fix(think): keep the prompt-cache prefix stable under truncation (#2200) by threepointone · Pull Request #2356 · cloudflare/agents

threepointone · 2026-09-24T01:08:03Z

This measures how each context-reduction mechanism changes the prompt prefix from one turn to the next, and fixes the one that rewrote it every turn.

Measurement

A new test agent runs real Think turns against a mock model and records the full prompt of every model request. For each turn it compares the first request with the request sent before it. Providers cache on a byte-identical prefix, so the shared prefix is the part the cache can hit. packages/think/src/tests/prompt-cache.test.ts asserts the results:

Mechanism	Before	After
No reduction (baseline)	prefix never breaks	unchanged
Read-time truncation (tool outputs over 500 characters, text over 10,000)	prefix breaks every turn from turn 3	breaks once every 4 turns (turns 6, 10, 14)
Media eviction	breaks once, when the file part is evicted	unchanged
Compaction	breaks once per compaction	unchanged

The sliding cutoff (messages.length - 4) rewrote a message near the end of the prefix on every turn. The measured cost uses character units, with cached input billed at a tenth of fresh input:

16 turns, 4,000-character tool output per turn	Cost
No truncation	58.6k
Cutoff moves every turn (`main`)	129.7k
Cutoff every 4 messages	81.5k
Cutoff every 8 messages (this PR)	64.3k
Cutoff every 16 messages	55.3k

So on main, truncation cost about 2.2 times what sending the untruncated history would. With 12,000-character user messages the ratio is 1.4 times.

Fix

Think now cuts at a multiple of 8 messages, using keepRecent = 4 + ((length - 4) % truncationStep), and passes the same keepRecent to truncateOlderMessages and truncateOlderToolResults. The model still always sees at least the 4 most recent messages in full, and at most 11 between cuts. The hydration floor and the media eviction clamp are unchanged, because they only need the most recent 4. A new truncationStep class field (default 8) sets the step; 1 restores the previous cut-every-turn behavior for models with a small context window.

A compaction threshold that the compacted history still exceeds compacts on every append, which rewrites the summary every turn. The docs now warn about this. hydrationByteBudget (32 MiB by default) is larger than any context window, so it does not affect caching in practice.

Closes #2200

Docs: a new "Prompt caching" section in docs/think/index.md, and a stepped-cutoff recipe for direct truncateOlderMessages users in docs/agents/sessions.md.

Not done here: moving these mechanisms into agents/context, as #2200 suggests. The stepped cutoff is the reference point that move would need.

changeset-bot · 2026-09-24T01:08:08Z

🦋 Changeset detected

Latest commit: 33b1e73

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@cloudflare/think	Patch
@cloudflare/agent-think	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

agent-think · 2026-09-24T01:09:57Z

⚪ agents import sizes

Measured 344 runtime imports as minified bundles. The primary size is gzip; raw minified size is included for diagnosis. An existing import growing by more than 10% is marked red. This report is informational.

Red	Yellow	Green	Unchanged	New	Removed
0	0	0	344	0	0

Compared ed9365ca with 33b1e738. Open workflow run.

No import sizes changed.

