fix(opencode): retry on 5xx errors from non-standard provider error types

Some API gateways throw non-APICallError errors with status codes in
varying shapes (error.status, error.statusCode, error.response.status,
or JSON-encoded in error.message). These were not being detected,
causing 5xx errors to be classified as UnknownError instead of
retryable APIError.

Add ErrorWithStatus interface and multi-path status code extraction
to the Error case in fromError(), with JSON message fallback.

Author: okuyam2y

packages/opencode/src/session/message-v2.ts

@@ -23,6 +23,14 @@ interface FetchDecompressionError extends Error {
   path: string
 }
 
+/** Optional HTTP status fields found on non-APICallError error objects from providers */
+interface ErrorWithStatus {
+  status?: number
+  statusCode?: number
+  response?: { status?: number; statusCode?: number }
+  message?: string
+}
+
 export namespace MessageV2 {
   export function isMedia(mime: string) {
     return mime.startsWith("image/") || mime === "application/pdf"
@@ -998,8 +1006,31 @@ export namespace MessageV2 {
           },
           { cause: e },
         ).toObject()
-      case e instanceof Error:
+      case e instanceof Error: {
+        // Non-APICallError with HTTP status — treat 5xx as retryable.
+        const typed = e as Error & ErrorWithStatus
+        const code =
+          typed.status ?? typed.statusCode ??
+          typed.response?.status ?? typed.response?.statusCode
+        if (typeof code === "number" && code >= 500)
+          return new MessageV2.APIError(
+            { message: errorMessage(e), statusCode: code, isRetryable: true },
+            { cause: e },
+          ).toObject()
+        // Fallback: status may be embedded in a JSON error message.
+        try {
+          const obj = JSON.parse(e.message) as ErrorWithStatus
+          const jsonCode = obj?.status ?? obj?.statusCode
+          if (typeof jsonCode === "number" && jsonCode >= 500) {
+            const msg = typeof obj?.message === "string" ? obj.message : errorMessage(e)
+            return new MessageV2.APIError(
+              { message: msg, statusCode: jsonCode, isRetryable: true },
+              { cause: e },
+            ).toObject()
+          }
+        } catch {}
         return new NamedError.Unknown({ message: errorMessage(e) }, { cause: e }).toObject()
+      }
       default:
         try {
           const parsed = ProviderError.parseStreamError(e)

packages/opencode/test/session/message-v2.test.ts

@@ -928,6 +928,67 @@ describe("session.message-v2.fromError", () => {
     })
   })
 
+  test("retries 5xx Error with statusCode property", () => {
+    const err = new Error("Internal Server Error")
+    ;(err as any).statusCode = 502
+
+    const result = MessageV2.fromError(err, { providerID })
+
+    expect(MessageV2.APIError.isInstance(result)).toBe(true)
+    expect((result as MessageV2.APIError).data.isRetryable).toBe(true)
+    expect((result as MessageV2.APIError).data.statusCode).toBe(502)
+  })
+
+  test("retries 5xx Error with status property", () => {
+    const err = new Error("Bad Gateway")
+    ;(err as any).status = 503
+
+    const result = MessageV2.fromError(err, { providerID })
+
+    expect(MessageV2.APIError.isInstance(result)).toBe(true)
+    expect((result as MessageV2.APIError).data.isRetryable).toBe(true)
+    expect((result as MessageV2.APIError).data.statusCode).toBe(503)
+  })
+
+  test("retries 5xx Error with response.status", () => {
+    const err = new Error("Gateway Timeout")
+    ;(err as any).response = { status: 504 }
+
+    const result = MessageV2.fromError(err, { providerID })
+
+    expect(MessageV2.APIError.isInstance(result)).toBe(true)
+    expect((result as MessageV2.APIError).data.isRetryable).toBe(true)
+    expect((result as MessageV2.APIError).data.statusCode).toBe(504)
+  })
+
+  test("retries 5xx from JSON-encoded Error message", () => {
+    const err = new Error(JSON.stringify({ statusCode: 500, message: "server error" }))
+
+    const result = MessageV2.fromError(err, { providerID })
+
+    expect(MessageV2.APIError.isInstance(result)).toBe(true)
+    expect((result as MessageV2.APIError).data.isRetryable).toBe(true)
+    expect((result as MessageV2.APIError).data.statusCode).toBe(500)
+    expect((result as MessageV2.APIError).data.message).toBe("server error")
+  })
+
+  test("does not retry 4xx Error", () => {
+    const err = new Error("Not Found")
+    ;(err as any).statusCode = 404
+
+    const result = MessageV2.fromError(err, { providerID })
+
+    expect(result.name).toBe("UnknownError")
+  })
+
+  test("does not retry Error without statusCode", () => {
+    const err = new Error("something went wrong")
+
+    const result = MessageV2.fromError(err, { providerID })
+
+    expect(result.name).toBe("UnknownError")
+  })
+
   test("classifies ZlibError from fetch as retryable APIError", () => {
     const zlibError = new Error(
       'ZlibError fetching "https://opencode.cloudflare.dev/anthropic/messages". For more information, pass `verbose: true` in the second argument to fetch()',