feat(agents): add agent override configuration support

- Add AgentName, AgentOverrideConfig, AgentOverrides types
- Implement createBuiltinAgents with disabled_agents and overrides support
- Support oh-my-opencode.json config for:
  - disabled_agents: disable specific built-in agents
  - agents: override model, temperature, tools, permission per agent
- Tools and permission objects are shallow-merged with base config
- Export types for external consumers
- Update README with agent override documentation

src/agents/index.ts

@@ -12,3 +12,6 @@ export const builtinAgents: Record<string, AgentConfig> = {
   "frontend-ui-ux-engineer": frontendUiUxEngineerAgent,
   "document-writer": documentWriterAgent,
 }
+
+export * from "./types"
+export { createBuiltinAgents } from "./utils"

src/agents/types.ts

@@ -0,0 +1,12 @@
+import type { AgentConfig } from "@opencode-ai/sdk"
+
+export type AgentName =
+  | "oracle"
+  | "librarian"
+  | "explore"
+  | "frontend-ui-ux-engineer"
+  | "document-writer"
+
+export type AgentOverrideConfig = Partial<AgentConfig>
+
+export type AgentOverrides = Partial<Record<AgentName, AgentOverrideConfig>>

src/agents/utils.ts

@@ -0,0 +1,55 @@
+import type { AgentConfig } from "@opencode-ai/sdk"
+import type { AgentName, AgentOverrideConfig, AgentOverrides } from "./types"
+import { oracleAgent } from "./oracle"
+import { librarianAgent } from "./librarian"
+import { exploreAgent } from "./explore"
+import { frontendUiUxEngineerAgent } from "./frontend-ui-ux-engineer"
+import { documentWriterAgent } from "./document-writer"
+
+const allBuiltinAgents: Record<AgentName, AgentConfig> = {
+  oracle: oracleAgent,
+  librarian: librarianAgent,
+  explore: exploreAgent,
+  "frontend-ui-ux-engineer": frontendUiUxEngineerAgent,
+  "document-writer": documentWriterAgent,
+}
+
+function mergeAgentConfig(
+  base: AgentConfig,
+  override: AgentOverrideConfig
+): AgentConfig {
+  return {
+    ...base,
+    ...override,
+    tools: override.tools !== undefined
+      ? { ...(base.tools ?? {}), ...override.tools }
+      : base.tools,
+    permission: override.permission !== undefined
+      ? { ...(base.permission ?? {}), ...override.permission }
+      : base.permission,
+  }
+}
+
+export function createBuiltinAgents(
+  disabledAgents: AgentName[] = [],
+  agentOverrides: AgentOverrides = {}
+): Record<string, AgentConfig> {
+  const result: Record<string, AgentConfig> = {}
+
+  for (const [name, config] of Object.entries(allBuiltinAgents)) {
+    const agentName = name as AgentName
+
+    if (disabledAgents.includes(agentName)) {
+      continue
+    }
+
+    const override = agentOverrides[agentName]
+    if (override) {
+      result[name] = mergeAgentConfig(config, override)
+    } else {
+      result[name] = config
+    }
+  }
+
+  return result
+}