refactor(cli): parse variants from model refs

packages/schema/src/model.ts

@@ -15,7 +15,27 @@ export const Ref = Schema.Struct({
   id: ID,
   providerID: Provider.ID,
   variant: VariantID.pipe(optional),
-}).annotate({ identifier: "Model.Ref" })
+})
+  .annotate({ identifier: "Model.Ref" })
+  .pipe(
+    statics((schema) => ({
+      parse: (input: string) => {
+        const providerEnd = input.indexOf("/")
+        if (providerEnd <= 0) throw new Error(`Invalid model reference: ${input}`)
+        const providerID = input.slice(0, providerEnd)
+        const variantStart = input.indexOf("#", providerEnd + 1)
+        const id = input.slice(providerEnd + 1, variantStart === -1 ? undefined : variantStart)
+        const variant = variantStart === -1 ? undefined : input.slice(variantStart + 1)
+        if (!id || providerID.includes("#") || (variant !== undefined && (!variant || variant.includes("#"))))
+          throw new Error(`Invalid model reference: ${input}`)
+        return schema.make({
+          providerID: Provider.ID.make(providerID),
+          id: ID.make(id),
+          ...(variant ? { variant: VariantID.make(variant) } : {}),
+        })
+      },
+    })),
+  )
 export interface Ref extends Schema.Schema.Type<typeof Ref> {}
 
 export const Family = Schema.String.pipe(Schema.brand("Model.Family"))

packages/schema/test/model.test.ts

@@ -0,0 +1,22 @@
+import { describe, expect, test } from "bun:test"
+import { Model } from "../src/model.js"
+
+describe("Model.Ref", () => {
+  test("parses model references with optional variants", () => {
+    const variant = Model.Ref.parse("openrouter/openai/gpt-5#high")
+    expect(String(variant.providerID)).toBe("openrouter")
+    expect(String(variant.id)).toBe("openai/gpt-5")
+    expect(String(variant.variant)).toBe("high")
+
+    const standard = Model.Ref.parse("anthropic/claude-sonnet")
+    expect(String(standard.providerID)).toBe("anthropic")
+    expect(String(standard.id)).toBe("claude-sonnet")
+    expect(standard.variant).toBeUndefined()
+  })
+
+  test("rejects malformed model references", () => {
+    expect(() => Model.Ref.parse("gpt-5")).toThrow()
+    expect(() => Model.Ref.parse("openai/gpt-5#")).toThrow()
+    expect(() => Model.Ref.parse("openai/gpt-5#high#extra")).toThrow()
+  })
+})