All 344 current runtime imports

Status	Import	Gzip	Raw minified
⚪	`agents#__DO_NOT_USE_WILL_BREAK__agentContext`	261.1 KiB	1141.0 KiB
⚪	`agents#__DO_NOT_USE_WILL_BREAK__withInvocationScope`	261.1 KiB	1141.0 KiB
⚪	`agents#Agent`	261.1 KiB	1141.0 KiB
⚪	`agents#AGENT_TOOL_MILESTONE_PART`	261.1 KiB	1141.0 KiB
⚪	`agents#AGENT_TOOL_PROGRESS_PART`	261.1 KiB	1141.0 KiB
⚪	`agents#buildAgentPath`	261.7 KiB	1143.3 KiB
⚪	`agents#buildAgentUrl`	261.8 KiB	1143.7 KiB
⚪	`agents#callable`	261.1 KiB	1141.0 KiB
⚪	`agents#camelCaseToKebabCase`	261.1 KiB	1141.0 KiB
⚪	`agents#createHeaderBasedEmailResolver`	261.3 KiB	1141.4 KiB
⚪	`agents#DEFAULT_AGENT_STATIC_OPTIONS`	261.1 KiB	1141.0 KiB
⚪	`agents#DurableObjectOAuthClientProvider`	261.1 KiB	1141.0 KiB
⚪	`agents#getAgentByName`	261.1 KiB	1141.0 KiB
⚪	`agents#getCurrentAgent`	261.1 KiB	1141.0 KiB
⚪	`agents#getSubAgentByName`	261.4 KiB	1141.6 KiB
⚪	`agents#isDurableObjectCodeUpdateReset`	261.1 KiB	1141.0 KiB
⚪	`agents#isDurableObjectMemoryLimitReset`	261.1 KiB	1141.0 KiB
⚪	`agents#isDurableObjectStorageReset`	261.1 KiB	1141.0 KiB
⚪	`agents#isPlatformTransientError`	261.1 KiB	1141.0 KiB
⚪	`agents#MCP_SERVER_ID_MAX_LENGTH`	261.1 KiB	1141.0 KiB
⚪	`agents#MessageType`	261.2 KiB	1141.3 KiB
⚪	`agents#normalizeServerId`	261.1 KiB	1141.0 KiB
⚪	`agents#parseSubAgentPath`	261.1 KiB	1141.0 KiB
⚪	`agents#routeAgentEmail`	261.4 KiB	1141.7 KiB
⚪	`agents#routeAgentRequest`	261.7 KiB	1142.9 KiB
⚪	`agents#routeSubAgentRequest`	261.3 KiB	1141.5 KiB
⚪	`agents#SqlError`	261.1 KiB	1141.0 KiB
⚪	`agents#StreamingResponse`	261.1 KiB	1141.0 KiB
⚪	`agents#SUB_PREFIX`	261.1 KiB	1141.0 KiB
⚪	`agents#unstable_callable`	261.2 KiB	1141.2 KiB
⚪	`agents/agent-tools#agentTool`	112.5 KiB	538.2 KiB
⚪	`agents/browser#BrowserConnector`	50.5 KiB	176.6 KiB
⚪	`agents/browser#browserContent`	36.3 KiB	127.4 KiB
⚪	`agents/browser#browserExtract`	36.3 KiB	127.4 KiB
⚪	`agents/browser#browserLinks`	36.3 KiB	127.4 KiB
⚪	`agents/browser#browserMarkdown`	36.3 KiB	127.4 KiB
⚪	`agents/browser#browserPdf`	36.3 KiB	127.3 KiB
⚪	`agents/browser#BrowserRenderingError`	36.0 KiB	126.7 KiB
⚪	`agents/browser#browserScrape`	36.3 KiB	127.4 KiB
⚪	`agents/browser#browserScreenshot`	36.3 KiB	127.3 KiB
⚪	`agents/browser#browserSnapshot`	36.3 KiB	127.4 KiB
⚪	`agents/browser#CdpSession`	37.2 KiB	129.8 KiB
⚪	`agents/browser#CodemodeRuntime`	39.6 KiB	139.0 KiB
⚪	`agents/browser#connectBrowser`	37.8 KiB	131.4 KiB
⚪	`agents/browser#connectBrowserSession`	37.5 KiB	130.4 KiB
⚪	`agents/browser#connectUrl`	37.6 KiB	130.5 KiB
⚪	`agents/browser#createBrowserSession`	36.3 KiB	127.5 KiB
⚪	`agents/browser#DEFAULT_EXEC_SWEEP_IDLE_MS`	36.0 KiB	126.6 KiB
⚪	`agents/browser#DEFAULT_SWEEP_IDLE_MS`	36.0 KiB	126.6 KiB
⚪	`agents/browser#deleteBrowserSession`	36.1 KiB	126.9 KiB
⚪	`agents/browser#DurableBrowserSessionStore`	36.4 KiB	127.6 KiB
⚪	`agents/browser#getBrowserRecording`	36.2 KiB	127.1 KiB
⚪	`agents/browser#listBrowserTargets`	36.1 KiB	126.9 KiB
⚪	`agents/browser#loadCdpSpec`	36.6 KiB	128.3 KiB
⚪	`agents/browser#runQuickAction`	36.0 KiB	126.6 KiB
⚪	`agents/browser/ai#createBrowserRuntime`	147.0 KiB	632.8 KiB
⚪	`agents/browser/ai#createBrowserTools`	147.0 KiB	632.9 KiB
