@@ -100,7 +100,6 @@
   },
   "dependencies": {
     "@ai-sdk/alibaba": "1.0.17",
-    "@ai-sdk/amazon-bedrock": "4.0.112",
     "@ai-sdk/anthropic": "3.0.82",
     "@ai-sdk/azure": "3.0.88",
     "@ai-sdk/cohere": "3.0.27",
@@ -112,7 +111,6 @@
     "@ai-sdk/provider": "3.0.8",
     "@ai-sdk/provider-utils": "4.0.23",
     "@ai-sdk/vercel": "2.0.39",
-    "@aws-sdk/credential-providers": "3.1057.0",
     "@lydell/node-pty": "catalog:",
     "@modelcontextprotocol/sdk": "1.29.0",
     "@ff-labs/fff-bun": "0.10.5",
 
@@ -195,7 +195,9 @@ function mapBedrockSettings(
       ? { baseURL: settings.endpoint }
       : {}),
     ...(apiKey === undefined ? {} : { apiKey }),
+    ...(settings.auth === "bearer" || settings.auth === "sigv4" ? { auth: settings.auth } : {}),
     ...(credentials === undefined ? {} : { credentials }),
+    ...(typeof settings.profile === "string" ? { profile: settings.profile } : {}),
     ...(typeof settings.region === "string" ? { region: settings.region } : {}),
     ...(typeof settings.topP === "number" ? { topP: settings.topP } : {}),
   }
 
@@ -1,123 +1,59 @@
 import { Effect } from "effect"
-import type { LanguageModelV3 } from "@ai-sdk/provider"
 import { define } from "@opencode-ai/plugin/effect/plugin"
 import { Provider } from "../../provider.js"
 
-type MantleSDK = {
-  chat: (modelID: string) => LanguageModelV3
-  responses: (modelID: string) => LanguageModelV3
-}
-
-// Bedrock cross-region inference profiles require regional prefixes only for
-// specific model/region combinations. Keep the mapping narrow and avoid
-// double-prefixing model IDs that models.dev already marks as global/us/eu/etc.
-function resolveModelID(modelID: string, region: string | undefined) {
-  const crossRegionPrefixes = ["global.", "us.", "eu.", "jp.", "apac.", "au."]
-  if (crossRegionPrefixes.some((prefix) => modelID.startsWith(prefix))) return modelID
-
-  const resolvedRegion = region ?? "us-east-1"
-  const regionPrefix = resolvedRegion.split("-")[0]
-  if (regionPrefix === "us") {
-    const requiresPrefix = ["nova-micro", "nova-lite", "nova-pro", "nova-premier", "nova-2", "claude", "deepseek"].some(
-      (item) => modelID.includes(item),
-    )
-    if (requiresPrefix && !resolvedRegion.startsWith("us-gov")) return `${regionPrefix}.${modelID}`
-    return modelID
-  }
-  if (regionPrefix === "eu") {
-    const regionRequiresPrefix = [
-      "eu-west-1",
-      "eu-west-2",
-      "eu-west-3",
-      "eu-north-1",
-      "eu-central-1",
-      "eu-south-1",
-      "eu-south-2",
-    ].some((item) => resolvedRegion.includes(item))
-    const modelRequiresPrefix = ["claude", "nova-lite", "nova-micro", "llama3", "pixtral"].some((item) =>
-      modelID.includes(item),
-    )
-    return regionRequiresPrefix && modelRequiresPrefix ? `${regionPrefix}.${modelID}` : modelID
-  }
-  if (regionPrefix !== "ap") return modelID
-
-  const australia = ["ap-southeast-2", "ap-southeast-4"].includes(resolvedRegion)
-  if (australia && ["anthropic.claude-sonnet-4-5", "anthropic.claude-haiku"].some((item) => modelID.includes(item))) {
-    return `au.${modelID}`
-  }
-
-  const prefix = resolvedRegion === "ap-northeast-1" ? "jp" : "apac"
-  return ["claude", "nova-lite", "nova-micro", "nova-pro"].some((item) => modelID.includes(item))
-    ? `${prefix}.${modelID}`
-    : modelID
-}
-
-function selectMantleModel(sdk: MantleSDK, modelID: string) {
-  if (modelID === "openai.gpt-oss-safeguard-20b" || modelID === "openai.gpt-oss-safeguard-120b")
-    return sdk.chat(modelID)
-  return sdk.responses(modelID)
+// Ambient inputs the AWS default credential chain can turn into credentials
+// without any key stored in opencode. Mirrors the presence checks the AWS CLI
+// and SDK use before consulting shared config.
+const CHAIN_ENV = [
+  "AWS_PROFILE",
+  "AWS_ACCESS_KEY_ID",
+  "AWS_WEB_IDENTITY_TOKEN_FILE",
+  "AWS_CONTAINER_CREDENTIALS_RELATIVE_URI",
+  "AWS_CONTAINER_CREDENTIALS_FULL_URI",
+]
+
+const isBedrock = (item: { readonly package: string }) => {
+  const name = Provider.packageName(item.package)
+  return name.startsWith("@ai-sdk/amazon-bedrock") || name.startsWith("@opencode-ai/ai/providers/amazon-bedrock")
 }
 
