feat: add model_candidates and /switch-model command for runtime model switching

script/build-schema.ts

@@ -1,15 +1,15 @@
 #!/usr/bin/env bun
 import * as z from "zod"
-import { zodToJsonSchema } from "zod-to-json-schema"
 import { OhMyOpenCodeConfigSchema } from "../src/config/schema"
 
 const SCHEMA_OUTPUT_PATH = "assets/oh-my-opencode.schema.json"
 
 async function main() {
   console.log("Generating JSON Schema...")
 
-  const jsonSchema = zodToJsonSchema(OhMyOpenCodeConfigSchema, {
-    target: "draft7",
+  const jsonSchema = z.toJSONSchema(OhMyOpenCodeConfigSchema, {
+    io: "input",
+    target: "draft-7",
   })
 
   const finalSchema = {

src/agents/agent-builder.ts

@@ -4,6 +4,7 @@ import type { CategoriesConfig, CategoryConfig, GitMasterConfig } from "../confi
 import type { BrowserAutomationProvider } from "../config/schema"
 import { mergeCategories } from "../shared/merge-categories"
 import { resolveMultipleSkills } from "../features/opencode-skill-loader/skill-content"
+import { getActiveModel } from "../features/model-switcher"
 
 export type AgentSource = AgentFactory | AgentConfig
 
@@ -17,9 +18,13 @@ export function buildAgent(
   categories?: CategoriesConfig,
   gitMasterConfig?: GitMasterConfig,
   browserProvider?: BrowserAutomationProvider,
-  disabledSkills?: Set<string>
+  disabledSkills?: Set<string>,
+  agentName?: string
 ): AgentConfig {
-  const base = isFactory(source) ? source(model) : { ...source }
+  const activeModel = agentName ? getActiveModel(agentName) : undefined
+  const effectiveModel = activeModel ?? model
+
+  const base = isFactory(source) ? source(effectiveModel) : { ...source }
   const categoryConfigs: Record<string, CategoryConfig> = mergeCategories(categories)
 
   const agentWithCategory = base as AgentConfig & { category?: string; skills?: string[]; variant?: string }

src/agents/atlas/agent.ts

@@ -17,6 +17,7 @@ import { buildCategorySkillsDelegationGuide } from "../dynamic-agent-prompt-buil
 import type { CategoryConfig } from "../../config/schema"
 import { mergeCategories } from "../../shared/merge-categories"
 import { createAgentToolRestrictions } from "../../shared/permission-compat"
+import { getActiveModel } from "../../features/model-switcher"
 
 import { getDefaultAtlasPrompt } from "./default"
 import { getGptAtlasPrompt } from "./gpt"
@@ -47,6 +48,7 @@ export interface OrchestratorContext {
   availableAgents?: AvailableAgent[]
   availableSkills?: AvailableSkill[]
   userCategories?: Record<string, CategoryConfig>
+  agentName?: string
 }
 
 /**
@@ -93,6 +95,9 @@ function buildDynamicOrchestratorPrompt(ctx?: OrchestratorContext): string {
 }
 
 export function createAtlasAgent(ctx: OrchestratorContext): AgentConfig {
+  const activeModel = ctx.agentName ? getActiveModel(ctx.agentName) : undefined
+  const effectiveModel = activeModel ?? ctx.model
+
   const restrictions = createAgentToolRestrictions([
     "task",
     "call_omo_agent",
@@ -102,7 +107,7 @@ export function createAtlasAgent(ctx: OrchestratorContext): AgentConfig {
     description:
       "Orchestrates work via task() to complete ALL tasks in a todo list until fully done. (Atlas - OhMyOpenCode)",
     mode: MODE,
-    ...(ctx.model ? { model: ctx.model } : {}),
+    ...(effectiveModel ? { model: effectiveModel } : {}),
     temperature: 0.1,
     prompt: buildDynamicOrchestratorPrompt(ctx),
     color: "#10B981",

src/agents/builtin-agents.ts

@@ -22,6 +22,7 @@ import { maybeCreateSisyphusConfig } from "./builtin-agents/sisyphus-agent"
 import { maybeCreateHephaestusConfig } from "./builtin-agents/hephaestus-agent"
 import { maybeCreateAtlasConfig } from "./builtin-agents/atlas-agent"
 import { buildCustomAgentMetadata, parseRegisteredAgentSummaries } from "./custom-agent-summaries"
+import { loadCandidates } from "../features/model-switcher"
 
 type AgentSource = AgentFactory | AgentConfig
 
@@ -67,6 +68,8 @@ export async function createBuiltinAgents(
   disabledSkills?: Set<string>,
   useTaskSystem = false
 ): Promise<Record<string, AgentConfig>> {
+  loadCandidates(agentOverrides)
+
   const connectedProviders = readConnectedProvidersCache()
   // IMPORTANT: Do NOT call OpenCode client APIs during plugin initialization.
   // This function is called from config handler, and calling client API causes deadlock.

src/agents/builtin-agents/atlas-agent.ts

@@ -52,6 +52,7 @@ export function maybeCreateAtlasConfig(input: {
     availableAgents,
     availableSkills,
     userCategories,
+    agentName: "atlas",
   })
 
   if (atlasResolvedVariant) {

src/agents/builtin-agents/general-agents.ts

@@ -73,7 +73,7 @@ export function collectPendingBuiltinAgents(input: {
     if (!resolution) continue
     const { model, variant: resolvedVariant } = resolution
 
-    let config = buildAgent(source, model, mergedCategories, gitMasterConfig, browserProvider, disabledSkills)
+    let config = buildAgent(source, model, mergedCategories, gitMasterConfig, browserProvider, disabledSkills, agentName)
 