⚪	`agents/browser/ai#createQuickActionTools`	122.5 KiB	554.3 KiB
⚪	`agents/browser/tanstack-ai#createBrowserTools`	162.7 KiB	701.7 KiB
⚪	`agents/channels#ChannelHost`	3.3 KiB	9.1 KiB
⚪	`agents/channels#consumeChunks`	237 B	321 B
⚪	`agents/channels#createUserIdentityStore`	1.3 KiB	3.2 KiB
⚪	`agents/channels#fallback`	155 B	160 B
⚪	`agents/channels#fallbackChannel`	893 B	1.9 KiB
⚪	`agents/channels#fanout`	151 B	156 B
⚪	`agents/channels#fanoutChannel`	875 B	1.9 KiB
⚪	`agents/channels#identityKey`	178 B	223 B
⚪	`agents/channels#isChannelMessageSurface`	271 B	452 B
⚪	`agents/channels#linkChannelIdentities`	113 B	99 B
⚪	`agents/channels#matchesPath`	110 B	96 B
⚪	`agents/channels#routes`	307 B	507 B
⚪	`agents/channels#UserIdentityConflictError`	248 B	335 B
⚪	`agents/channels/ai-sdk#createSendMessageTool`	112.2 KiB	537.4 KiB
⚪	`agents/channels/ai-sdk#toChannelChunks`	112.5 KiB	538.4 KiB
⚪	`agents/channels/email#email`	23.5 KiB	75.4 KiB
⚪	`agents/channels/email#inboundEmail`	22.3 KiB	72.3 KiB
⚪	`agents/channels/slack#slack`	5.5 KiB	14.6 KiB
⚪	`agents/channels/slack#slackWebhook`	2.2 KiB	5.1 KiB
⚪	`agents/channels/tanstack-ai#createSendMessageTool`	16.2 KiB	68.4 KiB
⚪	`agents/channels/telegram#telegram`	3.8 KiB	10.3 KiB
⚪	`agents/channels/telegram#telegramWebhook`	1.6 KiB	3.6 KiB
⚪	`agents/channels/voice#browserVoice`	1010 B	2.2 KiB
⚪	`agents/chat#AbortRegistry`	2.5 KiB	8.9 KiB
⚪	`agents/chat#AGENT_TOOL_STREAM_PROGRESS_BUMP_THROTTLE_MS`	2.3 KiB	8.2 KiB
⚪	`agents/chat#AgentToolProgressEmitter`	2.7 KiB	9.5 KiB
⚪	`agents/chat#AgentToolStreamProgressThrottle`	2.4 KiB	8.3 KiB
⚪	`agents/chat#aiSdkRecoveryCodec`	2.3 KiB	8.2 KiB
⚪	`agents/chat#applyAgentToolEvent`	3.2 KiB	11.0 KiB
⚪	`agents/chat#applyChunkToParts`	2.3 KiB	8.2 KiB
⚪	`agents/chat#applyToolUpdate`	2.4 KiB	8.4 KiB
⚪	`agents/chat#AutoContinuationController`	2.3 KiB	8.2 KiB
⚪	`agents/chat#awaitWithDeadline`	2.4 KiB	8.4 KiB
⚪	`agents/chat#broadcastTransition`	3.2 KiB	11.6 KiB
⚪	`agents/chat#buildChatRecoveringFrame`	2.4 KiB	8.4 KiB
⚪	`agents/chat#buildInClauseStrings`	2.4 KiB	8.4 KiB
⚪	`agents/chat#bumpChatRecoveryProgress`	2.4 KiB	8.3 KiB
⚪	`agents/chat#byteLength`	2.5 KiB	8.5 KiB
⚪	`agents/chat#CHAT_LAST_TERMINAL_KEY`	2.3 KiB	8.2 KiB
⚪	`agents/chat#CHAT_MESSAGE_TYPES`	2.3 KiB	8.2 KiB
⚪	`agents/chat#CHAT_RECOVERING_FLAG_TTL_MS`	2.3 KiB	8.2 KiB
⚪	`agents/chat#CHAT_RECOVERING_KEY`	2.3 KiB	8.2 KiB
⚪	`agents/chat#CHAT_RECOVERY_ALARM_DEBOUNCE_MS`	2.3 KiB	8.2 KiB
⚪	`agents/chat#CHAT_RECOVERY_INCIDENT_KEY_PREFIX`	2.3 KiB	8.2 KiB
⚪	`agents/chat#CHAT_RECOVERY_INCIDENT_TTL_MS`	2.3 KiB	8.2 KiB
⚪	`agents/chat#CHAT_RECOVERY_PROGRESS_KEY`	2.3 KiB	8.2 KiB
⚪	`agents/chat#CHAT_RECOVERY_STABLE_RETRY_DELAY_SECONDS`	2.3 KiB	8.2 KiB
⚪	`agents/chat#CHAT_RECOVERY_TASK_NAME`	2.3 KiB	8.2 KiB
⚪	`agents/chat#CHAT_STREAM_PROGRESS_CREDIT_THROTTLE_MS`	2.3 KiB	8.2 KiB
⚪	`agents/chat#ChatRecoveryEngine`	4.5 KiB	15.5 KiB
⚪	`agents/chat#chatRecoveryTaskRunOptions`	2.4 KiB	8.6 KiB
⚪	`agents/chat#ChatStreamStalledError`	2.4 KiB	8.3 KiB
⚪	`agents/chat#classifyAgentToolChildRecovery`	2.4 KiB	8.5 KiB
⚪	`agents/chat#clearChatTerminal`	2.3 KiB	8.3 KiB
