fix(coding-agent): allow model-level baseUrl override in models.json closes #1777

packages/coding-agent/src/core/model-registry.ts

@@ -70,6 +70,7 @@ const ModelDefinitionSchema = Type.Object({
 	id: Type.String({ minLength: 1 }),
 	name: Type.Optional(Type.String({ minLength: 1 })),
 	api: Type.Optional(Type.String({ minLength: 1 })),
+	baseUrl: Type.Optional(Type.String({ minLength: 1 })),
 	reasoning: Type.Optional(Type.Boolean()),
 	input: Type.Optional(Type.Array(Type.Union([Type.Literal("text"), Type.Literal("image")]))),
 	cost: Type.Optional(
@@ -469,15 +470,15 @@ export class ModelRegistry {
 					}
 				}
 
-				// baseUrl is validated to exist for providers with models
+				// Provider baseUrl is required when custom models are defined.
-				// Apply defaults for optional fields
+				// Individual models can override it with modelDef.baseUrl.
 				const defaultCost = { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 };
 				models.push({
 					id: modelDef.id,
 					name: modelDef.name ?? modelDef.id,
 					api: api as Api,
 					provider: providerName,
-					baseUrl: providerConfig.baseUrl!,
+					baseUrl: modelDef.baseUrl ?? providerConfig.baseUrl!,
 					reasoning: modelDef.reasoning ?? false,
 					input: (modelDef.input ?? ["text"]) as ("text" | "image")[],
 					cost: modelDef.cost ?? defaultCost,
@@ -682,6 +683,7 @@ export interface ProviderConfigInput {
 		id: string;
 		name: string;
 		api?: Api;
+		baseUrl?: string;
 		reasoning: boolean;
 		input: ("text" | "image")[];
 		cost: { input: number; output: number; cacheRead: number; cacheWrite: number };

packages/coding-agent/test/model-registry.test.ts

@@ -237,6 +237,43 @@ describe("ModelRegistry", () => {
 			}
 		});
 
+		test("model-level baseUrl overrides provider-level baseUrl for custom models", () => {
+			writeRawModelsJson({
+				"opencode-go": {
+					baseUrl: "https://opencode.ai/zen/go/v1",
+					apiKey: "TEST_KEY",
+					models: [
+						{
+							id: "minimax-m2.5",
+							api: "anthropic-messages",
+							baseUrl: "https://opencode.ai/zen/go",
+							reasoning: true,
+							input: ["text"],
+							cost: { input: 0.3, output: 1.2, cacheRead: 0.03, cacheWrite: 0 },
+							contextWindow: 204800,
+							maxTokens: 131072,
+						},
+						{
+							id: "glm-5",
+							api: "openai-completions",
+							reasoning: true,
+							input: ["text"],
+							cost: { input: 1, output: 3.2, cacheRead: 0.2, cacheWrite: 0 },
+							contextWindow: 204800,
+							maxTokens: 131072,
+						},
+					],
+				},
+			});
+
+			const registry = new ModelRegistry(authStorage, modelsJsonPath);
+			const m25 = registry.find("opencode-go", "minimax-m2.5");
+			const glm5 = registry.find("opencode-go", "glm-5");
+
+			expect(m25?.baseUrl).toBe("https://opencode.ai/zen/go");
+			expect(glm5?.baseUrl).toBe("https://opencode.ai/zen/go/v1");
+		});
+
 		test("modelOverrides still apply when provider also defines models", () => {
 			writeRawModelsJson({
 				openrouter: {