fix(ai): handle remaining provider failures

2026-07-21 10:16:03 +00:00 · 2026-07-17 14:41:53 -05:00
parent 7c655f6a61
commit 0eacf8d736
8 changed files with 332 additions and 40 deletions
@@ -3,6 +3,7 @@ export { Auth } from "./route/auth"
 export { Provider } from "./provider"
 export { ProviderPackage } from "./provider-package"
 export { classifyProviderFailure, isContextOverflow, isContextOverflowFailure } from "./provider-error"
+export type { ProviderFailure } from "./provider-error"
 export type {
  RouteModelInput,
  RouteRoutedModelInput,
@@ -1,6 +1,6 @@
 import { EventStreamCodec } from "@smithy/eventstream-codec"
 import { fromUtf8, toUtf8 } from "@smithy/util-utf8"
-import { Effect, Stream } from "effect"
+import { Effect, Option, Schema, Stream } from "effect"
 import { Framing } from "../route/framing"
 import { ProviderShared } from "./shared"

@@ -53,8 +53,13 @@ const consumeFrames = (route: string) => (state: FrameBufferState, chunk: Uint8A
      })
      cursor = { buffer: cursor.buffer, offset: cursor.offset + totalLength }

-      if (decoded.headers[":message-type"]?.value !== "event") continue
-      const eventType = decoded.headers[":event-type"]?.value
+      const messageType = decoded.headers[":message-type"]?.value
+      const eventType =
+        messageType === "event"
+          ? decoded.headers[":event-type"]?.value
+          : messageType === "exception"
+            ? decoded.headers[":exception-type"]?.value
+            : undefined
      if (typeof eventType !== "string") continue
      const payload = utf8.decode(decoded.body)
      if (!payload) continue
@@ -84,4 +89,52 @@ export const framing = (route: string): Framing.Definition<object> => ({
  frame: (bytes) => bytes.pipe(Stream.mapAccumEffect(() => initialFrameBuffer, consumeFrames(route))),
 })

+class StreamExceptionError extends Error {
+  constructor(
+    message: string,
+    readonly code: string,
+  ) {
+    super(message)
+  }
+}
+
+// The AI SDK Bedrock decoder ignores AWS exception frames before its language
+// model stream can expose them. Fail the byte stream first so the shared AI SDK
+// adapter can classify the transport error instead of accepting a false finish.
+export function monitorExceptions(response: Response) {
+  if (!response.body || !response.headers.get("content-type")?.includes("application/vnd.amazon.eventstream"))
+    return response
+  let state = initialFrameBuffer
+  const body = response.body.pipeThrough(
+    new TransformStream<Uint8Array, Uint8Array>({
+      transform(chunk, controller) {
+        state = appendChunk(state, chunk)
+        while (state.buffer.length - state.offset >= 4) {
+          const view = state.buffer.subarray(state.offset)
+          const totalLength = new DataView(view.buffer, view.byteOffset, view.byteLength).getUint32(0, false)
+          if (view.length < totalLength) break
+          const decoded = eventCodec.decode(view.subarray(0, totalLength))
+          state = { buffer: state.buffer, offset: state.offset + totalLength }
+          const exceptionType = decoded.headers[":exception-type"]?.value
+          if (decoded.headers[":message-type"]?.value === "exception" && typeof exceptionType === "string") {
+            const payload = Option.getOrUndefined(
+              Schema.decodeUnknownOption(Schema.UnknownFromJsonString)(utf8.decode(decoded.body)),
+            )
+            const message =
+              ProviderShared.isRecord(payload) && typeof payload.message === "string" ? payload.message : undefined
+            controller.error(new StreamExceptionError(message ?? `Bedrock ${exceptionType}`, exceptionType))
+            return
+          }
+        }
+        controller.enqueue(chunk)
+      },
+    }),
+  )
+  return new Response(body, {
+    headers: new Headers(response.headers),
+    status: response.status,
+    statusText: response.statusText,
+  })
+}
+
 export * as BedrockEventStream from "./bedrock-event-stream"
@@ -46,26 +46,40 @@ export const isContextOverflowFailure = (failure: unknown) =>
    : Schema.is(ProviderErrorEvent)(failure) && failure.classification === "context-overflow"