 export const AmazonBedrockPlugin = define({
   id: "opencode.provider.amazon.bedrock",
   effect: Effect.fn(function* (ctx) {
+    yield* ctx.integration.transform((editor) => {
+      // models.dev advertises AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, and
+      // AWS_REGION alongside the bearer token. Only the bearer token is a key;
+      // the rest feed the SigV4 credential chain and must not become one.
+      editor.method.update({
+        integrationID: Provider.ID.amazonBedrock,
+        method: { type: "env", names: ["AWS_BEARER_TOKEN_BEDROCK"] },
+      })
+    })
     yield* ctx.catalog.transform((evt) => {
       for (const item of evt.provider.list()) {
-        if (!Provider.isAISDK(item.provider.package)) continue
-        if (Provider.packageName(item.provider.package) !== "@ai-sdk/amazon-bedrock") continue
+        if (!isBedrock(item.provider)) continue
         evt.provider.update(item.provider.id, (provider) => {
-          if (typeof provider.settings?.endpoint !== "string") return
-          // The AI SDK expects a base URL, but users configure Bedrock private/VPC
-          // endpoints as `endpoint`; move it into the catalog endpoint URL once.
-          provider.settings.baseURL = provider.settings.endpoint
+          const settings = provider.settings ?? {}
+          const chain = typeof settings.profile === "string" || CHAIN_ENV.some((name) => process.env[name])
+          // SigV4 authenticates through the AWS default chain rather than a key
+          // credential, so ambient AWS configuration is what makes Bedrock usable.
+          if (chain && provider.activation === "auto") provider.activation = "enabled"
+          // Same default the native package uses, made explicit here so catalog
+          // `${AWS_REGION}` URLs resolve without any region configured.
+          const region = process.env.AWS_REGION ?? process.env.AWS_DEFAULT_REGION ?? "us-east-1"
+          provider.settings = {
+            ...settings,
+            ...(typeof settings.region !== "string" ? { region } : {}),
+            // Users configure Bedrock private/VPC endpoints as `endpoint`; move it
+            // into the catalog base URL once.
+            ...(typeof settings.baseURL !== "string" && typeof settings.endpoint === "string"
+              ? { baseURL: settings.endpoint }
+              : {}),
+          }
           delete provider.settings.endpoint
         })
       }
     })
-    yield* ctx.aisdk.hook(
-      "sdk",
-      Effect.fn(function* (evt) {
-        if (!["@ai-sdk/amazon-bedrock", "@ai-sdk/amazon-bedrock/mantle"].includes(evt.package)) return
-        const options = { ...evt.options }
-        const profile = typeof options.profile === "string" ? options.profile : process.env.AWS_PROFILE
-        const region = typeof options.region === "string" ? options.region : (process.env.AWS_REGION ?? "us-east-1")
-        const bearerToken =
-          process.env.AWS_BEARER_TOKEN_BEDROCK ??
-          (typeof options.bearerToken === "string" ? options.bearerToken : undefined)
-        if (bearerToken && !process.env.AWS_BEARER_TOKEN_BEDROCK) process.env.AWS_BEARER_TOKEN_BEDROCK = bearerToken
-        options.region = region
-        if (typeof options.endpoint === "string") options.baseURL = options.endpoint
-        if (!bearerToken && options.credentialProvider === undefined) {
-          // Do not gate SDK creation on explicit AWS env vars. The default chain
-          // also handles ~/.aws/credentials, SSO, process creds, and instance roles.
-          const { fromNodeProviderChain } = yield* Effect.promise(() => import("@aws-sdk/credential-providers"))
-          options.credentialProvider = fromNodeProviderChain(profile ? { profile } : {})
-        }
-
-        if (evt.package === "@ai-sdk/amazon-bedrock/mantle") {
-          const mod = yield* Effect.promise(() => import("@ai-sdk/amazon-bedrock/mantle"))
-          evt.sdk = mod.createBedrockMantle(options)
-          return
-        }
-
-        const mod = yield* Effect.promise(() => import("@ai-sdk/amazon-bedrock"))
-        evt.sdk = mod.createAmazonBedrock(options)
-      }),
-    )
-    yield* ctx.aisdk.hook(
-      "language",
-      Effect.fn(function* (evt) {
-        if (evt.model.providerID !== Provider.ID.amazonBedrock) return
-        if (
-          Provider.isAISDK(evt.model.package) &&
-          Provider.packageName(evt.model.package) === "@ai-sdk/amazon-bedrock/mantle"
-        ) {
-          evt.language = selectMantleModel(evt.sdk, evt.model.modelID ?? evt.model.id)
-          return
-        }
-        const region = typeof evt.options.region === "string" ? evt.options.region : process.env.AWS_REGION
-        evt.language = evt.sdk.languageModel(resolveModelID(evt.model.modelID ?? evt.model.id, region))
-      }),
-    )
   }),
 })
@@ -311,7 +311,6 @@ describe("AISDKNative", () => {
             region: "eu-west-1",
           },
           baseURL: "https://bedrock-mantle.${AWS_REGION}.api.aws/v1",
-          profile: "ignored",
           credentialProvider: "ignored",
           fetch: "ignored",
           store: false,
@@ -333,6 +332,19 @@ describe("AISDKNative", () => {
     })
   })
 
+  test("forwards Bedrock profile and auth mode for the default credential chain", () => {
+    expect(
+      map("@ai-sdk/amazon-bedrock", { profile: "work", auth: "sigv4", region: "eu-west-1" }, "anthropic.claude"),
+    ).toEqual({
+      package: "@opencode-ai/ai/providers/amazon-bedrock",
+      settings: { profile: "work", auth: "sigv4", region: "eu-west-1" },
+    })
+    expect(map("@ai-sdk/amazon-bedrock", { auth: "bogus" }, "anthropic.claude")).toEqual({
+      package: "@opencode-ai/ai/providers/amazon-bedrock",
+      settings: {},
+    })
+  })
+
   test("maps the legacy Bedrock endpoint override", () => {
     expect(
       map(