⚪	`agents/chat#clientResolvableToolNames`	2.3 KiB	8.3 KiB
⚪	`agents/chat#ContinuationState`	2.7 KiB	9.8 KiB
⚪	`agents/chat#createAgentToolEventState`	2.3 KiB	8.3 KiB
⚪	`agents/chat#createChatFiberSnapshot`	2.5 KiB	8.6 KiB
⚪	`agents/chat#createChatRecoveryTaskDefinition`	2.6 KiB	9.0 KiB
⚪	`agents/chat#createChatStreams`	6.4 KiB	22.1 KiB
⚪	`agents/chat#createChatTurnTaskDefinition`	2.7 KiB	8.9 KiB
⚪	`agents/chat#createToolsFromClientSchemas`	114.3 KiB	545.4 KiB
⚪	`agents/chat#crossMessageToolResultUpdate`	2.4 KiB	8.6 KiB
⚪	`agents/chat#DEFAULT_CHAT_RECOVERY_MAX_ATTEMPTS`	2.3 KiB	8.2 KiB
⚪	`agents/chat#DEFAULT_CHAT_RECOVERY_MAX_OOM_RETRIES`	2.3 KiB	8.2 KiB
⚪	`agents/chat#DEFAULT_CHAT_RECOVERY_MAX_WORK`	2.3 KiB	8.2 KiB
⚪	`agents/chat#DEFAULT_CHAT_RECOVERY_NO_PROGRESS_TIMEOUT_MS`	2.3 KiB	8.2 KiB
⚪	`agents/chat#DEFAULT_CHAT_RECOVERY_STABLE_TIMEOUT_MS`	2.3 KiB	8.2 KiB
⚪	`agents/chat#DEFAULT_CHAT_RECOVERY_TERMINAL_MESSAGE`	2.4 KiB	8.3 KiB
⚪	`agents/chat#dispatchChatRecoveryToHandoff`	3.0 KiB	9.9 KiB
⚪	`agents/chat#drainInteractionApplies`	2.3 KiB	8.3 KiB
⚪	`agents/chat#enforceRowSizeLimit`	3.5 KiB	11.2 KiB
⚪	`agents/chat#hasIncompleteToolBatch`	2.4 KiB	8.6 KiB
⚪	`agents/chat#interceptAgentToolBroadcast`	2.5 KiB	8.7 KiB
⚪	`agents/chat#isPlatformFailure`	2.6 KiB	8.9 KiB
⚪	`agents/chat#isReplayChunk`	2.4 KiB	8.7 KiB
⚪	`agents/chat#iterateWithStallWatchdog`	2.6 KiB	8.8 KiB
⚪	`agents/chat#KV_DELETE_MAX_KEYS`	2.3 KiB	8.2 KiB
⚪	`agents/chat#listActiveChatRecoveryIncidents`	2.4 KiB	8.4 KiB
⚪	`agents/chat#MAX_BOUND_PARAMS`	2.3 KiB	8.2 KiB
⚪	`agents/chat#MessageType`	2.4 KiB	9.0 KiB
⚪	`agents/chat#normalizeToolInput`	2.3 KiB	8.2 KiB
⚪	`agents/chat#parseProtocolMessage`	2.5 KiB	9.0 KiB
⚪	`agents/chat#partAwaitsClientInteraction`	2.4 KiB	8.6 KiB
⚪	`agents/chat#pausedExecutionUpdate`	2.4 KiB	8.4 KiB
⚪	`agents/chat#pendingChatTerminal`	2.3 KiB	8.3 KiB
⚪	`agents/chat#persistReconstructedOrphan`	3.1 KiB	11.0 KiB
⚪	`agents/chat#PreStreamTurns`	2.6 KiB	9.3 KiB
⚪	`agents/chat#readChatRecoveryProgress`	2.3 KiB	8.3 KiB
⚪	`agents/chat#reconcileMessages`	2.8 KiB	9.6 KiB
⚪	`agents/chat#reconcileOrphanPartial`	2.4 KiB	8.5 KiB
⚪	`agents/chat#recordChatTerminal`	2.4 KiB	8.3 KiB
⚪	`agents/chat#repairInterruptedToolParts`	2.6 KiB	9.1 KiB
⚪	`agents/chat#resolveChatRecoveryConfig`	2.6 KiB	8.9 KiB
⚪	`agents/chat#resolveToolMergeId`	2.4 KiB	8.5 KiB
⚪	`agents/chat#ResumableStream`	5.2 KiB	17.3 KiB
⚪	`agents/chat#ResumeHandshake`	3.0 KiB	10.4 KiB
⚪	`agents/chat#ROW_MAX_BYTES`	2.3 KiB	8.2 KiB
⚪	`agents/chat#runChatRecoveryExhaustion`	2.6 KiB	8.9 KiB
⚪	`agents/chat#sanitizeMessage`	2.5 KiB	8.8 KiB
⚪	`agents/chat#sendIfOpen`	2.4 KiB	8.4 KiB
⚪	`agents/chat#setChatRecovering`	2.5 KiB	8.5 KiB
⚪	`agents/chat#shouldCreditStreamProgress`	2.4 KiB	8.3 KiB
⚪	`agents/chat#STREAM_RESUME_NONE_REASONS`	2.3 KiB	8.2 KiB
⚪	`agents/chat#StreamAccumulator`	2.9 KiB	10.7 KiB
⚪	`agents/chat#StreamProgressCreditThrottle`	2.4 KiB	8.3 KiB
⚪	`agents/chat#SubmitConcurrencyController`	2.9 KiB	10.3 KiB
⚪	`agents/chat#sweepStaleChatRecoveryIncidents`	2.4 KiB	8.5 KiB
⚪	`agents/chat#TextSegmentJoiner`	2.7 KiB	9.2 KiB
⚪	`agents/chat#TIMED_OUT`	2.3 KiB	8.2 KiB