     // Apply resolved variant from model fallback chain
     if (resolvedVariant) {

src/agents/builtin-agents/hephaestus-agent.ts

@@ -69,7 +69,8 @@ export function maybeCreateHephaestusConfig(input: {
     undefined,
     availableSkills,
     availableCategories,
-    useTaskSystem
+    useTaskSystem,
+    "hephaestus"
   )
 
   hephaestusConfig = { ...hephaestusConfig, variant: hephaestusResolvedVariant ?? "medium" }

src/agents/builtin-agents/sisyphus-agent.ts

@@ -70,7 +70,8 @@ export function maybeCreateSisyphusConfig(input: {
     undefined,
     availableSkills,
     availableCategories,
-    useTaskSystem
+    useTaskSystem,
+    "sisyphus"
   )
 
   if (sisyphusResolvedVariant) {

src/agents/hephaestus.ts

@@ -13,6 +13,7 @@ import {
   buildAntiPatternsSection,
   categorizeTools,
 } from "./dynamic-agent-prompt-builder"
+import { getActiveModel } from "../features/model-switcher"
 
 const MODE: AgentMode = "primary"
 
@@ -600,8 +601,10 @@ export function createHephaestusAgent(
   availableToolNames?: string[],
   availableSkills?: AvailableSkill[],
   availableCategories?: AvailableCategory[],
-  useTaskSystem = false
+  useTaskSystem = false,
+  agentName?: string
 ): AgentConfig {
+  const effectiveModel = agentName ? getActiveModel(agentName) ?? model : model
   const tools = availableToolNames ? categorizeTools(availableToolNames) : []
   const skills = availableSkills ?? []
   const categories = availableCategories ?? []
@@ -613,7 +616,7 @@ export function createHephaestusAgent(
     description:
       "Autonomous Deep Worker - goal-oriented execution with GPT 5.2 Codex. Explores thoroughly before acting, uses explore/librarian agents for comprehensive context, completes tasks end-to-end. Inspired by AmpCode deep mode. (Hephaestus - OhMyOpenCode)",
     mode: MODE,
-    model,
+    model: effectiveModel,
     maxTokens: 32000,
     prompt,
     color: "#D97706", // Forged Amber - Golden heated metal, divine craftsman

src/agents/sisyphus.ts

@@ -1,6 +1,7 @@
 import type { AgentConfig } from "@opencode-ai/sdk"
 import type { AgentMode, AgentPromptMetadata } from "./types"
 import { isGptModel } from "./types"
+import { getActiveModel } from "../features/model-switcher"
 
 const MODE: AgentMode = "primary"
 export const SISYPHUS_PROMPT_METADATA: AgentPromptMetadata = {
@@ -506,8 +507,10 @@ export function createSisyphusAgent(
   availableToolNames?: string[],
   availableSkills?: AvailableSkill[],
   availableCategories?: AvailableCategory[],
-  useTaskSystem = false
+  useTaskSystem = false,
+  agentName?: string
 ): AgentConfig {
+  const effectiveModel = agentName ? getActiveModel(agentName) ?? model : model
   const tools = availableToolNames ? categorizeTools(availableToolNames) : []
   const skills = availableSkills ?? []
   const categories = availableCategories ?? []
@@ -520,7 +523,7 @@ export function createSisyphusAgent(
     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: MODE,
-    model,
+    model: effectiveModel,
     maxTokens: 64000,
     prompt,
     color: "#00CED1",

src/config/schema/agent-overrides.ts

@@ -37,6 +37,8 @@ export const AgentOverrideConfigSchema = z.object({
   textVerbosity: z.enum(["low", "medium", "high"]).optional(),
   /** Provider-specific options. Passed directly to OpenCode SDK. */
   providerOptions: z.record(z.string(), z.unknown()).optional(),
+  /** Model candidates for fallback selection. */
+  model_candidates: z.array(z.string()).optional(),
 })
 
 export const AgentOverridesSchema = z.object({

src/config/schema/commands.ts

@@ -8,6 +8,8 @@ export const BuiltinCommandNameSchema = z.enum([
   "refactor",
   "start-work",
   "stop-continuation",
+  "handoff",
+  "switch-model",
 ])
 
 export type BuiltinCommandName = z.infer<typeof BuiltinCommandNameSchema>

src/features/builtin-commands/commands.ts

@@ -6,6 +6,7 @@ import { STOP_CONTINUATION_TEMPLATE } from "./templates/stop-continuation"
 import { REFACTOR_TEMPLATE } from "./templates/refactor"
 import { START_WORK_TEMPLATE } from "./templates/start-work"
 import { HANDOFF_TEMPLATE } from "./templates/handoff"
+import { SWITCH_MODEL_TEMPLATE } from "./templates/switch-model"
 
 const BUILTIN_COMMAND_DEFINITIONS: Record<BuiltinCommandName, Omit<CommandDefinition, "name">> = {
   "init-deep": {
@@ -94,6 +95,22 @@ $ARGUMENTS
 </user-request>`,
     argumentHint: "[goal]",
   },
+  "switch-model": {
+    description: "(builtin) Switch the active LLM model for a specific agent in the current session",
+    template: `<command-instruction>
+${SWITCH_MODEL_TEMPLATE}
+</command-instruction>
+
+<session-context>
+Session ID: $SESSION_ID
+Timestamp: $TIMESTAMP
+</session-context>
+
+<user-request>
+$ARGUMENTS
+</user-request>`,
+    argumentHint: "[agent] [model]",
+  },
 }
 
 export function loadBuiltinCommands(