fix(ai): restrict Bedrock cache checkpoints to Claude (#47660)

packages/ai/src/protocols/bedrock-converse.ts

@@ -415,10 +415,7 @@ const lowerMessages = Effect.fn("BedrockConverse.lowerMessages")(function* (
 
 // System prompts share the cache-point convention: emit the text block, then
 // optionally a positional `cachePoint` marker.
-const lowerSystem = (
-  breakpoints: BedrockCache.Breakpoints,
-  system: ReadonlyArray<LLMRequest["system"][number]>,
-) => {
+const lowerSystem = (breakpoints: BedrockCache.Breakpoints, system: ReadonlyArray<LLMRequest["system"][number]>) => {
   const content = system
     .filter((part) => part.text.length > 0)
     .flatMap((part) => textWithCache(breakpoints, part.text, part.cache))
@@ -431,7 +428,7 @@ const fromRequest = Effect.fn("BedrockConverse.fromRequest")(function* (request:
   const generation = request.generation
   // Bedrock-Claude shares Anthropic's 4-breakpoint cap. Spend the budget in
   // tools → system → messages order to favour the highest-impact prefixes.
-  const breakpoints = BedrockCache.breakpoints()
+  const breakpoints = BedrockCache.breakpoints(request.model.id)
   const toolConfig = (() => {
     if (flattened.tools.length === 0) return undefined
     return {

packages/ai/src/protocols/utils/bedrock-cache.ts

@@ -1,6 +1,6 @@
 import { Schema } from "effect"
 import type { CacheHint } from "../../schema/index.js"
-import { newBreakpoints, ttlBucket, type Breakpoints } from "./cache.js"
+import { newBreakpoints, ttlBucket } from "./cache.js"
 
 // Bedrock cache markers are positional: emit a `cachePoint` block immediately
 // after the content the caller wants treated as a cacheable prefix. Bedrock
@@ -13,24 +13,46 @@ export const CachePointBlock = Schema.Struct({
 })
 export type CachePointBlock = Schema.Schema.Type<typeof CachePointBlock>
 
-// Callers pass a shared counter through every `block()` call site so the
-// four-breakpoint budget is respected across `system`, `messages`, and `tools`.
+const LEGACY_CLAUDE = ["anthropic.claude-instant", "anthropic.claude-v1", "anthropic.claude-v2", "anthropic.claude-3-"]
+
+// These legacy Claude releases support explicit caching, but only for five minutes.
+const CLAUDE_5M = [
+  "anthropic.claude-3-5-sonnet-20241022-v2:0",
+  "anthropic.claude-3-5-haiku-20241022-v1:0",
+  "anthropic.claude-3-7-sonnet-20250219-v1:0",
+  "anthropic.claude-sonnet-4-20250514-v1:0",
+  "anthropic.claude-opus-4-20250514-v1:0",
+  "anthropic.claude-opus-4-1-20250805-v1:0",
+]
+
+// Callers share the four-breakpoint budget across system, messages, and tools.
 export const BEDROCK_BREAKPOINT_CAP = 4
 
-export type { Breakpoints } from "./cache.js"
-export const breakpoints = () => newBreakpoints(BEDROCK_BREAKPOINT_CAP)
+export const breakpoints = (modelID: string) => {
+  // Substring matching also handles regional prefixes and model-bearing ARNs.
+  const short = CLAUDE_5M.some((id) => modelID.includes(id))
+  return {
+    ...newBreakpoints(BEDROCK_BREAKPOINT_CAP),
+    // Assume modern Claude releases retain caching support; older generations need an explicit exception.
+    // Other model families use implicit caching where available.
+    supported: modelID.includes("anthropic.claude-") && (short || !LEGACY_CLAUDE.some((id) => modelID.includes(id))),
+    ttl1h: !short,
+  }
+}
+export type Breakpoints = ReturnType<typeof breakpoints>
 
 const DEFAULT_5M: CachePointBlock = { cachePoint: { type: "default" } }
 const DEFAULT_1H: CachePointBlock = { cachePoint: { type: "default", ttl: "1h" } }
 