 const decodeJson = Schema.decodeUnknownOption(Schema.UnknownFromJsonString)
+const CONTENT_POLICY_CODES = new Set(["content_filter", "content_policy_violation", "safety"])
 const QUOTA_CODES = new Set(["insufficient_quota", "usage_not_included", "billing_error"])
+const RATE_LIMIT_CODES = new Set(["resource_exhausted", "throttlingexception", "too_many_requests"])
 const SERVER_CODES = new Set([
  "api_error",
+  "internal",
  "internal_error",
+  "internal_server_error",
  "internalserverexception",
  "modelstreamerrorexception",
+  "modeltimeoutexception",
  "overloaded_error",
+  "response_error",
  "server_error",
  "server_is_overloaded",
  "serviceunavailableexception",
 ])
 const INVALID_REQUEST_CODES = new Set([
+  "invalid_argument",
  "invalid_prompt",
  "invalid_request_error",
+  "model_not_found",
+  "not_found",
+  "not_found_error",
+  "resourcenotfoundexception",
  "request_too_large",
  "validationexception",
 ])
-const RATE_LIMIT_TEXT = /rate increased too quickly|rate[-_\s]?limit|too[_\s]?many[_\s]?requests/i
+const RATE_LIMIT_TEXT = /rate increased too quickly|rate[-_\s]?limit|throttl|too[_\s]?many[_\s]?requests/i
 const QUOTA_TEXT = /insufficient[-_\s]?quota|quota[-_\s]?exceeded/i
-const CONTENT_POLICY_TEXT = /content[-_\s]?policy|content_filter|safety/i
+const CONTENT_POLICY_TEXT =
+  /content[-_\s]?(?:filter|policy)|safety (?:filter|policy|rating)|blocked (?:by|due to) safety/i
+const INVALID_REQUEST_TEXT = /validation (?:error|exception)/i
+const SERVER_TEXT = /internal server error|service unavailable/i

 export interface ProviderFailure {
  readonly message: string
@@ -98,7 +112,8 @@ export function classifyProviderFailure(input: ProviderFailure): LLMError["reaso
      texts.some(isContextOverflow))
  )
    return new InvalidRequestReason({ ...common, classification: "context-overflow" })
-  if (texts.some((text) => CONTENT_POLICY_TEXT.test(text))) return new ContentPolicyReason(common)
+  if (codes.some((code) => CONTENT_POLICY_CODES.has(code)) || texts.some((text) => CONTENT_POLICY_TEXT.test(text)))
+    return new ContentPolicyReason(common)
  if (
    codes.some((code) => QUOTA_CODES.has(code)) ||
    (input.status === 429 && texts.some((text) => QUOTA_TEXT.test(text)))
@@ -106,12 +121,15 @@ export function classifyProviderFailure(input: ProviderFailure): LLMError["reaso
    return new QuotaExceededReason(common)
  if (input.status === 401) return new AuthenticationReason({ ...common, kind: "invalid" })
  if (input.status === 403) return new AuthenticationReason({ ...common, kind: "insufficient-permissions" })
-  if (codes.includes("authentication_error")) return new AuthenticationReason({ ...common, kind: "invalid" })
-  if (codes.includes("permission_error"))
-    return new AuthenticationReason({ ...common, kind: "insufficient-permissions" })
+  if (codes.some((code) => code === "authentication_error" || code === "unauthenticated"))
+    return new AuthenticationReason({ ...common, kind: "invalid" })
  if (
-    codes.some((code) => code.includes("rate_limit") || code === "too_many_requests" || code === "throttlingexception")
+    codes.some(
+      (code) => code === "accessdeniedexception" || code === "permission_error" || code === "permission_denied",
+    )
  )
+    return new AuthenticationReason({ ...common, kind: "insufficient-permissions" })
+  if (codes.some((code) => code.includes("rate_limit") || RATE_LIMIT_CODES.has(code)))
    return new RateLimitReason({
      ...common,
      retryAfterMs: input.retryAfterMs,
@@ -123,8 +141,12 @@ export function classifyProviderFailure(input: ProviderFailure): LLMError["reaso
      retryAfterMs: input.retryAfterMs,
      rateLimit: input.rateLimit,
    })
-  if (codes.some((code) => INVALID_REQUEST_CODES.has(code))) return new InvalidRequestReason(common)
-  if (codes.some((code) => SERVER_CODES.has(code) || code.includes("exhausted") || code.includes("unavailable")))
+  if (codes.some((code) => INVALID_REQUEST_CODES.has(code)) || texts.some((text) => INVALID_REQUEST_TEXT.test(text)))
+    return new InvalidRequestReason(common)
+  if (
+    codes.some((code) => SERVER_CODES.has(code) || code.includes("unavailable")) ||
+    texts.some((text) => SERVER_TEXT.test(text))
+  )
    return new ProviderInternalReason({
      ...common,
      status: input.status,
@@ -160,8 +182,15 @@ function providerCodes(value: string) {
  const error = isRecord(decoded.error) ? decoded.error : undefined
  const response = isRecord(decoded.response) ? decoded.response : undefined
  const responseError = isRecord(response?.error) ? response.error : undefined
-  return [decoded.code, decoded.status, error?.code, error?.type, error?.status, responseError?.code, responseError?.type]
-    .filter((value): value is string => typeof value === "string")
+  return [
+    decoded.code,
+    decoded.status,
+    error?.code,
+    error?.type,
+    error?.status,
+    responseError?.code,
+    responseError?.type,
+  ].filter((value): value is string => typeof value === "string")
 }

