diff --git a/src/config/schema/athena.test.ts b/src/config/schema/athena.test.ts
index b8838bdf..713c1504 100644
--- a/src/config/schema/athena.test.ts
+++ b/src/config/schema/athena.test.ts
@@ -111,6 +111,17 @@ describe("CouncilMemberSchema", () => {
     expect(parsed.variant).toBeUndefined()
     expect(parsed.name).toBeUndefined()
   })
+
+  test("rejects member config with unknown fields", () => {
+    //#given
+    const config = { model: "openai/gpt-5.3-codex", temperature: 0.2 }
+
+    //#when
+    const result = CouncilMemberSchema.safeParse(config)
+
+    //#then
+    expect(result.success).toBe(false)
+  })
 })
 
 describe("CouncilConfigSchema", () => {
diff --git a/src/config/schema/athena.ts b/src/config/schema/athena.ts
index ec9e135b..b6270b16 100644
--- a/src/config/schema/athena.ts
+++ b/src/config/schema/athena.ts
@@ -16,7 +16,7 @@ export const CouncilMemberSchema = z.object({
   model: ModelStringSchema,
   variant: z.string().optional(),
   name: z.string().optional(),
-})
+}).strict()
 
 export const CouncilConfigSchema = z.object({
   members: z.array(CouncilMemberSchema).min(2),
@@ -26,7 +26,3 @@ export const AthenaConfigSchema = z.object({
   model: z.string().optional(),
   council: CouncilConfigSchema,
 })
-
-export type CouncilMemberSchemaType = z.infer<typeof CouncilMemberSchema>
-export type CouncilConfigSchemaType = z.infer<typeof CouncilConfigSchema>
-export type AthenaConfigSchemaType = z.infer<typeof AthenaConfigSchema>