 export const block = (breakpoints: Breakpoints, cache: CacheHint | undefined): CachePointBlock | undefined => {
+  if (!breakpoints.supported) return undefined
   if (cache?.type !== "ephemeral" && cache?.type !== "persistent") return undefined
   if (breakpoints.remaining <= 0) {
     breakpoints.dropped += 1
     return undefined
   }
   breakpoints.remaining -= 1
-  return ttlBucket(cache.ttlSeconds) === "1h" ? DEFAULT_1H : DEFAULT_5M
+  return breakpoints.ttl1h && ttlBucket(cache.ttlSeconds) === "1h" ? DEFAULT_1H : DEFAULT_5M
 }
 
 export * as BedrockCache from "./bedrock-cache.js"

packages/ai/test/provider/bedrock-converse-cache.test.ts

@@ -0,0 +1,119 @@
+import { describe, expect } from "bun:test"
+import { Effect } from "effect"
+import { CacheHint, LLM, Message, ToolCallPart } from "../../src/index.js"
+import { AmazonBedrock } from "../../src/providers.js"
+import { compileRequest } from "../../src/route/client.js"
+import { it } from "../lib/effect.js"
+
+const bedrock = AmazonBedrock.configure({ apiKey: "fixture" })
+
+describe("Bedrock Converse cache policy", () => {
+  for (const id of [
+    "deepseek.r1-v1:0",
+    "meta.llama3-3-70b-instruct-v1:0",
+    "mistral.mistral-large-2402-v1:0",
+    "qwen.qwen3-coder-480b-a35b-v1:0",
+    "openai.gpt-oss-120b-1:0",
+    "cohere.command-r-v1:0",
+    "anthropic.claude-instant-v1",
+    "anthropic.claude-v1",
+    "anthropic.claude-v2",
+    "anthropic.claude-v2:1",
+    "anthropic.claude-3-haiku-20240307-v1:0",
+    "anthropic.claude-3-sonnet-20240229-v1:0",
+    "anthropic.claude-3-opus-20240229-v1:0",
+    "anthropic.claude-3-5-sonnet-20240620-v1:0",
+    "amazon.nova-lite-v1:0",
+    "global.amazon.nova-2-lite-v1:0",
+    "custom-model",
+    "arn:aws:bedrock:us-east-1:123456789012:application-inference-profile/abc123",
+  ]) {
+    for (const policy of [undefined, "auto", "none", { tools: true, system: true, messages: { tail: 3 } }] as const) {
+      it.effect(`omits checkpoints for ${id} (${JSON.stringify(policy)})`, () =>
+        Effect.gen(function* () {
+          // Exercise both automatic placement and manual hints at every lowering site.
+          const cache = policy === "none" ? new CacheHint({ type: "ephemeral", ttlSeconds: 3600 }) : undefined
+          const prepared = yield* compileRequest(
+            LLM.request({
+              model: bedrock.model(id),
+              cache: policy,
+              system: [{ type: "text", text: "System prefix", cache }],
+              tools: [{ name: "lookup", description: "Lookup", inputSchema: { type: "object" }, cache }],
+              messages: [
+                Message.user([{ type: "text", text: "Question", cache }]),
+                Message.system([{ type: "text", text: "Update", cache }]),
+                Message.assistant([
+                  { type: "text", text: "Answer", cache },
+                  { type: "reasoning", text: "Unsigned reasoning", cache },
+                  ToolCallPart.make({ id: "call_1", name: "lookup", input: {} }),
+                ]),
+                Message.tool({ id: "call_1", name: "lookup", result: "Result", cache }),
+              ],
+            }),
+          )
+
+          expect(JSON.stringify(prepared.body)).not.toContain("cachePoint")
+          expect(prepared.body).toMatchObject({
+            modelId: id,
+            system: [{ text: "System prefix" }],
+            toolConfig: { tools: [{ toolSpec: { name: "lookup" } }] },
+            messages: [