⚪	`agents/chat#toolApprovalUpdate`	2.4 KiB	8.5 KiB
⚪	`agents/chat#toolPartHasSettledResult`	2.3 KiB	8.4 KiB
⚪	`agents/chat#toolResultUpdate`	2.4 KiB	8.5 KiB
⚪	`agents/chat#truncateOlderMessages`	3.2 KiB	10.5 KiB
⚪	`agents/chat#truncateOlderToolResults`	3.3 KiB	10.9 KiB
⚪	`agents/chat#TurnQueue`	2.6 KiB	9.2 KiB
⚪	`agents/chat#unwrapChatFiberSnapshot`	2.4 KiB	8.5 KiB
⚪	`agents/chat#wrapChatFiberSnapshot`	2.3 KiB	8.2 KiB
⚪	`agents/chat-sdk#ChatSdkStateAdapter`	263.5 KiB	1152.6 KiB
⚪	`agents/chat-sdk#ChatSdkStateAgent`	262.8 KiB	1150.0 KiB
⚪	`agents/chat-sdk#createChatSdkState`	263.5 KiB	1152.6 KiB
⚪	`agents/chat-sdk#defaultKeyShard`	261.2 KiB	1141.2 KiB
⚪	`agents/chat-sdk#defaultThreadShard`	261.1 KiB	1141.0 KiB
⚪	`agents/chat/react#detectToolsRequiringConfirmation`	3.3 KiB	8.3 KiB
⚪	`agents/chat/react#extractClientToolSchemas`	3.2 KiB	8.3 KiB
⚪	`agents/chat/react#getAgentMessages`	3.4 KiB	8.6 KiB
⚪	`agents/chat/react#getToolApproval`	3.1 KiB	8.0 KiB
⚪	`agents/chat/react#getToolCallId`	3.1 KiB	8.0 KiB
⚪	`agents/chat/react#getToolInput`	3.1 KiB	8.0 KiB
⚪	`agents/chat/react#getToolOutput`	3.1 KiB	8.0 KiB
⚪	`agents/chat/react#getToolPartState`	3.2 KiB	8.2 KiB
⚪	`agents/chat/react#useAgentChat`	133.5 KiB	611.6 KiB
⚪	`agents/chat/react#WebSocketChatTransport`	6.2 KiB	18.7 KiB
⚪	`agents/chat/transport#WebSocketChatTransport`	3.3 KiB	10.7 KiB
⚪	`agents/client#AgentClient`	21.8 KiB	75.2 KiB
⚪	`agents/client#AgentConnectionError`	16.3 KiB	57.8 KiB
⚪	`agents/client#agentFetch`	19.7 KiB	69.0 KiB
⚪	`agents/client#createStubProxy`	16.4 KiB	57.8 KiB
⚪	`agents/client#DEFAULT_CALL_TIMEOUT_MS`	16.2 KiB	57.6 KiB
⚪	`agents/client#isTerminalCloseEvent`	16.3 KiB	57.6 KiB
⚪	`agents/client#nativeCall`	16.5 KiB	58.3 KiB
⚪	`agents/client#NativeCallQueue`	16.7 KiB	58.9 KiB
⚪	`agents/client#splitCallOptions`	16.3 KiB	57.7 KiB
⚪	`agents/context#AgentContextProvider`	412 B	792 B
⚪	`agents/context#AgentSearchProvider`	640 B	1.3 KiB
⚪	`agents/context#ContextBlocks`	87.4 KiB	429.7 KiB
⚪	`agents/email#createAddressBasedEmailResolver`	193 B	227 B
⚪	`agents/email#createCatchAllEmailResolver`	110 B	97 B
⚪	`agents/email#createHeaderBasedEmailResolver`	334 B	492 B
⚪	`agents/email#createSecureReplyEmailResolver`	718 B	1.3 KiB
⚪	`agents/email#DEFAULT_MAX_AGE_SECONDS`	56 B	39 B
⚪	`agents/email#isAutoReplyEmail`	201 B	249 B
⚪	`agents/email#signAgentHeaders`	424 B	812 B
⚪	`agents/experimental/webmcp#registerWebMcp`	85.2 KiB	295.8 KiB
⚪	`agents/lifecycle#getCurrentAgent`	376 B	798 B
⚪	`agents/lifecycle#Lifecycle`	8.4 KiB	26.1 KiB
⚪	`agents/lifecycle#LifecycleCapability`	497 B	999 B
⚪	`agents/mcp#createLegacyMcpHandler`	378.6 KiB	1583.3 KiB
⚪	`agents/mcp#createMcpHandler`	390.9 KiB	1628.5 KiB
⚪	`agents/mcp#DurableObjectEventStore`	345.1 KiB	1441.8 KiB
⚪	`agents/mcp#ElicitRequestSchema`	345.1 KiB	1441.8 KiB
⚪	`agents/mcp#experimental_createMcpHandler`	378.7 KiB	1583.6 KiB
⚪	`agents/mcp#getMcpAuthContext`	345.1 KiB	1441.9 KiB
⚪	`agents/mcp#MCP_SERVER_ID_MAX_LENGTH`	345.1 KiB	1441.9 KiB
⚪	`agents/mcp#McpAgent`	345.1 KiB	1441.8 KiB
⚪	`agents/mcp#normalizeServerId`	345.1 KiB	1441.8 KiB
⚪	`agents/mcp#RPC_DO_PREFIX`	345.1 KiB	1441.8 KiB
