMetadata: AgentPromptMetadata = {
   category: "advisor",

src/agents/momus.ts

@@ -1,8 +1,10 @@
 import type { AgentConfig } from "@opencode-ai/sdk"
-import type { AgentPromptMetadata } from "./types"
+import type { AgentMode, AgentPromptMetadata } from "./types"
 import { isGptModel } from "./types"
 import { createAgentToolRestrictions } from "../shared/permission-compat"
 
+const MODE: AgentMode = "subagent"
+
 /**
  * Momus - Plan Reviewer Agent
  *
@@ -400,7 +402,7 @@ export function createMomusAgent(model: string): AgentConfig {
   const base = {
     description:
       "Expert reviewer for evaluating work plans against rigorous clarity, verifiability, and completeness standards. (Momus - OhMyOpenCode)",
-    mode: "subagent" as const,
+    mode: MODE,
     model,
     temperature: 0.1,
     ...restrictions,
@@ -413,7 +415,7 @@ export function createMomusAgent(model: string): AgentConfig {
 
   return { ...base, thinking: { type: "enabled", budgetTokens: 32000 } } as AgentConfig
 }
-
+createMomusAgent.mode = MODE
 
 export const momusPromptMetadata: AgentPromptMetadata = {
   category: "advisor",

src/agents/multimodal-looker.ts

@@ -1,7 +1,9 @@
 import type { AgentConfig } from "@opencode-ai/sdk"
-import type { AgentPromptMetadata } from "./types"
+import type { AgentMode, AgentPromptMetadata } from "./types"
 import { createAgentToolAllowlist } from "../shared/permission-compat"
 
+const MODE: AgentMode = "subagent"
+
 export const MULTIMODAL_LOOKER_PROMPT_METADATA: AgentPromptMetadata = {
   category: "utility",
   cost: "CHEAP",
@@ -15,7 +17,7 @@ export function createMultimodalLookerAgent(model: string): AgentConfig {
   return {
     description:
       "Analyze media files (PDFs, images, diagrams) that require interpretation beyond raw text. Extracts specific information or summaries from documents, describes visual content. Use when you need analyzed/extracted data rather than literal file contents. (Multimodal-Looker - OhMyOpenCode)",
-    mode: "subagent" as const,
+    mode: MODE,
     model,
     temperature: 0.1,
     ...restrictions,
@@ -53,4 +55,4 @@ Response rules:
 Your output goes straight to the main agent for continued work.`,
   }
 }
-
+createMultimodalLookerAgent.mode = MODE

src/agents/sisyphus.ts

@@ -1,5 +1,8 @@
 import type { AgentConfig } from "@opencode-ai/sdk"
+import type { AgentMode } from "./types"
 import { isGptModel } from "./types"
+
+const MODE: AgentMode = "primary"
 import type { AvailableAgent, AvailableTool, AvailableSkill, AvailableCategory } from "./dynamic-agent-prompt-builder"
 import {
   buildKeyTriggersSection,
@@ -434,7 +437,7 @@ export function createSisyphusAgent(
   const base = {
     description:
       "Powerful AI orchestrator. Plans obsessively with todos, assesses search complexity before exploration, delegates strategically via category+skills combinations. Uses explore for internal code (parallel-friendly), librarian for external docs. (Sisyphus - OhMyOpenCode)",
-    mode: "primary" as const,
+    mode: MODE,
     model,
     maxTokens: 64000,
     prompt,
@@ -448,3 +451,4 @@ export function createSisyphusAgent(
 
   return { ...base, thinking: { type: "enabled", budgetTokens: 32000 } }
 }
+createSisyphusAgent.mode = MODE

src/agents/types.ts

@@ -1,6 +1,20 @@
 import type { AgentConfig } from "@opencode-ai/sdk"
 
-export type AgentFactory = (model: string) => AgentConfig
+/**
+ * Agent mode determines UI model selection behavior:
+ * - "primary": Respects user's UI-selected model (sisyphus, atlas)
+ * - "subagent": Uses own fallback chain, ignores UI selection (oracle, explore, etc.)
+ * - "all": Available in both contexts (OpenCode compatibility)
+ */
+export type AgentMode = "primary" | "subagent" | "all"
+
+/**
+ * Agent factory function with static mode property.
+ * Mode is exposed as static property for pre-instantiation access.
+ */
+export type AgentFactory = ((model: string) => AgentConfig) & {
+  mode: AgentMode
+}
 
 /**
  * Agent category for grouping in Sisyphus prompt sections

src/agents/utils.ts

@@ -225,8 +225,10 @@ export async function createBuiltinAgents(
     const override = findCaseInsensitive(agentOverrides, agentName)
     const requirement = AGENT_MODEL_REQUIREMENTS[agentName]
     
+    const isPrimaryAgent = isFactory(source) && source.mode === "primary"
+    
     const resolution = resolveModelWithFallback({
-      uiSelectedModel,
+      uiSelectedModel: isPrimaryAgent ? uiSelectedModel : undefined,
       userModel: override?.model,
       fallbackChain: requirement?.fallbackChain,
       availableModels,