+              { role: "user", content: [{ text: "Question" }, { text: "<system-update>\nUpdate\n</system-update>" }] },
+              {
+                role: "assistant",
+                content: [{ text: "Answer" }, { text: "Unsigned reasoning" }, { toolUse: { name: "lookup" } }],
+              },
+              { role: "user", content: [{ toolResult: { content: [{ json: "Result" }] } }] },
+            ],
+          })
+        }),
+      )
+    }
+  }
+
+  for (const [id, ttl] of [
+    ["anthropic.claude-3-5-sonnet-20241022-v2:0", undefined],
+    ["us.anthropic.claude-3-5-haiku-20241022-v1:0", undefined],
+    ["eu.anthropic.claude-3-7-sonnet-20250219-v1:0", undefined],
+    ["apac.anthropic.claude-sonnet-4-20250514-v1:0", undefined],
+    ["anthropic.claude-opus-4-20250514-v1:0", undefined],
+    ["anthropic.claude-opus-4-1-20250805-v1:0", undefined],
+    ["anthropic.claude-sonnet-4-5-20250929-v1:0", "1h"],
+    ["global.anthropic.claude-sonnet-99", "1h"],
+    ["anthropic.claude-new-family-99", "1h"],
+    ["arn:aws:bedrock:us-east-1::foundation-model/anthropic.claude-sonnet-4-6", "1h"],
+    ["arn:aws:bedrock:us-east-1:123456789012:inference-profile/us.anthropic.claude-sonnet-4-6", "1h"],
+  ] as const) {
+    for (const ttlSeconds of [undefined, 3600]) {
+      it.effect(`preserves Claude checkpoints for ${id} (TTL: ${ttlSeconds ?? "default"})`, () =>
+        Effect.gen(function* () {
+          const prepared = yield* compileRequest(
+            LLM.request({
+              model: bedrock.model(id),
+              system: [
+                { type: "text", text: "Agent" },
+                { type: "text", text: "Project" },
+              ],
+              tools: [{ name: "lookup", description: "Lookup", inputSchema: { type: "object" } }],
+              prompt: "Question",
+              cache:
+                ttlSeconds === undefined ? undefined : { tools: true, system: true, messages: { tail: 1 }, ttlSeconds },
+            }),
+          )
+          const marker = {
+            cachePoint: ttlSeconds === undefined || ttl === undefined ? { type: "default" } : { type: "default", ttl },
+          }
+
+          expect(prepared.body).toMatchObject({
+            modelId: id,
+            toolConfig: { tools: [{ toolSpec: { name: "lookup" } }, marker] },
+            system: [{ text: "Agent" }, marker, { text: "Project" }, marker],
+            messages: [{ role: "user", content: [{ text: "Question" }, marker] }],
+          })
+          if (ttlSeconds === undefined || ttl === undefined)
+            expect(JSON.stringify(prepared.body)).not.toContain('"ttl"')
+        }),
+      )
+    }
+  }
+})

packages/ai/test/provider/bedrock-converse.test.ts

@@ -136,7 +136,7 @@ const captureHeaders = (target: LanguageModel) =>
 const model = AmazonBedrock.configure({
   baseURL: "https://bedrock-runtime.test",
   apiKey: "test-bearer",
-}).model("anthropic.claude-3-5-sonnet-20240620-v1:0")
+}).model("anthropic.claude-sonnet-4-5-20250929-v1:0")
 
 const baseRequest = LLM.request({
   id: "req_1",
@@ -155,7 +155,7 @@ describe("Bedrock Converse route", () => {
       const prepared = yield* compileRequest(baseRequest)
 
       expect(prepared.body).toEqual({
-        modelId: "anthropic.claude-3-5-sonnet-20240620-v1:0",
+        modelId: "anthropic.claude-sonnet-4-5-20250929-v1:0",
         system: [{ text: "You are concise." }],
         messages: [{ role: "user", content: [{ text: "Say hello." }] }],
         inferenceConfig: { maxTokens: 64, temperature: 0 },