⚪	`agents/mcp#RPCClientTransport`	345.1 KiB	1441.8 KiB
⚪	`agents/mcp#RPCServerTransport`	345.1 KiB	1441.8 KiB
⚪	`agents/mcp#SSEEdgeClientTransport`	345.2 KiB	1442.1 KiB
⚪	`agents/mcp#StreamableHTTPEdgeClientTransport`	345.2 KiB	1442.1 KiB
⚪	`agents/mcp#WorkerTransport`	348.5 KiB	1458.7 KiB
⚪	`agents/mcp/client#getNamespacedData`	62.9 KiB	240.0 KiB
⚪	`agents/mcp/client#MCP_SERVER_ID_MAX_LENGTH`	62.9 KiB	239.9 KiB
⚪	`agents/mcp/client#MCPClientManager`	158.6 KiB	702.6 KiB
⚪	`agents/mcp/client#normalizeServerId`	63.0 KiB	240.2 KiB
⚪	`agents/mcp/do-oauth-client-provider#DurableObjectOAuthClientProvider`	2.1 KiB	6.6 KiB
⚪	`agents/mcp/server#createMcpHandler`	80.5 KiB	307.2 KiB
⚪	`agents/mcp/server#getMcpAuthContext`	64.0 KiB	245.5 KiB
⚪	`agents/observability#channels`	259 B	549 B
⚪	`agents/observability#genericObservability`	470 B	1.2 KiB
⚪	`agents/observability#subscribe`	324 B	668 B
⚪	`agents/observability/ai#wrapAISDK`	8.8 KiB	30.5 KiB
⚪	`agents/queue#Queue`	3.1 KiB	9.6 KiB
⚪	`agents/react#_testUtils`	19.3 KiB	66.4 KiB
⚪	`agents/react#useAgent`	27.1 KiB	89.9 KiB
⚪	`agents/react#useAgentToolEvents`	21.1 KiB	73.7 KiB
⚪	`agents/routing#getAgentByName`	795 B	1.7 KiB
⚪	`agents/routing#routeAgentRequest`	1.6 KiB	3.6 KiB
⚪	`agents/routing#RoutedAgents`	2.4 KiB	6.2 KiB
⚪	`agents/schedule#getSchedulePrompt`	85.8 KiB	424.7 KiB
⚪	`agents/schedule#scheduleSchema`	85.3 KiB	423.6 KiB
⚪	`agents/schedule#unstable_getSchedulePrompt`	85.9 KiB	424.9 KiB
⚪	`agents/schedule#unstable_scheduleSchema`	85.3 KiB	423.6 KiB
⚪	`agents/schedules#Scheduler`	6.8 KiB	22.0 KiB
⚪	`agents/schedules/parser#getSchedulePrompt`	85.8 KiB	424.7 KiB
⚪	`agents/schedules/parser#scheduleSchema`	85.3 KiB	423.6 KiB
⚪	`agents/sessions#COMPACTION_PREFIX`	147 B	160 B
⚪	`agents/sessions#createCompactFunction`	1.7 KiB	4.0 KiB
⚪	`agents/sessions#isCompactionMessage`	177 B	200 B
⚪	`agents/sessions#Session`	2.0 KiB	6.3 KiB
⚪	`agents/sessions#Sessions`	9.6 KiB	34.3 KiB
⚪	`agents/skills#fromManifest`	309.8 KiB	1084.0 KiB
⚪	`agents/skills#parseSkillFrontmatter`	328.4 KiB	1146.2 KiB
⚪	`agents/skills#parseSkillMarkdown`	328.6 KiB	1146.5 KiB
⚪	`agents/skills#r2`	330.2 KiB	1150.4 KiB
⚪	`agents/skills#runner`	369.0 KiB	1297.8 KiB
⚪	`agents/skills#SkillRegistry`	416.4 KiB	1581.7 KiB
⚪	`agents/skills/compile#compileSkillScript`	15.4 KiB	43.4 KiB
⚪	`agents/skills/compile#isCompilableSkillScript`	15.4 KiB	43.3 KiB
⚪	`agents/state#State`	1.1 KiB	2.4 KiB
⚪	`agents/streams#DEFAULT_MAX_CHUNK_BYTES`	94 B	96 B
⚪	`agents/streams#sseResponse`	857 B	1.6 KiB
⚪	`agents/streams#StreamClosedError`	175 B	212 B
⚪	`agents/streams#StreamNotFoundError`	215 B	276 B
⚪	`agents/streams#Streams`	4.3 KiB	13.9 KiB
⚪	`agents/streams#StreamSerializationError`	171 B	201 B
⚪	`agents/tasks#DuplicateTaskStepError`	328 B	463 B
⚪	`agents/tasks#MAX_SERIALIZED_BYTES`	190 B	232 B
⚪	`agents/tasks#MissingTaskDefinitionError`	358 B	536 B
⚪	`agents/tasks#NonRetryableError`	238 B	308 B
⚪	`agents/tasks#TaskReplayDivergedError`	341 B	483 B
⚪	`agents/tasks#Tasks`	8.9 KiB	31.8 KiB
⚪	`agents/tasks#TaskSerializationError`	258 B	339 B
⚪	`agents/types#MessageType`	211 B	365 B
⚪	`agents/vite#default`	353.8 KiB	1356.1 KiB