 function isRecord(value: unknown): value is Record<string, unknown> {
@@ -121,6 +121,7 @@ describe("RequestExecutor", () => {
      yield* classify("Request rate increased too quickly")
      yield* classify('{"type":"error","error":{"type":"too_many_requests"}}')
      yield* classify('{"type":"error","error":{"code":"rate_limit_exceeded"}}')
+      yield* classify('{"code":"resource_exhausted"}')
    }),
  )

@@ -135,7 +136,6 @@ describe("RequestExecutor", () => {
          expect(error.reason).toMatchObject({ _tag: "ProviderInternal" })
        }).pipe(Effect.provide(responsesLayer([new Response(body, { status: 400 })])))

-      yield* classify('{"code":"resource_exhausted"}')
      yield* classify('{"code":"service_unavailable"}')
    }),
  )
@@ -26,6 +26,14 @@ describe("provider error classification", () => {
    )
  })

+  test("does not treat incidental safety text as a content-policy failure", () => {
+    expect(classifyProviderFailure({ message: "Internal safety check failed", status: 500 })._tag).toBe(
+      "ProviderInternal",
+    )
+    expect(classifyProviderFailure({ message: "Blocked by safety policy", status: 400 })._tag).toBe("ContentPolicy")
+    expect(classifyProviderFailure({ message: "Blocked", status: 400, code: "SAFETY" })._tag).toBe("ContentPolicy")
+  })
+
  test("classifies V1 plain-text rate limit fallbacks", () => {
    expect(
      [
@@ -47,12 +55,48 @@ describe("provider error classification", () => {
    ).toEqual(["RateLimit", "RateLimit", "RateLimit", "RateLimit"])
  })

-  test("classifies V1 overloaded provider codes", () => {
+  test("classifies canonical provider retry codes", () => {
    expect(
      ['{"code":"resource_exhausted"}', '{"code":"service_unavailable"}'].map(
        (message) => classifyProviderFailure({ message })._tag,
      ),
-    ).toEqual(["ProviderInternal", "ProviderInternal"])
+    ).toEqual(["RateLimit", "ProviderInternal"])
+  })
+
+  test("keeps temporary per-minute quota wording retryable", () => {
+    expect(classifyProviderFailure({ message: "You exceeded your per-minute quota", status: 429 })._tag).toBe(
+      "RateLimit",
+    )
+  })
+
+  test("classifies canonical Google error codes", () => {
+    expect(
+      ["UNAUTHENTICATED", "PERMISSION_DENIED", "INVALID_ARGUMENT", "NOT_FOUND", "INTERNAL"].map(
+        (code) => classifyProviderFailure({ message: "Provider failed", code })._tag,
+      ),
+    ).toEqual(["Authentication", "Authentication", "InvalidRequest", "InvalidRequest", "ProviderInternal"])
+  })
+
+  test("classifies stripped Bedrock stream errors from their messages", () => {
+    expect(
+      ["Internal server error", "Throttling exception", "Validation error: invalid input"].map(
+        (message) => classifyProviderFailure({ message })._tag,
+      ),
+    ).toEqual(["ProviderInternal", "RateLimit", "InvalidRequest"])
+  })
+
+  test("classifies documented Bedrock exception codes", () => {
+    expect(
+      ["accessDeniedException", "modelTimeoutException", "resourceNotFoundException"].map(
+        (code) => classifyProviderFailure({ message: "Bedrock failed", code })._tag,
+      ),
+    ).toEqual(["Authentication", "ProviderInternal", "InvalidRequest"])
+  })
+
+  test("classifies Anthropic not-found stream errors as invalid requests", () => {
+    expect(classifyProviderFailure({ message: "Model unavailable", code: "not_found_error" })._tag).toBe(
+      "InvalidRequest",
+    )
  })

