feat(config): add custom_agents overrides and strict agent validation

src/config/schema/agent-overrides.ts

@@ -1,5 +1,6 @@
 import { z } from "zod"
 import { FallbackModelsSchema } from "./fallback-models"
+import { OverridableAgentNameSchema } from "./agent-names"
 import { AgentPermissionSchema } from "./internal/permission"
 
 export const AgentOverrideConfigSchema = z.object({
@@ -55,7 +56,7 @@ export const AgentOverrideConfigSchema = z.object({
     .optional(),
 })
 
-export const AgentOverridesSchema = z.object({
+const BuiltinAgentOverridesSchema = z.object({
   build: AgentOverrideConfigSchema.optional(),
   plan: AgentOverrideConfigSchema.optional(),
   sisyphus: AgentOverrideConfigSchema.optional(),
@@ -70,7 +71,38 @@ export const AgentOverridesSchema = z.object({
   explore: AgentOverrideConfigSchema.optional(),
   "multimodal-looker": AgentOverrideConfigSchema.optional(),
   atlas: AgentOverrideConfigSchema.optional(),
-})
+}).strict()
+
+export const AgentOverridesSchema = BuiltinAgentOverridesSchema
+
+const RESERVED_CUSTOM_AGENT_NAMES = OverridableAgentNameSchema.options
+const RESERVED_CUSTOM_AGENT_NAME_SET = new Set(
+  RESERVED_CUSTOM_AGENT_NAMES.map((name) => name.toLowerCase()),
+)
+const RESERVED_CUSTOM_AGENT_NAME_PATTERN = new RegExp(
+  `^(?!(?:${RESERVED_CUSTOM_AGENT_NAMES.map((name) => name.replace(/[.*+?^${}()|[\]\\]/g, "\\$&")).join("|")})$).+`,
+)
+
+export const CustomAgentOverridesSchema = z
+  .record(
+    z.string().regex(
+      RESERVED_CUSTOM_AGENT_NAME_PATTERN,
+      "custom_agents key cannot reuse built-in agent override name",
+    ),
+    AgentOverrideConfigSchema,
+  )
+  .superRefine((value, ctx) => {
+    for (const key of Object.keys(value)) {
+      if (RESERVED_CUSTOM_AGENT_NAME_SET.has(key.toLowerCase())) {
+        ctx.addIssue({
+          code: z.ZodIssueCode.custom,
+          path: [key],
+          message: "custom_agents key cannot reuse built-in agent override name",
+        })
+      }
+    }
+  })
 
 export type AgentOverrideConfig = z.infer<typeof AgentOverrideConfigSchema>
 export type AgentOverrides = z.infer<typeof AgentOverridesSchema>
+export type CustomAgentOverrides = z.infer<typeof CustomAgentOverridesSchema>