⚪	`agents/voice#addSFUTracks`	324 B	424 B
⚪	`agents/voice#createSFUSession`	255 B	306 B
⚪	`agents/voice#createSFUWebSocketAdapter`	331 B	429 B
⚪	`agents/voice#decodeVarint`	157 B	160 B
⚪	`agents/voice#downsample48kStereoTo16kMono`	238 B	324 B
⚪	`agents/voice#encodePayloadToProtobuf`	189 B	279 B
⚪	`agents/voice#encodeVarint`	129 B	122 B
⚪	`agents/voice#extractPayloadFromProtobuf`	271 B	425 B
⚪	`agents/voice#iterateText`	1.6 KiB	3.8 KiB
⚪	`agents/voice#renegotiateSFUSession`	329 B	428 B
⚪	`agents/voice#SentenceChunker`	550 B	1.1 KiB
⚪	`agents/voice#sfuFetch`	294 B	358 B
⚪	`agents/voice#upsample16kMonoTo48kStereo`	211 B	272 B
⚪	`agents/voice#VOICE_PROTOCOL_VERSION`	51 B	31 B
⚪	`agents/voice#withVoice`	9.5 KiB	32.7 KiB
⚪	`agents/voice#withVoiceInput`	4.8 KiB	16.0 KiB
⚪	`agents/voice#WorkersAIFluxSTT`	1.5 KiB	4.3 KiB
⚪	`agents/voice#WorkersAINova3STT`	1.6 KiB	4.3 KiB
⚪	`agents/voice#WorkersAITTS`	682 B	1.4 KiB
⚪	`agents/voice/client#VOICE_PROTOCOL_VERSION`	473 B	768 B
⚪	`agents/voice/client#VoiceClient`	10.1 KiB	31.6 KiB
⚪	`agents/voice/client#WebSocketVoiceTransport`	4.6 KiB	13.3 KiB
⚪	`agents/voice/errors#logVoiceError`	132 B	173 B
⚪	`agents/voice/errors#toVoiceError`	94 B	80 B
⚪	`agents/voice/errors#voiceErrorMessage`	125 B	111 B
⚪	`agents/voice/errors#VoiceProviderError`	190 B	345 B
⚪	`agents/voice/react#useVoiceAgent`	13.6 KiB	42.5 KiB
⚪	`agents/voice/react#useVoiceInput`	13.3 KiB	41.4 KiB
⚪	`agents/voice/react#WebSocketVoiceTransport`	7.4 KiB	21.3 KiB
⚪	`agents/voice/sfu#addSFUTracks`	323 B	424 B
⚪	`agents/voice/sfu#createSFUSession`	254 B	306 B
⚪	`agents/voice/sfu#createSFUWebSocketAdapter`	329 B	429 B
⚪	`agents/voice/sfu#decodeVarint`	155 B	160 B
⚪	`agents/voice/sfu#downsample48kStereoTo16kMono`	236 B	324 B
⚪	`agents/voice/sfu#encodePayloadToProtobuf`	188 B	279 B
⚪	`agents/voice/sfu#encodeVarint`	129 B	122 B
⚪	`agents/voice/sfu#extractPayloadFromProtobuf`	270 B	425 B
⚪	`agents/voice/sfu#renegotiateSFUSession`	329 B	428 B
⚪	`agents/voice/sfu#sfuFetch`	292 B	358 B
⚪	`agents/voice/sfu#upsample16kMonoTo48kStereo`	209 B	272 B
⚪	`agents/voice/text#iterateText`	1.6 KiB	3.8 KiB
⚪	`agents/voice/text#SentenceChunker`	549 B	1.1 KiB
⚪	`agents/voice/types#VOICE_PROTOCOL_VERSION`	51 B	31 B
⚪	`agents/voice/workers-ai#WorkersAIFluxSTT`	1.5 KiB	4.3 KiB
⚪	`agents/voice/workers-ai#WorkersAINova3STT`	1.6 KiB	4.3 KiB
⚪	`agents/voice/workers-ai#WorkersAITTS`	682 B	1.4 KiB
⚪	`agents/websockets#CAPNWEB_TRANSPORT_QUERY`	12.4 KiB	43.3 KiB
⚪	`agents/websockets#CAPNWEB_TRANSPORT_VALUE`	12.4 KiB	43.3 KiB
⚪	`agents/websockets#capnWebTransportUrl`	12.5 KiB	43.5 KiB
⚪	`agents/websockets#CF_NO_PROTOCOL_KEY`	12.4 KiB	43.3 KiB
⚪	`agents/websockets#CF_READONLY_KEY`	12.4 KiB	43.3 KiB
⚪	`agents/websockets#isCapnWebTransportUpgrade`	12.5 KiB	43.4 KiB
⚪	`agents/websockets#registerInternalConnectionKeys`	12.4 KiB	43.4 KiB
⚪	`agents/websockets#WebSockets`	20.0 KiB	69.3 KiB
⚪	`agents/workflows#AgentWorkflow`	262.4 KiB	1145.7 KiB
⚪	`agents/workflows#WorkflowRejectedError`	261.2 KiB	1141.2 KiB
⚪	`agents/x402#normalizeNetwork`	14.7 KiB	61.1 KiB
⚪	`agents/x402#withX402`	23.0 KiB	89.2 KiB
⚪	`agents/x402#withX402Client`	104.1 KiB	346.5 KiB