  test("classifies nested provider codes when a top-level code is also present", () => {
@@ -6,6 +6,7 @@ import { CacheHint, LLM, Message, ToolCallPart, ToolChoice } from "../../src"
 import { LLMClient } from "../../src/route"
 import { AmazonBedrock } from "../../src/providers"
 import * as BedrockConverse from "../../src/protocols/bedrock-converse"
+import { BedrockEventStream } from "../../src/protocols/bedrock-event-stream"
 import { it } from "../lib/effect"
 import { fixedResponse } from "../lib/http"
 import {
@@ -34,6 +35,16 @@ const eventFrame = (type: string, payload: object) =>
    body: utf8Encoder.encode(JSON.stringify(payload)),
  })

+const exceptionFrame = (type: string, payload: object) =>
+  codec.encode({
+    headers: {
+      ":message-type": { type: "string", value: "exception" },
+      ":exception-type": { type: "string", value: type },
+      ":content-type": { type: "string", value: "application/json" },
+    },
+    body: utf8Encoder.encode(JSON.stringify(payload)),
+  })
+
 const concat = (frames: ReadonlyArray<Uint8Array>) => {
  const total = frames.reduce((sum, frame) => sum + frame.length, 0)
  const out = new Uint8Array(total)
@@ -48,6 +59,8 @@ const concat = (frames: ReadonlyArray<Uint8Array>) => {
 const eventStreamBody = (...payloads: ReadonlyArray<readonly [string, object]>) =>
  concat(payloads.map(([type, payload]) => eventFrame(type, payload)))

+const exceptionStreamBody = (type: string, payload: object) => exceptionFrame(type, payload)
+
 // Override the default SSE content-type with the binary event-stream type so
 // the cassette layer treats the body as bytes when recording.
 const fixedBytes = (bytes: Uint8Array) =>
@@ -357,10 +370,10 @@ describe("Bedrock Converse route", () => {

  it.effect("classifies throttlingException as a rate limit", () =>
    Effect.gen(function* () {
-      const body = eventStreamBody(
-        ["messageStart", { role: "assistant" }],
-        ["throttlingException", { message: "Slow down" }],
-      )
+      const body = concat([
+        eventStreamBody(["messageStart", { role: "assistant" }]),
+        exceptionStreamBody("throttlingException", { message: "Slow down" }),
+      ])
      const error = yield* LLMClient.generate(baseRequest).pipe(Effect.provide(fixedBytes(body)), Effect.flip)

      expect(error.reason).toMatchObject({ _tag: "RateLimit", message: "Slow down" })
@@ -371,7 +384,7 @@ describe("Bedrock Converse route", () => {
    Effect.gen(function* () {
      const error = yield* LLMClient.generate(baseRequest).pipe(
        Effect.provide(
-          fixedBytes(eventStreamBody(["validationException", { message: "Input is too long for requested model" }])),
+          fixedBytes(exceptionStreamBody("validationException", { message: "Input is too long for requested model" })),
        ),
        Effect.flip,
      )
@@ -384,6 +397,35 @@ describe("Bedrock Converse route", () => {
    }),
  )

