fix(core): preserve structured error messages (#33530)

packages/opencode/src/provider/provider.ts

@@ -1078,6 +1078,11 @@ export class ModelNotFoundError extends Schema.TaggedErrorClass<ModelNotFoundErr
   suggestions: Schema.optional(Schema.Array(Schema.String)),
   cause: Schema.optional(Schema.Defect()),
 }) {
+  override get message() {
+    const suggestions = this.suggestions?.length ? ` Did you mean: ${this.suggestions.join(", ")}?` : ""
+    return `Model not found: ${this.providerID}/${this.modelID}.${suggestions}`
+  }
+
   static isInstance(input: unknown): input is ModelNotFoundError {
     return input instanceof ModelNotFoundError
   }
@@ -1087,12 +1092,20 @@ export class InitError extends Schema.TaggedErrorClass<InitError>()("ProviderIni
   providerID: ProviderV2.ID,
   cause: Schema.optional(Schema.Defect()),
 }) {
+  override get message() {
+    return `Failed to initialize provider: ${this.providerID}`
+  }
+
   static isInstance(input: unknown): input is InitError {
     return input instanceof InitError
   }
 }
 
 export class NoProvidersError extends Schema.TaggedErrorClass<NoProvidersError>()("ProviderNoProvidersError", {}) {
+  override get message() {
+    return "No providers are available"
+  }
+
   static isInstance(input: unknown): input is NoProvidersError {
     return input instanceof NoProvidersError
   }
@@ -1101,6 +1114,10 @@ export class NoProvidersError extends Schema.TaggedErrorClass<NoProvidersError>(
 export class NoModelsError extends Schema.TaggedErrorClass<NoModelsError>()("ProviderNoModelsError", {
   providerID: ProviderV2.ID,
 }) {
+  override get message() {
+    return `No models are available for provider: ${this.providerID}`
+  }
+
   static isInstance(input: unknown): input is NoModelsError {
     return input instanceof NoModelsError
   }

packages/opencode/test/provider/provider.test.ts

@@ -1016,6 +1016,8 @@ it.instance("ModelNotFoundError includes suggestions for typos", () =>
       .pipe(Effect.flip)
     expect(error.suggestions).toBeDefined()
     expect((error.suggestions ?? []).length).toBeGreaterThan(0)
+    expect(error.message).toContain("Model not found: anthropic/claude-sonet-4")
+    expect(error.message).toContain("Did you mean:")
   }),
 )