Reported by agent-think[bot].

devin-ai-integration

Note

Newer findings are available below. Devin Review posted a newer report on this PR, in addition to the findings presented here.

Devin Review found 3 potential issues.

pkg-pr-new · 2026-09-24T01:20:38Z

Open in StackBlitz

agents

npm i https://pkg.pr.new/agents@2356

@cloudflare/ai-chat

npm i https://pkg.pr.new/@cloudflare/ai-chat@2356

@cloudflare/codemode

npm i https://pkg.pr.new/@cloudflare/codemode@2356

hono-agents

npm i https://pkg.pr.new/hono-agents@2356

@cloudflare/shell

npm i https://pkg.pr.new/@cloudflare/shell@2356

@cloudflare/think

npm i https://pkg.pr.new/@cloudflare/think@2356

@cloudflare/voice

npm i https://pkg.pr.new/@cloudflare/voice@2356

@cloudflare/worker-bundler

npm i https://pkg.pr.new/@cloudflare/worker-bundler@2356

commit: 33b1e73

devin-ai-integration

Devin Review found 2 new potential issues.

Measures how each context-reduction mechanism changes the prompt prefix turn over turn. Media eviction and compaction rewrite it once; read-time truncation rewrote it every turn because its cutoff slid with the message count. Cut at a multiple of 8 messages instead. Closes #2200. Co-authored-by: Cursor <cursoragent@cursor.com>

Co-authored-by: Cursor <cursoragent@cursor.com>

threepointone added this pull request to stack #2357 September 24, 2026 01:08

threepointone marked this pull request as ready for review September 24, 2026 01:12

devin-ai-integration Bot reviewed Sep 24, 2026

View reviewed changes

Comment thread packages/think/src/think.ts Outdated

Comment thread docs/think/index.md Outdated

Comment thread packages/think/src/tests/prompt-cache.test.ts

threepointone force-pushed the fix/think-stable-truncation-prefix branch from b772d69 to 5a8e256 Compare September 24, 2026 01:35

devin-ai-integration Bot reviewed Sep 24, 2026

View reviewed changes

Comment thread packages/think/src/think.ts

Comment thread docs/think/index.md

threepointone force-pushed the fix/think-stable-truncation-prefix branch from 5a8e256 to 5071db3 Compare September 24, 2026 01:43

threepointone force-pushed the fix/think-stable-truncation-prefix branch from 5071db3 to 2bdee44 Compare September 24, 2026 02:03

threepointone and others added 2 commits September 24, 2026 07:59

feat(think): add truncationStep to tune or disable the stepped cutoff

33b1e73

Co-authored-by: Cursor <cursoragent@cursor.com>

threepointone force-pushed the fix/think-stable-truncation-prefix branch from 2bdee44 to 33b1e73 Compare September 24, 2026 07:03

threepointone merged commit f92420f into main Sep 24, 2026
8 of 13 checks passed

threepointone deleted the fix/think-stable-truncation-prefix branch September 24, 2026 07:21

github-actions Bot mentioned this pull request Sep 24, 2026

Version Packages #2335

Merged

threepointone mentioned this pull request Sep 27, 2026

fix(think): messenger delivery, prompt truncation and media eviction #2387

Merged

Navigation Menu

Repository navigation

fix(think): keep the prompt-cache prefix stable under truncation (#2200) - #2356

fix(think): keep the prompt-cache prefix stable under truncation (#2200)#2356
threepointone merged 2 commits into
feat/think-gateway-optionsfrom
fix/think-stable-truncation-prefix

threepointone commented Sep 24, 2026 •

edited

Loading

Uh oh!

changeset-bot Bot commented Sep 24, 2026 •

edited

Loading

Uh oh!

agent-think Bot commented Sep 24, 2026 •

edited

Loading

Uh oh!

devin-ai-integration Bot left a comment •

edited

Loading

Uh oh!

Uh oh!

Uh oh!

Uh oh!

pkg-pr-new Bot commented Sep 24, 2026 •

edited

Loading

Uh oh!

devin-ai-integration Bot left a comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

1 participant

Conversation

threepointone commented Sep 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Measurement

Fix

Uh oh!

changeset-bot Bot commented Sep 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

🦋 Changeset detected

Uh oh!

agent-think Bot commented Sep 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

⚪ agents import sizes

Uh oh!

devin-ai-integration Bot left a comment • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

pkg-pr-new Bot commented Sep 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

devin-ai-integration Bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

1 participant

threepointone commented Sep 24, 2026 •

edited

Loading

changeset-bot Bot commented Sep 24, 2026 •

edited

Loading

agent-think Bot commented Sep 24, 2026 •

edited

Loading

devin-ai-integration Bot left a comment •

edited

Loading

pkg-pr-new Bot commented Sep 24, 2026 •

edited

Loading