+  it.effect("fails monitored AI SDK bodies on exception wire frames", () =>
+    Effect.gen(function* () {
+      const response = BedrockEventStream.monitorExceptions(
+        new Response(exceptionStreamBody("throttlingException", { message: "Slow down" }), {
+          headers: { "content-type": "application/vnd.amazon.eventstream" },
+        }),
+      )
+      const error = yield* Effect.tryPromise({
+        try: () => response.arrayBuffer(),
+        catch: (error) => error,
+      }).pipe(Effect.flip)
+
+      expect(error).toMatchObject({ code: "throttlingException", message: "Slow down" })
+    }),
+  )
+
+  it.effect("classifies serviceUnavailableException wire frames as provider failures", () =>
+    Effect.gen(function* () {
+      const error = yield* LLMClient.generate(baseRequest).pipe(
+        Effect.provide(
+          fixedBytes(exceptionStreamBody("serviceUnavailableException", { message: "Service unavailable" })),
+        ),
+        Effect.flip,
+      )
+
+      expect(error.reason).toMatchObject({ _tag: "ProviderInternal", message: "Service unavailable" })
+    }),
+  )
+
  it.effect("rejects requests with no auth path", () =>
    Effect.gen(function* () {
      const unsignedModel = AmazonBedrock.configure({
@@ -47,6 +47,7 @@ import {
  type UsageInput,
 } from "@opencode-ai/ai"
 import { Auth, Endpoint, type AnyRoute } from "@opencode-ai/ai/route"
+import { BedrockEventStream } from "@opencode-ai/ai/protocols/bedrock-event-stream"
 import { Cause, Context, Effect, Layer, Option, Schema, Scope, Stream } from "effect"
 import { ModelV2 } from "./model"
 import { ProviderV2 } from "./provider"
@@ -172,8 +173,9 @@ function prepareOptions(model: ModelV2.Info, pkg: string) {
      ...opts,
      timeout: false,
    })
-    if (!chunkAbortCtl || typeof chunkTimeout !== "number") return res
-    return wrapSSE(res, chunkTimeout, chunkAbortCtl)
+    const response = pkg === "@ai-sdk/amazon-bedrock" ? BedrockEventStream.monitorExceptions(res) : res
+    if (!chunkAbortCtl || typeof chunkTimeout !== "number") return response
+    return wrapSSE(response, chunkTimeout, chunkAbortCtl)
  }

  return options
@@ -739,10 +741,12 @@ function llmError(method: string, error: unknown) {
  const cause = error instanceof Error ? error.cause : undefined
  const failures = [error, cause]
  const code = failures.map(machineCode).find((value) => value !== undefined)
+  const providerCode = apiFailureCode(error)?.toLowerCase()
  const reason = (() => {
    if (
      error instanceof ChunkTimeoutError ||
      failures.some((failure) => failure instanceof Error && failure.name === "TimeoutError") ||
+      providerCode === "timeout_error" ||
      (code !== undefined && TRANSPORT_TIMEOUT_CODES.has(code))
    )
      return new TransportReason({ message: errorMessage(error), kind: code ?? "Timeout" })
@@ -751,8 +755,7 @@ function llmError(method: string, error: unknown) {
      return new TransportReason({ message: errorMessage(error), kind: code })
    const malformed = failures.find(isMalformedError)
    if (malformed) return new InvalidProviderOutputReason({ message: malformed.message })
-    if (LoadAPIKeyError.isInstance(error))
-      return new AuthenticationReason({ message: error.message, kind: "missing" })
+    if (LoadAPIKeyError.isInstance(error)) return new AuthenticationReason({ message: error.message, kind: "missing" })
    if (NoSuchModelError.isInstance(error)) return new InvalidRequestReason({ message: error.message })
    if (
      LoadSettingError.isInstance(error) ||
@@ -780,12 +783,13 @@ function apiCallReason(error: APICallError) {
  const malformed = isMalformedError(error.cause) ? error.cause : undefined
  if (error.statusCode !== undefined && error.statusCode < 400 && malformed)
    return new InvalidProviderOutputReason({ message: malformed.message })
-  const code = apiFailureCode(error.data) ?? apiFailureCode(error.responseBody)
+  const evidence = apiFailureEvidence(error.responseBody)
+  const code = apiFailureCode(error.data) ?? apiFailureCode(evidence)
  if (error.statusCode === undefined) {
    const reason =
-      code === undefined && error.responseBody === undefined
+      code === undefined && evidence === undefined
        ? undefined
-        : classifyProviderFailure({ message: error.message, code, evidence: error.responseBody })
+        : classifyProviderFailure({ message: error.message, code, evidence })
    if (reason && reason._tag !== "UnknownProvider") return reason
    if (error.isRetryable) return new TransportReason({ message: error.message })
    return reason ?? new UnknownProviderReason({ message: error.message })
@@ -793,16 +797,13 @@ function apiCallReason(error: APICallError) {
  const retryAfter = retryAfterMs(error.responseHeaders)
  const reason = classifyProviderFailure({
    message: error.message,
-    evidence: error.responseBody,
+    evidence,
    status: error.statusCode,
    code,
    retryAfterMs: retryAfter,
  })
  if (!error.isRetryable || (reason._tag !== "UnknownProvider" && reason._tag !== "InvalidRequest")) return reason
-  if (
-    classifyProviderFailure({ message: error.message, evidence: error.responseBody, code })._tag !== "UnknownProvider"
-  )
-    return reason
+  if (classifyProviderFailure({ message: error.message, evidence, code })._tag !== "UnknownProvider") return reason
  return new ProviderInternalReason({ message: error.message, status: error.statusCode, retryAfterMs: retryAfter })
 }

@@ -825,6 +826,7 @@ const TRANSPORT_CONNECTION_CODES = new Set([
  "FAILEDTOOPENSOCKET",
  "UND_ERR_SOCKET",
 ])
+const FAILURE_EVIDENCE_LIMIT = 65_536

 function field(error: unknown, name: string) {
  return typeof error === "object" && error !== null ? Reflect.get(error, name) : undefined
@@ -843,6 +845,8 @@ function apiFailureCode(error: unknown): string | undefined {
  const nested = field(error, "error") ?? field(field(error, "response"), "error")
  const nestedCode = nested === undefined || nested === error ? undefined : apiFailureCode(nested)
  if (nestedCode) return nestedCode
+  if (typeof field(error, "originalMessage") === "string" && typeof field(error, "originalStatusCode") === "number")
+    return "modelstreamerrorexception"
  const code = field(error, "code")
  if (typeof code === "string" || typeof code === "number") return String(code)
  const status = field(error, "status")
@@ -854,14 +858,18 @@ function apiFailureCode(error: unknown): string | undefined {
 function apiFailureMessage(error: unknown): string {
  const message = field(error, "message")
  if (typeof message === "string") return message
+  const originalMessage = field(error, "originalMessage")
+  if (typeof originalMessage === "string") return originalMessage
  const nested = field(error, "error") ?? field(field(error, "response"), "error")
  return nested === undefined || nested === error ? String(error) : apiFailureMessage(nested)
 }

 function apiFailureStatus(error: unknown): number | undefined {
  const status = field(error, "status")
+  const statusCode = field(error, "statusCode")
+  const originalStatusCode = field(error, "originalStatusCode")
  const code = field(error, "code")
-  const value = [status, code]
+  const value = [status, statusCode, originalStatusCode, code]
    .map((value) => (typeof value === "number" ? value : typeof value === "string" ? Number(value) : undefined))
    .find((value) => value !== undefined && Number.isInteger(value) && value >= 400 && value < 600)
  if (value !== undefined) return value
@@ -869,6 +877,10 @@ function apiFailureStatus(error: unknown): number | undefined {
  return nested === undefined || nested === error ? undefined : apiFailureStatus(nested)
 }

+function apiFailureEvidence(error: string | undefined) {
+  return error === undefined ? undefined : error.slice(0, FAILURE_EVIDENCE_LIMIT)
+}
+
 function retryAfterMs(headers: Record<string, string> | undefined) {
  if (!headers) return undefined
  const normalized = Object.fromEntries(Object.entries(headers).map(([name, value]) => [name.toLowerCase(), value]))
@@ -492,12 +492,53 @@ it.effect("classifies structured AI SDK stream errors", () =>
  }),
 )

-it.effect("classifies structured stream messages without codes", () =>
+it.effect("classifies AI Gateway errors with statusCode", () =>
  Effect.gen(function* () {
    const error = yield* streamFailure(
-      streamingLanguage({ type: "error", error: { message: "Rate limit exceeded" } }),
+      streamingLanguage({
+        type: "error",
+        error: { type: "internal_server_error", message: "Gateway failed", statusCode: 503 },
+      }),
    )

+    expect(error).toMatchObject({ reason: { _tag: "ProviderInternal", status: 503 } })
+  }),
+)
+
+it.effect("classifies AI Gateway timeouts as retryable", () =>
+  Effect.gen(function* () {
+    const error = yield* streamFailure(
+      streamingLanguage({
+        type: "error",
+        error: { type: "timeout_error", message: "Gateway timed out", statusCode: 408 },
+      }),
+    )
+
+    expect(error).toMatchObject({ reason: { _tag: "Transport", kind: "Timeout" } })
+  }),
+)
+
+it.effect("classifies stripped Bedrock model stream errors", () =>
+  Effect.gen(function* () {
+    const error = yield* streamFailure(
+      streamingLanguage({
+        type: "error",
+        error: {
+          message: "The model stream failed",
+          originalMessage: "Upstream provider failed",
+          originalStatusCode: 424,
+        },
+      }),
+    )
+
+    expect(error).toMatchObject({ reason: { _tag: "ProviderInternal", status: 424 } })
+  }),
+)
+
+it.effect("classifies structured stream messages without codes", () =>
+  Effect.gen(function* () {
+    const error = yield* streamFailure(streamingLanguage({ type: "error", error: { message: "Rate limit exceeded" } }))
+
    expect(error).toMatchObject({ reason: { _tag: "RateLimit" } })
  }),
 )
@@ -528,11 +569,81 @@ it.effect("classifies numeric string stream statuses", () =>
  }),
 )

+it.effect("classifies readable stream failures", () =>
+  Effect.gen(function* () {
+    const error = yield* streamFailure({
+      ...failingLanguage(new Error("unused")),
+      doStream: async () => ({
+        stream: new ReadableStream<LanguageModelV3StreamPart>({
+          start(controller) {
+            controller.error(Object.assign(new Error("connection reset"), { code: "ECONNRESET" }))
+          },
+        }),
+        request: { body: {} },
+      }),
+    })
+
+    expect(error).toMatchObject({ method: "readStream", reason: { _tag: "Transport", kind: "ECONNRESET" } })
+  }),
+)
+
+it.live("times out stalled SSE chunks", () =>
+  Effect.acquireUseRelease(
+    Effect.sync(() =>
+      Bun.serve({
+        port: 0,
+        fetch: () =>
+          new Response(
+            new ReadableStream<Uint8Array>({
+              start(controller) {
+                controller.enqueue(new TextEncoder().encode(": connected\n\n"))
+              },
+            }),
+            { headers: { "content-type": "text/event-stream" } },
+          ),
+      }),
+    ),
+    (server) =>
+      Effect.gen(function* () {
+        const aisdk = yield* AISDK.Service
+        let wrappedFetch: typeof fetch | undefined
+        yield* aisdk.hook.sdk((event) => {
+          wrappedFetch = event.options.fetch
+          event.sdk = {}
+        })
+        yield* aisdk.hook.language((event) => {
+          event.language = {
+            ...failingLanguage(new Error("unused")),
+            doStream: async () => {
+              const fetcher = wrappedFetch
+              if (!fetcher) throw new Error("AI SDK fetch was not configured")
+              const response = await fetcher(server.url, { method: "POST" })
+              if (!response.body) throw new Error("AI SDK response body was missing")
+              return {
+                stream: response.body.pipeThrough(
+                  new TransformStream<Uint8Array, LanguageModelV3StreamPart>({ transform() {} }),
+                ),
+                request: { body: {} },
+              }
+            },
+          }
+        })
+        const resolved = yield* aisdk.model(model("@ai-sdk/openai", { chunkTimeout: 10 }))
+        const request = LLM.request({ model: resolved, prompt: "Hello" })
+        const prepared = yield* LLMClient.prepare<LanguageModelV3CallOptions>(request)
+        const error = yield* resolved.route
+          .streamPrepared(prepared.body, request, { http: { execute: () => Effect.die("unused") } })
+          .pipe(Stream.runDrain, Effect.flip)
+
+        expect(error).toMatchObject({ method: "readStream", reason: { _tag: "Transport", kind: "Timeout" } })
+      }),
+    (server) => Effect.promise(() => server.stop(true)),
+  ),
+)
+
 it.effect("classifies missing AI SDK API keys", () =>
  Effect.gen(function* () {
-    const error = yield* streamFailure(
-      failingLanguage(new LoadAPIKeyError({ message: "API key is missing" })),
-    )
+    const error = yield* streamFailure(failingLanguage(new LoadAPIKeyError({ message: "API key is missing" })))

    expect(error).toMatchObject({ reason: { _tag: "Authentication", kind: "missing" } })
  }),